# Adding second 12V battery



## Guest

I've decided to add a second 12V battery, to extend my available time to dry camp before having to run the generator. Before you get started, I know that the best answer is to switch to two large capacity 6V golf cart or forklift batteries. I don't have the funds for that, yet.

What's the best configuration for two 12V batteries. I've heard of systems with a battery switch, and systems with a battery isolator. For my stated purpose, which should I use, or is there a better answer. I would appreciate any advice from some of you more experienced Outbackers.

Happy camping

Gary


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## Y-Guy

Gary since you have a Generator I think you're heading in the right direction by not going with the dual 6v. You want to add another battery just like the one you have, if the dealer is close it maybe best to go back and buy from them since they will carry the same brand and might even give you the necessary wiring. If you have a Group 24 or Group 27 battery you want to replace with the same size, and age if possible. Then you can wire them in parallel to give you the most amp hours. Another option would be to switch over to a second battery when the first one is down, but to me that's a pain since when I'm camping I try to minimize doing extra things. I don't mind mods at home, but fiddling with the camper while camping isn't as much fun. You may want to take a look at The 12v side of life since it covers some great info about batteries. Good luck and happy camping.


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## aplvlykat

Y-Guy gave you some good advise. I would also like to add that the jumper between the two batteries( pos to pos & neg to neg) should be equal or larger than the incoming wires. In the outbacks case 6 AWG, if you have crimping pliers you can make your own with 6AWG thhn wire and battery crimp ends or you can purchase some pre-made ones from any auto parts store or walmart. The only other change would be to remove the positive wire coming from the TT and reconnect it to the new battery. It should end up that the existing neg is on original battery and existing pos is on new battery. Doing this will discharge and charge both batteries equal. Kirk


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## NDJollyMon

Well said. I'd hook the batteries in parallel too. Ever have to tiptoe out in the cold to switch on a propane tank or battery switch in the cold???


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## Y-Guy

NDJollyMon said:


> Ever have to tiptoe out in the cold to switch on a propane tank or battery switch in the cold???


Isn't that what kids are for?

Have you see one of these before? Remote Changeover Indicator

I like that idea!


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## NDJollyMon

Yes. As long as they are with you. (Sometimes I just take the dogs and leave the kids!)









Ahhh the luxury of grown children.


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## Guest

Thanks for the advice. Two identicle 12V batteries in parallel it is. Following Steve's, advice I went to the dealer and got one just like the one that they had installed originally. There's a month or so of usage difference in them, but they're even the same lot number. He also had the cables already made-up for the installation. Total cost after discounts and sport haggleing was 88 bucks. I like it! The dealer recommended that I fully charge both batteries (marine/RV deep cycles) before I hooked them up, so that one was not charged more than the other initially. They are on the charger now. I did forget to pick up a plastic battery case and strap for the second battery. Guess I'll have to go shopping at the RV store again







,darn the bad luck!

Happy camping

Gary


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## aplvlykat

Gary, go to the local walmart they sometimes carry the boxes. good luck Kirk


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## NDJollyMon

You'll love having more JUICE!


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## mhbandy

I had the same question that was posted here but still am unsure of the final hookup. Camper positive to new battery positive and negative from camper to original battery but how do you finish??

Also, do you find that the batteries discharge faster this way or to simply hook them up one at a time.

Just curious, thanks for the info.


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## Y-Guy

mhbandy said:


> I had the same question that was posted here but still am unsure of the final hookup. Camper positive to new battery positive and negative from camper to original battery but how do you finish??
> 
> Also, do you find that the batteries discharge faster this way or to simply hook them up one at a time.
> 
> Just curious, thanks for the info.











This is the proper setup for a dual 12v battery and a dual 6v setup as well.

Two batteries hooked up together will last longer as far as AMP hours and as years of service in most cases.

If you have the time head over to The 12v Side of Life it has some great material for batteries and its in pretty straight forward language too.


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## aplvlykat

Guys, if you connect it like the drawling above it will work fine. Notice that the pos and neg are connected to one battery then it jumpers to the other. If you leave it this way you will discharge from the first battery a little faster than the second battery. If you move the pos terminal from the first battery to the second battery then you will discharge equally from both. From what I have read this is called cross connectting and is the best way do get even useage out of both 12 volt batteries. When you install the jumpers and install the neg on the first battery and the pos on the second battery you are finished and ready for the box covers. hope this helps, Kirk


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