Since the topic of batteries came up...

[JeepSJ]

Space is really at a premium under my hood. I'm going to be hard pressed to find room for 2 batteries. Anyone running a single battery? If so, how is it working for you?

I can get a single battery (Odyssey dry cell) (http://www.odysseybatteries.com/battery/pc925mjt.htm) that has 925 cranking amps. Think that will be enough? I could go up to their 1200 amp version.

From their site -
Odyssey combines in one box the characteristics of two batteries. It can deep cycle as well as provide serious cranking power. These batteries are capable of providing engine cranking pulses of 1700a for 5 sec as well as 400 charge/discharge cycles to 100% depth of discharge (DOD). A typical battery can do one or the other, but not both. With other batteries such as Optima, you must decide between a deep cycle or a high power starting battery, but Odyssey does both.

The cranking power of a Odyssey battery is double to triple that of equally sized conventional batteries, even at low temperatures.
Also with simple constant voltage charging, there is no limitation on the inrush current. This means you can charge your battery with as many amps as your charger, alternator, stator, or generator can put out as long as it doesn't exceed 15 volts. Lead acid, gel cell, and other AGM batteries can only accept 10amps per hour during charge.

[ 08-15-2005, 04:02 PM: Message edited by: JeepSJ ]

[gmenor]

Friend of mine converted his 6.2 military CUCV to 12 volt system. Don't know if this applies to the 6.5 (shouldn't be too much of a difference) Here is the link:
http://www.roscommonequipmentcenter.com/news_notes/nn10.pdf

[NH2112]

I'm running a single Wal-Mart EverStart (1000CCA I think) in my C1500 and haven't had any problems because of it. I have had instances when it wouldn't start on really cold days (usually weekends when I don't plug it in for the 0630 drive to work) but my K1500 w/dual batteries didn't start under those circumstances either.

[tom.mcinerney]

SJ-
I once spoke with owner of a local Interstate Battery distributorship. He said most all automotive batteries are really the cheapest items the manufacturers can figure to make.

A better dual battery setup would involve two 6-volt cells in series. A large, premium quality battery will probably work fine.

The battery rep also pointed out that extreme temps are the killer of batteries. If you use oversized (welding) cables you could move the battery out of the hot engine compartment , lighten the weight on front suspension , and significantly increase battery life. {I assume you intend to put significant mileage on your jeep on warm CA roads}. Some cars fit an insulating blanket around the battery to insulate it from underhood temps....

[JohnC]

the original batteries in one of my trucks were only 575 CCA, IIRC. since it doesn't get cold where you are, and especially if you use synthetic 0W-40 oil, I think 1000 CCA woudl work fine for you.

Aside: Tom M is correct, a pair of 6 volt batteries in series would work better. The reason is that a 6 volt battery has lower internal resistance than a 12 volt battery does.

[David Brady]

A couple of years ago I replaced my batteries and found I was running on one, the other was DEAD! It wouldn't even make any spark on a direct short. I have no idea how long I was running on one but it started just fine in my area.

[JeepSJ]

Thanks, gentlemen. You have just made my life a bit easier.

[Craig M]

I have run my dually and Suburban (both with 6.2's) occasionally with only one Optima battery. Starts just fine in the relatively warm Southern California climate. If going to colder areas, the second battery gives you a little more cranking time. Have an 8V71 Detroit that will also start with a single Optima battery. I did melt the lead post connector of the single Optima battery once when trying to reprime the 6.2 (after I had run it out of fuel). Quick answer is yes a single large battery will work.