connecting additional leisure battery

[ROBRIOS]

Hi guys

I would like to fit an extra leisure battery to my camper.

I have a zigg cf6 and the existing leisure battery connects to the zigg to then feed the 12v and receive charge from either mains hook up or whilst driving.

would it be best to connect the new battery direct to the zigg or in tandem direct to the existing battery ?

cheers

[ed_crouch]

tricky one this. you can either connect in series (if the Zig can handle 24V input off the leisure system and DC-DC convert it to 12V for the load) or parallel. Series works well if the Zig is sophisticated enough to do the voltage conversion, and parallel is the way to go if you want it simple.

Trouble is, one new LA battery and one old LA battery in parallel is a bit iffy because their internal resisances increase with age (sulphation of the plates), so the older battery can effectively drag the performance of the new battery down by mechanisms I cant remember right now (wikipedia is your friend here if you're curious).

The normal advice for this sort of thing is either to buy two Trojan 6V traction batteries and wire them in series (LOADSA amp-hours and loadsamoney), or buy two IDENTICAL 12v leisures from Tayna of the like and wire them in parallel...

You certainly CAN do one old and one new in parallel, but the results might not live up to the advertised capacities.

[ROBRIOS]

Thanks for the input

[Joker79]

I'm also looking to add an additional leisure battery and I'm going to go down the Tayna route http://www.tayna.co.uk/XV100MF-Powerlin ... P8960.html

Looking to put 2 x XV100MF Powerline Leisure Battery 12V 100Ah under each seat to give me 200Ah wired in parallel. I know there is a whole debate on Trojans etc but I like the idea of using the space under the seats for batteries and I intend to put a 100W Solar panel on the roof to keep the batteries topped up.

My question is what is the best way to wire them together in Parallel and where to run the cable? I've gotten hold of some buckshee 32amp shielded electrical cable and thinking about using this as well as using it replace the standard Westfalia very small wire (in comparison) from the BBB and alternator.

[ed_crouch]

Where does the starter battery live if you plan to put a leisure battery under each seat?

I think its a good plan, but big batteries only delays the moment when you run out. Enough solar power can ensure you never do.....

I've got 200W of solar, and its awesome.

[ed_crouch]

Best cable run would be out the bottom of one battery bay, across under the floor and up into the other. Use big cable. Like 50-100A. Remember to clad the cable in chafe-resistant sleeving and grommet any holes it passes through. Battery shorts of that scale are baaaaad news. ~8.5 Megajoules in those batteries when charged... enough to boil 20 litres of water or to melt the battery connecting leadseveral times over. Earth each battery to its battery box with a good quality earth strap.

[Joker79]

Class now if my crusty old turbo diesel did 88 mph I might end up Back to the Future!!!!

My starter battery is in the engine bay so I can use the space under the seats for the battery storage. 200 Ws sounds awesome, have you got any pics of your set up?

Also how have you mounted the panels to the roof and what sort of charge controller have you got? I've looked on the forum and the Wiki for a decent thread on a Solar install and can't seem to find anything.