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Stayed at a cabin in the Ozarks last weekend and their solar setup blew my mind
They had this tiny 10 watt panel hooked to a car battery that ran a fan and charged phones all weekend no problem. Has anyone else seen those cheap PWM controllers hold up better than MPPT for small builds?
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the_anthony5d ago
People get hung up on efficiency numbers but forget that PWM controllers are basically just a switch. They're so simple they barely have anything to break. I've got an old Morningstar PWM from 2017 that's been sitting outside in the rain running a 15 watt panel for a chicken coop door timer. Meanwhile my buddy's MPPT unit died after two years because the capacitor blew out. Sometimes the clunky stuff just keeps working because there's nothing fancy to fail.
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elliotc105d ago
Bring up how PWM actually works better with smaller systems because of battery chemistry. A lot of people forget that PWM controllers end their charge cycle by fully saturating the battery with a steady low current, which matches how lead acid batteries like to be charged. MPPT controllers sometimes skip that final saturation stage because they're chasing voltage points instead of current flow. For a little 15 watt panel on a battery that sits most of the day, that trickle charge actually keeps the battery healthier over time.
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