[EricH]

First off, are your current battery chargers showing a green light to say that the batteries are charged?

Second, how fast do the batteries run down?

Third (optional), have you exposed your batteries to higher than normal heat recently?

It sounds like you are getting a surface charge on your batteries. They act fully charged, but are not. If the answer to at least the first two questions is yes, you may need to mark the batteries in question as unfit for competition, then get them fully tested. (If the answer to the third question is also yes, don't bother with the testing; of course, this is at the team's option.)

This happened to us once under the circumstances above.