Battery setup help

[mgermasi]

Hi Guys
I have two gel batteries of 55Ah each to run all my accessories such as camping lights, fridge, water pump and compressor.
I have an electronic isolator Projecta DBC150 from the main battery managing the charging.

Can I install the 2 batteries in parallel (like having a single 110Ah) or do i have to install a VSR between them?

Thanks a lot
Maximus

 

[gunning1987]

Wouldn't it be easier to have one large single battery?

 

[mgermasi]

It was a....dirty deed done dirt cheap!

Please help!

 

[Saitek]

Generally batteries don't have a problem running in parallel so i don't see a problem with doing this without the vsr between them. Yeah sometimes two smaller batteries is actually nicer to mount and hide them away instead of one Goliath sized battery.

 

[NFURY8]

You should be runnin ur compressor of ur main battery, u will only realy need 1 55ah battery. I get 4days out of my 55ah optima battery running a 60L arb fridge and 3 LED lights and runnin a little stereo

 

[mgermasi]

That means I can run 2 fridges = more beer LOL

Thanks any way NFURY8

 

[sparra04]

i run 2x 55 ah optimas in parralel
one in tray and one under bonett
charged with a redarc bcdc
works fine

 

[Old.Tony]

As long as the batteries are the same capacity and type, they are generally ok to use in parallel. Do NOT draw power from one and then hook the other up - draw power from them both by maintaining the parallel connection at all times. It will look like a 110Ah battery.

Please measure the voltage at the rear. It should never, ever exceed 14.1V - any more than that and the gel will start to bubble - that's permanent damage. Never, ever conduct a "recovery" charge, or an "equalisation" charge on a gel battery - both will destroy the battery.

If you try to charge batteries that are mismatched, the smaller battery will charge faster, causing the apparent voltage to rise higher which makes the charging system think the batteries are charged, when the larger capacity battery is still expecting more. This (in the long term) will shorten the life of the larger battery and as expected, won't provide as much power as you'd hoped.

 

[RustyNav09]

Old Tony

You mention don't mismatch batteries. You mean types of batteries or just any battery in general? I have a 100ah agm battery at the moment and I'm planning on adding another agm battery but of a different brand andcontaining 90ah capacity, can I do this? I will be connecting them in parallel and having a cut off switch between so I can take one battery out when its not needed

 

[mgermasi]

It's me again...What size fuse? 100, 120 or 150 amp? Thanks a lot

 

[sparra04]

i used 100 at each end

 

[Old.Tony]

You can't mismatch capacity or type, really. Different battery types need to be charged at different rates and smart chargers can do this - as long as they can see the battery and 'read' it properly.

That's apart from the problem with voltages when charging mismatched capacities! Thanks for drawing attention to that, I should have explained it a little better.

Basically (to keep it simple) you should really only parallel batteries that are the same type and capacity.