I believe Gale is talking about the low cost simple NiCd analog chargers I was talking about in post #55.
Most of those would not terminate charging, once the NiCd pack was full. Of that type, the ones that gave a reasonable (for the day) re-charge time, would usually end up frying the NiCd pack if left connected for days/weeks. The work-around for those was to use a lamp timer on the charger, only programmed for one charge cycle of 8-14 hours, or whatever was needed.
For safety reasons, no sane manufacturer will release a Lithium product without a really sophisticated charger supplied - hence, you can't overcharge a lithium pack. NiCd batteries can take quite a bit of overcharge abuse, so their low end chargers were cost reduced accordingly.
Rgds, D.