I have a 1977 Corvette with a stereo that I built in order to be able to hear music at normal highway speeds with the T-tops off. So I have a 250 watt amp powering a bass box behind the seats, a 150 watt amp powering 6 inch 3-ways in the kick panels, and a Kenwood head unit powering tweeters in the dash. It sounds pretty good, considering it was put together by a computer geek.

I don't drive the car all the time, mostly on weekends. However, I think that I have to put the battery on the charger much more often than I would prefer. This happened with the previous battery too.

I was wondering if a higher output alternator would help. Barring that, would the installation of a larger wire from the alternator output fix the problem?

 

You have a bigger problem somewhere. IMO, even a 1977 altenator should be able to handle the extra load of 500 watts. I'm running close to 2,000 watts rms with my stock C5 altenator. Of coarse the C5 has a much bigger alt than a C3 but not THAT much.
Are you sure all the componets shut off when the car is turned off?? A amp will drain a battery even in idle mode. The only drain a aftermarket system like your's is the head-units memory and that is so so little. How old is the battery? I would suggest taking your vette down to a Autozone or Advance Auto and have them check the battery and altenator. They will do this service for free and takes very little time.
Larger wire will help the overall electric system but IMO it is not your problem. An upgrade to 4-guage wire will be more than adequate. You should run the new wire from the negitive battery post to the chassis ground, the battery positive post to the altenator, the battery positive post to the amplifiers, and the amplifiers ground to the chassis ground. Good luck and let us know what you find

 

I found the problem last weekend. It was indeed one of the amps. When I built the stereo, I used an old amp that had been in 2 previous cars, and it was a cheap swap meet special even back in the day. Well, this amp wasn't shutting itself off like it was supposed to do when it gets the signal from the head unit. Still, 15 years of service out of a cheap amp isn't bad at all.

How I located the problem: I have a dedicated battery lead going to both amps via a fuse box. I pulled this lead off the battery and there was continuity to ground. I then pulled each fuse in the box until the meter showed no continuity. That fuse has been temporarily removed.

So now I have an excuse to update my stereo... I figure that I'll probably move the current "big" amp to the other side of the car and put in an even "bigger" amp to power the woofers. In the meantime, I can limp along without that amp... it powers the 6 inch 3-ways in the kick panels. I still have bass and the 4x6 plate speakers in the dash.

The only thing holding me back is the "while I'm in there" factor... I'm going to want to replace the icky old carpet, stain the plywood panels on which the amps are mounted so they blend in with my Dark Brown interior, and God knows what else I'll decide needs done while it's apart. Naah, I think I'll just drive it this summer as is.

 

you know what i'm thinking!

 

OMG....I was right....someone put this down on their calendar

 

Uh-oh... if I want to do it over the 4th of July weekend, I'd better order my new amp this week!

I need to find the paperwork on the one that still works and find out how powerful it is. If I remember correctly, it's 100 or 120W/ch into 4 ohms. (The dead one was 60 W/ch.) I figure a 200 W/ch amp would be a welcome step up in terms of bass, and amps in that class will still fit in my preferred location (the new amp can't be more than 15 inches along its long axis)... basically I built two small shelves that sit in the rear compartment above the wheel wells, so the cargo compartment is almost all usable (when the bass box isn't in it ). It's a sweet setup, but a bear whenever I have to work on it.

 

Already there. I did that when I installed the amps. Ran the chassis ground to the frame when I discovered that a body ground wasn't good enough, and the power lead is 4 gauge direct from Lowe's.

 

heh.. i was actually thinking that you should put a computer in yours... you know: computer geek + excuse for a new system= car computer