Sorry, I'm still not getting it. If the PowerWall's are wired such that they could see the entire load of the house (including the air conditioner(s)) I just don't see how such a system could pass engineering design review / inspection. It's not good enough to just say that you'll turn them off (been there, tried that).
You must demonstrate that the reasonably anticipated diversity of the load is not likely to exceed the current carrying capacity of the UPS/generator WITHOUT human intervention to shed loads. If load shedding is required (because the UPS/generator) is sized smaller than would be necessary, load shedding must be automatic. Hence separate UPS protected and non-UPS protected panels.
Two PowerWall's can provide 48.3 amps continuous and 60 amps peak (for 10s) at 240 VAC per spec's available (granted if one had access to the Tesla partner portal, more detailed specs are available). Any normally sized air conditioner (3-5 tons) will draw roughly 25-40 amps. Larger homes, say ~3000 square feet an up, often have two HVAC units here on the East Coast -- where its not that hot -- typically with a 3-4 ton for the first floor and a 2-3 ton for the second floor.
Here's a top of the line 20 SEER York, older, and less efficient units will draw even more when running.
http://www.upgnet.com/PdfFileRedirec...YTG-B-0517.PDF
The Condenser alone draws (all 240VAC):
3 ton 25.7 amps continuous (30 amp breaker), starting inrush will be at least 2x to 3x granted only for a second or two
4 ton 28.6 amps continuous (40 amp breaker), starting inrush will be at least 2x to 3x granted only for a second or two
5 ton 33.9 amps continuous (50 amp breaker), starting inrush will be at least 2x to 3x granted only for a second or two
Plus the blower fan in the air handler will use another 3 to 4 amps @240VAC, plus any other loads that might happen to be active in the house at the time the Poco power goes out.
All will be well until you're away at work one day, for example, and the compressor tries to cycle on automatically and stalls due to insufficient voltage/current from the inverter causing 1) a brownout in your home, 2) damage to your electronics / compressor while it tries to start with insufficient voltage, and 3) the PowerWall inverters sense the overload and shutdown abruptly dropping all of the other loads in your home (fish tank, security system, Solar PV, etc.)
Many such UPS systems will try to automatically restart when this happens and the system goes through these start, fail, stop cycles for hours until something fails -- compressor motor, starting capacitor, inverters, etc.
But, obviously, its not up to me. If your AHJ is willing to sign off on your engineering design AS IS covering the whole house mains panel, then that's up to them and you. But, it doesn't mean its going to work (well). Regardless, I suggest you find this out sooner rather than later as it could potentially cause a lot of re-work in your wiring design.
I agree it's close. But IMHO, either three PowerWalls or separate UPS/non-UPS panels is what would be needed from my perspective, Especially given little or no current consumption info. Unless the house is particularly small and we're talking room or mini split AC systems.
You must demonstrate that the reasonably anticipated diversity of the load is not likely to exceed the current carrying capacity of the UPS/generator WITHOUT human intervention to shed loads. If load shedding is required (because the UPS/generator) is sized smaller than would be necessary, load shedding must be automatic. Hence separate UPS protected and non-UPS protected panels.
Two PowerWall's can provide 48.3 amps continuous and 60 amps peak (for 10s) at 240 VAC per spec's available (granted if one had access to the Tesla partner portal, more detailed specs are available). Any normally sized air conditioner (3-5 tons) will draw roughly 25-40 amps. Larger homes, say ~3000 square feet an up, often have two HVAC units here on the East Coast -- where its not that hot -- typically with a 3-4 ton for the first floor and a 2-3 ton for the second floor.
Here's a top of the line 20 SEER York, older, and less efficient units will draw even more when running.
http://www.upgnet.com/PdfFileRedirec...YTG-B-0517.PDF
The Condenser alone draws (all 240VAC):
3 ton 25.7 amps continuous (30 amp breaker), starting inrush will be at least 2x to 3x granted only for a second or two
4 ton 28.6 amps continuous (40 amp breaker), starting inrush will be at least 2x to 3x granted only for a second or two
5 ton 33.9 amps continuous (50 amp breaker), starting inrush will be at least 2x to 3x granted only for a second or two
Plus the blower fan in the air handler will use another 3 to 4 amps @240VAC, plus any other loads that might happen to be active in the house at the time the Poco power goes out.
All will be well until you're away at work one day, for example, and the compressor tries to cycle on automatically and stalls due to insufficient voltage/current from the inverter causing 1) a brownout in your home, 2) damage to your electronics / compressor while it tries to start with insufficient voltage, and 3) the PowerWall inverters sense the overload and shutdown abruptly dropping all of the other loads in your home (fish tank, security system, Solar PV, etc.)
Many such UPS systems will try to automatically restart when this happens and the system goes through these start, fail, stop cycles for hours until something fails -- compressor motor, starting capacitor, inverters, etc.
But, obviously, its not up to me. If your AHJ is willing to sign off on your engineering design AS IS covering the whole house mains panel, then that's up to them and you. But, it doesn't mean its going to work (well). Regardless, I suggest you find this out sooner rather than later as it could potentially cause a lot of re-work in your wiring design.
I agree it's close. But IMHO, either three PowerWalls or separate UPS/non-UPS panels is what would be needed from my perspective, Especially given little or no current consumption info. Unless the house is particularly small and we're talking room or mini split AC systems.
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