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I have fitted a second leisure battery in parallel and my onboard charger works fine.

John

I  charge my two 90ah batterys connected together with jump leads...using a heavy duty charger..when i said this to manager at halfords as i wanted to purchase proper connecting leads he stated that this was dangerouse as you can only charge one batt at a time....yet the batt charger is capible of charging up to 370ah......so am i right or is the manager right...he reckons i would need industral leads to connect the batts together if i was going to charge them both.. ANY INFORMATION ANYONE!!!!

I have looked into this and there are two ways you can charge these batteries together.

1) connected in series with a suitable supply ie. 24 volt charging system with a charge current of 1/10 of the combined AH of the batteries. This is a charge at what is called the 10 hour rate. ie. If the combined AH rate is 150 AH then in theory you can charge it at 15 amps. You can also charge at the 20 hor rate (AH divided by 20 which apparently is OK but would take longer and is the second option) but I would stress that you need suitable cables and connectors, not clips. Also suitable fuses should be in the input AND OUTPUT cables. frequent checks of charge states should be carried out during charging using a voltmeter and hydrometer.

2) Charging in parallel should be avoided as large circulating currents can occure between the batteries if they are at a different charge STATE (one discharged more then the other) and it is recommended that the batteries are the same type, same AH rating, same age same charge state and are used together.

I have looked into the whole subject of charging Leisure batteries (An entirely different ball game) and I would NOT charge them in parallel. I am at the moment wiring a system that connects them in the same circuit BUT will only allow them to be used seperately and charge seperately, so getting rid of the problem I had that my deep charger only had an output of 7 amps. I can therefore charge the discharged battery quicker, while using the other battery in the van.

By the way, I used to be a battery servicing electrician in the air force and am familiar with normal lead/acid and alkaline battery servicing. I have been working abroad for 15 years and these leisure batteries were not around then. Hence my original question. Any problems drop me a line but I (Hopefully) will be away in the van for the next 2 weeks 

I charge two 100ah bats no problem got them connected to my solar panels as well been all over the continent away for months at a time, not a bit of trouble

Thanks chris and bob for your replys.....first chris..i have a RAC heavy duty charger/engine starter...the out put is 12v..15A DCfast charge..  24v....7.5A DC standard charge......12v...2A DC trickle charge...min capacity 7ah-375ah               my question is this....is this an ideal charger or is there one more suited...it cost £70 and is returnable...i brought it as i thought it would charge both batterys...not so sure now....and like you..would i be better off charging only one batt??...though again is there a cheaper charger to charge one batt..or stick with it??? your help please..

now bob...i have a solar panal...40w....would this be ok to charge both or just the one?? be interested to know what out put your panal is....

thanks to you both...

Normal vehicle and leisure batteries are two different beasts. The vehicle battery is designed to give frequent high current outputs and take high charge currents. The leisure battery is designed to give constant low current output. Your charger would be ideal for a normal vehicle battery both 12 and 24 volt. I would be carefull using it for the leisure battery as I don't know how you would control the charging current. Either automatically or manually. There are specific chargers for leisure batteries which give an automatic stepped charge which prolongs battery life. Be warned these are not cheap. My 7.5 amp output one was just over £100 while the cost of the 15 amp one was about £190. I think you must consider the price of chargers and batteries and make your decision on that. What decided it for me was that I could use and charge the batteries seperately using a split system and so hopefully I would be able to maintain battery charge to usable voltage. The first time I used the van I had no idea of the characteristics of leisure batteries. Run it down to a very low voltage and was unable to charge it. Brand new and ruined .

I have not tried solar panels, how does it perform in the UK as opposed to the continent Bob? also what is the output and is this sufficient for the UK

Regards and thanks to all Chris

 Hi,

your 40w solar panel will work just fine even if you just clip it on your bats when your not using your van it will keep the bats up and you wont loose them, but you must have a charge controller so you dont over over charge them, my bats are up at 13.50v all the time when the van is not being used. as regards to uk they will charge as long as there is light even in over cast conditions , not as much as bright sun light but it will keep the bats up and that's all you want. AS for chargers you wont need one as long as your not taking a lot out of the bats the panels them up , i have 120W panels and on a nice sunny day they will run my TV and they cost nothing to run,  good luck