CHARGE CONTROLS
Charge controls prevent overcharging the battery. When battery voltage rises to a preset maximum, where the battery is completely charged, the control automatically reduces or stops the solar charge.
Some charge controls are that simple, but most include some other features like volt & amp meters, amp boosting, voltage conversion, or night light timer.
Select a control able to handle a little more than the amperes your solar modules are rated to generate. Though solar modules don't usually produce more than their rated amperes, they can momentarily produce more on cold bright days. We recommend leaving a 25% margin, that is, for a 45 amp solar array use a 60 amp control rather than a 50 amp control. Or if you plan future expansion of your solar array, allow a lot more headroom to accommodate the added current. Be sure the model you choose is available in the battery voltage you use. Controls that can switch between several battery voltages will handle twice as many solar modules in a 24 volt system as in a 12 volt.
Since a battery voltmeter and solar amp meter are needed to show that the battery is really getting charged, most controls have those meters built in or optional.
User-adjustable battery voltage set points is a feature of most controls, so voltage can be set exactly for your type of battery. A Battery Temperature Sensor is available for some to automatically adjust charging voltage for batteries exposed to large temperature changes. Automatic or Manual equalizing gives an occasional overcharge to restore all cells to 100%.