Originally Posted By: JKB
Originally Posted By: wbuffetjr
Well I am thinking at that point I would have the solar rig AND the windmill. On cloudy days when the solar production is poor the wind should be better and surely there would be some windy nights as well.

Let's just assume we are talking about solar tho? How hard would it be to add batteries to this system JKB? Is that just a cost factor? Could I just start with a couple batteries and then add more battery capacity as funds allowed?

DC voltage will be rather high, which would require a lot of batteries to spin the motor.

In this scenario you are taking a VFD that typically runs from AC power, which internally converts it to DC to kinda chop it up and reorganize it to spit it back out as AC to the motor.

Like on the ABB Solar Drive, and many other VFD's like my Allen Bradley PowerFlex drives, you can directly apply DC Voltage to the DC Bus to run the motor and skip the AC altogether. ABB Solar Drive has all solar stuff in the run Macro like MPPT and a bunch of other stuff, so it would be an easier choice.

However, DC voltages required are about 35%-40% higher than the name plate rating of the AC motor. An ABB engineer told me that with a 230VAC 3 phase motor, optimum solar design voltage should be no less than 312VDC, but not more than 400VDC. Somewhere in between that would be good. With (4) 96VDC, 300 watt panels, you should be easily able to run a 1hp 3 phase motor, which could get you into a decent rotary vane compressor.

I know this has to be quite confusing, and it is. Definitely not plug and play.

I'll probably get one to mess with tho. Little solar rig I want to put out back would just be to run a small irrigation pump for the garden and such.

Well, assuming I am reading this right, then that is our answer right there. We go with the "run when there's sun" version and that's it. If running half the day all summer and as much of the winter as we can can't keep fish alive up there then I'll just grow the biggest crayfish anyone has ever seen lol.

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