Traction batteries

[Tunneltug]

I guess this has been discusses to death but I thought I'd just document my recent battery experience.

 

My boat is steam powered so battery charging will always be a bit difficult because the engine turns at about 150rpm Max. I do have a 70amp alternator running on a 1:20 belting system so it does get up to 3000rpm. There is a separate steam powered generator which gives 20A and I have a portable Honda powered alternator charging set capable of 70a.

 

Knowing that charging batteries would be a bit hap hazard I decided to use a set of small traction batteries bought second hand on eBay for £150. Each 2v cell is 400mm tall, 200mm wide and 65mm deep and they were made in 1992. Their total when wired up to 12v is 480Ah. I put them in 2 wooden boxes and fitted a good quality desulfator. I have 30a 12v charger built into the boat electrical system.

 

When not planning to light the boiler, I would regularly use the boat for a week without charging the batteries and the voltmeter would drop from 13.5v to 12.5v but the alternator would charge them up fully in about six good hours in steam.

 

Recently after 3 years installed in the boat, a cell went down and the voltage was difficult to maintain although still very useable. I bought a replacement cell for £80.00 dropped it and all was back to normal. Out of interest I checked all the other cells, all of them were exactly 2.25v and the electrolyte was toward the top of green section on the hydrometer so basically like new. I put this down to the permanently wired-in 65mA desulfator because the electrolyte condition wasn't that good or voltage as even when I bought them.

 

Out of interest, the cost of a brand new set of 12 cells was about £800+vat which sounds steep but if they are going to last 20 to 25 years without any real problems or difficulties I think it's well worth it.

 

Just thought I would write this down for you to make of it what you will.

 

Regards - Keith

[peterboat]

I have 2 banks of traction batteries both about 720ah one bank is over 9 years old and still has readings in the green after a good days sun its solar for me widebeam and big roof makes it easy. I am a heavy power user but in winter time I plan the washer and dishwasher around the wispergen to save drawing to much out of the batteries. The solar controllers are supposed to desulphate so maybe they do who knows

 

Peter

[Tunneltug]

I was a skeptic about desulfators at first but the kit only cost £16 on eBay and I couldn't see it doing any harm being only 65mA. I installed it last year when the batteries had been in use for 2 years. At that time the voltage across the individual cells varied from 2.1 to 2.25 volts and the acid varied accordingly so when I saw that after only about 12 months the cells had been completely equalised at the top end of the range was a pleasant surprise. Interestingly all but one of the cells were Fiamm but the one that had to be replaced was a hawker, unfortunately the replacement cell is also a hawker because Fiamm are no longer available I'm told.