• Similar to NiCd but no toxic cadmium.

• Zinc is less expensive than cadmium.

• The nickel and zinc can be fully recycled.

• Even lower internal resistance than NiCd.

• Higher than normal voltage, nominal 1.6V per cell.

• Can be recharged many times (500-600) if treated gently.

• Fast recharge.

• Reduced life (100-200 cycles) if heavily discharged - one manufacturer recommends using 80% discharge for longest life.

• Moderate self discharge rate.

• Careful handling required because of high current output - don't carry in your pocket, especially with a set of car keys.

• Charging can be tricky - for 100% charge one manufacturer suggests using 2.5C for one hour, pause 5 minutes, then use constant voltage at 2.05V.

• Actually first patented in 1901 but the tendency for the cathodes to break down due to dendrite formation have kept them off the shelves.