with the backup fuse in my stereo works but causes my battery to die when car is off after a few days. With the fuse out my battery stays charged but have no radio etc. I was wondering if any one else has this prob or knows what could be causing the drain when the fuse is in. When the fuse is in and the car is off. My amps and stereo are not on and can not be turned on. So it is not those. There is an alarm on the car as well.

 

Here a couple of solutions.

1. Your battery is crap...or rather has a "dead" cell. It will show voltage
on a meter..but really wont hold a charge for long periods of time. Any
parasitic draw ( alarm led/radio clock memory) will "kill" it but if you
jump it off it its "good as new".

2. You have a severe draw on the car electrical system..ie a relay has
latched open or the radio is wired so that its still on..which can cause
that battery to be drained.

In either case have the system checked out... hope this helps.

 

Is the alarm wired to the fuse also? [will the alarm work if the fuse is out?]

You need to isolate what is drawing the power, if this is the fuse in fuse box under hood, it also powers other things in the car, and just because the stereo is off and you cant turn amp on doesn't mean the amp can't draw power.

Try this, disconnect amp power wire,[or pull fuse] at batt., if batt. still discharges, its not the amp,now unplug the HU, if batt. still discharges, its not the the stereo, then the alarm if its wired to fuse also.

You can do this test in a few min. with a multimeter, set to DC amps, disconnect batt. posative and put meter between batt. and cable, make sure every thing is off in car, [dont forget domelight, trunk/hatch light, turn off or close doors] your amp draw should be no more then .025 or less, if more, unplug things one at a time till it drops below this, [that means anything that is powered by the fuse that you pull, the amp can be isolated by pulling trigger wire off amp.

hope this helps 94

 

Thanks for the input, I forgot to mention that the batt under the hood is a brand new optima yellow top. I then ran 0awg to an isolator mounted under the hood. Which goes back with more 0awg to another opitima red top in the trunk. The isolator is fused both ways. I always some how come up with the idea that the isolator is the prob. Most likely b/c I am not to expierienced with them. If anyone has used the Wrangler MBC series let me know. I guess I will start disconnecting things one at a time to start testing

 

Did you upgrade your alternator after adding the batteries?