On 13/04/2014 10:19, bm wrote:
wrote in message
...
Following on from the thread about second use for old electric car
batteries: surely as end of life is reached for any cell the self
discharge increases and thus a higher proportion of the charge gets
expressed as heat?

I need to provide hot washing water in one of our vans, about 10
litres is enough and these basin units are readily available for £250.

I can see a split charge system will only charge the second battery
when the main vehicle battery exceeds 13.5V, and even a facility I'm
told that will only charge it on overrun. This will get the water hot
on the run to work.

I understood that when the engine was running the split charge relay would
energise and connect both batteries in parallel -
https://www.marcleleisure.co.uk/Sund...itCharge01.htm


What a *really* useful link; I have been thinking about fitting a
leisure battery to my horsebox, and they have done all the work!