I’m curious how they will handle local requirements, like National Grid in the NE, that require a second meter to measure the solar generation. According to the folks here, that is an issue, one that was over looked. As of now there is no solution hence they are continuing to install Gateway + PW.
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Discussion: "Powerwall +"
- Thread starter willow_hiller
- Start date
FurryOne
Member
Well, I'll be finding out in the next month or so. I'm in permitting right now, and on National Grid's VTOU metering.
They say that the CTs inside are "revenue" grade so maybe they are hoping to get them certified and used as the second meter.
It's kinda funny how confusing the Powerwall names are now. Elon really confused things by calling the Powerwall with 50% greater output "Plus" on the earnings call.
I've been watching the mainstream Tesla subreddits and this news really hasn't spread yet because people keep downvoting it assuming it's old news about the greater output.
I did notice on the certification of the higher output Powerwall in the state of Hawaii they called it "Powerwall 2.1" https://www.hawaiianelectric.com/documents/clean_energy_hawaii/qualified_equipment_list.pdf
So maybe internally one is called "Powerwall 2.1" and this one is called "Powerwall+" and Elon accidentally mixed them up on the call?
I've been watching the mainstream Tesla subreddits and this news really hasn't spread yet because people keep downvoting it assuming it's old news about the greater output.
I did notice on the certification of the higher output Powerwall in the state of Hawaii they called it "Powerwall 2.1" https://www.hawaiianelectric.com/documents/clean_energy_hawaii/qualified_equipment_list.pdf
So maybe internally one is called "Powerwall 2.1" and this one is called "Powerwall+" and Elon accidentally mixed them up on the call?
Or the combined unit uses a PW+ / 2.1 plus solar ppt?
It's actually a good question. Are Tesla's spec sheet dimensions usually pretty accurate? We don't know how tall or thick the battery portion PW+ is by itself (unless someone wants to measure pixels and work that out), but the diagram says it's 755 mm wide where PW2.0 is meant to be 753 mm wide.
If 2 mm is enough to go by, someone with a confirmed PW2.1 unit could let us know whether it's 755 mm wide or 753 mm wide...
The solar is not really what I was talking about. I was mostly talking about the grid connection to the whole system. I just don't understand how you can have a useful whole home backup system that is only tied in with a 40A or 50A breaker in the main panel.
If you were able to take the main breaker and redirect that feed to the gateway and use the main panel as a sub, this whole thing would make sense and you could have multiple Powerwalls. The box on the top of the Powerwall + would just be a combined Gateway 2 and Tesla Solar Inverter in one enclosure. The problem is that it's not legal to do that with a lot of main panel designs. It would work great with my panel, but there are a lot of panels out there that don't work that way. If the main goal is to eliminate nearly all main panel upgrades in Powerwall installs while maintaining whole home backup, they must be a lot more clever than me.
Ah, well, if the intermediate meter disconnect device also includes connection lugs, then they
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SilverSp33d3r
No Longer Silver
Meter socket adapter acting as an interface for the system? Meters are pretty standard and the Utility is notified with tampering so it seems for some that may be an option.
Edit - similar to this one SDG&E produces.
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Will PG&E allow this? It would simplify my installation significantly. Only problem is that my all-in-one MSP is flush mounted, so connecting in a conduit from the powerwall+ may be a challenge.
Per the spec sheet, it's a 50A breaker.
My guess, as we are all guessing here, is that Tesla expects the plurality of its installs going forward will be only one PW. Since they are requiring PWs on every install, all those solar only installs are going to become solar + 1 PW installs. So PW+ is optimized for that case.
As to how you could extend the PW+ design to handle multiple PWs, the easiest solution is to get it listed as a Power Control System, 2020 NEC 705.13. Then in jurisdictions that follow the 2020 NEC or will allow early use of it, the PW+ connection to the main panel can be increased in size without the need to qualify under the 120% rule or its ilk. The system controller in the PW+ will monitor the grid draw and ensure that grid current + inverter current < main panel busbar rating at all times.
Cheers, Wayne
pdx_m3s
Active Member
But if they are only installing them in a whole-house backup configuration, one Powerwall doesn’t seem adequate for the majority of homes.
That obviously depends on the house, so I'm not sure about "majority". Certainly it won't support a 40A (continuous) EVSE at night.
If the Powerwall can reliably protect itself from overload, the worst case is that you get no backup when the grid is out. Maybe they will offer some simple load shed devices for larger loads when there is only one PW. Adding a few of those is easier than adding a panel and segregating circuits.
Cheers, Wayne
RKCRLR
Active Member
My whole home backup configuration has never been able to start the AC unless the solar is generating. Tesla thought my compressor would be compatible with a SureStart but it isn't.
Tesla is proposing load shedding using a 24V line from the gateway to my AC to stop it from trying to start if the grid is down.
Well, let's talk about the possible average current draw available from 13.5kWh PWs assuming: Winter outage needing backup from 4PM until 10AM the next (sunny) morning-- 18 hours or about 3.13A per PW on average. Summer 7PM until 8AM--13 hours or 4.33A per PW.
I'll guess that a unit like non-inverter AC or heat pump that can't be started by one or sometimes two ordinary PWs, can't be actually used in backup mode except for quite short power outages. An easily started unit (inverter or soft-start) may need to operate at a temperature closer to the exterior temperature if it is to last overnight, even if 2 PWs are involved.
Looking at Green Meter Adapter (PG&E) or Generation Meter Adapter (SCE) or RMA (SDG&E), the allowed currents vary but SCE allows 65A (15.6kW). The other two are 60A (IIRC), but PG&E only allows installation on 125A or less panels. Not sure how 2 PW s could be supported unless their combine power output is limited circa 14kW.
Quick point: with the Green Meter Adapter or Generation Meter Adapter, the cable to the meter adapter is actually carrying the power generated. Whereas the inferred meter adapter that is part of PW+ only needs to have the relay for the Microgrid Interconnect Device; power would flow through the 50A breaker in the main panel installed for connection to the PW+ per the spec sheet.
Cheers, Wayne
Cheers, Wayne
Enginerd
Member
This is the answer I'm looking for: which (Tesla) components would I need to drive my AC, at night and without the grid? Before PW+, the Tesla configurator suggested 3 PW for my fully electric house, mainly to drive the AC units. Is this even possible with the PW+, given the 50A overcurrent protection limit? You mention SureStart as a way to mitigate the current spike when starting the compressor, and that it didn't work in your case. The Powerwall+ brochure says it includes an "integrated soft starter capable of powering motors and air conditioning units (supports devices up to 105 LRA)." Unfortunately, my AC lists 140 LRA (Locked Rotor Amps).
SilverSp33d3r
No Longer Silver
14 kW is reasonable amount of power for most homes during outages.
In the spec document you can clearly see tesla applying some type of socket adapter, with a control wire or CT wires. This potentially will allow fully automated disconnect from utility being integrated.
This would allow for the simple installation Elon spoke of and no issues of overloading the bus on the panel as it would be before the main breaker. (Combined grid and solar would remain 200 amps max).
I will find out soon as Im awaiting install, on delay is getting a reputable roofing company out here. If anyone has any recommendations for a reputable roofer in the San Gabriel Valley please pm me the details.
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