Solar panel hookup question

[gnarles]

I have two 6 volt golf cart batteries in series in my camper. I am hooking up a solar panel controller to the batteries. I am assuming I can hook up the controller to a single of the batteries, since the whole circuit is now 12 volt rather than 6v (as opposed to have to connect the positive on one battery and the negative on the other). But never hurts to ask to be sure. 

Thanks

Harley

 

[Ned]

Your 2 6V batteries should be treated as a single 12V battery for all purposes.

 

[gnarles]

I am not sure I understand the ramifications of that answer per the hookup. Could I be causing damage by hooking up the solar panel to a single of the 6 volt batteries rather than hooking one lead to each battery?

Thanks

harley

 

[Ned]

Possibly, but you'll only be charging that one battery.  You need to charge both at the same time, so ignore the fact that there are 2 batteries and look at it as 1 12V battery.

 

[kjansen]

Hook your solar panel to the same terminal as the battery cables that go to the coach.  Most likely that will be the neg from 1 battery and the pos from the other

 

[Ken & Sheila]

Keven is correct.

Positive on one battery and negative on the other battery.

ken

 

[donn]

If you are hooked to only one battery you will be pumping 12 volts into a 6 volt battery.  That is a recipe for instant boom.
Two 6 volt batteries if hooked up correctly equals one very large 12 volt battery.  So you need to connect the solar panel to the 12 volt battery.

 

[SWNimz]

While we are on this subject. I have 2 12 starting batteries in a bank and 4 6 volt batteries for the house bank.  House bank holds a charge between uses so no problem.  The starting bank I have just discovered is not included in the cut off switch I have.  This means little things like radio memory and apparently a few other things take the starting bank down enough that I can start the gen. but there is not enough to start the main. I start the gen. and charge up the batteries for a while before attempting to start the main.  Time between uses that this occors is approx. 3-4 weeks.  I have just installed a 15 watt solar charger with charge controller. I hooked the leads up to just one of the batteries figuring that the juice would run from one to the other as they are connected in one bank.  Correct?  I figure that by the time I get anywhere my alternator and battery charger will bring both banks  back up to 100%.  Anyone see a problem with this setup?  Should I connect the house to the controller also? 

 

[kjansen]

My thinking is that your batteries are going bad or you have something else drawing your batteries down.  I will let my pickup set for a month and have no problem starting it.

 

[denmarc]

Think of your two starting batteries as one BIG starting battery.  The starting batteries are wired in parallel.  Whatever you are using to charge them, hook up the charging source with the positive to positive on one battery and the negative to negative on the other battery.  In other words, your charging both batteries together at the same time.  Charging would be equalized.

In between trips, maybe you should consider a float charger.  Unless you have sunlight for the solar all the time.  Doesn't happen in my state!

As for charging the 2-6v batteries.  They would be wired in series to equal 12v to the camper.  Same rule applies.  Charge both batteries together.  Ned is correct for equalized charging.

 

[SWNimz]

Thanks Guys -  you answered a couple questions but open others. I have wondered about the condition of the batteries but was assured that they were new when I bought the coach last fall. LOL then again as many have said better not to believe everything a MH dealer tells you.  Probably best I run a load test on them.  Would you use the same panel and controller to charge both the 12 batteries and the 6 v at the same time? 
I am out in Sunny California and I store my unit unfortunately outside in Petaluma with no electric source at present. That's why the solar.  We tend to get plenty of sun between the rain drops.

 

[Water Dog]

Thanks Guys -  you answered a couple questions but open others. I have wondered about the condition of the batteries but was assured that they were new when I bought the coach last fall. LOL then again as many have said better not to believe everything a MH dealer tells you.  Probably best I run a load test on them.  Would you use the same panel and controller to charge both the 12 batteries and the 6 v at the same time? 
I am out in Sunny California and I store my unit unfortunately outside in Petaluma with no electric source at present. That's why the solar.  We tend to get plenty of sun between the rain drops.

There is either a problem with your chassis batteries not holding a charge or there is a small draw on them that shouldn't be there. So number one should be having your chassis batteries load tested. If you hook your charge controller to both your house and your chassis batteries without isolation that in itself will present a path for battery draw down of your chassis battery while parked; in effect tying the two systems together

 

[TwoTmblwds]

Steve,
I  wouldn't hook the controller to the house batteries too, you would be connecting the batteries together, and they would both discharge, either from a phantom draw or bad batteries. Although it would be possible with the right electronics and relays to isolate them, I don't think it would be worth it for a 15 watt solar panel.
I doubt 15 watts will cover the self discharge from just the starting batteries, remember, you only get at the most 5 hours of full charging from it, plus the losses from the wiring and charge controller. A total of maybe 5 Amp hours of charge(probably closer to 1 or 2), versus 3 to 10% typical self discharge rate (per month) for a Lead Acid battery.  Also, once lead acid batteries are left discharged below 50% state of charge they deteriorate very rapidly, hope you can figure out how to keep them up.
Tom