Post by michaelk on Jul 2, 2016 7:01:40 GMT -8
I'm building a new system now with 4 arrays of three-300 watt panels for an off-grid home in the mountains. Renogy's 3600 watt cabin kit. Each array will be putting out 8.0 amps at 112VDC. They'll all be directed to a combiner box before going into the charge controller (max 32amps at 112VDC).
I'm interested in using at least one of the arrays for pumping water with a Grundfos SQFlex 6 SQF-3 Submersible Pump, the specs of which are 8.4 amps maximum at a recommended 100-300 VDC (can also run on 240VAC).
I want to install spliters and additional breakers so I can chose where to direct the power. Either to the combiner box (then to the charge controller) or directly to the well pump (bypassing the controller). On a regular day, I could simply flip switches to direct array #4 power either to the charge controller or the well pump depending on what I need more, water or charge. The well's negative terminal would be connected to the combiner's negative bus because all circuits are running at the same voltage.
Now for the question. Suppose in the driest parts of summer I want to use two arrays in series so that I'm producing 224VDC instead of 112VDC. I would do this by directing the positive output of array #3 to the negative connection of array #4 (4 would be off the negative bus bar). The positive terminal of array #4 then goes off to the well pump (not the positive busbar). Can the negative terminal of array #3 still be attached to the negative bus bar of the combiner box, or does it need to be totally separate? Intuitively I would say separate, but I thought I'd check.
I'm interested in using at least one of the arrays for pumping water with a Grundfos SQFlex 6 SQF-3 Submersible Pump, the specs of which are 8.4 amps maximum at a recommended 100-300 VDC (can also run on 240VAC).
I want to install spliters and additional breakers so I can chose where to direct the power. Either to the combiner box (then to the charge controller) or directly to the well pump (bypassing the controller). On a regular day, I could simply flip switches to direct array #4 power either to the charge controller or the well pump depending on what I need more, water or charge. The well's negative terminal would be connected to the combiner's negative bus because all circuits are running at the same voltage.
Now for the question. Suppose in the driest parts of summer I want to use two arrays in series so that I'm producing 224VDC instead of 112VDC. I would do this by directing the positive output of array #3 to the negative connection of array #4 (4 would be off the negative bus bar). The positive terminal of array #4 then goes off to the well pump (not the positive busbar). Can the negative terminal of array #3 still be attached to the negative bus bar of the combiner box, or does it need to be totally separate? Intuitively I would say separate, but I thought I'd check.