Dual battery solar controller

[Heelshock]

I'm running two size 27 batteries on our TT. We occasionally dry camp for 3-4 days without needing to charge. I take the batteries off and charge them separately when we get home and maintain them until we use the trailer again. I'm curious if I went to a solar charging system how that would be connected if the batteries are wired in parallel. Everything I've been told about charging dual batteries is to make sure I didn't charge them together at once. The dual controllers I've seen have connections for each battery, but that doesn't separate the charge if they're still wired in parallel, right? How do folks end up charging a pair with solar?

[2oldman]

Heelshock wrote:
(charge two) I honestly can't remember where I picked that up.

Maybe you go to coffee with a bunch of old guys. Maybe they also told you to not store batteries on a concrete floor. 🙂

Most diesel trucks come with 2 batteries. I'm pretty sure they charge those at the same time.

[Heelshock]

2oldman wrote:

Heelshock wrote:
Everything I've been told about charging dual batteries is to make sure I didn't charge them together at once.

Who told you that?

I honestly can't remember where I picked that up. Good information for all, though. I'll be all set for some extended dry camping with the family.

[2oldman]

Heelshock wrote:
Everything I've been told about charging dual batteries is to make sure I didn't charge them together at once.

Who told you that?

[the_happiestcam]

What everybody else has said so far X2.

[KD4UPL]

The best bet for any battery bank made up of multiple identical batteries is to connect them together and leave them that way. They will simply function as one larger battery.
The wiring must be done correctly as pianotuna illustrated. Also, the charger must be large enough to fully recharge the entire bank.

[westend]

No worries, you can charge your batteries with a solar charge controller while they are wired together. You don't need a dual controller, a regular charge controller is all that is needed.
Right now, my solar controller is charging 2-6V golf cart batteries and 3-AGM 12V batteries. I have the controller set to charge and float at the voltages I think are optimum and it does all the work, even monitoring the temperature of the batteries.

The only bad thing about solar is that I wish I had it 30 years ago. Either that or a nickle for every battery that I moved.

[pianotuna]

Hi,

So long as you wire the batteries in a balanced manner they may be charged together. This is what is balanced and best for twin twelve volt batteries.



As it often doesn't cost a dime more to do this, I think it is worth the trouble.

If you wish to understand the "why" surf here:

correctly interconnecting multiple twelve volt batteries

Others may say it doesn't matter--but unless there is a compelling reason to not optimize charging and discharging why not do it the best possible way?