Forum Discussion

MrWizard's avatar
MrWizard
Moderator
Jun 24, 2015

why don't Solar controller mfg/sellers use honest ratings

example most 30amp controllers are listed at 390w of panels and 40amp controllers at 500w of panels but we don't charge batteries at 12.0v we charge at 14v or higher 14v*30 amps 420w output, ...
time2roll's avatar
time2roll
Nomad
Jun 27, 2015
With 41 amps Isc it would appear you need a PWM controller rated 51.25 amps minimum to meet NEC. That probably puts you at a 60 amp controller.

Those panels in series would need just 45 amp MPPT to meet NEC and not clip the amps. Actually if you rarely see 35 amps a 30 amp MPPT might be fine with minimal clipping. Still meets NEC.

There is no 125% applied to voltage that I am aware of.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,188 PostsLatest Activity: Jan 19, 2025