I recently bought a project car (1964 International pickup) I found it with a dead battery. I replaced it with a new one, and the car started. I disconnected the + terminal and left it disconnected for about a week while I waited for a replacement clutch cylinder. When I hooked it back up, the new battery was dead. (Reads about .4 volts) The negative cable was attached the whole time, but it was otherwise isolated. What might cause this?
Thanks!
Unless the battery made contact to some grounded metal above the post it looks like you got a defective battery.
I would guess a defective battery, but remember you should have fully charged the battery. The don’t come with a full charge. Just starting it once and not recharging it can damage a battery.
I recharged the battery for about 8 hours and the voltage read 10.45. I disconnected the charger, planning to finish charging the next day. The next morning when I checked it again, it read 0.14 Volts. I’m guessing it’s defective. Thanks.
I had the same problem with a new battery. When it discharges without having a load, it is shorted internally. The battery should still be on the replacement rather than pro-rated part of the warranty.