2006blackmustang

My mustang goes through the following cycle:
Although the car's interior lights work, there is not enough battery power for the car to start. There is a clicking noise when I turn the key - but that's it.

Then, I jumpstart the battery and the car starts and operates just fine.

Then I stop the car/turn off ignition, wait up to a few minutes before attempting to restart, and then car will usually not restart...until I re-jumpstart it.

Other facts:

Whenever I jumpstart the car, the car radio turns on even though it is always turned off before I kill the ignition. The lights and AC are always turned off as well before killing the ignition.

I usually only drive the car once a week at most.

The car has an added 500 watt amp and two subwoofers with a cable attached to the positive node of the battery.

The car is supercharged.

The battery has checked fine when I have it tested at Autozone.

What should I do to resolve this issue?

Thanks.

BruceH

......

Nuke

Is it the stock MotorCrap battery? If you use the search feature you'll find dozens of threads regarding battery issues and also alternator issues. I'd have the alternator checked also. Low voltage wreaks havoc on our electronics which may explain the radio coming on when you get a jumpstart.

Is the amp connected directly to the battery? From your post and w/o additional info, it almost sounds as if your amp is "on" 24/7.

2006blackmustang

The amp and cable to the battery were installed about a year before this started happening. I already had the Ford stock battery replaced by the dealership when this first started. I have an Autozone battery now (third battery).

Can I go to a mechanic and ask them to test the alternator by itself?

Also, can't I just detatch all cables to the positive node on the battery when the car is just sitting in the garage?

Thanks. I'll search the forums too.

2006blackmustang

Yes, I am assuming the amp is directly connected to the battery. There is definitely an additional cable resulting from the installation of the amp/subwoofer that was added to the normal attachments to the positive node.

Nuke

Most shops should be able to test the alternator. If nothing else, you'll be able to rule that out.

Disconnecting the positive lead to the battery every time you finish a drive is a rather uneccessary activity. You could attach a tender every time but that's still a pain. I'd fix the problem permanently. Consider finding another terminal point that's dead with the ignition off or install a control relay as BruceH mentioned. The amps in the Shaker 500's were known to remain on with the ignition off and was the cause for many a dead battery. If your amp is staying on then I'll say you found the culprit.

DreamerGT

You say you only drive it once a week. How long of a drive would it be? My car was doing the same thing as yours. I took it to autozone and it checked out good so I took it out for a nice long drive about 45 minutes or so. Turned it off for 20 minutes and started it back up and it started strong. Maybe you just need to drive it longer and let the alternator fully charge the battery.

Diabolical!

I had the same issues a while back. Switched to an optima red top and never had another slow startup, even when the car sits for over a month.

2006blackmustang

I only drive it for about 20-30 minutes at a time. But I've always done that. I am taking it to a mechanic today to check the alternator.

stealth_GT

parasitic drain off the amp perhaps?

(O_o)?