Sizing Charge Controller For 600w Solar Panel {Beginners Guide}

a charge controller regulates the DC current from the solar panels to charge the batteries or power banks, a wrong size charge controller can decrease your power output or even can damage your batteries and solar panels.

so in this blog, I share with you details about sizing a charge controller for your 600w solar panels and how to calculate the charge controller size so in the future you don’t have to read any other article. also some details about the different types of charge controllers available in the market and the sizing of a PWM or MPPT charge controller

What Size Charge Controller For 600w Solar Panel

For 24v 600w solar panels a 30A MPPT charge controller is recommended to charge 24V batteries, to calculate the regulator or charge controller size use this formula wattage/volts = amps + 25%, the extra 25% is recommended by many experts for safety reasons which I’ll explain later on this article.

i recommend the Renogy 24v 30A MPPT Charge controller which can handle up to 800w solar load. if you’re looking for more details stay with me I’ll explain how to size your charge controller for your different sized solar arrays.

What is a charge controller and How do they work?

a charge controller or regulator works between the solar panels and batteries to regulate the DC current produced by solar panels in volts and amps to charge the batteries according to their voltage requirement otherwise if you’ll directly connect your solar panels it can damage the batteries due to the fluctuation in the power output from the solar panels because of weather conditions.

The solar panels can sometimes pull the power back from the batteries, it can happen in some cases, not in all, so having a charge controller will block it from happening, or else your batteries will get discharged quickly.

How do I choose the right size solar charge controller?

There are many factors which involve in the calculating size of the charge controller for your solar panels.

first of all, keep in mind the power output of your solar panels in voltage and amps, a minimum of a 24v connection is recommended for a 600w solar power system or you can use 48v as well.

so choose your battery’s voltage according to your solar panel’s voltage for example if you have a 24-volt system of solar panels buy a 24 battery to store that power.

you can use low voltage batteries for higher voltage solar panel systems but it will cost you a lot of power loss.

a 24v 600w solar panel will produce 600 watts per hour but the voltage can go higher about 35 volts in peak sunlight hours so this is why you need a charge controller so it can regulate the power in volts and amps to charge your batteries or otherwise it can damage the batteries capacity.

Use this formula to calculate the size of the charge controller for any sized solar panels Watts / Volts = amps + 25%

in the voltage, we’ll put the number of our solar panel’s voltage and batteries voltage like 24v.

600/24 = 25 + 25% = 31.2 Amp-Hours

So a 30A MPPT charge controller can handle the load of 600w solar panels. the extra 25% is recommended for these safety factors.

here’s why most of the experts don’t advise running any electronic for many hours at its higher capacity which will decrease its lifespan in the long term, and secondly it gives you some other room to expand your solar panels if you wanted to do in the future so don’t have to invest in any other charge controller.

But if you’re wiring your solar panels in 12 volts by connecting them in parallel you’ll need a 60Ah MPPT charge controller and 12v batteries. But i don’t recommend this because it will increase the amps you’ll have to use larger and expensive wires to travel this many amps from solar panels to charge controller and batteries which will cost more and can also cause a power loss.

To calculate the power use Ohm’s law volts x amps = wattage or wattage/volts = amps

I have explained here about parallel vs series connections

But in short, if you’re connecting two 300w 24v solar panels together to make it 600w watts connecting them in parallel will give you 24 volts and the amps will add up but connecting them in series and make the total voltage 48v and amps will stay the same

Make sure to use 24v 250Ah deep cycle batteries or 125Ah Lithium batteries with 600w solar panels.

How many watts can a 30 amp solar controller handle?

Renogy Rover 30A MPPT charge controller can handle up to 400W on 12V or 800W on 24V systems. A rule of thumb is to not use these charge controllers at their maximum power which may cause damage to your batteries or it can also damage the charge controller.

Difference between MPPT & PWM Charge controller

Watch this video for a more clear idea but in short and MPPT charge controller will produce 30% more than the PWM charge controller.

Because an MPPT charge controller uses its internal capacity to adjust the volts and amps according to the input from the solar panels and battery voltage.

For example, if your solar panels are producing 35 volts and if you have 24v batteries then the MPPT charge controller will lower the voltage and will increase the amps which result in you’ll not loos any total power output.

But on the other hand, if you have a PWM charge controller it will lower the voltage and the amps will stay the same which will cause the total power output loss. Watch the above video for more details

And PWM charge controller is recommended in small solar panel arrays like 50-200 watts but still, it will cause some electricity loss but not much as the wattage will increase the percentage of loss will increase as well

PWM charge controller is ideal if you same voltage solar panels and batteries and an MPPT charge controller are recommended if you have different volts of battery and solar panels.

Some other important notes

  • Plug only DC devices with the charge controller like batteries
  • Check the volts and wattage capacity of the charge controller every brand have different wattage limits
  • Keep the charge controller and batteries as near as you can.
  • Buy a 24v charge controller for a 24v solar system and so on…
  • Always go for the MPPT charge controller it may cost a few bucks more but they are worth the money.


Choosing the right size charge controller can determine the power output of any solar panel system and also it keeps the batteries safe. By keeping in mind the above points you can select a regulator or charge controller for any sized solar panel system

i hope this article was helpful if you have any queries do ask them at ThankYou!

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Chris Tsitouris is a renewable energy professional with 10+ years of experience as Director of Engineering at Solar Spectrum, previously working as Project Manager at SunPower and Energy Analyst at the National Renewable Energy Laboratory. As a thought leader, Chris has authored numerous articles and research papers.

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