Solar Regulator

A solar regulator, sometimes called a solar charge controller, takes the highest voltages your solar panel array can produce, and feeds it to your battery bank at a controlled rate of current that's calculated to keep your batteries in top condition.

It's the job of your system's solar regulator to pamper your storage batteries as much as possible so the life of the batteries is extended to the maximum possible. So your solar charge controller (solar regulator) keeps the batteries from over-charging and can also prevent the battery power from discharging into the solar panels overnight. This is known as back feeding.

This is because rechargeable batteries, such as sealed lead-acid (SLA batteries), and nickel metal hydride (NiMH batteries) have a maximum number of charge/discharge cycles they can go through before they need replacing. Overcharging a battery causes gassing and the loss of electrolyte. This causes permanent damage to the batteries and dramatically shortens the battery life.

The better solar regulators all have a low-voltage disconnect feature, which switches off the supply to the load if your battery's voltage falls below a preset cut-off voltage. This saves your battery from permanent damage and a greatly-shortened life.

And good modern solar regulators also use PMW (pulse-width modulation) which is the most effective way of charging your batteries at a constant voltage while raising or lowering the charging current (Amps) to suit the battery's condition and charging needs.

Some names to look out for in good-quality solar regulators include:

• Blue Sky Energy/Solar Boost (USA)
• Morningstar Corp (USA)
• Outback (USA)
• Plasmatronics (Australia)
• Steca (Germany)

In September 2008, prices for a solar regulator or solar charge controller ranged from $50 for a simple 5 Ampere (5 Amp) controller to around $1,000 for a 70 Amp solar booster controller.