PowerWall agumentation, new layout

 https://photos.app.goo.gl/1wHoSgrKHEsAT3n66

Last photo of wall mounted components:

1) Upper left: two 250w grid tie micro inverters as intended for  60 cell PV panels.
2) Upper right: two "500w" 12vdc grid tie inverters.
3) Lower center:  12vdc  to 36 vdc converter.
4) Lower right:  240vac recepticles used to accept power.

Several possible configurations, some could be concurrent:
1) 36vdc from batteries into either one or two 250w micro inverters.  Batteries from hoverboards repurposed to power golf carts are shown in first two photos.  Up to about 80 4ah hoverboard batteries are on hand to be paralleled.  About 12 kwh of available energy.
2) 36vdc from the 12v to 36v converter powered from a car into either one or two 250w micro inverters.
3) 12vdc inverter powered from a car.

In my case, "car" could be one of two Mitsubshi imievs or a Tesla Model 3.
With either type of car, the 12vdc can be up to about 1kw and depletes the car's main battery through the car's DC-DC which converters main battery voltage to about 14vdc.

For my purposes, 500 watts of augmentation is more than sufficient so no more than two micro inverters need be used.  Though several more could be easily configured.  The MC4 splitters photographed have space for one more inverter;
power outputs can easily be daisy chained together.
The 12vdc inverters are undesirable because of low efficiency; they produce only about 200 watts each and that not efficiently.  Producing ~400 watts overnight nearly depletes an imiev 16kwh battery.  Energy supplied at 240vac would be only about 6kwh.   The micro inverters are 95%+ efficient.

I have a single PowerWall which can supply 10-12 kwh at up to 5kw.  The battery size is marginal for using night time air conditioning during the summer.  Cloudy days can result in not full PW charges at dusk.  Either condition can make augmentation desirable.

I have about 112 kwh of energy available from four sources: 12 kwh from hoverboard batteries, 70kwh from the Tesla, 15kwh from each of two imievs.  Efficiency from the hoverboard batteries is very good, 95%+.  Efficiency of cars into the 12vdc inverter is poor, perhaps as low as 50%.  Efficiency going through the 12vdc -> 36vdc converter (car -> converter -> microinverters) is yet to be undetermined.  With some additions and reconfiguring, peak powers could reach 3-4kw.  Starting with fully charged batteries, I have hope of getting through about a week with no grid and no sunlight.  The single battery PowerWall will do 5kw with ~12kwh stored.  The PowerWall supplies power as demanded; the augmentation supplies fixed power.  The fixed power augmentation typically goes into demand.  If demand is insufficient, the augmentation power is either sold to grid or charges the PW battery.  In order to avoid sales to grid, with my current PW set up, I must go off grid.

See previous augmentation discussion:
https://wmckemie.blogspot.com/2019/09/micro-grid-and-augmentation.html

1/15/2020

A series of very cloudy days, leaving me starting some nights with ~50% PW charges, have encouraged me to do some more testing.
1) The 36v golf cart battery -> one or two microinverters -> house 240vac continues to work very well.  One inverter gives a solid continious ~230 watts; two inverters gives twice that.
2) 12vdc from an EV -> 12vdc/36vdc "upverter" -> microinverters works less well.  Output power varies quite a bit from the expected to near zero.  Average is about half that expected.  This is almost certainly a microinverter power tracking problem that I do not yet have a solution to.  Perhaps I'll find a high efficiency gridtie microinverter without power tracking to test.  Suggestions solicited.
3) 12vdc from an EV -> 12v cheap chinese inverter -> house 240vac has not recently been tested due to previous inefficiency.