Adding Second Battery

[cico7]

Has anyone added a 2nd battery?

[07JeepXK]

I had thought about it at one point in time but since I dont have a which or sounds system that idea was nixed.

[Doc in AZ]

i get this question a lot at my shop. then i ask why?

a second battery will only be as good as a the alternator charging it. if you have such a large amperage draw (lights, winch, sound system etc.) that you think you need a second battery for it, but haven't got an alternator strong enough to keep one battery charge, you will just end up with a two dead batteries instead of one. i highly recommend a gel cell battery like an optima, and if you are going to buy one, spend the extra coin on the blue top deep cycle, it makes a world of difference over the standard red top.

the best way to go about this is to find out the amperage of your alternator and work within those parameters. every little bit helps. i've got LED interior lights in place of my factory dome lights. this means i have more light throughout the rig & also a fraction of the amp draw. i have switched my rock lights out from halogen to LED and can now turn my jeep off and not have to worry about a parasitic draw when out on the trail, or wasting gas leaving it running for the light.

the only benefit IMHO for having a second battery is to have an isolator that would allow that battery to change but not to discharge or be introduced into the system unless you switch it "ON". this is good when you have inadvertantly drained your battery by leaving the lights on. you will still have a second battery to start the vehicle and keep it running until your primary recharges.

[cico7]

Excellent response to my question because it does help define a better answer.
The reason I am interested is to run dc things without running my starting battery down.
I would use an isolator with a dual switch. If I want to run game, fan, or what ever while I am camping.
When we were out in May, my son and his buddy ran my battery down playing games and music. I replaced my
battery shortly after that as is was over 50,000 miles. It was due. But I want a backup battery to run options.

[Doc in AZ]

Excellent response to my question because it does help define a better answer.
The reason I am interested is to run dc things without running my starting battery down.
I would use an isolator with a dual switch. If I want to run game, fan, or what ever while I am camping.
When we were out in May, my son and his buddy ran my battery down playing games and music. I replaced my
battery shortly after that as is was over 50,000 miles. It was due. But I want a backup battery to run options.

For that application I would recommend a small "super quiet" type of generator. It would cost less, be a lot easier, less maintenance cost over time and be more versatile

[08crd]

I have a second battery mounted in the the rear they are used a lot in Australia to enable the running of a car fridge. With the hot weather over here you need the fridge when you go camping as you end up in some fairly remote areas and a long way from towns or shops. i run a Redarc battery isolator solenoid, this is fitted between the start battery and the second battery. The batteries are connected together when driving however when stopped the solenoid seperates the batteries when the start battery voltage drops to 12.5v. When the car is started the solenoid stays open untill the start battery voltage reaches 13.2v then the solenoid closes and starts charging the second (deep cycle)battery. There is quite a good write up on it here http://www.fridge-and-solar.net/dual_bat.htm

[Sal-XK]

I think for running stuff like games music and such a generator would be pretty cool if you could mount it and run it off the the fuel tank like an RV now that would be pretty bad ass. Lets not forget about solar power as well, I used these in Afghanistan for charging and running small things like Ipods and stuff like that not sure if its even practicable for larger things but a thought. Although it wouldn't of helped us any the last two trips to Flag Pole LOL.

[08crd]

Running a generator for small current draw items seems like a huge waste of money. The second battery is charged while you are driving and makes no noise while you are stopped. Generators are noisy, smelly pieces of crap that really only need to be used when running high load appliances like airconditioners in R.V's.

[Adondo]

The XK has a 160 amp alternator, so generator power is a non issue. but, if you want to run a 'fridge, high power stereo, etc. without running the engine, then a 2nd battery makes sense. That way, battery two runs down, and you still have a starting battery.

A lot of cop cars have a 2nd battery in the trunk to run radio equipment and lights. We use one of these to connect the 2nd battery. This device will allow the 2nd battery to go dead, yet you start with an untouched main battery. Or... if the main goes dead, you have an auxiliary to help start up with.

[08crd]

Hi Adondo, I like the smart relay you have used, I don't think they are available in Australia. The 200amp rating is much better than the 100amp rating of the Redarc relay I used. That is the one down side of Australia it is such a small market that a lot of the gear available to you guys never make it here.