How do I connect the second battery

Sometimes a picture is worth a thousand words:



Here is an excellent article from which this diagram is taken:

12 Volt Side of Life

If you aren't familiar enough with electronics to understand the answers given, you would be farther ahead to get help from someone that does. You can cause a lot of damage hooking things up wrong.

Mark

As stated, start out with 2 new, equal batteries. Charge them fully before connecting together. Connect positive of battery 1 to positive of battery 2 and negative of battery 1 to negative of battery 2 with EQUAL LENGTH cables. Your loads (connections to the trailer wiring) should be connected with positive wires going to the positive terminal on battery 1 and the negative wires connected to the negative terminal on battery 2.

Just another quick suggestion. Once you finally figure out the correct hookup, take a picture of it. We actually printed one out and keep it in the trailer. That way we have no questions about just how we did it when reinstalling the batteries after winter storage.

Highest amp hr I can remember on a 12v battery is around 85 for a group 24. You can use about half of that before your battery is dead. If you add another 12v group 24 you will be up to 85 amp hrs. As someone said earlier 2 6v will give you about 110 usable amp hrs. If that battery disconnect switch is a 2 battery on1-on2-both-off switch that may explain the extra red wire.

Yes, two equal 12v batteries will increase your usage time till you hookup to shore power to recharge them. No one here can really say how much more time you'll get. There's no way to figure out your existing wiring from the photo. You can find plenty of battery hookup info in youtube videos, but you still need to know what purpose the extra red cable serves.

dpgerson wrote:
Thanks for your answers, but nobody really answered my questions,

Everyone answered your questions. If these responses aren't clear to you perhaps get a buddy to help.

dpgerson wrote:
Thanks for your answers comma but nobody really answered my questions, other than to say positive to positive negative to negative. So does that mean hook the two free red cables to the positive terminal
Of the new battery, and the free green one to the negative terminal?

Will this allow me to boondock longer?

First off, I wouldn't answer your wiring question because I can't see where the cables run. I can ass-u-me where they run, and be wrong, and you could be hosed with a bunch of burned up stuff, which is why I answered as I did. I did answer your second question, if in a roundabout way, by saying that, with 12v batteries, you add the amp-hour ratings together to get your total capacity. More amp-hours = more days off the grid.

Lyle

Thanks for your answers comma but nobody really answered my questions, other than to say positive to positive negative to negative. So does that mean hook the two free red cables to the positive terminal
Of the new battery, and the free green one to the negative terminal?

Will this allow me to boondock longer?

Busskipper wrote:

dpgerson wrote:
When I bought my 2000 Snow Bird, it only had one battery. I'd like to add the second one to extend my boondocking capability. How do I hook up the second one? There are 2 free red wires and one free green one as shown in the picture.

Also, this is a dumb question, but will this make allow me to boondock longer? the reason I ask is that I had a truck camper with 2 batteries and the second didn't seem to make much of a difference.

But till the old one goes you could carry a spare, just not hook it up unless needed - (then disconnect and hook up other battery) - or get two NEW batteries and save the original as a back up.

No good/simple/cheap solution.

JMHO,

When I look at this picture I see a potential issue - Either disconnect or tape up the positive battery cable as it could be an issue if grounded.

Just a thought.