It actually seems fairly common. The current inverters they make are 3.8kW and 7.6kW. And people very commonly have more than 7.6 kW of solar panels. But maybe they will make a larger inverter option for the combined Inverter/Gateway unit. I would think they need up to 20, or 30, kW maximum capacity. Maybe two 15kW units?
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Existing Powerwall 2s to get 50% power capacity increase with SW update?
- Thread starter sorka
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It actually seems fairly common. The current inverters they make are 3.8kW and 7.6kW. And people very commonly have more than 7.6 kW of solar panels. But maybe they will make a larger inverter option for the combined Inverter/Gateway unit. I would think they need up to 20, or 30, kW maximum capacity. Maybe two 15kW units?
aesculus
Still Trying to Figure This All Out
But do we actually know that? I've never seen a breakdown of install sizes, although this is possibly (probably?) ascertainable information, from permit records if nothing else. I would be cautious about taking the user population on TMC as being representative (e.g. if you believe TMC, more than half of Model 3's sold are Performance models). But yeah, maybe they need a larger inverter option to simplify things
On today's earnings call, Elon said that in future installs, the existing house circuit breaker panel would essentially remain untouched and that solar power will be routed through the Powerwall and then Gateway.
This really means that the Gateway must be located in between the grid and existing main circuit breaker panel.
The real question then, even if a single Powerwall (roughly made since November of last year) is able to handle "about twice" the peak power as claimed (10 kW vs 5 kW) - that still isn't enough to replace a 200A grid feed connection (48 kW). Does that mean that if you have a 200A main panel, you'll have to buy at least 3 Powerwalls? (7.5 kW peak * 2 = 15 kW)
IMO this isn't always going to be cheaper - if you have an underground utility feed, moving that is non-trivial in most circumstances. But I would love to see if they have some unique solutions to this. Or what if your main panel also houses the meter? Your meter will also have to be replaced in that case as well.
Example of a common setup in my area:
Underground utility feed - feeds through the foundation of the garage through the wall. In the wall is a combined meter / whole-house load center.
Only possibility to avoid touching the main panel would be to cut the PVC conduit feeding the main panel, install a junction box and replace with a new meter and junction box to tie in the Gateway.
Edit: Thanks wwhitney for correcting my math.
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There are a couple issues with this strategy:
1) If the Gateway is between the meter and the current service panel, then it needs to become the service disconnect. Which is fine, it has provisions to have a main breaker. But that also means that the grounding electrode connections in the prior service panel have to be moved to the Gateway, the conductors from the Gateway to the prior service panel have to be replaced to include an EGC, and that grounds and neutrals will need to be separated in the prior service panel. Plus if there is an existing 3-wire dryer or range circuit with a bare neutral, that circuit will need to be replaced with a 4-wire circuit, which means changing out the cord and plug on the dryer or range.
2) As you mention, if the existing service panel is a combination meter/main/distribution distribution breakers are in the same enclosure as the meter, it's not possible to install the Gateway between the meter and the existing service disconnect, so the usual strategy of emptying the distribution section of breakers will be required. If it's just a meter/main, with distribution in a separate enclosure, that should be no problem, as the feeder from the meter/main to the distribution panel can be intercepted (and in fact that's the easiest configuration for whole house backup).
A 200A grid connection is 48 kW, or 38.4 kW continuous.
Cheers, Wayne
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Thanks for that - whoops!
Lots of good points as usual. Let's say a Powerwall can do 10 kW continuous now and 15 kW peak - just how many Powerwalls will you need to supply a 200A panel? I would guess at least 3, but you might be able to get away with 2 depending on your actual loads in the house for emergency use...
Yeah I got lucky on this one. The Sunrun guys who did my install had already replaced my main service panel and had emptied the distribution center there of everything except a bond that routed the energy out of the MSP into a giant blade disconnect (yay). From the blade disconnect things went into the input of the TEG2.
Since Sunrun was re-doing my grounding rods to comply with whatever wacky codes as well, so they went ahead and bonded the neutral to ground in the TEG2.
The inspector was like "hey now buddy, you can't have neutral to ground bonded except in the main." But then he looked at the main and didn't see any loads. So he took the approach that all Sunrun effectively did was drop in the a really expensive meter enclosure, and the Gateway was the "main distribution" source. So he was ok with it even though the TEG2 wasn't the "main panel." Crisis averted on this one...
BTW, assuming most people have integrated meter sockets and main service panels with distribution... what are your thoughts of someone intercepting the energy coming from the homeowner side of the meter socket... routing that to the input side of the gateway 2, then connecting the backup side of the TEG2 to the service disconnect in the main service panel?
Aside from the 36" rule from a gas riser, is this allowed? In this configuration the main service panel distribution side becomes the backup loads panel right?
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Generally not allowable. The conductors from the meter socket to the main breaker in the meter/main/distribution are factory installed and typically wouldn't be something an electrician is allowed to replace. If the conductors are wires and the enclosure provides adequate bending space for rerouting the wires, an inspector might allow it. But they are often busbars or wires with a sharp factory bend. The other approach would be to get the manufacturer to sign off the changes, which is both unlikely and could be expensive.
Cheers, Wayne
Yeah, I figured as much. So how could Elon's idea ever be implemented except in homes where the meter socket and main breaker are basically two different enclosures?
It won't be. [Well, with an overhead service, it might be possible to install a new enclosure for the meter and then jumper and close off the meter opening in the existing meter main.]
But not all of the country follows the California tradition of using meter/main/distribution panels.
Cheers, Wayne
As @wwhitney says, there is a lot of the country that doesn't have a meter integrated main service panel. I think it is about scale.
Along the lines of Henry Ford; "you can have it in any color you want as long as it is black".
Maybe it helps to think of it as "Tesla's integrated system works for everyone, as long as they don't have the meter integrated with their main service panel."
All the best,
BG
Along the lines of Henry Ford; "you can have it in any color you want as long as it is black".
Maybe it helps to think of it as "Tesla's integrated system works for everyone, as long as they don't have the meter integrated with their main service panel."
All the best,
BG
As @wwhitney says, there is a lot of the country that doesn't have a meter integrated main service panel. I think it is about scale.
Along the lines of Henry Ford; "you can have it in any color you want as long as it is black".
Maybe it helps to think of it as "Tesla's integrated system works for everyone, as long as they don't have the meter integrated with their main service panel."
All the best,
BG
Lol, the Universe revolves around California! I think we should change it to:
"Tesla's integrated system works for everyone, as long as they don't have the meter integrated with their main service panel, and their natural gas riser isn't within 36 inches of all the crap that is being spliced in."
OK, I figured out a possible solution that would work even where you have service panel with integrated meter.
SDG&E will sell you a nifty adapter for your main meter called a "Renewable Meter Adapter", specifically designed to avoid costly main service panel upgrades when you main service panel is full or you want enough solar that it would exceed the 120% rule. It is a meter adapter that plugs your main meter socket which allows you to perform the equivalent of a "line side tap". The adapter also holds the main meter and has a conduit fitting for you to feed your solar into.
This particular adapter is rated for 60A, but it's easy to see that a higher power adapter could be designed to do this and function as a grid disconnect in the event of a service outage.
This type of solution would literally be basically plug and play - the only wiring you would need to touch after installing this adapter would be the Powerwall and Solar related hardware.
Biggest challenge I see here is that you need the utility to come out and install the adapter and reinstall the meter, since they are the only people that are supposed to work with the meter.
SDG&E will sell you a nifty adapter for your main meter called a "Renewable Meter Adapter", specifically designed to avoid costly main service panel upgrades when you main service panel is full or you want enough solar that it would exceed the 120% rule. It is a meter adapter that plugs your main meter socket which allows you to perform the equivalent of a "line side tap". The adapter also holds the main meter and has a conduit fitting for you to feed your solar into.
This particular adapter is rated for 60A, but it's easy to see that a higher power adapter could be designed to do this and function as a grid disconnect in the event of a service outage.
This type of solution would literally be basically plug and play - the only wiring you would need to touch after installing this adapter would be the Powerwall and Solar related hardware.
Biggest challenge I see here is that you need the utility to come out and install the adapter and reinstall the meter, since they are the only people that are supposed to work with the meter.
jhn_
Member
In New England every house I have every lived in and seen has the meter socket and main breakers as different enclosure. I would say all single family residences are this way but I haven’t checked them all.
My house now definitely falls into Elon’s category. When we got the whole home backup solution installed last year, what they did to our electrical setup is exactly what they are describing as their way forward. Our main 200A panel got turned into a “backup” panel but nothing actually changed in the panel. All they changed was the underground feed from the grid to the meter was left in place but they rerouted from the meter to the new gateway in the garage, which then routed to the existing now “backup” panel. Solar and PW were also fed into the gateway. Very clean setup with minimal changes to existing wiring.
Anyone know if this is the same/equivalent as PG&E's GMA (Green Meter Adapter)? Can't seem to find any mention of price or actual installs in PG&E land.
https://www.pge.com/pge_global/comm...tion/greenbook-manual-online/TD-7001B-007.pdf
Edit:
Bummer for those of us with 200A service panels:
The GMA is not allowed on electric meter panels that: ...are rated above 125 amps...
While SDG&E's RMA "Fits on electric meter panels rated up to 200 amps maximum"
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Yes, as far as I know as well, it is a regional thing. I have only seen them in the West, though from the post by @wwhitney, there will be more of them across the country per the 2020 NEC. Personally, I always liked having the main service panel indoors, though I can see for fire safety reasons why the fire department might want it outside.In New England every house I have every lived in and seen has the meter socket and main breakers as different enclosure. I would say all single family residences are this way but I haven’t checked them all.
My house now definitely falls into Elon’s category. When we got the whole home backup solution installed last year, what they did to our electrical setup is exactly what they are describing as their way forward. Our main 200A panel got turned into a “backup” panel but nothing actually changed in the panel. All they changed was the underground feed from the grid to the meter was left in place but they rerouted from the meter to the new gateway in the garage, which then routed to the existing now “backup” panel. Solar and PW were also fed into the gateway. Very clean setup with minimal changes to existing wiring.
All the best,
BG
I guess Elon didn't really specify when his "splice in between the meter socket and main panel" idea would be. Maybe he is talking about a time where we're all watching the news of the Mars space colony.
California currently accounts for about 1/3 of solar installs in the USA. So I think overcoming California's prevalent use of the combo meter socket + panel hardware will be important.
Also keep in mind the line-side tap is only a means to get energy to the busbar at the panel. For a home backup solution, the backup loads would need to be behind the energy gateway. Assuming this, then the backup lugs of the Tesla Energy Gateway must be connected to the line side tap. So, how can the Gateway power the home when the utility were offline without sending the power back to the grid? The tap would need some other relay or disconnecting means when the utility goes offline.
I think Tesla will eventually just sell a main service panel replacement that has an integrated energy Gateway. I don't see them splicing into existing equipment in California with much luck. And hopefully PG&E views their new Gateway+MSP as a like-for-like swap.
BTW, here are some cool charts with trend data on installs and ESS from the SEIA.
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