Find out more about Solar Charge Controllers
A Solar Charge Controller (or Regulator) is a device which protects the batteries in a solar electric system from being overcharged or being over-discharged. Overcharged batteries have a much shorter life time than well cared for batteries since the electolyte is boiled off as gas and lost. Overly discharged (i.e. flat) lead acid batteries are damaged permanently and so the solar charge controller is used to disconnect any load when the battery is running low to prevent the batteries getting too low.A charge controller is not always required if the maximum current going into the battery is more than 10% of the batteries Ah capacity - i.e. if the battery is 60Ah then a charge controller is certainly required if the current from the solar panel is likely to exceed 6 Amps - as long as you make sure you don't over-discharge the battery. Some suggest a charge controller is required if the maximum current from the solar panel is just 1% o f the Ah capacity of the battery bank.
Well known manufacturers of solar charge controllers include: BZ Products, Iota, Morningstar, Outback, RV Power Products, ProStar, Solar Converters, Statpower/Xantrex,Trace/Xantrex. Prices range from around £15 to many hundreds of pounds depending on the size of the solar power system to be regulated and the features of the controller. For example, pictured below is a Sunguard solar charge controller for small PV solar power systems (up to 4.5A at 12V) which costs around £25.
LEDs and (in the more expensive regulators) LCD displays are used to show the current state of the charge of the battery, the state of the current entering the batteries from the solar panel(s), and the current being drawn from the battery by loads.
http://www.reuk.co.uk/Solar-Charge-Controller.htm
