In the course of charging, the Nikon EN-EL2 multi-charger become hot, so you'd better using your multi-charger in ventilative place.

The light shows "Red" when you insert your battery into charger, and the battery plug light turns into "Green" when the battery is fully charged.

When charging, do not use metal object touch the EN-EL2 battery charger's connect metal , or it may be short.

When your EN-EL2 battery charger is working, it can disturb your radio and TV. So take Nikon EN-EL2 multi-charger away from them.

Don't disassemble or attempt to open the battery charger.

In the end you must avoid setting your Nikon EN-EL2 battery charger in the following place:
(1). The place with very high humidity and high temperature
(2). Strong vibrative place
(3). Dusty place

See more battery tips at Battery Tips and Battery FAQs.