Severe Battery Drain


Asked by KentuckyGuitarPicker... Aug 20, 2019 at 12:22 AM about the 1982 Ford F-100 Standard Cab LB

Question type: Maintenance & Repair

I'm trying to resurrect and make roadworthy a 1982
Ford F100 that had sat unstarted/undriven for
about a year. Bought and installed a new battery
and poured some fresh gas into the tank. With a
little priming on the carb it started and ran like a
champ. About two weeks in, my brand new battery
went dead. Charged it and started the truck and
took it for about a 10min test drive around my
property. Came back to the house, shut it off and
went inside long enough to get a cold drink (about
2 minutes) and came back and the battery was
stone dead. Cannot keep it charged no matter
what. Can start the truck from a battery charger, it
will run with the cables off the battery, even tried
disconnecting the cables before shutting it off,
battery will hold a charge for as long as I want
while disconnected, but will be sapped dead before
I can get to the drivers seat after reconnecting the
cables. Got any good ideas where to look first?

2 Answers


Yes, sir, I'm certain the battery is going totally dead. I replaced the terminals myself and they're tight and corrosion free. And the reason I ran the truck with the cables off was momentarily to see if the alternator was functioning and in hopes to keep charge in the battery so that I could use it at a later date as I have observed it being almost instantly drained when the truck is shut off. I guess what I was mostly wanting clues for, is where could there be a short/ground so severe as to sap a fully charged battery in like 15 seconds? I've dealt with drains/grounds that would kill a battery in a couple days or some such but never seconds. Thanks.

2 people found this helpful.

Well, I considered the bad diode idea, but would this apply when the truck has an external regulator? I've changed that part, btw. And I'm actually on my second battery with no change in the symptoms. Thanks!

1 people found this helpful.

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