The rule of thumb is that different solar panels use different charge controllers due to the difference in size. For instance, a solar charge controller for a 200w is smaller than a charge controller for a 400w solar panel.

Don’t worry about how you will know the right size for your panel. This guide will help you determine that without troubling your mind with several calculations.

**What size charge controller for 200w solar panel?**

**Therefore the ideal size of charge controller for a 200-watt solar panel should be at least 8 amperes. **

If you choose a smaller size than the recommended, you will be running the risk of damaging the battery and burning the entire equipment. So, choose wisely.

**What size charge controller for 250w solar panel?**

For instance, the current produced by a 250-watt panel usually ranges around 12 amps. **Thus, the recommended charge controller size for a 250w solar panel is 14.4 amps**.

One more thing to consider when looking for a charge controller is the system’s voltage. The charge controller has 12, 24, and 48 volts in most cases. Ideally, the nominal voltage of the panel should match the controller. Consequently, a 20-volt 250-watt solar panel should use a 20 volt 15 amps charge controller

**What size charge controller for 300w solar panel?**

For instance, a 12v 300-watt solar panel current is given by dividing the power by the volts. That is, 300w divided by 12v, which offers 25 amps.

Hence, the current supplied by this panel is 25watts.

However, the charge controller should have a current flow of at least 120% of the solar panel. Hence, we add 20% of 25 apps to the size of the charge controller.

**Consequently, a 12v 300-watt solar panel should use a 30amps charge controller**.

**What size charge controller for 400w solar panel?**

A 400-watt solar panel has 80 inches in length and 40 inches in width. It weighs approximately 50 pounds and is usually mounted on rooftops.

You should never be tempted to think that because a 400 watt is slightly large than a 350-watt panel, its charge controller will be marginally higher. That might be true; it might not always give you the correct sizing.

Solar panels come in different voltage supplies. For example, some have 12v while others are 20 volts.

Let’s assume that the 400watt solar panel has a voltage rating of 40 volts. Thus, its current will be 10 amps, that is, power rating divided by volts.

Consequently, its charge controller sizing should be higher than 20 amps. Considering the environmental consideration, you should get a charge controller whose size is 20% more than the panel’s current rating.

Therefore, a 40 volt 400 watt supplying 10 amps needs a charge controller of 12 amps.

**What size charge controller for 500w solar panel?**

A 500-watt solar panel ideally supplies 1,500 to 2,500Wh of energy. However, this amount of power usually depends on the amount of sunshine.

**Additionally, most 500-watt panels use 30 amps charge controllers.**

However, there is no harm in purchasing a bigger-sized charge controller because it gives you room for expansion if you consider adding more solar panels to the system.

**What size charge controller for 1000w solar panel?**

To determine the size of a 1000 watt, take the total watts of the solar array and divide it by the battery bank’s voltage.

Let us assume that our battery bank is 24 volts. Then the current is 1000 watts divided by 24 volts, giving 41.7 amps.

Putting in the environmental factors, we find 120% of the current output.

Thus, we have 1.2 multiplied by 41.7, which gives approximately 50 amps.

**As a result, a 1000watt solar panel with a 24-volt battery bank should use a charge controller of 50 amps**.

**What size charge controller for 1200w solar panel?**

Assuming that the battery bank of the solar panel is 20 volts, then the current supplied by the solar panel is given by 1200 / 20, which is equal to 60 amps.

The recommended charge controller size should be 120% of the current output of the panel.

Thus, the charge controller size of a 100-watt solar panel using 20 volts battery bank is 72 amps. You can always get a higher charge controller sizing to allow room for expansion in the future.

Eng. Matthew Joseph Nandirio is the Founder of walkingsolar.

After graduating from the University of Houston in 2002, matt started working as a Solar Electrical Engineer for several multi-national solar energy companies.

He has a wide range of experiences including solar system requirement analysis, planning, maintaining, debugging and even solar device development through research.

He now shares his 20 years of expertise through his articles on the walkingsolar website.

Further, he is also the author of two books on Solar Technology, “Solar Power for Villages” and “DIY Solar System for Dummies”.