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Battery charging advice.

I have recently bought a Narrowboat for leisure use and am concerned about how best to keep the batteries charged during the winter period when I will only be using the boat about one weekend a month. It has 3 domestic batteries and one starter, plus a small solar panel. Is it sensible to leave the solar panel permanently connected to trickle charge, or will I need to take the batteries out periodically and use a mains battery charger?

Asked by: Richard Drage  | 12.58pm, Sunday 8 November

WW says:

It depends on how much you charge the batteries during your monthly visits. If they are fully charged when you leave the boat - and particularly if you leave the solar panel trickle charging them between visits - you should not have too much to worry about.
The worst thing you can do to a battery over the winter is ignore it. Over a period of time, it will discharge itself and a layer of lead sulphate will build up on the plates inside. This layer is sometimes dissolved back into the electrolyte when you recharge the battery but, if it is not completely removed, the battery becomes more and more difficult to recharge and a vicious circle begins. Also, the electrolyte becomes diluted and more prone to freezing which can split the outer casing.
If you think that the batteries are not being sufficiently charged, you may have to take them home to recharge them from the mains. It is probably better not to remove all the batteries at once, and essential that you don't if you have an automatic bilge pump.
Provided the sulphation process is not too far advanced, it can be reversed by connecting the battery to a device like the Megapulse FAB Mk4. See www.megapulse.uk.net

Graham Booth  | 2.33PM, Sunday 8 November

If you do need to remove a battery from the boat, always take off the negative (black) cable off first, then the positive (red). When replacing it, fit the red first, then the black. It may be a good idea to photograph your battery bank first to ensure that you get any ancillary cables for shunts etc in the right place.
Finally, keep an eye on the level of the electrolyte in the battery cells and top up with de-ionised water if necessary. If one cell needs much more water than the rest, it may be that the battery is nearing the end of its life.

Graham Booth  | 9.45PM, Sunday 8 November

Readers say:

Thanks very much for the advice.

Richard Drage  | 10.25PM, Sunday 8 November

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