You gotta be kidding me. Electricians won't add a Tesla wall connector on the backup side of ESS

[jjrandorin]

Is this only a concern because it's Sunrun?

I'm planning a whole home backup and Tesla Solar has approved it. However, I don't have an A/C or Tesla vehicle right now but I do plan on purchasing both next year. Would there be any issues adding both the A/C and Tesla to the backed up loads next year?

Hard to say, because these are construction projects, but my gut feeling is "probably" as the answer to your question of "will there be any issues adding an AC and tesla charger to the backup loads panel after install".

You would be MUCH MUCH MUCH better off with buying those things first, and getting the load calcs / system setup with them there, than trying to add them later. you probably wont have much issue adding them to the home in general, but adding them to the backup side? I believe that would be a cluster!!@$## as evidenced by OP here, and many others (like myself) who have stickers on their systems that basically forbid adding anything to the backup side.

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(moderator note: thread title changed as requested)

 

[jjrandorin]

This issue isn't because of Sunrun. I've asked the mods to update the thread title.

Sunrun hasn't opined one way or another. The electricians themselves are the ones that don't want to touch "Sunrun's sub panels" because of their own internal polices around touching backup loads. Since the entire house is backed up, that kind of messes things up.

I think you should talk to your Tesla solar rep to get in writing what you are supposed to do if you add AC and EV chargers in the future. You'll have two major options when the time comes:

1) Adding the new loads on the backup side; which would require someone to re-assess whether your Powerwalls would support the new loads

2) Adding the new loads on the non-backup side; which would require someone to provide some method of metering the non-backup side and ensuring your ESS could export energy upstream (when the utility were operational).

I guess it'd help to know Tesla's policies around a 3rd party Electrician touching their gear to begin with. "Their gear" in my point of view is anything on their solar or backup side of your house as well as the Tesla Gateway.

I am no expert on this, but I believe #2 requires the CTs be "in the right place". I can only go by my own install, where my tesla wall connector is on the NON backup side (so wont be powered in an outage), however, when the grid is up, solar + powerwalls provide power to it just fine, and it is shown as a load in the tesla app.

Said another way, when I charge my car, I can see the load spike in the tesla app, even though my wall connector is the only thing in my non backed up former main service panel.

 

[holeydonut]

I am no expert on this, but I believe #2 requires the CTs be "in the right place". I can only go by my own install, where my tesla wall connector is on the NON backup side (so wont be powered in an outage), however, when the grid is up, solar + powerwalls provide power to it just fine, and it is shown as a load in the tesla app.

Said another way, when I charge my car, I can see the load spike in the tesla app, even though my wall connector is the only thing in my non backed up former main service panel.

Yeah, when I first started with Sunrun, their designers/electricians didn't think what you said were possible. They didn't understand the Gateway 2 and how the CTs would help it push energy upstream when the PoCo were operational.

But once the designers realized Powerwalls could push energy upstream, their brains went to the stupid extreme. They thought the Powerwalls could then push 15 kW upstream to the PoCo grid. Because if the energy can go to your non-backup EV charger, what's stopping the energy from going into my neighbor's house???

I told them "because I didn't put the CT on my neighbor's MSP". But they don't care... they're just like "OMG the 120 percent rule must include both PV and ESS sources!!!!!!!!!!" And PG&E agreed with the Sunrun engineers. It's been absolutely INFURIATING dealing with Sunrun's "experts" and PG&E's desire to be as difficult as possible.

Anyway, back on topic... Unfortunately a 3rd party electrician down the road wouldn't be allowed to add this upstream CT since they wouldn't be allowed to touch the Gateway 2.

And Tesla Energy may not send out their own Power Ranger (lolz) to just add a CT. Maybe the OP can ask for an extra CT to be added during construction of his PV+ESS system to meter the main panel?

 

[holeydonut]

You would be MUCH MUCH MUCH better off with buying those things first, and getting the load calcs / system setup with them there, than trying to add them later. you probably wont have much issue adding them to the home in general, but adding them to the backup side? I believe that would be a cluster!!@$## as evidenced by OP here, and many others (like myself) who have stickers on their systems that basically forbid adding anything to the backup side.

Definitely recommend you get the other stuff installed first to avoid my pain.

But if you do anticipate later items Tesla may build in the expectation of the loads for you so things are good to go when you finally do get the AC and EV. I just don't think Tesla will do that "nice planning" for you since they're only doing cookie cutter plans and special consideration may be tough.

 

[Ampster]

.....sub-optimal setup since I couldn't charge the EV with any stored energy even if the utility were operational.

I think charging an EV from storage is sub optimal anyway so not an issue for me. I do have a small 20 Amp receptacle on the backup side so if the grid is down and my backup batteries are fully charged, then I have the option to get some solar energy into my cars if needed.
It is good to see from the comments above that there are solutions, but with everything, there are trade offs.
Just one general observation; even though you have large breakers on those sub panels, it does not mean that that three Powerwalls will be able even get close to that amount of Amps for any extended time.

 

[Akikiki]

@holeydonut, What inverter are you using? Solaredge? They have a version that has an EV charging option. It does not put an additional load on the system. Maybe Sunrun would swap that component out for you?

I have two PV systems. One is 11.53 and the other side 4.44 with 2 PWs. One was two years old and one is two months old. Didn't want to mess with the 11.53 so we added a second Solaredge. I insisted on the EV charging option on both. So with my NEMA 14-50, I have three ways to charge. My backup has a backup too.

 

[holeydonut]

I think charging an EV from storage is sub optimal anyway so not an issue for me. I do have a small 20 Amp receptacle on the backup side so if the grid is down and my backup batteries are fully charged, then I have the option to get some solar energy into my cars if needed.
It is good to see from the comments above that there are solutions, but with everything, there are trade offs.
Just one general observation; even though you have large breakers on those sub panels, it does not mean that that three Powerwalls will be able even get close to that amount of Amps for any extended time.

Yeah if worse comes to worse, there's one electrician that will add a charger on the non-backup side (and non-metered). So that load will still get PV and Grid energy, just no ESS energy. I guess that's not a big deal if I only charge with off-peak energy from PG&E.

 

[Ampster]

I guess that's not a big deal if I only charge with off-peak energy from PG&E.

I have been trying to optimize my true up and that means keeping my NBCs about equal to my Minimum Delivery Charges. Most of my charging is done at off peak but I have been playing around with doing some low Amperage charging from excess solar during mid peak. It is more of an intellectual challenge since the cost of those NBCs are only $0.025.

 

[wwhitney]

What a clusterf&*% there is no reason to not add the HPWC, except they don't want to.

This. Find an electrician who will install the HPWC on the panel in the OP. Apparently that means finding someone sufficiently educated about PV + storage that they can tell it's fine to do. The two electricians who objected are doing so out of ignorance. Maybe that caution is better than the alternative, but you need someone else.

Cheers, Wayne

 

[SMAlset]

I have been trying to optimize my true up and that means keeping my NBCs about equal to my Minimum Delivery Charges. Most of my charging is done at off peak but I have been playing around with doing some low Amperage charging from excess solar during mid peak. It is more of an intellectual challenge since the cost of those NBCs are only $0.025.

i mentioned somewhere that my husband prefers to recharge our PWs in the AM sunlight and when needed around noon to charge a car for some extra range. Our amps are turned down to kind of match the incoming solar so as not to use any from the PWs. More efficient use of energy coming straight from sun that way. Our non-peak hours run to 4pm so we get to add an okay amount of charge this way especially given he’s WFH and the vast majority of driving is local grocery and restaurant pick up. With days getting longer we’ll still be getting more sun back into PWs or grid after 4pm (sunset now after 5pm) and our aggregate generator provides equal credit for adding back to grid for that rate period not fractional so nice. Apart from winter months we are generally low cloud cover rest of year. Haven’t had system online for a summer yet so this will be interesting to see how we do throughout the year with 3 PWs and the solar array we have (8.16kW, limited by roof area).

 

[holeydonut]

@holeydonut, What inverter are you using? Solaredge? They have a version that has an EV charging option. It does not put an additional load on the system. Maybe Sunrun would swap that component out for you?

I have two PV systems. One is 11.53 and the other side 4.44 with 2 PWs. One was two years old and one is two months old. Didn't want to mess with the 11.53 so we added a second Solaredge. I insisted on the EV charging option on both. So with my NEMA 14-50, I have three ways to charge. My backup has a backup too.

Sunrun uses Enphase, and I don't think they have a similar tech.

 

[SMAlset]

Sunrun uses Enphase, and I don't think they have a similar tech.

Curious when you were discussing with them what you wanted in the way of a system, did the subject of future use or EVs come up? Rather common future addition these days. I know Tesla asked that question of us initially but we already had our 14-50 and cars at that point so the system was designed with our current requirements. I am glad we did our remodeling years prior though. We added a lot of additional circuits but were still left with expansion to solar and PWs.

 

[Akikiki]

Enphase? Oh my. I had Enphase on my early system. After their dumb micro inverters were prone to failure. That was no big deal at first - under warranty. but after 10 years, they stopped paying the contractors the labor fee to replace the free/warrantied micro inverters. After I paid $150-$175 for each of 15 visits to replace them scattered over a couple of years, - it was time get rid of them. No tax credits for replacing the sub system (micro inverters) so decided it was time to get big. Replaced 25 each 200-220 panels with 25 370's and all of the Enphase gear for Solaredge. Replacing all those panels and combining the inverter with it qualified for federal 30% and state 35% tax credits Soooo, much better.

Enphase had problems with their first generations of micro inverters. Well, that's not accurate. WE had problems with their micro inverters. They simply gave us another one just like it over and over. Then a few years ago they created the IQ version that does have smarts in it. When they sent me literature and a upgrade/replacement plan at my expense, I noticed they had the same warranty as the first gen. So, I believe I would find myself going through that onesy-twosy replacement again and me paying labor for each swap. No thank you.

That's not to say that Solaredge's single inverter system won't fail. I've read here on TMC of people with failed SE inverters. But its one component to replace to get back up, not 10-40 failing one at a time. I am very pleased with my SE system. I apologize for my biased towards Solaredge, but after the mess with Enphase it's like comparing Rolling Rock to Coors or Molson. I wonder how the new Tesla inverter will compare next to the performance of the Solaredge equipment.

 

[holeydonut]

Curious when you were discussing with them what you wanted in the way of a system, did the subject of future use or EVs come up? Rather common future addition these days. I know Tesla asked that question of us initially but we already had our 14-50 and cars at that point so the system was designed with our current requirements. I am glad we did our remodeling years prior though. We added a lot of additional circuits but were still left with expansion to solar and PWs.

Yeah, it was discussed in the very beginning. But with the 100 of other stupid derail-ers that I bumped into, the slot for an EV kind of got lost in the shuffle.

The last I spoke with Sunrun about this, they actually didn't have that 200A sub-panel for backup loads. At that time, they were using the sub-panel you see in the photo as a generation panel. They actually put the 90A and 70A breakers on the Gateway 2's internal panelboard.

They said the future EV charger breaker could just go on the last remaining spot of the internal panelboard. Easy peasy in their mind. And totally bad.

That's why I'm pretty sure Sunrun doesn't care if a EV charger goes in that 200 A box now that I flipped their design so the internal panelboard is for generation while the Square D box is for home loads. Unfortunately some 3rd party installers just don't want to get involved it seems. Sad.

 

[NathanielHrnblwr]

I'm planning a whole home backup and Tesla Solar has approved it. However, I don't have an A/C or Tesla vehicle right now but I do plan on purchasing both next year. Would there be any issues adding both the A/C and Tesla to the backed up loads next year?

Yes, absolutely. Ask them to plan and install the breaker for those items and design for it. When they do the install, they may not put in a panel rated for the amount of power you'll need later vs. what you'll need now.

 

[Notadog]

Yes, absolutely. Ask them to plan and install the breaker for those items and design for it. When they do the install, they may not put in a panel rated for the amount of power you'll need later vs. what you'll need now.

That's the frustrating part. My project advisor is refusing to plan for an addition of an AC unit in the future unless I purchase 3 Powerwalls. Is he incorrect then? I see so many people on this forum running AC off of 2 Powerwalls. Is it possible for me to change my project advisor or ask for a second opinion? Thanks.

 

[h2ofun]

That's the frustrating part. My project advisor is refusing to plan for an addition of an AC unit in the future unless I purchase 3 Powerwalls. Is he incorrect then? I see so many people on this forum running AC off of 2 Powerwalls. Is it possible for me to change my project advisor or ask for a second opinion? Thanks.

Who is running AC off 2 PW's? And for how long do they run?

 

[jboy210]

Who is running AC off 2 PW's? And for how long do they run?

Each Powerwall 2 can deliver a max of 5 kW continuous and has a capacity of 13.5 kWh. I have 2 and they start and run my A/C. I don't know how long they will last because I only tested it for a few minutes. If we were in a power outage I would likely not use the A/C.

 

[jjrandorin]

That's the frustrating part. My project advisor is refusing to plan for an addition of an AC unit in the future unless I purchase 3 Powerwalls. Is he incorrect then? I see so many people on this forum running AC off of 2 Powerwalls. Is it possible for me to change my project advisor or ask for a second opinion? Thanks.

AC specifically has such a variable amount of load and requirements to start, they cant plan for "future A/C" unless there is a specific make / model that you are in process of installing. 2 powerwalls might work for some A/C, and not for many others. I understand the desire to have A/C on the backup side, but if your home does not have A/C now, you obviously live in a location where A/C is not "a requirement".

You also likely dont know how fast AC would drain your powerwalls. You would likely not use them for very long if you were in a power outage. With that being said, yes I understand wanting A/C backed up so you have the choice. You will need to install it before your tesla install if you want it on the backup side, they will likely not install it later. Other electricians are likely not going to install it on the backup side later either.

See a picture of my backup loads panel below, which includes every load in my home except my EV charger, and that was excluded by my choice because the load balancing feature didnt exist then and I didnt want any chance of car charging draining powerwalls. Red sticker added by tesla for permitting, it as not an option:

Who is running AC off 2 PW's? And for how long do they run?

I actually have (2) A/C condensers connected to my "backup loads" panel, which as I said above, includes every single load in my house except for the tesla wall connector, by my choice. I live somewhere hot, where A/C is "required" (in every home, and apartment), so wanted the A/C backed up. If a home is over 3000 square feet in this area, it has to have 2 A/C units. Mine came with the home and one is for upstairs and one for downstairs. This home is not nearly the size you mentioned yours is, but is 3200 square feet, give or take, so its not "small" either.

Since these are the AC units that came with the home, built in 2005, they are "builder grade" ones that are not very efficient at all. They are 3 ton units but as the picture below will show, they are both on the backup loads panel. How long I could run them is another thing. Because each of these takes close to 4kWh of power, thats roughly 8kWh of power used every hour. That means if I had them both on, with the rest of my home, it would be 2 1/4 to 2 1/2 hours from full powerwalls to empty.

We almost never run both units at the same time, even during normal operation. In a power outage, they would only be used in 10-15 minute increments to keep the home from being "unbearable" inside.

In a power outage, if it happened in the middle of the summer, having them backed up means I could use the A/C to "increase my load" so the PV doesnt shut off, and I dont even need to try to put that energy into my vehicle (which I current cant because my charger is on the non backed up loads side).

So, I get wanting to have them on there, even if you wouldnt use them much, but @Notadog is going to have to get A/C installed first, or not have it on the backup loads side. I dont think there is an option for "pre plan for my A/C, when there isnt at least a purchase of the AC unit in progress.

If @Notadog checks these boards, they will find many instances of people being promised an A/C unit would work with a backup (specifically with 2 powerwalls) then people finding out that soft start units dont work with their specific A/C, or that it doesnt work properly. There would be no guarantee that it would work "later". If its a "must have" then it likely needs to be done before the powerwall install.

 

[h2ofun]

AC specifically has such a variable amount of load and requirements to start, they cant plan for "future A/C" unless there is a specific make / model that you are in process of installing. 2 powerwalls might work for some A/C, and not for many others. I understand the desire to have A/C on the backup side, but if your home does not have A/C now, you obviously live in a location where A/C is not "a requirement".

You also likely dont know how fast AC would drain your powerwalls. You would likely not use them for very long if you were in a power outage. With that being said, yes I understand wanting A/C backed up so you have the choice. You will need to install it before your tesla install if you want it on the backup side, they will likely not install it later. Other electricians are likely not going to install it on the backup side later either.

See a picture of my backup loads panel below, which includes every load in my home except my EV charger, and that was excluded by my choice because the load balancing feature didnt exist then and I didnt want any chance of car charging draining powerwalls. Red sticker added by tesla for permitting, it as not an option:


View attachment 637547




I actually have (2) A/C condensers connected to my "backup loads" panel, which as I said above, includes every single load in my house except for the tesla wall connector, by my choice. I live somewhere hot, where A/C is "required" (in every home, and apartment), so wanted the A/C backed up. If a home is over 3000 square feet in this area, it has to have 2 A/C units. Mine came with the home and one is for upstairs and one for downstairs. This home is not nearly the size you mentioned yours is, but is 3200 square feet, give or take, so its not "small" either.

View attachment 637545

Since these are the AC units that came with the home, built in 2005, they are "builder grade" ones that are not very efficient at all. They are 3 ton units but as the picture below will show, they are both on the backup loads panel. How long I could run them is another thing. Because each of these takes close to 4kWh of power, thats roughly 8kWh of power used every hour. That means if I had them both on, with the rest of my home, it would be 2 1/4 to 2 1/2 hours from full powerwalls to empty.

We almost never run both units at the same time, even during normal operation. In a power outage, they would only be used in 10-15 minute increments to keep the home from being "unbearable" inside.

In a power outage, if it happened in the middle of the summer, having them backed up means I could use the A/C to "increase my load" so the PV doesnt shut off, and I dont even need to try to put that energy into my vehicle (which I current cant because my charger is on the non backed up loads side).

So, I get wanting to have them on there, even if you wouldnt use them much, but @Notadog is going to have to get A/C installed first, or not have it on the backup loads side. I dont think there is an option for "pre plan for my A/C, when there isnt at least a purchase of the AC unit in progress.

If @Notadog checks these boards, they will find many instances of people being promised an A/C unit would work with a backup (specifically with 2 powerwalls) then people finding out that soft start units dont work with their specific A/C, or that it doesnt work properly. There would be no guarantee that it would work "later". If its a "must have" then it likely needs to be done before the powerwall install.

Yep, that was my thought, if you ran JUST the AC, 2 PW's a few hours. But of course we have the rest of the house one so no one would risk IMO running AC. Now, I hope to have 3 PW's just for my heating cooling, which the other 2 PW's would be connected to the house. At least if I were to use up the 3 PW's, my refrig, etc in my house still work. And even then, my generator would kick in for the heating/ac load only so I am all set for either short of long term shutdown's, sun or no sun.

I have heard about folks who put in 1 PW and were shocked when after using for like an hour or 2, it was dead. But they were told it was whole house. They now installed a 22K generator.