Solar Panel Voc-MPPT?
Wondering if there is any relationship between measured Voc and MPPT performance with a 24v panel. My 12v panel has a Voc rating of 21.9 and Isc of 8.2, but I often see 8.2ish when Voc is only 20....
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Is that a bunch of hot air, or are you going to provide analysis to prove your assertion? Talk is cheap! This isn't kindergarten.
I'll help you out. You'll need the following info for the analysis. Assume 95% efficiency for controller and cabling. Panel temperature is 75C. You'll have to calculate pwm current. It is NOT 6A.
Show me what you're capable of.
Sal
I'll help you out. You'll need the following info for the analysis. Assume 95% efficiency for controller and cabling. Panel temperature is 75C. You'll have to calculate pwm current. It is NOT 6A.
Show me what you're capable of.
Sal
12thgenusa wrote:Salvo wrote:
Careful when making a mppt to pwm comparison. Not only is mppt highly temperature dependent, but also battery voltage dependent. PWM can also be effected, but not as extreme.
For example, you got a mppt controller that outputs 100W. If battery voltage is 12.0V, charging current is:
I = P / V = 100W / 12.0V = 8.33A
If battery voltage rises to 14.0V, charging current is 7.14A, a 14.3% reduction.
Sal
OTH, assuming no losses from panel output to controller output, a 100W panel through a PWM controller will give you less than 6A all the time, 16% less than the MPPT at 14V and 28% less at 12 volts.
