Jeep Wrangler Forum banner
  • Hey everyone! Enter your ride HERE to be a part of September's Ride of the Month Challenge!
1 - 7 of 7 Posts

·
Registered
Joined
·
15 Posts
Discussion Starter · #1 ·
Would like to see some opinions on a duel battery set up in TJ. Don't seem to be much room in there. My jeep is all stock under the hood. Thanks for any information,
Ron
 

·
Registered
Joined
·
3,547 Posts
Driver side there is a battery tray. But why do you want dual batteries?

Unless you have ABS then that tray is already being used.
 

·
Knows a couple things...
Joined
·
49,623 Posts
Dual batteries seem like they'd be a cool thing to have but in reality, they are not needed by most of us, even those of us who use our winches on a regular basis. Physically, the only way to get dual batteries mounted is to stack them on top of each other laying on their sides where the single battery is mounted now. That requires a sealed AGM battery like a Sears Diehard Platinum P4 or Odyssey P1200 If you have a/c, that would require an a/c shop to modify the a/c lines by cutting, moving, and brazing/ressoldering the lines back together.

Electrically speaking, dual batteries causes a major challenge to make them work automatically as most potential dual battery users envision. A simple dual battery rectifier-based battery splitter like is used on RVs doesn't play well with the TJ's charging system, in that it won't be able to tell when the batteries are charged as would be needed to prevent continually overcharing them. Other dual battery setups that use relays etc. are have their own issues that make them difficult to manage and get working properly.

The best way to get dual batteries working that isn't expensive is via a simple mechanical marine battery switch that simply selects between Battery A, Battery B, or Both. But even that requires the batteries be virtually identical to each other in terms of brand, type, and even their age for when the switch is in the Both position. If the batteries were not identical, they would just create problems between each other when the battery switch was in the Both position.

If I were to ever go with dual batteries for my winch-equipped Jeep, and I wouldn't, I'd go for two good batteries like the above mentioned Odyssey P1200 or Diehard Platinum P4 which is essentially the same as the Odyssey P1200 but is less $$$, and a good heavy duty marine battery switch.

My personal choice is a single Diehard Platinum P4 which is a shock & vibration resistant battery that holds to pretty much everything you can throw at it. And in 15 years of offroading TJs with winches, I've yet to have a dead battery on the trail... even after repeated winching sessions, some of which happening when I couldn't even start the engine which meant the winch was running of just my single battery. No jump start was needed afterward. No you can't do that for an extended winching session but I was able to run the winch long enough to get my Jeep off the trail each time yet start the engine once I fixed the problem without needing a jump start. So for most of us, a single good heavy duty battery is all that is needed... and a little proper battery management kept in mind, plus a good set of jumper cables for just in case. :p
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #4 ·
Well, my thinking was that I could have one in use and one isolated but kept charged that I could switch to if one went dead for what ever reason.
 

·
Registered
Joined
·
451 Posts
I have had a dual battery setup such as Jerry described since 2004, switching two Optima Yellowtop Group 34 batteries (top post only, as they lay on their sides). I use a "Mean Green" battery tray to hold them, and that did NOT require any A/C changes (the Kilby dual battery tray does).

I actually use TWO of the switches Jerry describes, (B1/B2/Both/Off). One manages all the stock Jeep loads, the other manages the mods I have added (winch, lights, inverters, etc.). My exact need was to be able to switch the auxillary loads onto one battery, allowing me to run a refrigerator overnight and save one battery for starting the Jeep. I do have and use a diode isolator for charging, as it does so automaticly with no thought on my part - other than I do not switch either battery switch into the "Both" position while one is fully charged and one is discharged, knowing that would cause sparks.

I use the classic "Boston Whaler" dual battery/dual engine factory schematic:

http://continuouswave.com/whaler/reference/dualBattery.html

Where "To Breaker Panel" goes to the alternator, "Port Engine" is the stock Jeep loads (starter, fuse/relay panel, ignition) and "Starboard Engine" is the Auxillary loads (winch, lights, inverters, etc).



I use two of these for switches, and 2-gauge wire for batteries and winch, and upgraded from stock 6-gauge to 4-gauge wire for starter, alternator, fuse panels (I have one extra fuse panel in the glovebox, and one in the Add-A-Trunk), and diode rectifier (aka "Dual battery Diode Isolator").
 

·
Registered
Joined
·
1,044 Posts
RonaldL said:
Well, my thinking was that I could have one in use and one isolated but kept charged that I could switch to if one went dead for what ever reason.
why not just have one good battery and buy a booster pack? dual batteries is a tough project, and unless you have a purpose for it, running a fridge or heater overnight while your asleep, why bother? ive had the same thought and as jerry described its easier to just have one battery.
 

·
Registered
Joined
·
681 Posts
I thought about a dual battery setup for camping, but then I installed a Viper remote start system that has the smart start feature; I have it set so that if the battery drops below 11 volts, the Jeep starts itself and runs for 12 minutes. I have my power inverter wired directly to my battery, so I don't need to keep the keys in the ignition - once the battery drops too low the Jeep starts up. This works fine for running a heater at night or a boombox for music around the campsite. The first time the Jeep started itself while I was sleeping scared me a bit, but I got used to it and usually don't even wake up anymore.
 
1 - 7 of 7 Posts
Top