Powerwall 2: Installation

[Frankman60]

What about this situation. I only plan to install one PW now, but may want to expand to two PWs in the future if the price decreases or other incentives are introduced. I understand if I want to stack two Powerwalls, they must be placed on the ground. In my situation I am only installing one PW now, and would prefer that it be mounted at least several inches off the ground on the side of my house (to keep rain runoff from touching the PW). This elevated wall mounting is fine for one PW but not if I want to add a second PW later. If I add a PW later, the first one that is already on the wall will need to be dropped several inches to the ground. My question is, is there a place to leave some excess wire in the PW or the gateway so this can be done without pulling new wire through the conduit? I assume that the metal conduit can be extended the few inches needed. Any thoughts on this?

 

[wwhitney]

Again, if you get a second Powerwall, you could build a little pedestal to go under both Powerwalls to keep them off the ground and so you don't have to relocate the first Powerwall.

Otherwise, if there is going to be exposed exterior conduit coming into the side of the Powerwall, then just make sure the conduit penetrates the exterior wall less than 30" above grade. That's the height of the conduit coming into the side of a Powerwall that is sitting on the ground. So with the Powerwall elevated on the wall, the conduit run will have to turn up to get to the proper elevation, and when you lower the Powerwall, that upturned segment can be shortened. No increase in conductor length required. The conduit would need rerouting, though, so the wire would have to be partially pulled out (maybe to an LB installed at the wall penetration) for that to happen.

BTW, if you qualify for SGIP step 2, then the net cost of a second Powerwall from Tesla is about $1500. That's $5,500 for the unit, plus $200 in additional labor, plus about $500 in sales tax, less about $4,700 in SGIP rebate. And if you are taking the ITC because you have an existing solar system and you are going to commit to only charging the Powerwalls from solar, that goes down to a little over $1,000.

Cheers, Wayne

 

[Frankman60]

I like your idea about the conduit height. But in my case the conduit will be running down the outside wall from above, which is the same wall that the PW will be mounted on. So the conduit feeds into the PW at 30 inches high when the PW is ground mounted. Which side of the PW does the conduit feed into?

Again, if you get a second Powerwall, you could build a little pedestal to go under both Powerwalls to keep them off the ground and so you don't have to relocate the first Powerwall.

Otherwise, if there is going to be exposed exterior conduit coming into the side of the Powerwall, then just make sure the conduit penetrates the exterior wall less than 30" above grade. That's the height of the conduit coming into the side of a Powerwall that is sitting on the ground. So with the Powerwall elevated on the wall, the conduit run will have to turn up to get to the proper elevation, and when you lower the Powerwall, that upturned segment can be shortened. No increase in conductor length required. The conduit would need rerouting, though, so the wire would have to be partially pulled out (maybe to an LB installed at the wall penetration) for that to happen.

BTW, if you qualify for SGIP step 2, then the net cost of a second Powerwall from Tesla is about $1500. That's $5,500 for the unit, plus $200 in additional labor, plus about $500 in sales tax, less about $4,700 in SGIP rebate. And if you are taking the ITC because you have an existing solar system and you are going to commit to only charging the Powerwalls from solar, that goes down to a little over $1,000.

Cheers, Wayne

 

[wwhitney]

When facing the front of the Powerwall, the left (from the photos posted here).

I think building a little pedestal to go under your elevated Powerwall would be the easiest way to add a second one stacked.

If you still want to think about lowering it on the ground to add a second one, then having your conduit come down from on the exterior of the wall complicates things. You could use an LR conduit body to transition from vertical to horizontal and set it so its horizontal outlet is about 30" off the ground. Then with your elevated Powerwall you'd have to have a offset in the horizontal conduit run to get back up to the correct elevation. To lower the Powerwall you'd open the LR conduit body, pull back the conductors, and then replace the offset horizontal run with a straight horizontal run to the lowered unit, and re pull the conductors.

Also, not sure if Tesla is using a different size conduit for serving one Powerwall versus two Powerwalls. If so, you'd obviously want the larger conduit size.

Cheers, Wayne

 

[Frankman60]

I see your point about the Pedestal for the second PW Wayne. I was first concerned about how secure the second PW would be on a pedestal. But I think when two PWs are stacked, there is some type of joining hardware that holds them together. And since the first PW would be mounted on the wall, the second one on the pedestal would be more stable right? BTW, in my region I am on Step 4 SGIP so the second PW would be a little more costly than on Step 2. But also I’m not sure right now I will need a second PW.

 

[markb1]

So does “floor-mounted” really mean that it’s mounted to the floor and wall? If so, that’s annoying, because one location I was considering would be next to the block wall on the property line, where the HOA rules say nothing can be permanently attached.

 

[Frankman60]

I don’t think so. I believe that PWs can be put on the floor side by side without being attached to a wall. But if they are stacked, I believe that one is required to be anchored to a wall. This is on the Tesla FAQ:

What does a multiple Powerwall installation look like?
Multiple Powerwalls can be mounted as single side-by-side units on a wall or on the floor, or stacked front-to-back (up to 3 deep per stack) on the floor only. When mounted side-by-side on a wall, Powerwall units must have sufficient clearance on each side for electrical connections and proper ventilation. When stacked front-to-back, Powerwalls must be floor-mounted, the stack must be anchored to an adjacent wall, and the Powerwalls must be joined together with Powerwall Stack Kit hardware. For stacked systems with more than 3 Powerwalls, separate stacks of 3 units should be installed, with each stack attached to a wall.

So does “floor-mounted” really mean that it’s mounted to the floor and wall? If so, that’s annoying, because one location I was considering would be next to the block wall on the property line, where the HOA rules say nothing can be permanently attached.

 

[wwhitney]

So does “floor-mounted” really mean that it’s mounted to the floor and wall? If so, that’s annoying, because one location I was considering would be next to the block wall on the property line, where the HOA rules say nothing can be permanently attached.

If you think about how slender the Powerwall units are, they'd be a tipping hazard without something to laterally stabilize them. Structurally, it ought to be enough to install a single pole like a fence post and fasten them to the pole. [E.g. a wooden post embedded in concrete in the ground, or a metal post with a welded base plate that is bolted to a concrete slab.] Whether Tesla would have any reservations about that installation, I couldn't say.

Cheers, Wayne

 

[Kren]

My Solar City installers were super cool. Were were originally suppose to be installed all outside. We have some wiring inside that in the beginning all estimates where that we would have to have a licensed electrical contractor remove or reroute the wiring. But when the Solar City electricians/installers came for their pre-install inspection, they said for my installation, better to install inside because of worst case weather related scenario concerns and no need to move wiring. Inside we also had a huge dart board system (4'X4') on the wall where they wanted to install. They said they would try their best to figure an installation that would keep the dart board in its place. Turns out they couldn't do it. They had to remove the dart board.But I really appreciate their effort and expertise in trying to maintain our original space plans. all this to say that when you have some preference of where and how you want things install, Tesla Engineers may say no we can't do it. But in my case, installers worked with me, saw possibilities and adjusted layout.

 

[arnolddeleon]

My Solar City installers were super cool. Were were originally suppose to be installed all outside. We have some wiring inside that in the beginning all estimates where that we would have to have a licensed electrical contractor remove or reroute the wiring. But when the Solar City electricians/installers came for their pre-install inspection, they said for my installation, better to install inside because of worst case weather related scenario concerns and no need to move wiring. Inside we also had a huge dart board system (4'X4') on the wall where they wanted to install. They said they would try their best to figure an installation that would keep the dart board in its place. Turns out they couldn't do it. They had to remove the dart board.But I really appreciate their effort and expertise in trying to maintain our original space plans. all this to say that when you have some preference of where and how you want things install, Tesla Engineers may say no we can't do it. But in my case, installers worked with me, saw possibilities and adjusted layout.

It seems field installers are rocks stars, "designers" not so much. As I mentioned before I really appreciated the work for the first crew. They were willing to ask me about things, offer options and in the end even I didn't get what I wanted I felt good about it. I'm pretty sure I caused some some extra grief but I also believe by working with me I was able to save them work and come something that benefited us both. Even my battery crew which didn't give me installation options on the battery options was savvy enough to find a better location for the generation panel. Given the size of the feeders that needed to go between the gateway and that panel I'm sure it was huge win for them.

arnold

 

[jeep1979]

First big test of my installation came today with a planned SCE outage lasting 8 hours and 41 minutes from about 9am to 5:30pm. Everything worked as expected and hoped for. I noticed nothing when the grid power was shut off and ran on a combination of solar and/or battery as they day went on. A weather front moved in around noon and the skies grew cloudy reducing my solar production. I went about everything normally running the heater, microwave, lights, TV and everything else. Very pleased with the system.

 

[Frankman60]

Can someone help me understand the hardware required to install 2 PWs in a home with a single electrical panel with 200 amp service for whole home backup? I see on page 8 of the Tesla Installation manual it shows that the backup gateway would be installed between the utility meter and the main panel. There is no subpanel shown in the diagram like on page 9 where presumably one PW is installed and backs up only selected loads (eg under 30 amps). One contractor said that he would install a 400 amp subpanel and the gateway for the installation, which would look like the diagram on page 9. Why is a subpanel needed for my installation of 2 PWs? I think it is because of the limitations of the 200 amp main panel (I have 7.6 kW solar and 50 amp car charger) but just wanted to confirm with the knowledgeable folks on this forum. If it is a limitation of the 200 amp main panel, could the main panel be upgraded rather than using a sub panel?

 

[markb1]

Can someone help me understand the hardware required to install 2 PWs in a home with a single electrical panel with 200 amp service for whole home backup? I see on page 8 of the Tesla Installation manual it shows that the backup gateway would be installed between the utility meter and the main panel. There is no subpanel shown in the diagram like on page 9 where presumably one PW is installed and backs up only selected loads (eg under 30 amps). One contractor said that he would install a 400 amp subpanel and the gateway for the installation, which would look like the diagram on page 9. Why is a subpanel needed for my installation of 2 PWs? I think it is because of the limitations of the 200 amp main panel (I have 7.6 kW solar and 50 amp car charger) but just wanted to confirm with the knowledgeable folks on this forum. If it is a limitation of the 200 amp main panel, could the main panel be upgraded rather than using a sub panel?

I don't think a subpanel should be required, or at least Tesla didn't include one in the quote for me, and my situation is similar. Where is this installation manual you are referencing? I've be very interested in reading that.

 

[Kren]

Can someone help me understand the hardware required to install 2 PWs in a home with a single electrical panel with 200 amp service for whole home backup? I see on page 8 of the Tesla Installation manual it shows that the backup gateway would be installed between the utility meter and the main panel. There is no subpanel shown in the diagram like on page 9 where presumably one PW is installed and backs up only selected loads (eg under 30 amps). One contractor said that he would install a 400 amp subpanel and the gateway for the installation, which would look like the diagram on page 9. Why is a subpanel needed for my installation of 2 PWs? I think it is because of the limitations of the 200 amp main panel (I have 7.6 kW solar and 50 amp car charger) but just wanted to confirm with the knowledgeable folks on this forum. If it is a limitation of the 200 amp main panel, could the main panel be upgraded rather than using a sub panel?

I am not technically inclined and I don't have lovely install photos like some. But I PM'd a diagram of my install which is very similar. No subpanel.

 

[Frankman60]

Manual is here: Resources for Powerwall Owners

I don't think a subpanel should be required, or at least Tesla didn't include one in the quote for me, and my situation is similar. Where is this installation manual you are referencing? I've be very interested in reading that.

 

[markb1]

Manual is here: Resources for Powerwall Owners

Oh, yeah, I've seen that. I think there is also an installation manual that is only available to installers.

 

[Frankman60]

If your existing main panel is 200 amps, did the Tesla estimate include upgrading the panel to a higher amp panel?

I don't think a subpanel should be required, or at least Tesla didn't include one in the quote for me, and my situation is similar. Where is this installation manual you are referencing? I've be very interested in reading that.

 

[markb1]

If your existing main panel is 200 amps, did the Tesla estimate include upgrading the panel to a higher amp panel?

There is a line item for "main panel upgrade", but it is $0. The existing panel is 200A, and I'm pretty sure they don't intend to upgrade it.

 

[SoundDaTrumpet]

If your existing main panel is 200 amps, did the Tesla estimate include upgrading the panel to a higher amp panel?

It is most straightforward to install a new backup loads subpanel, and render your existing main service panel (MSP) empty with only one breaker to the new subpanel. The existing MSP is just for the meter and to hold a single 175 or 200 Amp breaker to the gateway and everything downstream. I did got not charged (N/C) for a main panel upgrade. My explanation for the N/C is they are adding panels and not removing/replacing the main service panel (the one that's flush mounted into your house). Adding surface mount panels are cheap and easy ($100 load center plus conduit and relocating breakers, which they were planning to do anyway) compared to replacing a main service panel (significant chore: disconnect PG&E feed, stucco work). Even so at $2500 for a true upgrade say 100A to 200A would be a reasonable. If it was to a 400A service all inclusive, that'd be a steal.

 

[jeep1979]

Can someone help me understand the hardware required to install 2 PWs in a home with a single electrical panel with 200 amp service for whole home backup? I see on page 8 of the Tesla Installation manual it shows that the backup gateway would be installed between the utility meter and the main panel. There is no subpanel shown in the diagram like on page 9 where presumably one PW is installed and backs up only selected loads (eg under 30 amps). One contractor said that he would install a 400 amp subpanel and the gateway for the installation, which would look like the diagram on page 9. Why is a subpanel needed for my installation of 2 PWs? I think it is because of the limitations of the 200 amp main panel (I have 7.6 kW solar and 50 amp car charger) but just wanted to confirm with the knowledgeable folks on this forum. If it is a limitation of the 200 amp main panel, could the main panel be upgraded rather than using a sub panel?

This is my setup. There appears to be two different way Tesla does installs. In my case, they took the incoming service through my 200A panel directly to their 200A switch and then ran power back to the breakers in my main panel. In other installation they installed a second 200A panel, i.e Main 200A panel has just the 200A breaker to their switch to the second 200A panel with all the breakers in it. Tesla installs their own subpanel of 125A that contain a 30A breaker for each Powerwall battery and a 40A (in my case) breaker for my solar (6.2KW). No other subpanels are required. Hope this helps.