MrM1
I'm Here, But I'm Not All There
Conclusion about Over Paneling a Midnite Solar Classic 150.
1. Over paneling is an excellent way to increase overall daily output. My average daily went from about 7-8 to over 12 kwh per day . On mostly sunny days in late Dec I am seeing 15.5 - 17 kwh per day. Before over paneling in early Dec on mostly sunny days it was 10-11 at most.
2. Over Paneling will not harm the Classic. With a 24v system it will simply clip at 94 amps or about 2600 watts.
3. But over paneling will cause the classic to be running at max out for a good majority of day.
4. This "running at max" creates heat. And the classic's FETs will exceed 90c, sometimes for hours.
5. The Classic is designed to start automatically limiting current above 90c FET temp to reduce heat
6. External fans only provide limited heat dispersion
7. The best way I have found to limit heat is to decrease the Classic's max output down from 94 (at 24v). It seems to be an almost 1:1 ratio of temp to amps for the first 5-8 amps of decrease
8. Running at 85 amps output the over paneled classic's FET temp dropped 10c with only 1 120mm external pc fan blowing on it. This still produces over 2300 watts from the array.
I'm still tweaking for a sweet spot of output to Temps , but will definitely NOT allow the classic to out put at max 94 amps due to heat.
1. Over paneling is an excellent way to increase overall daily output. My average daily went from about 7-8 to over 12 kwh per day . On mostly sunny days in late Dec I am seeing 15.5 - 17 kwh per day. Before over paneling in early Dec on mostly sunny days it was 10-11 at most.
2. Over Paneling will not harm the Classic. With a 24v system it will simply clip at 94 amps or about 2600 watts.
3. But over paneling will cause the classic to be running at max out for a good majority of day.
4. This "running at max" creates heat. And the classic's FETs will exceed 90c, sometimes for hours.
5. The Classic is designed to start automatically limiting current above 90c FET temp to reduce heat
6. External fans only provide limited heat dispersion
7. The best way I have found to limit heat is to decrease the Classic's max output down from 94 (at 24v). It seems to be an almost 1:1 ratio of temp to amps for the first 5-8 amps of decrease
8. Running at 85 amps output the over paneled classic's FET temp dropped 10c with only 1 120mm external pc fan blowing on it. This still produces over 2300 watts from the array.
I'm still tweaking for a sweet spot of output to Temps , but will definitely NOT allow the classic to out put at max 94 amps due to heat.