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I've been working on this problem for months. 68 Ford F250, 390. Constantly having to charge battery, or jump it off. Battery, alt, volt regulator, solenoid - all good.
When it won't start and have to charge battery, battery is really low.
I can usually jump it off with no problem whatsoever. Could this mean a bad battery ground?
Also, what could be draining the battery?
I know it's probably something simple, but I just can't figure it out.
if you are sure that the alt. is good then i would make sure all the connections are good and there is not any corrosion around the battery terminals. if this is not it get back with us i'm sure we can find an answer.
I had a problem like this before. My truck used to draw almost 12 volts just sitting there (I don't have a radio or clock). I used to have to pull the cable off when I parked it. I did a little probing and found that the alternator regulator (located next to the radiator, near the battery) was the culprit. I replaced that and my problems were gone! It might be worth looking into that. If you have a volt - ohm meter, try pulling the positive cable off the battery (or solenoid). Stick one meter probe to the cable and the other to the terminal (do this with the truck off!). Assuming there is nothing else that draws when the truck is off (radio, clock, etc)... you will be able to see if something is drawing power. I did this, and then pulled the cable off the regulator - power stopped drawing! I replaced this and retested - problem gone! Might be worth trying..
And a bad ground can cause problems too.. it can't hurt to clean your connections up!
That is my problem - something is draining the battery. If "draining" means the voltage is still good but amperage is low.
I have changed the regulator also while tracking down this problem.
Did you just unhook the posive lead when you weren't driving??
Draining means something is drawing current from the battery. Basically, voltage is the speed of the electricity. Current is the amount flowing. If you have a device drawing power, it is not drawing voltage. It is drawing current which is measured in amps.
But the meter test mentioned will work otherwise. If you use the current metering position, and have the leads in series, you can measure the current in amps. You can pull fuses to circuits until you find the one that is the problem. I was thinking bum alternator first, but you say it's been checked...Bad diodes can cause that. MK
I had heard something about diodes in the alternator once. Will the alt still test good with bad diodes??
I'm thinking about trying to unhook the battery while not driving it to see if the problem stays or goes away, then I could eliminate some of the ideas???
I'm trying to eliminate what is not wrong now. I fully charged the battery, it started right up with no problem. Turned it off, checked the battery, and it was at a 75% charge. Is that normal, or did that just give me a clue as to what the problem is?
It shouldn't since there's no battery, correct? There is a wire going to the input and one coming from the output. One wire has an inline fuse. Not sure where they go, I lose them when tracing. Also, a crossconnect wire from S terminal of solenoid hooked to battery to I terminal of other solenoid.