My problem started last night. let me begin with my set up I have a seperate battery in the back its an optima yellow top it is connected to a capacitor and running three amps 1 for my highs, 1 for my mids, and 1 running my 3 subs. my alternator is connected to both my car which also runs my radio and audio battery that runs my system. I have been running this setup for 2 years now. well last night i turned on my car and my radio would turn on but my amps wouldn't. When i checked my capacitor it read that my yellow top was at 7.2. when i drove to my chicks house it went up to only 8.2. then when i turned my car off a liitle bit after it went back down to 7.2. My reading for my other battery (car battery) always stayed at about 13.5. My chicks dad checked the batteries and the meter read read both as low batteries. This morning nothing changed. So i disconnected the ground wire from my yellow top audio battery and started the car. that is when i noticed that my car battery had taken a second or two to go up to 13.5 i drove it for about 30 seconds to my cousins house down the street and the meter by then was between about 12.8 and 13. it really wasn't steady at just one spot, but when i turned on my lights to check if it would change the reading it did as normal that reading went up and then back down when i turned them off just like normal. I have never changed my alternator and my Z28 is a 00.

 

First thing to check the fuse going to the seperate battery, then the ground on the second battery. I bet the ground is bad on the second batttery. But it could be that fuse from the first battery to the second. When the radio is off, that's why the voltage goes back up. I bet the second battery isn't getting the charge. I had a similar problem, but it was the ground. But either one will cause it not to charge.

 

I changed my car battery cuz it was bad but it is still doing the same thing. I have checked all of my grounds and fuses. I am going to check my alternator today, but someone told me that they had the same problem and that it ended up being that the capacitor was bad and it was draining his battery. thanx for the response.

 

It seems to be more than just the cap. Even with the car running, the cap shouldn't be outdraining what the alternator can put out. Does the car run fine? Normally, if it's the alternator, there's a cluster light telling you there's a charging problem. Make sure the light isn't blown by pre-testing bulbs before you start it up. But looks like you have a handle on things. And Your Welcome, any input is sometimes better than nothing. If anything, it points you in the right direction. Good luck.