A new Rechargeable Battery comes in a discharged condition and must be charged before use (refer to the devices manual for charging instructions). Rechargeable batteries undergo self-discharging when left unused. Always store battery pack in a fully charged staged for storage.When charging for the first time the device may indicate that charging is complete after just 10 or 15 minutes. This is a normal phenomenon with rechargeable batteries. Remove the batteries from the device, reinsert it and repeat the charging procedure. If the battery will not be in use for a month or longer, I recommend that battery be removed from the device and stored in a cool, dry, clean place.
Invest in a good charger. NiMH batteries should not be charged in a NiCad charger, unless the charger is specifically made for both chemistries. There are cheap chargers and there are expensive chargers. Make sure the charger you get has good reviews and is well made. Chargers with micro-controller chips are usually the best choice. Be sure to store your Rechargeable Battery properly. Do not leave your batteries in a hot car, or in humid conditions. The best storage conditions are a cool, dry place. The refrigerator is fine if you stick in a packet of silica gel with your battery in a sealed bag to keep them dry. It is a good idea to charge your NiCad or NiMH batteries fully before use if they have been in storage.