Originally Posted by beechfield
I tested the battery, it has enough voltage across it to power a small lightbulb but somewhat inconsistently.
Then you should heed this advice.
Originally Posted by tsac
A new battery should correct the problem. Avoid draining it past 20%
Originally Posted by Dubdub
Have you let the battery run down past 20% more than a few times? If so, you may have damaged the battery.
If that fails, try a new OEM battery made for your specific model.