4183jose

need help on denali.I have a battery connected to the aux post 1 on fuse box and it blows the 40amp fuse as soon as I connect it.The battery is a new optima yellow top.I disconected everything except battery and it still blows.I tried charging the battery on my slow charger, but maybe the charger is no good.am I doin this wrong or what?

MDTAHOE

Do you have one battery hooked up normal and one hooked to the fuse box?

4183jose

yes.got one normal and the other to post 1 on fuse box.It shouldnt blow the fuse right?
Thats the concept isn't it?to charge aux battery.Got ground off of engine block.I took battery to get charged,I would not think new battery is shorted out.

MDTAHOE

Did it ever work? Who wired it?

4183jose

I bought it used and it had amps which they took out,and it was wired this way.The battery was dead so I put in the optima and it was working good,until it started blowing the fuses.Took the battery back to autozone and charged 12hrs.They tested the batt and told me it was good,but only took in 65% charge.The manager insisted I had a short in my vehicle.I tried explaining to him,but its like beating a dead dog.Anyways he swapped it for a new one I threw it in,put a fuse in there and it was good. I'll run it like that and see what happens.Do you think this setup would damage a battery?

73shark

4183jose: Welcome to the forum.

I've read that you shouldn't discharge a AGM battery below 45% charge. You may have ruined the Optima.

HOE-N-IT

I'm confused as to how you are hooking it up. Mabe this is some way to hook up dual batteries that I don't know about. I have a 2011 Tahoe and I recently hooked up dual batteries in parallel without an isolator just like they come on the police Tahoe with the dual battery option. I used the same GM cables that come on the police Tahoe and the positive cable connects to the starter on the same lug as the main battery and the negative cable is bolted to the motor. I got these ACDelco cables on Amazon.com for way cheaper than a dealer. They will work on any NNBS truck.

SWHouston

Try running/clamping Jumpers between the two Batteries, before you actually make the permanent connection.

- to - and + to +.

I think you have a Voltage Differential, the jumpers should equalize that and allow a connection.

4183jose

Well the aux charges good and when the main battery dies you still have the charged one that you can jump to.so far Im running subs with amp and 800 watt inverter and holding good.aux battery not tapped in to vehicle electrical so no dimming lights when my subs are pounding hard. So far so good will watch it closely for next few weeks.

SWHouston

You know there's a switch/relay that separates your 2nd battery/sound system away from the main starting battery. It lets you run your sound sys battery down, and still preserves the start battery. Then when you crank back up, it automatically brings the sound battery back into the system, charges it, and you're ready to go again.

I used to have a link for it, but I had a computer crash and lost a lot of info.