Dual Battery Question

[starscreamer]

I have installed a second battery under the hood. I have a Battery Relay (PAC-200) between them. I need a remote/Acc signal to activate the relay. Is the control wire on the alternator a suitable signal for this purpose? If not, are their other good sources of Acc signals on the passenger side(opposite fuse/relay) box. I would really perfer to have the source on the passenger side, because that's where the relay is. Also the battery runs are across the front, and I used 4/0 flex cable (yes 4/0 not 4 AWG), so there's not much room for another run. I have a 1998 Tahoe.

Thanks,
Starscreamer

 

[qlc1964]

no - thats not a good place for acc you need to probe the wires under the dash

and find the wire thats hot only with the ign turned foward like your going to start it.

i don't think you want put the trigger wire on acc because if you have it in acc you will drain both batts with the seloniod engaged listening to your system .

you only want it engaged when it's running so it will be charging both batts.

try and find a thick yellow or purple wire they won't light up the tester in the acc
positoin but will light up in the on/ start position plus with the truck running.

hoped i help you.

 

[jwpotts0413]

why not just toss the relay and wire them parallel?

 

[jwpotts0413]

or you could use the power that engages the starter solenoid if u wanna keep the relay

 

[qlc1964]

the batts will drain each other while the truck is parked which will shorten the life
of them.
the relay will disconect the batts from each other when the truck is parked.

my reply last night didn't post

 

[JKmotorsports]

You need to hook the relay up to an ignition source. An accessory wire will trigger the relay and close the loop anytime the key is in any position other than off. This will defeat the purpose of isolating one from the other if you want to keep one battery isolated for starting purposes. Using an ignition wire will only trigger the relay while the key is in the run position. This way, both batterires will charge while the engine is running, but only one will power your aftermarket accessories while in the accessory position and keep the other battery from draining so you can still start the vehicle afterwards. If you look at the harness going into the fusebox, pink is usually ignition source.

 

[starscreamer]

Thanks for the advice. I will try to find one in the fuse box harness.