Expected Amps with MPPT
BlueSky 3000 manual says for a rule of thumb, "... Ignoring conversion losses the conversion process produces an output current roughly equal to PV current times the ratio of PV voltage to battery...
Forum Discussion
The temperature is just a possible factor in what I am seeing. My object is to understand and maybe fix why my max amps to the battery in the summer is so much lower than in the spring.
My Eco-Worthy controller only displays output watts, battery volts and amps to the battery. it also shows panel Isc when it does its "demo" trick, but that is not the amps I need, which is Imp.
I get the "panel voltage" from either end of the panel-to-controller path with the panel connected. I take this as being the Vmp the controller has selected for the moment. Typically, 29.3 at the panel vs 29.0 at the controller, so I have a 1% loss on that path.
Last summer, JiminDenver suggested it might be the fault of the controller's temp comp. The controller is in the shade in a breezeway, so not in the sun. I put ice bags around the controller and got its ambient down quiet a bit, confirmed with my IR gizmo, and it didn't help any with the amps. Anyway, I will explore this whole thing some more this summer.
The blurbs all say my PWM should only come up close to the MPPT when the panel is hot, but at 25C ambient I get more amps with the same watts of PWM than with MPPT, so that seems peculiar if you believe the blurbs. I do know when I see 13.5 amps MPPT and I could get 14.5 with PWM that I get annoyed! I will explore using PWM with the 230w panel, but that means making the batteries into a 24v bank, which is not convenient. I will do it just for the testing, but not to live with. While I have the bank at 24v I will also try the MPPT so I will have a comparison between 12v and 24v with that too.
If anyone is already at 25C ambient, on solar with MPPT, and has input and output readings to share, that would be very interesting. maybe it is just my set-up! Or not?
My Eco-Worthy controller only displays output watts, battery volts and amps to the battery. it also shows panel Isc when it does its "demo" trick, but that is not the amps I need, which is Imp.
I get the "panel voltage" from either end of the panel-to-controller path with the panel connected. I take this as being the Vmp the controller has selected for the moment. Typically, 29.3 at the panel vs 29.0 at the controller, so I have a 1% loss on that path.
Last summer, JiminDenver suggested it might be the fault of the controller's temp comp. The controller is in the shade in a breezeway, so not in the sun. I put ice bags around the controller and got its ambient down quiet a bit, confirmed with my IR gizmo, and it didn't help any with the amps. Anyway, I will explore this whole thing some more this summer.
The blurbs all say my PWM should only come up close to the MPPT when the panel is hot, but at 25C ambient I get more amps with the same watts of PWM than with MPPT, so that seems peculiar if you believe the blurbs. I do know when I see 13.5 amps MPPT and I could get 14.5 with PWM that I get annoyed! I will explore using PWM with the 230w panel, but that means making the batteries into a 24v bank, which is not convenient. I will do it just for the testing, but not to live with. While I have the bank at 24v I will also try the MPPT so I will have a comparison between 12v and 24v with that too.
If anyone is already at 25C ambient, on solar with MPPT, and has input and output readings to share, that would be very interesting. maybe it is just my set-up! Or not?
