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Old 09-11-2016, 09:30 AM   #16
DavidM
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City: Litchfield, Ct
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Well, at the risk of supporting this thread shift, let me expound on MPPT controllers:


Solar panels have gotten cheaper over the years, but controllers (except for questionable Chinese ones) have stayed the same. So if you are installing up to a couple of hundred watts of 12V nominal panels, MPPT controllers don't make much sense. They do add 10-15% to the power produced, but you can add panel wattage to make up the difference cheaper than you can switch from PWM (the cheaper pulse width modulation) to a MPPT controller.


That is the basis for the PP's statement, but it isn't applicable to all situations and particularly not for 24V panels.


If you install more wattage or you use 24V or higher panels (which are required for anything more than 135 watts per panel) then use an MPPT controller. The MPPT controller is an absolute no brainer for the 24V panels. You would lose 60% of your power if you just connected a PWM controller to a 24V panel.


The above are of course generalities and the specifics of the installation can make a difference.


David
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