A power charge controller is a smart piece of electronic device which has been designed to do a few tasks: to receive the power from a solar panel power system or a wind turbine and to charge a battery bank. It can also equivalate the the power in each battery in within a battery bank and to stop charging the batteries when they are fully charged.
A power charge controller has the capability to receive the power produced by a solar panel or a wind turbine and charge a battery or a battery bank.
A second feature is that it will only allow the current to travel one way from panels or wind turbine to the batteries and not the other way so your solar panels or wind turbine doesn't get damaged.
A third handy feature is that it stops the power from going in to the batteries once they are full so will not overcharge or damage them. Some power charge controllers have some extra features. Some have the capability, once the battery bank is full, to send the power to a load not to have any loss or waste.
Another feature some have is a temperature control. Some have an accessory which gets plugged into the charge controller with a long wire and a temperature sensor at the other end. The sensor must be attached to the side of your battery or between batteries in within your battery bank. What this does from here, it reads your battery temperature and keeps your charge controller updated about it. If the temperature goes above a factory set temperature point, the charge controller will turn itself off to protect the batteries in case there is a fault in within your battery bank.
Another little feature can be an LCD which can tell your battery bank's voltage, the amount of watts or amps being sent to your battery. I tried a few different brands in the past but most advanced brand that I had in hand and I'm currently using in Xantrex. It has all the above mentioned features. Some other people's favorite brand is Sunnyboy. There are lots of brands to choose from.