13-04-2012, 03:34 PM
CHARGE CONTROLLER FOR WIND AND SOLAR POWER SYSTEMS
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Once our wind generators and solar panels were up and running, the next obvious requirement was some sort of charge controller, since continuous overcharging would boil the electrolyte dry and ruin the expensive battery bank. Several small controllers came bundled with the solar panels, but they were totally unsuitable for wind power use.
Charge controllers intended for solar panels work by monitoring the battery voltage, and once it reaches full charge, the controller simply shorts the solar panel leads together. This doesn't harm the solar panels, but it does waste whatever power they're generating. The energy ends up heating the transistors in the controller.
Since the incoming power is produced by several different types of surplus solar panels and homebuilt wind generators each producing different voltages, they can't just all be hooked together... each has it's own blocking diode in series with the positive lead. When the battery is charging, each source is pulled down to the battery terminal voltage, so each source contributes whatever current it's capable of producing. Each blocking diode has to be sized for the current that source can generate. The negative lead from each source is connected to ground.