Beware of cheap MPPT Solar Charge Controllers
I recently bought a 30 Amp capable Solar Charge Controller on Amazon that was described as "MPPT30 Solar Charge Controller" for $ 51. I should have known that it would not be MPPT for $ 51 but it had a review from another buyer claiming it had improved charge current over a PWM controller. I found this not to be the case that it performed the same as a PWM controller in my 300 Watt RV solar system.
Anyway sellers can get away with listing cheap Solar Controllers as MPPT by calling it "Part function of MPPT" in the fine print of their listings, so BEWARE. With the right fine print in their sales listing they can avoid being de-listed as "fake" or "counterfeit" .
The best value for a true MPPT Solar Charge Controller big enough to handle three 100 W solar panels I have found is the Grape Solar GS-MPPT-320W, available at Home Depot, Sears, Amazon.com, etc. priced at about $ 175. This one actually does work as MPPT is supposed allowing the 3 solar panels in full sun to put out their peak output of 17.5 volts at 5.5 amps each which the DC-DC converter inside the controller converts to over 21 amps charge current, an improvement of about 27 percent over what a PWM controller does.
Randy - Manhattan, Kansas
2015 Vista 27N
2020 Ford Escape Hybrid