Have been living with a battery powered Micro grid now for three years. The system works pretty well when the days are sunny and long and gets strained during cloudy weather when the output can be reduced by as much as 90%. My Solar battery bank is ~ 48kwh of storage. My solution is to switch back to the grid during those long cloudy spells in winter, and then back to the batteries when the output returns to normal. I usually get the solar batteries fully charged during good weather by noon or slightly later. This leaves the excess power to be simply wasted for the remainder of the day. My Chevy Bolt has a 60KWH battery bank so I now have a place to dump the excess power. Sounds good on paper but in reality it is not so simple. Since the 48V solar battery bank charging needs to be highest priority , and the sun output is a variable, the best system would automatically adjust the EV charge rate to take max advantage of available solar output without exceeding it which would have to draw from the solar batteries. My level 2 charger selection required an adjustable charge current the car would be allowed to draw. After some research I got a Juice Box Pro 40 and installed it on the post right between my two garage bays. The full solar charging current for the 48V solar storage bank is ~ 110Amps The EV charger running at full output off my 9kw output outback inverter,can draw upwards of 145A from the batteries. by adjusting the EV charging current I can allow between 1.4KW to the full output of ~7.5KW to be drawn, therefore keeping the solar bank charged while dumping most of the excess production into my car. The EVSE has a network connection so I can set the max current on my cell phone. while this works fine, it is a tricky thing to manage as a microwave oven turning on could exceed the solar charging ability. Automating the load management is looking like a project that needs to be tackled.
Genesis One, LLC
If you would like to get involved or support any of these projects, please contact me at (860)935-5569.