Forum Discussion
BFL13
Nov 07, 2015Explorer II
Salvo, you ignored that I could not get Isc from the 60 cell panel doing 24-24 so I didn't get as many amps as I should have compared with 12v 36s.
So you just can't use the Iscs in proportion to compare. If you could, I would have been getting 9 amps (like 18)with the PWM instead of 8 amps (like 16) with the MPPT, but they were even at 8.
I don't know why the panel Isc (disconnected) was 9.2 amps (rated 9.0) but the controller only saw about 8 amps. With 36 cell 12v panels it sees the rated Isc doing 12-12.
The MPPT controller also saw 8 with 24-24 instead of 9 as usual with 24-12.
That makes it look like the lower "overhead" with the 60 on 24s put the amps farther to the right on the IV curve (so at a lower amount)?
EDIT- the 255w 60 with 9 Isc only drops to about 8.8 at 26v, but the 310w 72 stays at 9 way higher in battv, but 8.8 is still not much down like at the 8 in question, so IV curve can't be the real story I guess.
That would not affect MPPT output amps (which are based on output watts) but would affect the PWM which just does the actual amps never mind the watts.
the 24-12 MPPT amps with 60 cells were the same as the 12-12 PWM 72 cells would have been at Isc. I think the 60 cell and 72 cell amps with MPPT would be the same having the same watts.
The curiosity is how the 24v 60 cell panel Isc is higher in proportion than 72s but Salvo explained that earlier. It is just that you can't get at all of them :(
So you just can't use the Iscs in proportion to compare. If you could, I would have been getting 9 amps (like 18)with the PWM instead of 8 amps (like 16) with the MPPT, but they were even at 8.
I don't know why the panel Isc (disconnected) was 9.2 amps (rated 9.0) but the controller only saw about 8 amps. With 36 cell 12v panels it sees the rated Isc doing 12-12.
The MPPT controller also saw 8 with 24-24 instead of 9 as usual with 24-12.
That makes it look like the lower "overhead" with the 60 on 24s put the amps farther to the right on the IV curve (so at a lower amount)?
EDIT- the 255w 60 with 9 Isc only drops to about 8.8 at 26v, but the 310w 72 stays at 9 way higher in battv, but 8.8 is still not much down like at the 8 in question, so IV curve can't be the real story I guess.
That would not affect MPPT output amps (which are based on output watts) but would affect the PWM which just does the actual amps never mind the watts.
the 24-12 MPPT amps with 60 cells were the same as the 12-12 PWM 72 cells would have been at Isc. I think the 60 cell and 72 cell amps with MPPT would be the same having the same watts.
The curiosity is how the 24v 60 cell panel Isc is higher in proportion than 72s but Salvo explained that earlier. It is just that you can't get at all of them :(
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