Battery discharge
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From: Santa fe
Battery discharge
I have a 78 bronco, with a 351 C. The battery goes dead after running it for a long time. I have a 700 CCA battery in. I just replaced the alternator, and I still cannot figure this out. I get a reading of 12.8 on the battery terminals, and across the starter solenoid. I dont know of other places to check, and its killing me. I cant go anywhere until I find out what is going on with this thing.
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From: SE Texas
How old is the battery? Most will kick the bucket at 2yrs. old, evne the 60 mo. ones. Even a younger one can have internal problems, and will not hold a charge. I'm on my second InterState battery in 2 yrs, and have the same problem with it not holding a charge. Time for a different one, I guess.
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From: SE Texas
Are you sure the battery is the problem, and not the starter or ignition module??? If it won't start after a long drive, it colud be the starter is getting too hot to operate, especially if you have headers. A heat shield on the starter may help it out. In my case, I can jump start the Bronco, and it's fine as long as I drive it everyday. Let it sit a few days, and no start=dead battery. Alternator checks out, charging like it should. No electrical parts draining the battery with the motor turned off, either.
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From: Santa fe
Its a new starter, I had it replaced by a friend that works at a dealer, he even does house calls on the side. Even if the engine, and all parts have had a Chance to cool, it still does it. I dont know what the battery should read when the engine is running, but 12.8 seems a bit low. I also have a new starter solenoid in there as well. I dont know what the ignition part is your talking about, I'm a real n00b when it comes to working on cars.
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Try doing a search for "ignition module". I would just check the obvious, like the condition of the battery cables and any ground wires. If you can, check the battery and alternator both running the motor alone, and with any accessories on, like A\C, stereo, lights. If you have a large draw, like more than 1v difference, then there is a wiring problem. I've checked mine and so far have not found anything like this.
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From: Santa fe
OK, so I fired it up and did a check. With just the motor, it was 12.81, Lights on 12.69, lights and vent on 12.56. I'm thinking now that I have a wiring problem. Does anyone know a starting point for the wiring for this?
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From: SE Texas
That sounds normal to me, no major draw. Start from the battery and starter solenoid, then trace each wire as best as you can back to the cab. Use your tester to find any shorts. How do those battery cables look? If they are old, they can rust on the inside and look fine. I don't think that's your problem, but still check'em. Look for any mysterious black boxxes on the firewall or fender that have wires going to them connected to the coil. Even on the 78, you should have a voltage regulator somewhere for the alternator. Good Luck!!! I'll check in later tonight to see what you found!!!
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