How To Size Solar Panel Charge Controller

You have a 60a mppt charge controller and a nominal 24vdc battery.

How to size solar panel charge controller. Solar charge controllers also known as solar regulators are an integral part of any stand alone solar system. Take the number of panels x watts to get the total watts of the solar array. Now if you know the amperage of the controller and you would like to figure out how the maximum solar array wattage that can go into the controller you would also use ohm s law. 1 x 100 watt solar panel 12 vdc battery bank 25 10 amps.

All we have to do is find the current through the controller by using power voltage x current. 26 45 amps x 1 25 33 amps and would be too much for the controller. A solar array is producing 1 kw and charging a battery bank of 24v. Pv charge controllers are rated and sized depending on your solar array s current amps and the solar systems voltage push.

To be on the safe side it is advised to multiply the result by a safety factor of 1 25. Take the power produced by the solar panels and divide by the voltage of the batteries. Cold temperatures and as always round up. The average 12 volt solar panel produces between 12 and 21 volts a level that would overcharge and damage a battery if transferred directly to it.

8 12 amp x 2 x 1 25 20 3 amp minimum controller input current this is the input current that comes from the solar array. So really it s worth doing more investigation in your solar system for best sizing a proper solar charge controller. It is the key for longer life and higher efficiency for your battery bank as the charge controller optimizes the power and voltage coming from your solar panels to provide best charging voltage and current to the batteries. A typical recommendation is to limit the solar array to 110 125 of the maximum controller rating.

We recommended a factor of safety of at least 1 25 meaning you would multiply the current from your panels by 1 25 and then compare that to the 30 amps. Add 25 to allow for margin e g. 80 amp controller x 48 volt battery bank 3 840 watts of solar panels. For example five 100 watt panels in parallel would be 5 29 x 5 26 45 amps.

You then divide it by the voltage of your battery bank to get amps. The most common pv charge controllers come in 12 24 and 48 volts. We then go ahead and calculate the 110 125 of the maximum controller rating to get a range of 1584w to 1800w. This will give you maximum output amps from the controller.

Therefore solar charge controller sizing basically involves getting a charge controller big enough to handle the amount of power and current produced by your solar energy system. In this case it would be the 80 amp controller. That means we have 1440w of power. If you don t want to waste output in heat size the controller at around two thirds the rated output of the controller.