Solar Charge Controllers - Voltage Regulators

An Introduction To Solar Charge Controllers

Solar charge controllers, also known as solar charge regulators, are used in solar pv and wind energy systems to protect the battery from being overcharged and overdischarged. Either condition will damage a lead acid battery.

Small remote power systems that use both solar & wind energy sometimes have a 'hybrid' charge controller. On larger systems the solar pv array and the wind generator each have their own controllers, feeding the same battery bank.

The controller is a very important part of any energy system, as the latest technologies are equipped with some highly effective battery charging routines. An advanced charging routine ensures that the battery is charged as quickly as possible whilst ensuring the battery is not damaged by overcharging.

The most advanced solar pv controllers use maximum power point tracking (MPPT) charging, which can provide a power boost of up to 33% over normal controllers, especially in cold but sunny conditions.

The charge controller can also provide charging information to the user, often using a small digital display. Some units record the charging data over time and many offer a variety of electrical protection features such as surge protection.

Some solar charge controllers also offer an LVD (low volt disconnect) feature. This function is useful on remote solar pv systems to ensure that the connected loads don't discharge the battery to the point where it would get damaged.

Selecting a Solar Charge Controller

All solar controllers need to be selected according to the maximum amount of current going through them. Current in amps is calculated by wattage divided by voltage, which is taken from the solar pv panel or array specifications.

With an MPPT solar controller the voltage to use for the above calculation is the voltage of the battery bank (e.g. 12v). However with a non-mppt unit use the peak power output voltage of the solar panels (e.g. 17.5v).

It is normally recommended to oversize the controller by approx 20% to allow for peak outputs, although some manufacturers have already de-rated their units (in particular Morningstar).

If the charge controller also has an Low Volt Disconnect (LVD) function, then you also need to ensure that the load current does not exceed the load rating on the controller. Inverters are normally connected direct to the battery bank as they have their own internal LVD system.

We supply a comprehensive range of solar controllers from the world's leading manufacturers. If you need any friendly advice selecting the best controller for your application, please feel free to contact us.

For detailed controller information, full technical specifications, user manuals and latest prices please visit our webstore:

Steca Solar Charge Controllers

Morningstar Solar Charge Controllers

Outback MPPT Solar Controllers

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