What kinds of battery? That may make a big difference.
I took a VTC4 down to 2.14 once and it has lived a happy life ever since, only now starting to get a little shorter on its ability to perform after two years in rotation.
As was mentioned, verify it on a MM, just to make sure your charger is not telling lies. If that`s OK, it should take a long time to reach a full charge, like 4-6 hours depending on which charger you use. If it reaches full charge in an hour or two, or less, its surely toast.
Then it will come down to its ability to perform, if it only last`s for minutes, or one good hit, its toast.
And of course, if the VS has a real problem, that should be solved before it costs you a lot of
batteries.