I've looked thru the old posts, and not finding a thread that covers this topic....... Here goes.

Has anyone found the need to, or done a dual battery setup in their KJ??

I ask because the first order of business this spring will be to add a "Boiler" roof rack, complete with lights, etc.
My plan is to keep both batteries in the engine compartment, the question is where since space is at a premium.
I also plan on upgrading to a 160 amp alternator when the roof rack and lights have been installed.

I ran dual batteries in my old rig. Basically, anything that wasn't stock to the vehicle ran off the 2nd battery.
I like this setup, as it leaves the factory wiring, well, "factory".

I had the batteries isolated quite simply with a 200 amp Ford continuous duty starter relay wired to
a dash mounted dual pole switch.
Position 1 allowed me to charge both batteries, position 2 was momentary for those all important "jump starts"
when the primary battery was low.

So, I guess my question is for those of you who are running additional lights, high watt stereos, etc.
Have you found a need for dual batteries, or will upgrading the charging system and primary battery
be sufficient??

_________________
Brad
International Man of Mystery, Singer of Sentimental Ballads,
Soldier of Fortune, Guardian of the Holy Hand Grenade of Antioch,
Bass Player Extraordinaire, Keeper of the Eternal Flame
of the Immortals, Master Swordsman, The "5th" Beatle,
Expert Marksman, Stand-up Comedian, Martial Artist,
Jeep owner, and all around swell guy.

Unless you plan to run electrical items with the engine off, adding an additional battery will actually reduce the available power available. After the engine starts the alternator immediately sets to the task of recharging the battery, providing energy to the vehicle's electrical system and any components added.

When you go to a dual batt system, the output of the alternator goes to an isolator where there's a voltage drop, then the stock battery and electrical system. However, instead of just the additional load of components, you've added another battery as well which as it depletes becomes an additional load on the alternator.

If you were to do a dual batt system, it's very important that the batteries match and each battery is fused. There's an example posted here that I don't recommend following.

_________________
2006 CRD http://www.UtahPowderCoatings.com/ http://www.gorecon.com/ I'm kind of a big deal.
RL rear bumper, ARB front bumper, Mile Marker winch, Power Tank, Skids by Mopar & Skid Row, RL Super Skink Sliders, 235/85R16 MTR, Air Flow Snorkel, DTT, 4.10 gears, Frankenlift II, Katskin leather, JL Audio stereo, Rosen video.

a good quality battery and renegade alt (which requires some ecm reprogramming if yours didn't come with that amp alt) is typically more than enough to keep the battery excellently maintained

as JL mentioned, if you plan to run them with the vehicle off, depending on what they are, you'd be better off with a large marine deep cycle battery

with the whole battery, + isolator and all that additional cost, depending on what you're "trying to" accomplish, if it's wide area lighting for long periods, whether the vehicle is on or off.. i can tell you from experience a 200ish dollar LED light spreader is an excellent solution

depending on the model, one four bulb unit will put out as much light as a household outdoor flood light - ran a borrowed one all night fishing without killing my battery

for engine on lighting, 4 55w-100w beams will load it pretty good but unless you're sitting still the RPMs are up and charging

a more useful solution to a second battery would be a quality jumper kit that has 12v ports that can be charged while wheeling etc, used at the camp site to charge / operate 12v accessories etc or jump a vehicle

_________________
03 Renegade (Black)
177k miles 3.7L gas - 45RFE
Command Trac / 4.10s
Lift: ft. 790+ rr. JBA4+
The last of the TrailReady Front&Rear Bumpers and TR Rock Rails
Jarhead Offroad light covers
31x10.5R15 RedLetter Grabbers on Blackrock Dunes
L.O.S.T #KD098632

The extra cost is a non-issue, as I ran dual batteries in my old rig
for 8 years without a problem.
The only real issue is the available space under the hood.

I tend to do allot of low speed / slow speed wheelin' ... usually at night.
This requires that the trail be well lit.

I found out the hard way with one to many stalls on a steep hill, and having to "engineer" a jump start
one evening, that having a back up can never really be a bad thing.

My old setup was simple but efficient. I upgraded to a 200 amp alternator, added a marine deep cycle
under the hood using a bracket that I made myself. My "isolator" was a 200 amp relay.
A flip of a dash switch while at road speed ment both batteries received sufficient charge.\
When needed, two pairs of Cepek 900's mounted up top, and a pair of bumper mounted KC's
could run for hours of the 2nd battery while the engine idled along on the 1st.

As I don't get out in the "boonies" as often as I'd like, this may very well be a moot point anyway.

Perhaps I'll consult with "Wildman" on this one.
He seems to be up for anything that "can't or shouldn't " be done.

_________________
Brad
International Man of Mystery, Singer of Sentimental Ballads,
Soldier of Fortune, Guardian of the Holy Hand Grenade of Antioch,
Bass Player Extraordinaire, Keeper of the Eternal Flame
of the Immortals, Master Swordsman, The "5th" Beatle,
Expert Marksman, Stand-up Comedian, Martial Artist,
Jeep owner, and all around swell guy.