Adding third battery questions.

[cem17]

I currently have a dual battery setup using a solenoid to separate batteries 1 and 2. I would like to add an additional battery to the main/starting bank. Is it as simple as adding a second battery and wiring it in parallel with a fuse at the new battery? Batteries would be identical, alternator upgraded, main battery and alternator cabling will be upgraded as well. Any issues with charging? The cable run will be about 8 feet, would 4 gauge be good? What size fuse? Is it ok not to isolate in this situation?

Any opinions or recommendations would be appreciated.
Thanks
-cem

05 Jeep Wrangler Unlimited

 

[rickc]

Hi Cem:

Why do you need so much house power for a Wrangler? Do you have or plan to install a winch?

Why not just get the biggest CCA battery that will fit your existing tray? It's usually only diesels that run two house batteries. If you need more to power your regular auxillary equipment, you may want to consider rewiring this stuff to run from your auxillary deep cycle battery.

Pairing-up two main 'house" batteries is as simple as connecting in parallel but the two should be identical and preferably physically together. Sounds like at 8' you are locating the extra one at the back. 4 gauge is the most common jump starter cable size and they are often around 10' long so 4 gauge should work fine.

My pair of house batteries are directly connected - no isolators or extra fuses. Where are you planning to locate #2? It's always best to keep the high amp equipment outside the firewall!

 

[762X39]

If you are going to add a second starting battery in parallel with your main battery, make sure it is the same size and age as the first battery or you will find that the older battery will shorten the life of the new battery.

 

[xcmountain80]

Wow I thought this was for a big rig or Unimog. But a wrangler? Don't worry I have though of this too, yea I think you just add it in parallel to your starting or your backup, as this is how I ran my dual setup until I got a National Luna system.


Aaron

 

[cem17]

Ya I've got the winch, lights, stereo, fridge, shower, computer, lcd, compressor...water faucet soon... Also, for work I use the jeep for powering my GPS base station and/or 35 watt radios. Plus its winter and I need light for horseshoes!

I just keep killing optimas. My 2nd battery is a batcap. Its good for starting but not much else. So I went out and got a couple of platinums.

Since it is so tight in the engine bay at this point, it will probably end up in my shelf behind the passenger seat. And add a simple disconnect in the engine bay in case I need to remove it.

I should fuse the remote battery, correct?

 

[xcmountain80]

Whichever battery is not connected to the winch should be fused.

Aaron

 

[ntsqd]

If you are going to pair two batteries together then addition to the warnings about same age, type, etc. be sure to connect both the (+) and the (-) posts of the two batteries directly together. Grounding each nearby is not good enough, run a (+) jumper cable and a (-) jumper cable - then ground them to where ever. Your goal is the lowest possible resistance between each pair of terminals. Any resistance in either connection will start the see-saw destructive self-discharging event.

I tried it first by just grounding both near to each and it cost me a pair of Exide Spiral cells. BT, DT and learned from it.

 

[Antichrist]

I wouldn't add a second to the starting battery, which realistically should just be used for starting/normal vehicle operation. All the accessories you list should be powered off an auxiliary deep cycle, such as the Platinum PM-1. If you find the PM-1 isn't enough to power them, add a second auxiliary PM-1.
This is really personal preference, but I always wire them so there's no chance of killing my starting battery. I always want to get home. Anything not required for getting me home goes on the auxiliary battery.

Running just a winch at 350amps would need #2 for an 8' run if you want to keep below 0.5v drop, which you should. #1 for a 400amp load. I would size the cable for that in the event your first one dies and you have to pull it from the circuit and run everything off the second one.