I have a cordless drill from DeWalt that I got from a clearance sale a while
back I think for something like $129 and it included two batteries and
charger.

Now the batteries are charging up but draining very fast. I went and looked
at the new ones and they go for $70 a piece. WOW! $70 for a new
replacement 12V battery?

Is there a way to fix this instead of getting new ones?

I guess it's because I charged them before they were fully drained, or that
I left them on the charger too long after they were fully charged? or just
they go bad after two years?

Or is there a reliable online source to get good "used" or reconditioned
batteries?

Thanks,

MC