Fangpusun PWM and MPPT Solar charge controller can protect the battery well in the PV System. It has Overcharge protection, Deep discharge protection, Reverse polarity protection of the load, module and battery,Automatic electric fuse, Short circuit protection of load and module and so on. EG.Fangpusun Solar charge controller, or Solar regulator is basically a voltage and/or current regulator to keep batteries from overcharging. It regulates the voltage and current coming from the solar panels going to the battery. Most "12 volt" panels put out about 16 to 20 volts, so if there is no regulation the batteries will be damaged from overcharging. Most batteries need around 14 to 14.5 volts to get fully charged.