Cheap China Solar Controller Failure
For a couple days been noticing higher than the 14.6 voltage,.....going to 15, and even 15.5,....I knew something was not right. The next day it was showing 16, then quickly went to 17+.......I quickl...
Forum Discussion
jrnymn7 wrote:
I found this to be an interesting read:
http://www.victronenergy.com/upload/documents/White-paper-Which-solar-charge-controller-PWM-or-MPPT.pdf
It verifies BFL's observations, regarding the effect of panel temperature on mppt output, but it also shows there is range of panel temperature, with-in which pwm has an advantage, and with-out which mppt has the advantage.
That's the link that Pianotuna posted in another thread.
I don't see anywhere that it shows that PWM out performs MPPT. Specifically look at figs. 15 & 16. They both use MPPT as the baseline and show that PWM is almost as good (within 10%) as MPPT for a certain range of temps and batt voltages, but MPPT is much better at lower cell temps, lower batt voltages and extremely higher cell temps.
Granted they are comparing power output, not amperage. But if you use your system as a power source rather than just a battery charger as I do, higher wattage output will always win.
If you only compare amperage output you are partially missing or misunderstanding what MPPT can do for you.
I have never quite understood the obsession with cheap controllers. The equivalence of several tanks of fuel will buy a quality MPPT controller with monitoring, data recording and visual displays and no need to worry about carrying a spare. To paraphrase Mex, you buy a BMW and put Pinto tires on it.
I fully believe PWM controllers have their place but why go cheap which ever controller you choose?
