Solar Help
I have an older Class B motorhome and have been thinking about solar. I can boondock now for 2 days before I have to recharge my 125ah battery. The only thing that draws power is the 12V fridge whic...
Forum Discussion
The OP found these 190w 12v panels earlier in the thread.
http://www.sunelec.com/Specs/Evergreen/ES-A-190_195_fa2.pdf
Isc is 11.8a
Using my formula, 190/130 x 8.2 = 11.98a so that checks out given that the Voc is 22 instead of 21v.
Now we get another 190w panel but this one is a 24v
http://www.windturbine.ca/sun_panels.html
Isc is 5.91 and Voc is 44v (note how Isc is half the 12v version's and Voc is twice)
AFAIK (based on jimindenver) you would still get about 12a with the 24v panel and MPPT (required for the 24 to get it back to 12v and to get the proper amps per watt)
Using just the watts 190 divided by battery voltage of say 13v and rising, you would expect to get 190/13 = 14.6a or a 2.6 amp gain over the PWM version. 2.6/12 = 21% which is the sort of claim you see in MPPT advertising. BUT:
jimindenver gets 15a from his 230w panel with MPPT using a 20a controller (so it does not clip the amps)
Others with 230w panels and the 15L 15amp controller also get 15a but that controller does clip the amps to its rated 15, so it could be they are missing an amp or two. jimindenver example shows they are not. Nobody else has posted "actuals" that would change this story (so far! :) )
The OP has a typo in the amps for his latest find so it is hard to follow. A 90w panel will have an Isc of approx 5.7a so with two, you would get about 11.4a.
http://www.sunelec.com/Specs/Evergreen/ES-A-190_195_fa2.pdf
Isc is 11.8a
Using my formula, 190/130 x 8.2 = 11.98a so that checks out given that the Voc is 22 instead of 21v.
Now we get another 190w panel but this one is a 24v
http://www.windturbine.ca/sun_panels.html
Isc is 5.91 and Voc is 44v (note how Isc is half the 12v version's and Voc is twice)
AFAIK (based on jimindenver) you would still get about 12a with the 24v panel and MPPT (required for the 24 to get it back to 12v and to get the proper amps per watt)
Using just the watts 190 divided by battery voltage of say 13v and rising, you would expect to get 190/13 = 14.6a or a 2.6 amp gain over the PWM version. 2.6/12 = 21% which is the sort of claim you see in MPPT advertising. BUT:
jimindenver gets 15a from his 230w panel with MPPT using a 20a controller (so it does not clip the amps)
Others with 230w panels and the 15L 15amp controller also get 15a but that controller does clip the amps to its rated 15, so it could be they are missing an amp or two. jimindenver example shows they are not. Nobody else has posted "actuals" that would change this story (so far! :) )
The OP has a typo in the amps for his latest find so it is hard to follow. A 90w panel will have an Isc of approx 5.7a so with two, you would get about 11.4a.
