The battery has been damaged by letting it go too far below 12v for too long.
It needs replacing. When you fit, or before you fit the new one, make sure it is fully charged.
If the vehicle will only see occasional use, then use a battery tender or charger to keep the battery topped up.
Got a 1998 Toyota Camry that has an empty battery and am wondering what the best course of action is.
Why is it empty?
Is it empty because the battery is old and dying and won't hold capacity?
Or is it empty because you yesterday forgot the lights on?
The correct course of action depends on the reason for it being empty.
If the battery is good but you just ...
If the battery is completely flat, then it will have been severely degraded in capacity. Lead acid batteries don’t hold their full charge after going completely flat, so it would be best to replace the battery and make sure this doesn’t happen again.
However if you want to try to charge it, it will be less stressful for the battery to be slowly charged by a ...