dubyas-eep

So I have been talking with a buddy of mine about dual batteries and there purpose. I am thinking they are so you do not run down your battery while vehicle is off and you are running accessories. Correct or Incorrect and what else?

JK-Ford

Well sorta correct. You could isolate the accessories to one battery while leaving the other just to handle the Jeep. But a battery is kinda like a glass of water. It is a resivor of power. Its better to have two than one.

JKBobAZ

Here is the link to an info sheet on a very good dual battery isolater. This is the one that Benchmark uses (They are a sponser of this site) They have great products but have had some "Shipping" issues latley but seem to have them worked out. I just installed their system and love it. I go camping in some very remote areas and wanted the back up of a second battery.



http://www.colehersee.com/pdf/hot_fe...BatteryIso.pdf

jkerr

The benchmark battery setup has a smart isolator that will separate the two batteries when the voltage drops below a threshold. This works well for winches, amps or anything that is directly connected to the second (aux) battery. However, when the ignition key is in Aux or On, both batteries can run down. They will still separate at the voltage limit, but the main battery will be what feeds anything connected through the ignition (e.g. radio, cigar lighter, power windows, dome light, headlights, etc.) and the Aux battery will continue to feed anything that is directly connected to it (e.g. Amps, aux lights, winch, etc).

Another caveat to keep in mind... If the main battery runs down before the Aux (e.g. big draw from cigar lighter), the Aux battery will not start the Jeep unless you force them to combine. Benchmark has a secondary lead that comes from their isolator that needs to momentarily switched on to override the isolator. This effectively lets you jump start yourself. To set this up, you need a simple momentary switch installed somewhere easy to access.

To JK-Ford's point, if you have a simple 2 battery setup without an isolator, both batteries will run down equally. A smart isolator setup is the safest way to go as long as you understand its limitations.

TIE1ON

I was talking with dubyas-eep and also wondering why the dual batteries ... but have seen them on boats for the same purpose stated above ... so I am wondering now ... has anyone installed a Marine Battery Switch on their dual system?

Kinda thinking this is a great idea, and I will do this now, unless there are issues with the set up.
Seems to me a hidden switch could act as a redundant security device to deter theft? and control the battery flow? ... Am I off base here?

dubyas-eep

alot of good points looks like I will be adding a second battery

JK-Ford

Wouldn't be a very good battery if you had to hold a switch to make it work?

Guess that depends on how you look at it? Agreed that a dual battery charging system would be better for recharging. But lets just say that you use 50% capacity of the entire system? That would mean that you would have ( 1 ) battery depleted. Or ( 2 ) batterys at 50% capacity?. Just food for thought.