Solar-Panel to Controller Loss
Much has been made of the lower losses on the panel to controller path with MPPT because the amps are less. So once you have your loss measured, how valuable is it to improve on that if you don't lik...
Forum Discussion
Salvo wrote:
I don't recall calling it trash. I believe I commented that either you got a measurement error or the controller is not functioning correctly. I'll stand by that comment. I'm not going to search through a bunch of threads. If you're going to post measured quantities here, at least define what you measured. Let's get a little more professional! The measured mppt panel voltage will shed some light what's going on.
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Posted earlier on page 3 of this thread, repeated here--
The spac coefficient for that power loss lets you calculate that loss. Eg, the earlier mentioned 45C -25C = 20C difference and -o.43%/C times 20 is 8.6% and 8.6% of 255w is 22w, so panel wattage now at 255-22 = 233w
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However, at the time I measured Voc at 35.1 (37.4 at STC), Isc at 9.12 (9.00 at STC) and panel at 45C. ( was about 20C ambient)
So my calculation, seeing 215w output (12.7v x 17a) and starting with that 233w panel, is that the missing 18w went to 4w for line loss as measured and that leaves 14w for controller loss, which came out as reasonable with 1.7% line loss and 94% controller efficiency.
