Solar chargers can charge lead acid or Ni-Cd battery banks up to capacity. For such type of solar chargers, generally intelligent charge controllers are used.
A battery charger is a device used to put energy into a secondary cell or (rechargeable) battery by forcing an electric current through it. The charge current depends upon the technology and capacity of the battery being charged. For example, the current that should be applied to recharge a 12 V car battery will be very different from the current for a mobile phone battery.