I'll recheck on that. But normally you store NiMH & NiCads fully charged. Especially NiMH, if they are left for any length of time fully discharged, they will not take a new charge. And NiMH are bad for self discharge, up to 5% or so a week, depending on conditions.

In any case, the battery is definitely NOT the problem, I have opened my old motor box and the battery is charged. But, I'll recheck the manual.