The Sunforce 7 Amp Charge Controller is designed for solar panels that are used to charge 12-volt batteries. When used in conjunction with 12-volt solar panels, the charge controller prevents the batteries from overcharging. It is rated at up to 7 amps of array current and solar electricity of up to 100 watts. The device features two LED light indicators: one to indicate a currently charged battery and one to indicate a fully charged battery. The unit measures 2.5 inches wide x 4 inches high x 1 inch deep and weighs only 1 pound.
Ease-of-use: The Sunforce 7 is simple to use, but it could have been made simpler by equipping it with screw-on terminals for the connecting wires. Instead, it simply has connector wires, and these are not of the best quality. Of course, they are designed for low current use, but stronger connector wires would mean they last longer, especially if the unit is to be moved around.
Solar charge controllers help in protecting batteries from overcharge and excessive discharge. The controller assures that the battery is charged fully and keeps it that way without causing damage to the battery.
A basic solar charge controller will monitor the battery voltage, open the circuit and then stop charging when the voltage rises to a given level.
Pulse Width Modulation (PWM)
The modern solar charge controllers use pulse width modulation (PWM) which gradually lowers the amount of power as the batteries get closer to being fully charged.
The battery is charged with lesser stress thus prolonging the battery life. PWM has no mechanical connections that need to be broken although it’s quite complex.
The battery is the main component of your power station. Monitoring means knowing the state of charge in your battery. You can choose a voltmeter or use a purpose built monitoring system.
Using a 12 volt battery full of charge let’s say … 120 amp/hours.
If we measure the voltage of fully charged 12 volt battery with nothing connected it should be around 12.6 volts.
If we connect a reasonable load to the battery the voltage will drop to around 12.1 but the battery is still full of charge at this point.
If we connect a charging source to the battery, for example an 80 watt solar panel, the voltage will rise to about 15 – 16 volts.
If the battery was flat we might see the following:
- No load: 12 volts
- With load: 11.0 volts
- Charge connected: 13 volts