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Narrowboat Heating Part 1 – Stoves

By Tim Davis Onboard Solar

As a long term live aboard and ex boat builder I have been involved with many different heating systems over the years. The aim of this article is to look at all the options and to give some insight into the relative advantages and disadvantages of each of the different options.

When we look at heating systems on a  boat we are generally considering two things.

  1.  Heating the cabin space
  2. Heating the domestic water

First, let’s tackle the heating of the cabin. This broadly divides into two common methods.

  1. The solid fuel (or “multi fuel”) stove
  2. Some form of central heating

Part 1 – Solid Fuel Stoves

Let’s start with solid fuel stoves. The first point to make here is that heating using a solid fuel stove is generally the most reliable way of heating the cabin space. The vast majority of boats out there have a stove in the saloon area. Traditional boats with a back cabin will almost certainly have a small cooking range just inside the aft doors on the port side.

In the days of working boats when this was the only accommodation this would have been the source of heat, hot water (via a kettle) and cooking and would have been used 24 hours a day all year round. Many historic boats that have been converted by having extra cabin added over the hold space retain this range as do newer boats built in a replica style to a vintage boat.  This can be an advantage – in my boat for example which is a replica BCN tug, I have a stove in the saloon and a range in the back cabin.

The solid fuel stove is generally the most reliable and effective source of heat in a boat. Once up to temperature the saloon is kept very warm. It is a dry heat too, sucking in any moist air from the cabin and effectively drying it out so and condensation is quickly dispersed. Boat stoves are of the multi fuel variety which means they can burn coal and wood.

For the most effective heat a mix of the two works well. A bed of coal to start with then use logs on top once it has got well under way. Care needs to be taken in the choice of both the coal and the logs though! Coal generally is available as either “house” coal or “smokeless” and within smokeless there are many different makes.

The house coal is traditional coal that has been used for centuries. It lights very easily and quickly and gives a very good heat with lots of flame BUT gives a lot of smoke which, depending on where you moor, might cause problems. This also means that both chimney and fire get quite sooted up and thus need regular brushing and cleaning.

The general feel of using house coal is that it is quite dirty all round.  House coal also does not tend to stay “in” very well – that is, it does not stay alight all night as it’s a much quicker burn.

Smokeless coal however comes in the form of manmade “briquettes” which are smooth in appearance. These take a lot more effort to light so lots of kindling wood and paper or firelighters are needed to get it going. It also takes a lot longer to come up to temperature, once there though it will burn for hours on end.

Normal procedure is to get the fire up to temperature with all the vents open then close the vents right down so the fire just simmers with a red glow. There tends not to be much in the way of flames with smokeless coal but it is very clean burning compared to house coal.

I tend to have both house and smokeless in. I use the house coal to get the fire up quickly and easily, then add smokeless – this is a good mix. To enhance smokeless coal a log or two can be added to a hot fire in the evening to give flames and a rapid boost of heat. Logs of course have the great advantage that you can find them close to the towpath and collect for free. However beware!

It is important that logs are well “seasoned” that is left to dry out all of the liquid sap that was present when the wood was growing or “green”. It takes around a year to season logs but often you will come across trees by the cut that have blown down and may well already be seasoned.

You can soon tell if they are seasoned enough when you saw through them. If they are seasoned the saw will cut trough like butter with very dry sawdust if not then you will feel the saw bind up and have a very damp like sawdust in which case they will need to be kept for next year.

You will also notice the off cut log is very light in weight. Alternatively of course, if this foraging for logs all sounds a bit much, you can buy logs ready seasoned either in net bags or by the load which is cheaper (When short I have looked in news agent windows wherever I am moored – you often see signs for people offering a load of logs for not much money.

Non seasoned logs will burn, but not as well as seasoned logs and they will cause a nasty sticky tar which runs everywhere, often down the inside of the chimney and onto the roof and down the side of the boat! There is a new type of manmade log available now which is made of compressed wood shavings. I tried some this year and they were very good and not too expensive.

Types of Stove

Morso SquirrelThere are many different makes of stove. You may have heard of Arrow, Morso, Torgem, Boatman to name a few. They all work in the same way and usually have two vents on the front, one below the fire which must be fully open to light the fire and one above the glass which acts as an air wash to help clean the glass. Which one is best?

This is a question I am often asked.

In my experience the Morso Squirrel seems to be excellent. It has a good size so can hold a lot of fuel, it has good vents so draws really well which is important when lighting and has two doors the bottom, one of which can be opened to rapidly assist in the lighting process.

Another good one is the Corner Bubble multi fuel. This is an unusual triangular shaped stove that sits neatly in a corner of the boat and again burns very well. At the budget end of the market is the Boatman Stove made by Northern Fabrications. A simple little stove but one that burns really well and takes up a small amount of space.

corner bubble stoveA good tip from old working boatmen is always have a kettle on top of your stove – it means you’ve always got a bit of hot water for tea or washing up – very useful I find.

What about heating the rest of the boat?

A solid fuel stove outputs a lot of heat and will comfortably keep the saloon and immediate area very cosy indeed, but what if you want heat at the other end of the boat where the bedroom typically is?

The first important “must have” accessory is the “Eco Fan” This is a two or three bladed fan that sits on a stand on the top of the stove. It uses technology called a “Peltier” plate which generates electricity from heat to drive a small electric motor that turns the fan. It very effectively directs the heat away from the stove and “spreads” it around the boat. A small boat of say 30 to 40 ft with a stove and eco fan would have no problems heating that entire cabin space.

There is a new stove fan available that uses a tiny heat driven piston engine (a Sterling engine). A friend has one and it is very impressive with the joy of a little engine driven by heat from the fire (I know – boys toys!).

Eco Fan

Back Boiler

Another way of spreading the heat is to have a back boiler on the stove. This is simply a steel tank with an inlet at the bottom and an outlet at the top. The stove is connected into a circuit of radiators – standard household type radiators – and filled with water via a small header tank at the end of the pipe run.

This system can be setup in one of two ways; gravity fed or circulation pump. The gravity fed system required large bore pipe work (28mm typically) and has to be setup very carefully so the hot water leaving the fire from the outlet at the top rises away from the fire and the return to the fire drops via a gentle slope back to the inlet at the bottom of the fire.

There is quite a bit of “science” behind getting a gravity fed system to work well and not boil when the fire is too hot, so it is not for the faint hearted!

More common these days is a pumped system. Here the pipe work can be kept hidden low down with a small 12v pump located close to the inlet of the fire (the bottom) and pumps water towards the fire. These work reliably but have the big downside of consuming power and of course must be switched on the whole time the fire is lit otherwise the water will boil and then explodes out of the header tank (which is normally located in a wardrobe!).

Back boilers are great. On a long boat with many cabins they work very well BUT as a user of them you need to be aware of them potentially boiling. It is possible to rig up a temperature controlled switch that will turn the pump on when the fire is hot enough and turn it off when it cools. I highly recommend this if you have a pumped back boiler system – it makes it much easier to manage!

It’s also important to have a simple bleed valve at the hot water outlet of the fire to make it easy to bleed off any stream that builds up – I use a simple drain cock for this purpose. See diagram showing the layout of a pumped back boiler system.

Back Cabin Ranges

Epping StoveThere is another way to heat the whole boat. Use the stove in the saloon to heat that part of the boat. Then if you have a traditional, vintage or replica type boat, light the range in the back cabin as well! I have this arrangement on my boat and sometimes have both stoves lit but it does get quite expensive running two

The range prefers to run on coal rather than wood (apart from lighting of course) and has the great advantage of a cooking plate and a small oven. On a cold winters day its great standing at the tiller with a range just inches in front of you perhaps with a casserole in the oven! One of the most popular ranges you will see is the Epping.

Oil Stoves

Another alternative to the solid fuel stove is the oil stove. This looks the same from the outside as a solid fuel stove, and they are available with and without a back boiler just like a solid fuel stove.  Popular makes are the Bubble (from Haworth who also make the solid fuel Bubble) and Kabola to name two.

The main difference is these stove run from the same diesel oil that is used to propel the boat. They are often fitted with their own tank separate from the main engine tank and often located in one of the bow lockers. These stoves were very popular for a time around 10 years ago when diesel was very cheap (I recall it was about 19p a litre then – happy days!). They are called a “natural draft” oil burner.

The main problem with diesel oil is it is actually difficult to light  – if you drop a match in diesel it will go out. These diesel stoves work by allowing diesel to drip feed onto a tray inside the stove, this is then lit using either a piece of tissue paper or better still breaking up a fire lighter into small pieces and using a small piece to start the fire. Basically you light the piece of fire lighter and drop it into the stove, drop in a cage called the catalyst which will shape the flame once its lit, then turn the diesel tap on, as the diesel slowly reaches the firelighter it heats and the vapour ignites.

This can be a bit fiddly and there is a definite knack to getting a diesel stove going! Once lit you have a tap allowing you to vary the height of the flame, however care must be taken as a very high yellow flame will cause a lot of sooting up inside the stove.

Compared to a solid fuel stove the heat is less too. In part because of the fiddly lighting process and the need to clean the fire out after use which is quite messy coupled with soaring diesel prices mean this type of stove has become much less popular and many boats have replaced them with solid fuel types which is not difficult as they are physically very similar. Indeed a corner Bubble oil stove could be replaced with the much better corner Bubble solid fuel stove with ease. It’s important to consider the issues with diesel stoves when buying a used boat.

Part 2: Narrowboat central heating systems

Useful Information

Narrowboat Electrics Part 2: Generators and Inverters

By Tim Davis

This is the second of two articles exploring power generation and use on board narrowboats. The first part is a very detailed look at batteries. You can read it here.

 Generators come in different types. The petrol hand pull type, and the more expensive “suitcase” type which are now very quiet.

Petrol Hand Pull Generators

These are very useful but great care must be taken with petrol storage and use – fumes dropping into the cabin from a generator being filled on deck combining with the gas cooker being on have caused many an explosion – so always fill on the bank!

These output AC mains 230V which you simply run from the plug on the generator to the socket on the back of the boat. The boats electrics see the power as a landline (you may have a transfer switch that will need to be set to landline position). All your 230v sockets will work as normal, though you will only have the maximum output that your particular generator has to offer. A small generator is typically 1000W and a larger one maybe 3000W, so you do need to choose a generator that will run everything you have on board.

If you have a washing machine you will probably need at least a 2000W generator and probably a 3000W. Really importantly, don’t forget that when your generator is running to turn the mains battery charger on too! You may as well get some valuable charge in while the washing machine is on! This is where having a smaller output charger might be a benefit as it will run happily on a lower powered generator- some of my customers have two chargers – a big one when on shore power and a smaller one when using the genny. Most generators do have a 12V charging plug as well, but they generally only output a low taper charge of about 6 amps so you are far better off using the mains output to run your 3 step charger instead.

Built in suitcase diesel generators

These offer all the benefits of the petrol generator but are built into the boat, enclosed in a sound proof capsule and start by pressing a button inside the boat. I have one of these and it works very well.

Generator Use

 The usual practice is to “save up” things that require a lot of power and do them all at once when the generator is on. So I generally do the washing, vacuum the boat and run the immersion heater to heat my water, and of course put the battery charger on at the same time as watching the television! You get into a routine really quite quickly.

Other types of generator

A/C Mains generators mounted on the main engine like another alternator.

This is actually another alternator on the boats main engine but it outputs 230V mains which is fed into your system through a transfer switch (see below). They are usually 3500 watts and are quite expensive (around £2K). They basically allow you to run heavy 230v loads while the engine is running without having to use the batteries and an inverter.


 Now this is the important one and a great source of flat batteries if used incorrectly! An inverter is a device that takes your precious 12V power from the battery bank and converts it into 230V mains electricity which is then fed into your boat through a transfer switch (see below). It sounds great doesn’t it? Mains power with no noise coming from nowhere by magic! However, beware – generating mains this way is VERY costly on battery power. Let’s take an example….

Sterling Inverter 1800wA boater has an electric kettle (bad idea!) that takes 3 minutes to boil and consumes 3kw of power to do so. The boater has a 3kw inverter on board so that’s all fine – it will work! However if we do the sums 3000W divided by 12V = 250 amps -that’s a massive amount to draw from the batteries and remember leisure batteries DON’T like a high current draw. So we have a general rule of thumb here. Avoid using an Inverter to run things that heat up as they all consume VAST amounts of power.

The inverter should be used for light duty things like entertainment equipment and such like. If you are in a position where you need to run the washing machine and don’t have a generator of any sort but do have a big inverter then the rule is you MUST run the engine at the same time as drawing that load so that you are at least putting the bulk of the current back in AS you draw it out through the inverter.

It also pays to have one of the alternator controllers I mentioned earlier to optimise the charge going in. In fact if you have a big alternator, a charge controller and a decent inverter coupled with a decent sized battery bank then you have kind of got all the benefits of a portable generator BUT you are still running that big main engine, that’s where generators score as they are small engines consuming much less fuel and much quieter.

The other golden rule with inverters is to switch them OFF when you don’t need 230 power. They all consume valuable power (around 2 amps typically) just sitting in idle mode, though some new inverters do have a standby function that reduces this I would still adopt the mantra of if you don’t need it right now TURN IT OFF. That goes for ANY device on board not just inverters.

Transfer Switches

 I mentioned that your portable generators just plug into the landline, but if you have a built in one and an inverter there must be some way of separating these 230V power sources in case you were daft enough (by mistake of course!) to have them all on at once! This is done using a Transfer Switch. This is usually a manual switch with either two positions (Land line, Inverter) or three (Land line, Inverter, Generator). So you select your power source then either plug it in or switch it on depending on what the power source is. Some newer boats have automatic transfer switches that will detect the incoming mains power source and select accordingly.

 Tips and Tricks for getting the best out of your power system.

 OK, this is a critical bit of the article – there’s lots you can do both technology wise AND with the way you think about and use power that can make a huge difference for those of you living without that marvelous landline plugged in like a soothing umbilical cord! Part of living afloat, if you’ve recently come from land is changing your whole thought process of how you live.

Minimising your power draw

DO have a12V fridge, and if you really must, a 12V freezer. I have a combined 12V fridge freezer that fits under the counter taking up the space of a normal fridge. Obviously the fridge is smaller but it has an 18 litre freezer compartment with its own door. Advantage: only one compressor to run and takes less space! Many new built boats have a 230v mains fridge – great if you are plugged in but a nightmare to live with on the cut as you have to have an inverter on with all the loss that goes with it for 24 hours every day!

Change your lighting for LED bulbs. This is a relatively new invention. LED lights now give fabulous light output in a nice warm tone, but with a fraction of the current draw. If you have say fifteen 20W halogen lights on your boat, when switched on they will draw 25 amps. That’s a huge amount! Replace them with LED bulbs. You don’t have to change the fittings. You will draw around 2.25 amps for a similar level of brightness. For further technical information on LEDs go to www.baddiethepirate.co.uk  Note that you can also convert favourite table lamps from 230v to LED and 12V.  -You really can’t tell the difference when they are lit!

Try to minimise use of an inverter to an absolute minimum – try to run as much as possible on 12V power. There are many good 12V TVs these days for example. What about laptops? Most are a voltage of around 18 or 19 volts but they do vary. As a result most people switch the inverter on to run them. If you are working from the boat this might mean the inverter is on all day – not good!  It is possible to buy from shops like Maplin or indeed on line a 12V charger. This takes 12V from your boat and steps it up to the required voltage of the laptop.

Be careful with other bits of equipment that run on 12V but normally have a mains adapter. They will likely not like the variable nature of boats voltage (between 14.4 and 11.5) if you just connect them directly to the 12V but it can be done using a voltage stabaliser unit. This sits in the power line to the device and ensures it always gets exactly 12V. Please contact me for further info.

So there is one critical message in here. You need 12V sockets throughout the boat! Interestingly older boats tend to have them while newer boats only have 230V sockets backed up by a big inverter, in which case I would advise having some 12V sockets fitted. 12V sockets are either 3 round pins so you can put a plug on the end of your old 230 table lamp and plug it into the 12V socket, or the car cigar type. They are however invaluable. I have three in the saloon dotted around, one in the galley and one in the bedroom.

Have solar panels (see my last article) these provide a low amp charge but plenty to cover the use of a fridge and lighting and make a REAL difference to life afloat. I recommend them highly!

If you use the inverter to run the washing machine, make sure the engine in running and consider an alternator controller to improve the charge.

If you use an inverter beware of the silent battery killers! Most common problem is many boats have electric water heaters (immersion heaters), great when you are plugged in, but if you “accidentally” leave it on when the inverter is on it will silently drain the batteries VERY quickly! It’s another good reason to have a monitoring panel. When I switch my genny off I always glance at the panel to see if its drawing an unusually high amount as it is so easy to leave something on by mistake!

The other killer is leaving the battery charger on when the inverter is on. This most commonly happens when the generator has been running and the charger quite correctly switched on to get a bit of charge, then the boater switches over to inverter when the generator is turned off leaving the charger on – well you can’t charge batteries from batteries can you?! So all that happens is they drain down fast trying to!

I encourage new boaters to write a check list to help get into the routine – it doesn’t take long but saves you the heartache of running out of power prematurely!

If you decide to have a portable generator, make sure it is big enough to run the heaviest load, and make sure your battery charger is switched on when the generator is on for another reason.

DON’T even consider having an electric kettle or toaster unless you are plugged in at a marina. If you are off grid then use the gas cooker! In the winter I have a kettle on top the stove all the time so I always have a bowl full of hot water when I need it.

Remember – if you are not using it SWITCH OFF most importantly if you have been using the inverter to say run the sewing machine, don’t just turn the sewing machine off when you’ve finished, turn the inverter off too!

In a later article I may well talk all about heating and water so watch this space!

 Building the Perfect Power System

 OK what would I do with an unlimited budget?

Batteries and charging:-

1. A battery bank of 6 x 110 ah batteries

2. A 100 amp or more alternator with a smart controller

3. 300W of solar panels with an advanced controller

4. Built in diesel generator giving 3.5KW of mains

5. 100 amp 3 step 230V charger

Power use: –

1. 1500W inverter for occasional light 230v loads

2. LED Lighting throughout

3. All entertainment equipment 12V

4. A laptop running through a 12V charger

5. A full power monitoring and management panel

Of course you would struggle to achieve all of these goals. I know I haven’t achieved them all but it’s important to aim for perfection!

I hope this article has been of interest, anyone who has specific questions please feel free to email me at tim@onboarsolar.co.uk  I can supply and fit any of the systems talked about as well and a lot of my work is taking a boat and just adding the bits and providing the knowledge to make it better! My full contact details are on my website www.onboardsolar.co.uk  I am considering the following future articles, any feedback you can give with regard to this OR suggested other articles to do with the technical side of boats would be welcome.

Tim is considering writing one of the following articles. Please let him know which one you are interested in most by completing this lightning fast survey

1. Wiring up your narrow boat – what are the issues?

2. Heating your boat

3. Water systems

Useful Reading

The 12 Volt Bible – Miner Brotherton

An American book so some of the standards a different but a good insight into all things electrical

Electrics Afloat – Alastair Garrod

A great book with lots of diagrams and pictures

Boat Owner’s Illustrated Wiring Handbook – Charles Wing

A great book for those wanting deep technical stuff!

If you haven’t done so already, read the first part of this two part series: Narrowboat Electrics Part 1: Batteries

Useful Information

Narrowboat Electrics Part 1: Batteries

Understanding Onboard Power Systems

By Tim Davis

In this follow on from my recent solar power article, I want to talk about power systems in general, the considerations, issues, best practices and trouble shooting of power problems. I have been working on “off grid” power systems for over 20 years, initially remote telecommunication facilities for the oil industry and for the last 12 years on boats.

Interestingly the challenges of living with off grid power are the same regardless of the actual situation. I have also lived aboard for 12 years, most of that time continually cruising the system so get to “live” the issues as well. As with my last piece I am going to focus on the all important “need to know” practical issues rather than deep technical understanding of how it all works. I have tried to give info for everyone from complete novices to those with more experience but who want to understand more. To this end I have used headed sections so you can scroll through and pick a section that is of interest. I hope you enjoy! Before starting to unravel the boats electrical systems, it is important to categorise the different boat “situations”.

  • A live aboard boat based in a marina that only “goes out” for the odd weekend and a couple of weeks once or twice a year. It is plugged into 230V with a decent charging system (more on chargers later), This type of boat doesn’t really have to worry about power at all.
  •  A live aboard continuous cruiser who spends one or two weeks sat in one location before moving on for a day or two (my profile). This type of boat is fine while moving as batteries are kept charged, but then has constant battles with keeping power up and running whilst sat enjoying time in one place.
  •  A live aboard on a permanent mooring without power. The hardest type of boat to power manage as it doesn’t need to travel with the benefit of charging batteries as it moves. It is these second two categories that this article will focus on.

Boat Power – Best practices and source

A boat setup according to accepted best practice will have two power systems.

  1. 12V DC low voltage for all “essential” systems. An essential system is one that in theory you do not want to do without and needs to be available at any time. Things that fall into this category would be; Lighting, pumps for water and drainage, toilet systems and most importantly refrigeration.
  2. A 230V “mains” system that has standard 13A plugs and to the untrained eye works the same as in a house. This however is power for “luxury” systems – that is to say things you can do without and only use occasionally, such as washing machines, vacuum cleaners and entertainment systems. Why have these at 230V instead of 12? In an ideal world it would be great if you could buy 12V domestic appliances at an affordable price with the same range of choice we are used to in Currys. However the market does not exist for 12v luxury appliances so for many of these items 230V is the only way to go. Where it really IS worth spending extra money on a 12V unit is the fridge or freezer as these are on 24 hours a day and if you are not plugged in and where is that power going to come from? An inverter, I hear the more informed of you cry! Yes, but see later for the big power cost….

Source of Power

In my first category of boat, in a marina, the boat is plugged into mains power – this means all 230v sockets on the boat are running straight from the mains power as they would be in a house. Most boats will also have a 12V charging system fitted. This will not only keep the batteries topped up it will also act as a mains powered “battery” and run all the boats 12V services directly from the mains – so in this scenario life is a doddle!

Once off shore power however, as my other categories of boat are, then everything changes. The source of ALL power is the humble 12V battery. I would say without doubt the hardest part of living afloat without being plugged in is power management. In this scenario essential systems described above run straight from the batteries, luxury 230V systems get their power from an inverter – a device that converts 12V DC power to 230V AC power as if by magic BUT in doing so generally consumes HUGE amounts of power (yes, more on this later too…!)

Understanding Batteries

OK, quick reminder from the last article of the volts/amps thing. A battery is like a water tank, but full of volts. (12 of them). Imagine a pipe from the battery instead of a wire and a tap on the end. Open the tap and amps flow down the pipe and out of the tap (opening the tap is, say, turning on the telly). The more the tap is opened, the more amps are flowing. As the amps flow, the volts in the battery drop until it’s empty. Charging the battery refills the battery with volts by passing current in amps back into the battery. This is done using some sort of charging system (the most well known method is, like a car, by running the engine).

Anatomy of a battery

On most boats 12V batteries are used. These batteries come in two main types; starter battery and leisure batteries. The starter battery is used as its name suggests to start the engine only (same as a car starter battery) and is isolated from the leisure batteries that are used to provide 12V power for everything in the cabin described above. You will also here these referred to as “house” or sometimes “ships” batteries. Noticed that I have used the term “batteries” plural. This is because to provide the considerable about of power required to keep a boats essential and luxury systems going it is normal to “bank” up batteries (to provide a bigger overall “tank” of power). Although it is possible to buy a very big battery it is not usually practical to do so therefore it is usual to have, say 4 x 12V leisure batteries connected together to form one large battery (just as you would put multiple batteries in say, a torch). Batteries of course have a positive and negative terminal and it is just a case of connecting all of the positives together and all of the negatives together and taking a single supply from each.

Individual batteries – the familiar shoe box + sized black box )that weighs a ton!) are actually made up of 6 x 2V “cells” that together deliver 12V. Starter batteries and leisure batteries differ in that starter batteries are designed to deliver a very high current for a very short time – the time it takes to start the engine – and are never drained (or “deep cycled”). Leisure batteries are designed to deliver a smaller current steadily over a long period of time and are likely to be regularly drained or deep cycled. The difference is actually to do with the structure of the plates inside, however from our purely practical point of view it’s important to note that key difference.

Leisure batteries are further divided into different technologies. The first of these and by far the most common out there is the wet lead acid battery. These are the oldest technology consisting of two lead plates in each cell dipped in sulphuric acid. Chemical changes occur between the metal and the acid when a voltage is passed through the positive to negative plate that cause it to store a voltage, a reverse reaction taking place when the battery is being used or drained. That’s as technical as were going to go!

Lead acid batteries have several advantages.

  1. They are the lowest cost
  2. They can be “topped up”, when a battery starts to deplete its power some of the acid turns to water, this evaporates off over time resulting in loss of fluid. This can be replaced with de ionised water (distilled water). You just open the cap on each cell and pour some in! Lead acid leisure batteries will tolerate 200 – 300 “deep cycles”.That is to say taking the battery from fully charged to flat. There are now available so called “maintenance free” lead acid batteries. These are sealed lead acid and use a process where gases are condensed and self “top back up”. However if they become over charged due to a faulty or poor charging system then the safety valve blows and electrolyte is lost that cant then be topped up. So I would say instead of the term “maintenance free” how about “cant be maintained”. I’m not a big fan of these sealed lead acid batteries for this reason. Later we shall look at this in more detail – however on with battery types!

Gel batteries are often raved about. These are batteries where the acid electrolyte is contained in a gel paste. They are permanently sealed and were originally designed for applications where the battery may be turned upside down such as ocean going boats, airplanes etc. They can in fact be installed sideways which can sometimes be an advantage. One important thing – Its VERY important to understand that two identically rated batteries, one gel and one lead acid will have the same amount of stored power. Gel batteries do not give you more power in some clever way as some believe. They do however give more deep cycles – a 1000 is about par for the course AND you can leave them is a discharged state then re charge them and they will happily come back up again.

A similar battery type is the AGM (Absorbed Glass Mat). These use glass fibre matting between plates which makes for a bigger plate contact area and thus a battery that can deliver starter type high current and deep cycle. If you have the budget AGM batteries are the best way to go for a long reliable life. However they are not tolerant of being over charged so you need to be really sure your charging systems are in good order. The choice for you the boater is normally a simple one of, pay a small amount on lead acid batteries, treat them as a consumable -use them for a couple of years then replace, or invest in AGM with a “potential” longer life and a “potential” greater tolerance of deep cycling. What do I do? I have lead acid and replace them when they wear out – careful use and monitoring tools I shall chat about later usually give me 3 years of intense “live aboard” use – I’m happy with that!

There is one final class of battery you may hear of and that is the “traction” battery. These are big 2V individual batteries designed and built for mobile electric vehicles such as golf carts and disabled buggies. They are very tolerant of very deep cycling and although take up a vast amount of space to achieve a half decent battery bank size with a lot of expensive cable interconnects are the BEST system but also probably overall the MOST expensive.

Battery Capacities

Most boats have a bank of 12V lead acid or Gel/AGM batteries. Individual batteries have their capacity rated in AMP Hours. That is to say how many amps they can deliver over one hour. So a 110ah battery can deliver 110 amps over one hour if you are drawing 1 amp). So this means if you are drawing say 10 amps with the TV, lighting etc during an evening then every 6 minutes you will draw 1 amp hour. However – a battery’s usable range is not the full range of the batteries voltage.

Imagine the water tank analogy – the pipe running to the tap is a long way up from the bottom! A fully charged battery will sit at around 12.6 volts assuming you don’t draw anything from it. The usable voltage runs down to about 11.5 volts. Beyond that level if you continue to drop the voltage the battery life will suffer so it’s not advisable to lower the voltage beyond this point. Beyond this 11.5V level the battery will quickly drop down to 10.4 volts which is a truly dead battery – referred to as “voltage end point”.

So we have this relatively small operating range between 12.6 and 11.5 which means you actually only have access to about 30% of the actual capacity or about 36 ish amp hours. I would expect (and have seen through the monitoring tools discussed later) around 120 amp hours of actual usable power out of a bank of 4 x 110ah batteries

Battery Charging

The most widely known form of charging is just like a car, running the engine which turns an alternator that charges the batteries. Batteries need a voltage of 14.4 volts to accept a charge. Alternators use a very simple system called a taper charge. The alternator outputs a voltage of 14.4 volts and the battery bank at a much lower voltage accepts this and starts reversing the chemical process of discharge and “takes on a charge” as the battery voltage rises, its resistance to the alternator increases and so the alternator current reduces. It’s a bit like an old fashioned balance type weighing scale, eventually the resistance from the charged battery becomes great enough so that the alternator output drops to close to zero. However, at that point the battery is generally only at 80% of its maximum charge. This is not a problem for a starter battery – that is plenty to start the engine BUT if your leisure batteries are only at 80% charge that is another huge drop in usable battery power. It’s just the simple balanced way that alternators work. Alternators range in their output – older boats tend to have alternators of around 50 amps output where as newer engines are often fitted with alternators as high as 175 amps. Clearly the larger the output the quicker those amps get put back into the battery!

Another important point to be aware of here is, remember we have a starter battery and a bank of leisure batteries? These are two separate battery banks so that if you drain the domestic batteries, you still have the fully charged starter battery to crank over the engine. How is this possible? Older boats typically only have one alternator so some kind of “split” charging is needed. This means that while the engine is running the charge goes to both the starter and domestic batteries, but once the engine is shut down, the batteries are “separated” so the starter does not get discharged by domestic services.

There are a number of ways of doing this. A split charge relay can be used. This is a simple electro mechanical “switch” that closes when the starter motor is energised and ensures charge flows to both sets of batteries, then opens when the engine is shut down so both battery banks are isolated. Alternatively a split charge diode can be used. This is an all electronic device that performs the same task BUT diodes introduce a voltage drop of a little over 0.5 volts – this hugely reduces the charge.

There are also voltage sensing relays that are very simple to fit that connect both banks together when they sense a charge voltage and split them when the voltage typically drops below 13V. Newer engines also tend to have two alternators, a large output one used to charge the domestic batteries and a smaller one to charge the starter battery – this naturally keeps the batteries separated without the need of a relay or “splitter”

Battery Chargers

The second way of charging batteries is to use a built in mains powered charger. Most new boats are fitted with these as standard and they run while in the marina plugged into a land line. These use a 3 step charge process which is a much higher quality charge than that which you get out of an alternator. This works as follows:

  1. Bulk charge phase – the charger puts in its maximum current at a voltage of 14.4 bringing the battery up to its 80%.
  2. Absorption charge phase – The voltage is held at 14.4 but the current is gradually reduced creating a trickle charge that takes the battery up close to its 100%.
  3. Float charge phase – Voltage is dropped to just below 13.5 so the so the batteries don’t start to gas and current is reduced to very close to 0 amps, but if a consumer demands power from the battery the current is raised to support this.

The float charge stage is very useful as it means while plugged in you simply leave the charger on all the time, it will keep the batteries in tip top condition AND runs all of your 12V services at the same time acting like a mains powered battery in effect. This makes marina living very easy!

Chargers range in power output rather as alternators do typically from 10 amps to 120 amps depending on your budget and the speed with which you want to charge the batteries. In reality somewhere around a 40 amp charger is more than sufficient for a typical 4 x 110ah battery bank. In fact many marina berths have a limited mains power supply and large chargers can cause the trip to go off on the “post” that you connect to. Some charger manufacturers provide a way of turning down the input to cater for this.

Smart Alternator Charging

There are devices available that will take the output of an alternator and convert it into the same 3 step charge that mains powered charges use – this is quite an expensive bit of kit but if you are relying on engine charge all the time it is well worth the investment giving you the enhanced charge quality of a land line charger.

How can I monitor my batteries?

Now we are onto the really useful stuff! Battery monitoring is very important if you are living out on the cut with no shore power land line – it’s the only way you can know what’s going on. However it’s amazing how many customers I have that don’t have any way of monitoring their batteries. So what can you monitor and what are the options?voltmeter

Let’s just review battery voltages: 13.5 – 14.4 volts is a battery under charge. Once the charge stops the battery will quickly drop to 12.6 volts which is where it will sit until you start to draw power. You then have from 12.6 down to 11.5 volts as you use the battery, then it needs charging again to avoid damage.

The simplest “tool” is a volt meter. An analogue gauge measuring between 0 and 14 volts usually. Many boats have these and whilst they give you a guide ,because we are only interested in that small window between 11.5 and 12.6 its actually quite difficult to “see” where your batteries are in that small band on an analogue dial.

battery condition meterA better and still cheap option is a thing called a battery condition meter. These can be a similar analogue dial to the volt meter but instead of being marked up in volts the scale has a red section, an amber section a green section and a white section at the far right hand end. The gauge actually measures from 11 to 14.4 volts but the coloured scale usefully shows you where you are.

If the needle is in the green then you are ok, if it drops into amber you need to start thinking about charging and if it drops into red then you need to charge. When under charge the needle goes all the way over to the right into the white “charging” section so it also gives you a good indication that your charging is correct. (see volt meter and battery condition meter pics) These are also available quite cheaply from car accessory places in a rectangular meter about 1 inch wide and about 3 inches tall with 6 LEDs on that you can permanently fit on the boat. See http://images.npautoparts.co.uk/images/products/zoom/1339674342-59023800.jpg.

Alternatively a digital volt meter is another good tool. There are various different types all mountable like an analogue gauge. Using a digital meter you can accurately monitor that window between 12.6 and 11.5.

However the ultimate tool to have is a full battery management panel. These are quite expensive and more complicated to fit BUT give you the full picture. The battery voltage is there, plus a view of the amps you are drawing (shown as a negative figure) or charging (shown as a positive figure). This allows you to see how much current you are drawing “at a glance” and “trim” your power down if need be by turning off things that don’t need to be on. It can be a real eye opener when you are running the inverter with a big 230v load on it – you may see over 100 amps!

power management panelThe third very useful bit of info these devices give is the number of amp hours used. This tells you exactly how much you have used since you last charged. Say, for example, you moor up and spend the evening with some lights on and watching the television. At the end of the evening your meter shows you that you have used 65 amp hours. When you run the engine the next day it will count those amp hours back down to zero by monitoring the amps coming off the alternator. So using this you know for sure how long you need to run the engine for. I wouldn’t be without one of these. It really is the ONLY way to know where you are with your batteries.

If you make use of solar charging, this too can be wired through the system so all solar charge will count back the amp hours too. In fact when these are installed it is essential that all services and all forms of charging are wired through the measuring bit of the monitor (called a shunt) Please contact me for further info if you would like to know more about these devices.

What about battery testing?

The various gauges described above are great for monitoring batteries that are known to be good and in use but what about when you start to have problems? What problems typically occur?

A common problem is that batteries that have been under charge for hours do not “appear” to hold the charge for very long. This is usually an indication there is a problem. A common failure of a battery is for one of the 2v cells to “die” leaving you with a 10V battery – this is because metallic substances from the plates drop to the bottom of the cell during discharge, eventually building up to a level where the cell shorts out. But of course your batteries are in a bank of maybe 4 or more so it’s not immediately obvious what is going on but what happens is the good batteries keep draining into the one with the dead cell as soon as the charging stops. The only way to check for this is to disconnect each battery so they are no longer in a bank and run a volt meter over each one in turn until you find the 10V one.

In the short term you can just leave this battery out and reconnect the remaining batteries. Strictly speaking you should then replace the ENTIRE bank of batteries as replacing just one is not a good practice as it will have different charge characteristics to the others. However if you know the remaining batteries are good then you can get away with it as long as it’s of the same type and size.

One “gotcha” to watch for is that many lead acid batteries have a little window on top of the battery that shows whether it’s fully charged by turning green. Do not rely on this as it’s only looking at ONE of the 2V cells, another cell in the battery might be dead, or need topping up for example.

Other issues can arise with the electrolyte (the acid) not being strong enough any more due to water build up and sulphation of the plates (a build up of material that stops the electrolyte reacting with the plate properly). With lead acid batteries the only way to properly identify if the battery is holding a charge is with a hydrometer. This is a big syringe type device with a float inside it which measures the specific gravity of the acid. You just draw some acid – very carefully I must add – into the hydrometer and see where the float is. This is a sure fire way of telling if a battery is fully charged.

A fully charged battery should measure 1.265 on the hydrometer. You then need to test each cell in turn, taking care not to spill any of that nasty acid anywhere! Cells that have low acid will also output a lower voltage and should be topped up with de-ionised water which can be bought in car accessory shops very cheaply. Lead acid batteries should have their levels checked and be topped up I would say every 3 months.

Another test is to monitor the battery voltage once the batteries have been charged with everything switched off and see if it rapidly drops below 12.6. If it does then chances are the bank needs replacing.

Another classic problem I see often is that without battery monitoring tools a boat owner will run their engine for a couple of hours each day but find that the level of charge seems to get less each day. This is because on day one the batteries get charged to 80% then on day two 80% of 80% and so on, so the actual capacity dwindles. Hence you can see the benefit of the proper management panel (and certainly this is where solar power charging as covered in my last article makes a REAL difference putting a small current back but all day long).

Narrowboat Electrics Part 2: Generators and Inverters

Useful Information

Satellite Television for Narrowboats

Narrowboat satellite system installer Martin Hicks emailed me to ask if I would be interested in letting you know about satellite television for narrowboats. In the spirit of providing you with as much information as possible about all aspects of narrowboats and what goes into them, I have copied his information below. Please note that this is not an endorsement of satellite television systems in general or Martin’s in particular. I know nothing about satellite systems and whether they work on narrowboats. There is a link at the bottom of the post to take you to the forum where you can add any comments you’d like to make.

Here’s the information Martin sent me…

Satellite television has two main attractions for anyone who wants to watch TV on a canal boat, firstly, you can forget ghosting, crackling sound, fading and all other problems associated with watching television when out and about. In theory a 100% perfect picture is available just about anywhere where a dish has a clear view of the satellite. Secondly the choice of channels is huge and you can pick up radio channels as well as TV.

However, receiving satellite TV is not just a matter of connecting a dish to a TV and pointing it at the sky.
In the UK, analogue is being phased out and all UK satellite transmissions intended for the UK are only broadcast in digital form, this means that a digital receiver is required as well as a digital compatible dish.

The number of channels available is far greater than with analogue TV and digital freeview with an aerial. Free to view channels change all the time, however some of the channels which are broadcast on sky and are available without any payment, these include BBC 1, 2, 3 and 4, BBC news 24, ITV 1, 2, 3 and 4, Channel 4 and 5, E4, More 4, several travel, sports, movie and general entertainment channels together with a variety of digital radio channels.

Freesat was set up by the BBC and ITV to ensure that everyone can access the best of free digital TV no matter where they are in the UK, Freesat brings you over 140 great digital TV and radio, favourites like BBC one, BBC two BBC three, BBC four, ITV 1, ITV2, ITV3, ITV 4, More 4, E4 and film 4 are all yours and that’s just a few and no monthly bills either, plus Freesat offers up to 70 hours a week of HD from the BBC and ITV at no extra cost.

The number of options can of course be increased to include film, sports and documentary channels with a regular monthly subscription. If you subscribe to SKY you can use your digi box from home, or even remove the card and use it in the digi box on the boat but it wont work the SKY sports and main Movies channels.

The dish is the aerial which collects the signal from the satellite, every satellite dish has an LNB (low noise block) this is the part of the dish which receives the signal from the satellite, it’s the mushroom like object mounted on an arm and pointing towards the dish centre.

Standard domestic satellite dish’s can be used but, for most people their size, weight and design make them a lot less convenient to carry and much more harder to set up than a purpose made portable dish. The smaller portable dish is easier to aim at the satellite and once lined up, they are not so badly affected by small movements of a boat, also a free standing dish can be sited at either end of the boat to avoid a building or a tree if necessary. If you have a large permanently mounted dish, you will have to move the whole boat.

A dish can be mounted in many ways, speed and simplicity is essential, temporary mounting can be achieved using a suction and magnetic mount, or with a special designed pole fixing bracket.

With digital transmissions the satellite dish must be positioned absolutely precisely, and if it isn’t, you simply wont get a picture. A satellite finder is a device, which, using some form of indicator makes locating the satellite easy, reliable and quick.
It’s connected between the dish and the receiver and should be disconnected when the satellite has been found, used in conjunction with the test screen on the television your signal should be found within minutes.

A compass is useful for checking the direction in which the dish must be pointed.

In order to watch satellite transmissions you must have a receiver. The sky digi box is the best known in the uk, there are several different makes but they all have essentially the same features and they all perform the same task, taking the signal from the dish, unscrambling it if necessary and then translating it into a form which a television can recognise, its connected by a co-axial cable to the dish and to the TV via a scart, rf lead or HDMI cable. Sky + and Sky +HD can also be used but require a monthly subscription.
Freesat can be watched via a Freesat digi box, Freesat HD digi box, or a Freesat HDTV recorder digi box, which digi box you have depends on your requirements.

You do not need a special TV to receive satellite transmissions, using a sky digi box any television of any size or type will do, as the output from the digi box can be connected to the TV’s aerial socket, scart socket or phono sockets.

Because satellite TV is such a complex subject, sensible, straight forward and accurate advise is essential, to help you set up for the first time and to get your new system working, an on site fitting service is available, this will include all cable, connectors and leads.
But importantly time spent with you showing how to set it up easily and quickly.


  • MAGNETIC MOUNT if needed £25
  • TOTAL £510……

AFTER SALES SERVICE I’M’ AVAILABLE TO TALK TO, A 12 MONTHS GUARENTEE ON ALL PRODUCTS,  customers may wish to have a recordable freesat receiver or may choose to have a up market satellite finder and also may want a LCD/DVD TV…RECEIVERS and all TV’s CAN COME IN 12 VOLT OR 240VOLT TO SUIT REQUIREMENTS…

Useful Information

Narrowboat Solar Power

By Tim Davis

Before we start exploring all the ins and outs of solar power, an introductory paragraph to “set the scene“ as it were.

Firstly a bit about me and my involvement in solar energy; I have been a live aboard boater for 12 years now and during that time have worked exclusively in the boat building and maintenance industry.

My role has always been all the technical side of boat building; things like engine fitting, heating and plumbing, gas and of course one of the biggest jobs on a boat, wiring and electrics, in fact anything that’s not wood work. My wood working colleagues often joked than no one knew what Tim did as all his work was covered up with lovely wood!

Narrowboat Solar Panels

It was around 4 years ago I first got involved in fitting of solar panels for a customer. It was a very impressive system but also hugely expensive which largely made it prohibitive for most boaters at the time, as although it undoubtedly worked very well the payback time would have been many years with too greater upfront cost to make it practical.

Two years later and I was planning an extended cruise around the system and decided to re visit solar and see if I could build a system for my boat as I was getting fed up with running either the engine or generator for a couple of hours each day when I wanted to sit somewhere for a week or two and the pain of having to turn the fridge off if I wanted to leave the boat for a day or two. After a lot of research I came up with the system I have now and found many boater friends became interested it how good it was.

As my main objective was to come up with a system that gave me the MOST output for the LEAST cost I had “accidentally” created a product that other boaters might want. Within a short space of time it turned into my current business “Onboard Solar” a complete service supplying and fitting of complete solar packages AND helping people reduce their energy draw on the boat!

So what do solar panels actually do?

Well, it’s really quite simple, they act as a battery charger – and that’s it! Many of you will have built in chargers that you switch on when plugged into a marina shore supply (Luxury!). The panels effectively do the same thing, but the power comes from the sun. They don’t have anything like the same output as a mains charger though – not even on a relatively large solar installation so one myth to quickly dispel is you can fit solar and then expect an abundant supply of power as you would when plugged in. A solar system effectively trickle charges your domestic batteries during the day. Most boats have one piece of equipment that is on all the time and they want to keep going every day – can you guess what it is? The TV? No! it’s the fridge of course! Most boats sensibly have a 12V fridge and this can be kept running comfortably through the spring and summer/early autumn by a modest solar system – indeed I left my boat tied up for a week in the summer and left the fridge ON oh yes! Remember though the solar system charges the batteries which the fridge then runs from.

So a solar system is designed to keep your basic 12V needs up and running while you sit on the cut in a lovely place somewhere for a few days (or perhaps as many of my customers do have a linear mooring with no power). They won’t run heavy duty mains appliances like washing machines (you still need to run the engine and use the inverter for that) and you WILL still have to be as careful as ever with your power but you WONT have to run your engine anywhere near as often – AND you can leave the boat for a day or two and not worry.

Solar Power ControllerI also encourage boaters to adopt power saving technologies such as LED lighting (fantastic these days and amazing – you can have around 10 LEDs on for the power of one halogen bulb – oh and we sell them too!). The thing is you can spend a relatively large amount on solar and it will work very well IF you think about minimising your draw and continuing (as we all do) to be careful with your power.

There are other tricks too like running laptops through power converters rather than using the big inverter – please feel free to contact me for further details on all of these “asides”

How do they work?

Good news folks – you don’t need to know! It’s all quite boring talking about silicon atoms, photons and electrons! (email me if you do want to know)  In short, you shine the sun on a panel and it outputs low voltage DC electricity (just what we need on a boat eh?). That it! However what you DO need to know is that as the sun changes brightness the voltage varies enormously and often way above the charge rate a battery likes to have so you have to use a regulator between the panels and the batteries. These have a side advantage that there is a digital display on them giving you info such as battery voltage, charge rate in amps and amount of charge in amp hours – all quite handy to know! Surprisingly, many boats don’t have any way of telling what’s in the battery. There are actually different types of regulator as well which I will come back to later.

I’m thinking of buying a solar package – what size? How many panels?

Well this is tricky to answer as it’s the old “how long is a piece of string thing“. Be very careful here though as you could spend a couple of hundred pounds on say an 80W system that only gives you 2 or 3 amps which is just not quite enough and you will still need to run the engine often.

However from experience I can tell you that for most boats that are what I like to call “12V” based. That is to say you have a 12V fridge and have done your best to minimise your power draw so a 200W system is a good start.

In my packages (remember the mantra of MAXIMUM power for MINIMUM outlay?) I discovered that 100W panels offer the best price per watt, whilst still being of a manageable size. Therefore to achieve bigger output one simply has multiple 100W panels – thus a 200W system would have 2 panels etc.

It seems smaller panels and larger panels do not have this economy on cost. This gives the system a nice modular approach and means with forward planning you can add another panel at a later date easily. A 200W system will give a charge rate, using the standard controller, of around 12 amps on a good midsummer day. That’s 12 amps continuously going into the batteries all day long while the sun shines. The fridge draws about 4 amps when the compressor is running so there is plenty left over to charge the batteries as well ready for the evening when you want to use the power for lighting and the TV.

On a dull winter’s day like this late November (more rain!) I was seeing 1.7 amps off mine, OK, not much but it is still a charge. Over last weekend we had some of that lovely unbroken winter sun all day on Sunday and I tilted my panels into the low sun and saw 5 amps. So the motto here is you need to have enough watts to make it worthwhile and you can never have too much. It’s then down to your budget. And, yes, sadly there WILL be days especially in the winter where you will need to run that engine still.

So what types of panels are best? Are stick on ones any good?

Another very often asked question. There are different types of panel available; the two common types seen are the rigid panel type, usually glass coated and in an aluminium frame, and the flexible type which sit flush on the roof and look great!

However beware – I did a lot of investigation in my research and came up with this: Do I want a panel that looks great and really enhances the look of the boat, or do I want one that works better AND is much lower cost?

Joking aside, the issues are as follows.

1. Panels work best when aimed directly at the sun – there is no scope for tilting the stick on panels into the sun.
2. The light transfer capability of the gel coating on the sticky panels as opposed to glass on the rigid panels doesn’t work as well.
3. Panels like to stay a cool as possible, when hot they output less – we all know how hot the roof gets in the summer, imagine how hot a stick on panel would get!

So the system I chose for my boat is as follows: I use 100W panels. I, as many of my customers do, have 2 of them. They are the rigid frame type with aluminium surround. They are mounted on tilting brackets (see photo). These are A shaped brackets 8” high mounted at each end of the panel. These brackets have several great advantages.

1. You can easily tilt the panels into the sun – this can make a difference of plus 60%
2. As they are above the roof on the brackets they keep really cool.
3. Having them on the brackets mean they can be installed on the centre line of the boat as they ride beautifully over the top of any mushroom vents, are easy to get round and actually look quite smart.
4. They are very easy to clean under with no rust or dirt traps and of course easy when you want to repaint the roof.
5. The final advantage is without doubt the MOST important. The stick on panels are about twice the price of the system I have just described.

As an aside, I was worried. I have a lovely vintage style BCN tug all in proper livery and I didn’t want to spoil it with solar panels, but I did want the power so I was very nervous, but you know what? A few weeks in I was used to them and people who always say admiring things about the boat when I’m in a lock still do and often actually complement the panels so it was not a big deal in the end! “Fusing technology with tradition” is what the marketing department would call it!

So what’s all this watts/amps/volts stuff?

Again it’s not critical to know any of this but it helps to understand what’s going on. Voltage is your store of power – like a water tank. Solar Panel BracketsFully charged batteries sit at 12.6 volts. Amps is the flow of current to a consumer such as the fridge or lights – like the flow of water in a pipe – it is critical as the more amps you draw the quicker the batteries go flat, the more you put in the quicker they get charged. Your shore power charger might be 50 amps or more so you can see that 200W of solar with an average of say 8A output is quite small. Watts is the actual power that a consumer uses so your 12V telly say might be 120W. From this you can easily work out how many amps it uses by dividing it by the volts (12) – that example tells me it’s drawing 10amps.

Solar panels are also all sized in watts because they are a power source. So 200W divided by 12 = around 16 amps right? So hang on, why don’t you get 16A out of a 200W system then? It’s all down to the regulator/controller. The standard one works by actually lowering the voltage of the panels down to an acceptable charge rate (maximum of 14.4 volts) in doing so it introduces loss as the extra volts are simply wasted. (My panels generate 21 volts in full sun for example). To overcome this I have a new regulator called an MPPT controller – it stands for Maximum Power Point Tracking and means just that – it allows the panels to run at their full voltage with no wastage and uses that to drive a more sophisticated charger (like a mains powered charger) within the controller. I have seen the full 16amps off of a 200W system using the new controller so it definitely works!

So what’s the deal with Onboard Solar?

The first thing I like to do is get an idea of what you are running on your boat and the size of the battery bank, together we look at any scope for trimming down power then I can recommend the right size system – my take on this is if you are going to spend a few hundred pounds on a solar system – you want to get the very best return. Though generally 12V based narrow boats start with 200W. Some wide beams with 230V fridge and freezer run through an always on large inverter require 400W or more just to keep up with the load.

In both cases I now encourage use of the new MPPT controller as it does make a difference. I then supply and fit everything – keeping cables and fittings as tidy as possible, then of course show you what‘s what – though you will be pleased to hear it all self manages!.  It takes a couple of hours and removes the headache and drama of drilling holes in your own boat because you have to get that right first time!

You will have a little controller that gives you useful info about the charge rate and more usefully the battery voltage so this time of the year you can look and see if your batteries are not getting enough charge so you know when it’s time to run the engine! Optionally I also supply power management panels. These show you the amps that you are drawing as well as the amps going in and keep a count up of amp hours used/charged.

So say at night you are drawing 6 amps for the television and some lights, every 10 minutes you will use 1 amp hour. In the morning once the solar kicks in these amp hours get counted back in again (or when the engine or charger is on) so it’s a fuel gauge for your batteries.

What sort of budget do I need?

Cost is currently £625 all inclusive for supply/fit of the 200W and £1,050 for the 400W system with an extra £150 for the MPPT upgrade. (300w or greater than 400W also available)

So in summary then, solar panels act as a charger to keep your basic 12V  needs up and running allowing you to sit anywhere for days at a time without having to worry. It is a great thrill to use power of an evening, get up on a bright spring or summer morning and see your batteries under charge at 13.5 volts instead of way down and thinking “ok better start the engine up”

What about payback?

This is a tricky one, because it depends how you measure it, financially most customers agree about a year IF you spend a lot of time out and about or especially if you are a live aboard on a mooring with no power – this is a real win situation. If you are in a marina then there is not a huge benefit as the main charger “takes over”. I do have a couple of customers in marinas who have opted for 400W systems (to increase the charge rate) and they no longer plug in and are thus saving the huge cost of marina electricity standing charges etc. However the payback of NOT running that engine every morning just to keep the batteries charged is huge – real convenience.

My final word is a quote from a customer and good friend of mine. We were sitting by his boat and having rather nice Gin and Tonics crammed full of ice from his 12V fridge/freezer on a lovely summer evening on the North Oxford canal. As he passed me the drink he gestured towards his solar panels on the roof and said – “there you go, Tim – ice cubes made from the sun!“  Brilliant!

I hope this brief article has helped to explain something of what the solar energy applied to boats is all about.  There are many pictures and lots of info on my web site www.onboardsolar.co.uk or please feel free to email me tim@onboardsolar.co.uk or call me on 07810 885734.

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Narrowboat TV Aerial: The Perfect Choice For Your Boat

If you’ve read through the posts on this site, you’ll know by now that I don’t think much of television. In my opinion it’s a waste of reading time, it’s a waste of time that could otherwise be spent enjoying the beautiful countryside that surrounds me and it’s a waste of what little electricity it uses. It kills conversation and deadens the brain. It makes vegetables of all who submit to its malign influence.

You may be surprised to hear then that I’ve just joined the legions of couch potatoes up and down the land.

I’ve had a television for a year or so but, until very recently, I haven’t used it as one. It’s sole purpose was to play the occasional DVD when I felt the need. Unfortunately (or fortunately as I happen to think most of the time), these days it’s not just my needs I have to consider. There are two of us now. Four, if you include two spaniels.

Sally has been living on James with me for quite a while now. She’s not complained about the lack of television on the boat and because I’m male and quite dense sometimes, I didn’t once wonder what she might do to entertain herself during the endless hours each week when I’m working on the site.

The penny finally dropped and I realised that I was being unfair. I have a television, a Logic 22″ HD ready make-your-tea-in-the-moring affair. All I needed was an aerial to go with it.

Ugly traditional narrowboat aerial

I don’t like traditional boat TV aerials. The reason I don’t like them is because they tend not to be boat TV aerials. It’s not unusual to see a full size house aerial strapped to the side of the boat and towering above all around it. We have one or two around the marina which haven’t been fixed to the boat terribly well. At this time of the year (late autumn) when there’s plenty of gusty wind about, it’s not unusual to see an escaped aerial dangling over the side of the boat.

We have televisions fitted in all the boats in the hire fleet at Calcutt. They have slightly more elegant aerials fixed to the roof. They can be quickly changed from receiving to travelling mode to prevent them from being ripped off the roof after making contact with any one of many low bridges around here. They’re still ugly.

At the beginning of the 2012 season one of the boats was fitted with a relatively cheap and very different looking aerial. It’s a small

SLX Gold Digidome Narrowboat Aerial

white plastic dome that sits on the roof. The aerial looks much better than the traditional scaffolding affair, doesn’t have to be bolted to the side of the boat every time you want to use it, and isn’t going to catch overhanging branches or low bridges as you cruise. It’s altogether a better bit of kit. It’s the Digidome SLX Gold.

I fitted one to James a fortnight ago. Actually, I didn’t. Russ, my boat’s guardian angel and all round narrowboat expert, fitted it for me. He told me it was a simple job, and for most normal males I suppose it was, but it involved cutting a but out of the bracket so the aerial would sit flat on the roof. Fitting the aerial, plus the modification took Russ all of fifteen minutes.

What a difference it’s made to life in our cosy little boat. The television now picks up over one hundred rubbish broadcasting channels. We have more mind numbing tedium on tap than we can ever hope to watch, and all with a crystal clear reception thanks to Digidome. I’m just off to watch a bit of Jeremy Kyle!

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Narrowboat Safety

Yesterday was the first day of the autumn with a below zero overnight low. There was a light frost on the grass next to the boat and a bitterly cold wind racing across the marina. It wasn’t really the best day of the year for me to take an involuntary dip in the marina.

I’m addicted to my smart phone. I love it, I really do. It’s a Samsung S2. It does everything for me apart from make the tea when I get up in the morning. I’m sure it can. I just haven’t worked out how to set it up yet.

I use my phone all the time to check my emails. That’s what I was doing yesterday morning while I was waiting for the dogs to jump onto the boat. I was walking along the pier reading a particularly interesting message not watching what I was doing when I stepped off the pier.

One leg plummeted into the water while the other stayed on the walkway. I stretched parts of me that I didn’t know could be stretched and flung out my arms to stop myself disappearing into the water completely. Unfortunately my phone was still in my hand at the time. I prevented a plunge into the icy depths but my phone flew out of my hand, into the water of course.

I stripped off to the waist as quickly as I could, lay on the pier and reached into the water where I could see my phone resting on the marina bottom. It was further away than I thought so I took a deep breath, put my head under the water and reached a little further. I still couldn’t reach so I wriggled my legs a little closer to the water and stretched my arm as far as I could. Unfortunately, I reached a little too far.

My legs slipped off the pier completely as I executed a perfect and stately dive into the mud through the weeds, grabbing my phone as I passed, before laying half naked on the marina bottom under the boat’s bow.

It’s not a view of the boat I ever expected to see. I pushed off against the mud with my feet and shot out of the water like a guided missile. In seconds I was back on the pier soaking wet and freezing cold but otherwise unharmed, which is more than I could say for my phone.

As you can see, it’s not very well at all. The screen is smashed beyond repair and the phone has a definite bend in the middle. Because of the protective case, very little water ended up inside but the blow it received has finished it off. I made a careless and expensive mistake. The replacement cost of the phone is about ?250 and then I’ve all the hassle of setting up a new one but I consider myself very lucky.

I consider myself very fit, but I’m not as young as I used to be. I fell with some force, and I fell into the water. I could have hurt more than my pride and suffered more than the inconvenience of having to find a new phone.

There’s always potential for accidents when you combine water, wood and steel, cold and wet weather and climbing on and off boats. Boaters are always falling off their boats. Falling off a boat into the water isn’t a problem in itself; falling off the boat – or onto the boat – and hitting something hard or something with moving parts can often have disastrous consequences.

I think all of our wharf staff have fallen into the cut at some stage. When this happens the only injury is to their pride. However, slipping on a wet or icy surface when working on a boat is another kettle of fish. A boat roof can be very slippery. Many have a non slip surface, a top coat of paint mixed with grit, which makes them much easier to walk on. Slipping on the roof and landing in its flat surface isn’t normally too much of a problem, but slipping off a boat roof can really hurt.

As a narrowboat owner you probably won’t be skipping from roof to roof as our wharf staff do when we’re preparing the hire fleet, but you may well step on and off the roof when your boat is in a lock. Be careful. Not only is your boat roof likely to be slippery during cold or wet weather, but so is the side of the lock. There are ladders fixed to the lock wall so you don’t have to step on and off the roof but you need to be equally careful with these. They are usually fixed only a few inches away from the wall so there’s little room to place your feet on the rungs.

Gunnels are also the source of many slips. The gunnel is the horizontal ledge that runs around the boat above the hull and below the cabin. Gunnels vary in width from almost nothing to four or five inches. A non slip coating is applied to the gunnel on some but not all boats. You need to make sure that you have two hands anchored to the roof rail or top of the cabin if you’re going to walk along the side of the boat. There have been two or three occasions in the last couple of months when we’ve had to fish wet boat owners out of the cut at our wharf. Some of them make a regular habit of it.

A couple of months ago a couple were reversing their narrowboat was reversing onto the wharf so that the owners could top up their diesel. The lady was steering; the man was standing on the gunnel reaching for a neighbouring boat so that he could tie up to it. He reached too far, slipped and disappeared under the water. The lady was totally unfased by it all. She heard the splash (didn’t even look in his direction), immediately put the boat in neutral in case the man came anywhere near the propeller, shook her head and groaned, “Not again! Not a-bloody-GAIN!” She later explained that he likes to go for a swim at least once every time they go for a cruise.

Slips and falls on either your boat or mooring are just some of the areas where you need to be careful. There are many more and they’re all covered in the excellent Boaters’ Handbook. You can download a copy for free from the Canal and River web site.


I don’t want you to think that serious injury lurks around every corner, but I do want you to where there’s potential for you to harm yourself. Read The Boaters’ Handbook, take it all in and enjoy your next trip out.


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