[BlenderHead]

What I want to know, is how low the voltage in a battery can get before the battery is no longer chargeable. I know that if you let the voltage get too low, it messes up the chemistry in the acid and the battery can no longer accept a charge.
my truck, with the old battery (2yrs) was left for a week or two without being started and the voltage drained down to about 3 volts. not sure why, had never done that before, maybe a parasitic draw or something,
so got a new battery (old one had 3 yr warrantee) seemed fine, sat for a week, voltage was down to 9 volts.
although i still need to find the cause of the voltage drain, i'm wondering if this new battery, which was drained down to 9 volts, is still usable and still chargeable. or is 9 volts too low for it to be revived?
i'm not sure what the store will say if i try to exchange a battery i just exchanged 2 weeks ago.
anyway, thanks very much.

[JeffB]

Since it is new it should charge up,until you find your drain I would disconnect the + cable when not in use or add the connection terminal that has a "shut off" knob on it.There is a good video on youtube about tracking a current drain.

[EOD Guy]

Internal regulator? I'd get your alt checked out..... sounds like your regulator might have taken a dump

[T-bucket23]

It should be ok. I would not let it charge off the alternator. Connect it to a battery charger and put a full slow charge into it. 9v is not that low.
Lead acid batteries do not like constant cycling between dead and fully charged however so make sure you get the issue fixed.

[BlenderHead]

Originally Posted by EOD Guy

Internal regulator? I'd get your alt checked out..... sounds like your regulator might have taken a dump

actually its an external regulator, its an old mopar.