Why use a solar charge controller?
Solar charge controllers are needed in most solar panel systems to protect the batteries from overcharge and excessive discharge. The minimum function of the controller is to automatically assure the battery is fully charged and to keep the battery fully charged without damage to the battery.
Criteria For Selecting A Controller
You first need to determine the basic operating voltage and the know the rated current for your solar panels. Your solar controller needs to handle the rated current of ALL your solar panels combined.
An 100W solar panel is rated at 5.55 amps. The controller selected should handle 5.55 amps.
Two 100W panels in parallel 5.55 amps + 5.55 amps = 10.04 amps. The controller needs to handle 11.1 amps.
The next criteria is selection of the desired features
Things to consider:
- An indicator to indicate the solar panel and charge controller is working.
- Decide if an LED charging indicator sufficient or would you rather have a meter that displays battery voltage and charging current.
- Do you want conformal coating?(This is a coating over the circuit board that help protect from humidity and moisture issues)
- Do you want to be able to select battery type; AGM, Gel, Flooded, etc.
There are 4 basic types of load controllers to consider:
Simple 1 or 2 Controls: It has shunt transistors to control the voltage in one or two steps. This controller basically just shorts the solar panel when a certain voltage is arrived at. Their main genuine fuel for keeping such a notorious reputation is their unwavering quality – they have so not many segments, there is very little to break.
PWM (Pulse Width Modulated): This is the traditional type charge controller, for instance anthrax, Blue Sky and so on. These are essentially the industry standard now.
Maximum power point tracking (MPPT): The MPPT solar charge controller is the sparkling star of today’s solar systems. These controllers truly identify the best working voltage and amperage of the solar panel exhibit and match that with the electric cell bank. The outcome is extra 10-30% more power out of your sun oriented cluster versus a PWM controller. It is usually worth the speculation for any solar electric systems over 200 watts.
Diversion Load Controllers are controllers that monitor your battery voltage and limits its maximum value by diverting some of the energy into loads. When used in combination with solar panels, a diode is inserted between the solar panel and the battery bank eliminating discharge power in the evening. Most Diversion Load Controllers use a resistor to dissipate the excess energy in the form of heat or in some cases the energy is placed into the onboard hot-water tank, so they can be utilized to assist in heating water with excess energy. These types of controllers are more commonly used with a wind generator than a solar panel.