Here are my top 3 tips for choosing the right charge controller for your application.
# 1. Choose the right capacity of controller for your solar application
This considers the total power produced by the combined solar panels that will be connected to your system. If you have a PWM charge controller, you can use the calculator below.
To size an MPPT controller, use the calculator below.
# 2. Decide on either an MPPT or PWM solar charge controller
You have the option of an Maximum Power Point Tracking (MPPT) or Pulse Width Modulation (PWM) solar charge controller.
When to use an MPPT controller
MPPT (maximum power point tracking ) controllers unlike the more common and lower priced PWM controllers can improve how quickly a battery is charged especially during cloudy weather.
There are reports of MPPT controllers resulting in a 10-40% gain in electricity storage in the batteries during cold weather compared to PWM controllers.
When to use a PWM controller
For smaller systems (< 100W), the gains in electricity storage realized may not amount to much compared to the investment in an MPPT controller. You can consider a PWM solar charge controller.
Therefore, it is advisable to consider MPPT controllers for larger solar PV systems > 200W if budget is not an issue because the gains in energy storage are sizable compared to the cost of the controllers.
# 3. Check that the charge controller can charge your battery type
Confirm that your controller is able to charge the type of battery that you plan to use in your solar system whether wet lead Acid, AGM, Gel or Lithium ion. You may need to consult the technical specification section of the controller or the manufacturer.
Some charge controllers have inbuilt presets that that automatically select the optimum charging parameters for selected battery type.
Other charge controllers give you the option of manually setting the charging parameters. Consult with the battery manufacturer or the charge controller manual.