Heat 1, MPPT 0--More on That
I have been noting that my 230w panel with MPPT is getting fewer amps to the battery lately in this hot weather, with the back of the panel at 51C according to the temp gun pointed at the white backin...
Forum Discussion
temperature effects are why solar in partly cloudy western oregon can actually be more effective than sunny summer Arizona. 80F vs. 110F outside. And why for panels matched to the battery back voltage (for us RV'rs "12V" panels, actually closer to 18V max output voltage) PWM system and MPPT are similar in performance at high temperature. PWM throws away power to start with and as panel heats up, less gets thrown away as voltage drops. MPPT harvests that extra power, but its gain drops off with temperature.
I've often wondered if running a small muffin fan with air ducted over the back of a solar panel would drop the temperature enough to more than compensate for the fan current draw. There are lots that draw 1/2A or less at 12V. Keeping the panel at ambient is much better than getting a absorption rise. And unforetunetly, silicon is a very good heat absorber from sunlight.
Or maybe a portable water mister on the front of the panel.
I've often wondered if running a small muffin fan with air ducted over the back of a solar panel would drop the temperature enough to more than compensate for the fan current draw. There are lots that draw 1/2A or less at 12V. Keeping the panel at ambient is much better than getting a absorption rise. And unforetunetly, silicon is a very good heat absorber from sunlight.
Or maybe a portable water mister on the front of the panel.
