alt discharging my battery?

[70challengerdane]

well in a nutshell, i get a large voltage drop from the 12v terminal on the alt being hooked up. when my battery reads 12.8v, the car running with no alt drops it down to 12.3v. if i connect the alt again im down to 12.2v before ive ever put the key in. im a little confused. i had a spare alt so i tried a different one but i get the same result. i also get that result with a field ground (i think thats what you call them) test. im very confused.

i narrowed it down to just the wire on the alt terminal being the draw, made sure my alt was grounded as well as my voltage regulator, and my ammeter is showing relative results, it just seems as if something has a completely overtaxing draw when the alt is powered. does any have any ideas?

im still working on it but i thought id do some digging. so far nothing has come close. thanks for all your help!

 

[74 challenger]

you should check your wires and connections,bulkheads and clean them use some de electric grease on them. Did you put the jumper wire from main alt to starter relay on your car yet? This will take most of the load of off your wiring harness. There is a write up on this. The challenger is known to have problems with the charging system. Make sure you look at the main wires coming into the car at the fuse box under the dash. People have had their cars catch on fire do to the alt wiring. My challenger was so bad i bought another dash and engine harness. Mine was over charging. You could have a bad voltage regulator.

 

[70challengerdane]

thanks for the reply! i ended up getting a reman alt and that was in fact the problem so i guess i had two bad alts lol but not it doesnt really charge, just maintains 12.46 so im still gonna clean all the connections. also drove it down the street for the first time ever!!! brakes need to be rebled again though gotta pump twice to stop lol

 

[74 challenger]

dont forget to install that jumper wire-alt to starter relay- so you dont have any fire issues. Glad to hear you got to drive the car.