Should I use a PWM or an MPPT Charge Controller?

Pulse Width Modulation (PWM) controllers are perfect controllers if you are on a budget or if you are venturing into solar with a smaller system. PWM controllers will typically have a maximum solar input of 25-50 volts D/C, so panels must be connected in parallel.  PWM controllers have a maximum efficiency of 79%, this is due to the way they regulate the electricity produced by the solar panels.  

Maximum Power Point Tracking or MPPT charge controllers are about 90% efficient and will maximize the production of your solar system. MPPT charge controllers will typically accept a solar input of 100-150 Volts D/C. This will give you the option to wire your panels in series or in parallel, we would recommend a series configuration with MPPT charge controllers as it is an easier installation. Having an MPPT charge controller and connecting your panels in series will reduce the resistance of your wiring. Less resistance means you can have a much larger distance between your solar panels and charge controller. If you are trying to set up a system and plan to have a distance larger than 30 feet between the solar panels and charge controller then you must use an MPPT charge controller.

Renogy is the author of this solution article.

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