dave17352 wrote:
BFL13 wrote:
dave17352 wrote:
2oldman wrote:
dave17352 wrote:
Going in series and mppt should double my panel output.
not sure what you mean by this..
Adding another panel will double your output.
Right now I have 2 100 watt panels with a pwm charger so max I can get is about 10 amps. With 3 100 panels and ( I am adding one) and a MTTP charger I can utilize all the volts. So lets say I am drawing 270 watts /14 volts roughly 20 amps. The mttp charger makes all the difference. I guess I should have said by going with the mttp and adding one panel I can harvest twice the energy. :)
Actual results--three 100w panels in parallel with PWM aimed at high sun, you get 6.2 amps (same as Isc) each for 18.6 amps. Swap to an MPPT controller with them in parallel--still 18-19 amps, change to series with the MPPT, still 18-19 amps.
You lose panel watts from panel heating, so your MPPT "advantage" disappears. You can get a little more amps with MPPT when the battery is low, but not enough to change your day's haul of AH that you would notice between battery 13 and 14.5 volts like you see RVing.
I am going to be going in series with these panels now. My Panels are rated and 5.29 amps at 18.9 volts. I have used these panels for two years and the most I ever get is 10 amps. With these panels in series at peak light I hope to get close to 270/14= 19.28 amps. I think I will gain about 5 amps overall. But we will see and I will update how many amps I see. I have done a lot reading on the net and it seems to be the concensus that series and mppt will net me a worthwhile gain.
You seem to be saying the extra voltage over the charging voltage is of no value. Interesting.
