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Tested cheap PWM vs MPPT charge controllers side by side on my shed setup
I ran a comparison on my 200 watt solar panel setup in Austin over two weeks. The PWM controller gave me maybe 8 amps to my battery bank on a sunny day, but the MPPT one pushed 11.5 amps consistently. That extra 30 percent juice is huge for charging my deep cycle batteries faster. Has anyone else seen that big a jump or was my PWM just garbage?
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the_olivia4mo ago
Oh dang, that's a solid point about voltage drop on the wire runs. Did you actually measure the voltage at both ends of your cables or just assume it was fine? Curious if that could be the real culprit here.
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jamesf294mo ago
Just a heads up, your math might be off for the voltage side of things. At 12 volts, 8 amps from PWM is only around 96 watts, while MPPT at 11.5 amps is about 138 watts. That extra 42 watts is a nice bump, but it's not really a straight 30 percent gain across the whole system since your battery voltage can change how those numbers work out. Your PWM might have been cheap though, since better ones can usually hold current closer to the panel's max power point. Did you check the voltage drop on your wire runs too, since that can really eat into PWM performance?
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