battery being drained

[oddiseeus]

greetings all,

ive got a 67 camaro that i run on the strip. i just changed out the alternator to a powermaster 100 amp. after changing out the alternator the battery
(3years old) lost its charge. i replaced it with an optima deep cycle 750cca battery. when i went to start the car 3 days later the new battery was dead. any ideas on what could be draining the battery? there is nothing hooked up to the battery other than the ignition and a fan. any ideas are appreciated.

thanks,

jamie

[John_Heard]

Well what I usually do is after getting the battery charged back up, watch to see if you have a spark when you hook the battery cables back up. If you do obviously something is draining the battery.

Take a brake light bulb and connect it between one of the battery posts and the cable and it will likely light it, the brighter it is the more drain you have on the system. Then start pulling fuses, see if the light goes out, if it does, you have isolated the circuit where the drain is at. If pulling fuses doesn't make the light go out, try unhooking the alternator. Sometimes a bad alternator will drain the battery, and you did say this started when you switched the alternator, so that is a likely problem area.

John

[ytnova]

Instead of using a bulb, try using a ammeter if one is available. Just make sure it is fused or can handle the potental power going through it. Any more than 200 milliamps and the battery will be dead ovenite. Try to shoot for less than 100 milli's. What the meter reads will also help you pinpoint what the problem is. Other than that, beyond is dead on, start puling fuses on at a time and go from there. Another trick is to use a small buzzer that only require about 100 milli's to make noise. Hook it up between a disconnected cable and the battery, then you don't have to keep looking at the bulb or meter, just keep pulling fuses or disconnecting stuff until the noise stops. Should be able to find something like that at radio shack or a electrical store. p.s. I always pull the battery disconnect when I get home from the track.

[nj]

if the only thing you did was change the alternator, I would look into the alternator itself. Make sure the new alternator is wire (hooked up) correctly. Also alternators have a diode in them. If by chance you hooked the alternator wrong or you arced out the alternator when installing it, you can short this diode. Once the diode blows it produce a short in the alternator an will slowly drain the battery.

[BBNova]

I had this same type of problem a while back. People watching me launch would see my taillights dim and sometimes even go out as soon as I would leave. I would get about 4 passes in and the car would lose its charge. At the time I was running one Optima red top in the trunk, a stock replacement alternator (mounted low), with an MSD 6AL ignition. I knew the MSD needed alot of power and I just thouht it was draining the battery. I put another red top in the trunk with the same result. The alternator was checked and showed good. I was angry at the money spent on good batteries and then having to forfeit because I couldn't make the call. I finally got fed up and had all new battery cables made with good ends to replace all the existing stuff. Come to find out, there were two tiny holes in the main cable running from the trunk up to the solenoid. I guess it was slowly draining the batteries to the frame. I don't think this is your problem, but this is good to anyone reading and is something that can be overlooked. Ever since the cables were changed the car starts like a champ everytime and even picked up some ET. The MSD loves the new cables!