DC Output Switching with PV Combiner?

Started by mjp24coho, July 23, 2012, 01:24:33 PM

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mjp24coho

I'm trying to find a way to wire in DC output switching ability for my PV/battery system. I currently have 450 Watts of panels feeding a charge controller that charges by 400 AH battery bank (12V).* I also have a separate PV array that powers a Grundfos deep well pump. However, that pump isn't need in the winter, so I'm looking at a way to utilize the well pump PV array to charge my battery bank via a separate charge controller in the winter (rather than having all that PV wattage go unused). To do that, I've looked into getting some kind of a transfer switch (which is wired to both the well pump controller and solar charge controller), where the well pump array wiring would come into the switch, and you could switch it to go either to the well pump controller or charge controller. The benefit of that system is that it would always be wired, and I could easily switch it back and forth.* However, I couldn't find any kind of a switch that could do this (especially given the ~140V DC coming from the pump panel array. One alternative I considered would be to modify a Midnite PV Combiner to do this, where the input from the pump array panels went to the combiner. Within the combiner, the DC- would go to the DC- busbar, with the positive going to the DC+ out bus bar, which would be confiugred to feed the input to (2) separate 300V DC breakers (on the input side). The DC+ output from one of the breakers would go to well pump controller, and the DC+ output from the other breaker would go to the solar charge controller. This way, the breakers could be used as switches – turn the pump controller breaker off (and the solar charge controller on), to send power only to the solar charge controller, and vice versa. Would this work (safely)? Anything I'm missing here? Any other ideas would be appreciated. Thanks.
Offgrid Cabin: 8x215 watt Kyocera panels (roof mount), Midnite E-Panel with Magnum MS4024 inverter, Midnite Classic 200, 800AH 24V forklift battery, Magnum battery monitor, online Magnum inverter & Midnite charge monitoring, Honda EM5000SX generator.