adding a 12 volt battery to a bank of 4 =6volt battery

As long as the solar is operating you should have no issues IMO.

Rather than just say "I wouldn't if I were you"...

Run the system for a month and then take a hydrometer reading on all cells. That'll fix you up with an answer you will hold in your hands.

"I have 4 new 6 volt batteries and a 12 volt battery that is like brand new"

NO. You can NEVER add any older battery to a new battery bank and expect the system to function at its optimal level. You cannot add a 12 volt to a 6 volt(producing 12 volts) type system and expect it to function correctly in the long run. 12 volt and 6 volt batteries have different charging design parameters. Doug

Most of us like to have LIKE BATTERIES in the same banks as well as same age of batteries... This allows the converter/charger to match the battery internal resistance better with the hope that all of the batteries charge at the same rate when being charged.

Like said above give it a try and see if all batteries attain the 90% charge state at the same time.

Roy Ken

Hi,

Are you running short of power? Is there some issue of voltage drop with an inverter?

You can get value from the spare 12 by paralleling it to your "big 12" 4-sixes temporarily using jumper cables. That will give you some extra AHs when needed for some reason. I have done this many times.

Normally charge the single 12v separately from the four 6s, but if this is impossible, and you are charging the 6s, leave the jumper cables on and the 12v will get some charge too.

I used to carry the extra 12v in the back of the truck and charged it with an extension adapter I made up for the 7-pin so it got charged some (not much really, but every bit helps) while we drove around sight-seeing or going to town.

With that much solar, if you get to near full on the 6s in early afternoon, you can swap the solar over to the 12v for the rest of the day using jumper cables.

It all works, as long as you don't mind managing and keeping track of it all so it doesn't cut into the camping fun any.

These discussions may help..

Add 12v to 2 6v
12 and 2 6v 2010

You need to re-think and then ask the question of yourself again.

You said "I have 4 six volt batteries"

No, you do not

You have two two piece 12 volt batteries.

Now, The quesiton becomes

I have 2 12 volt batteries in parallel, Can I add a 3rd, and the answer is: YES

Lesee, 5% antimony batteries on one side, 2% antimony on the other PROBABLY with a 1.5% calcium negative plate.

Mmmmmm

Chocolate covered Brussels Sprouts.


Bet'cha a person COULD eat it...

Say you are a heavy AH user and going out for four days and you will need to do a "50-90" on the second day

You have 460AH in the four sixes and by the second day you are at 50%. But now you can only recharge to 90%, so for the second set of two days you are short 10% going in, because on the first set you started from full, not from 90.

After doing the 50-90, you decide you don't want to drop to 40% the next set, so now add the spare 12 with the jumper cables. This is like having that 10% back. 10% of 460AH is 46AH and 50% of the 100AH 12v is 50AH.