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2xPowerwall whole house backup - HVAC sure start problem

BIC1

Member
Feb 19, 2020
90
16
Missouri USA
I'm neither an electrician or an HVAC tech---but I did play one on TV. On my indoor panel, my 2-ton has a 20 amp and my 3-ton has a 30 amp breaker. Outside, on the AC units, they both appear to have 60 amp ACD (Air Conditioning Disconnect). I believe these are just for the HVAC techs to service your AC unit without going inside to turn the breaker off. They can handle any inside breaker up to 60 amps but that has nothing to do with the inside breaker ratings, which would be your true max current.

Interestingly, since I have LRAs of 52 and 82 respectively, guess the breakers don't trip on the momentary LRA surge or maybe that surge stays outside.
 

RKCRLR

Member
Apr 13, 2020
480
199
Garden Valley, CA
The last technician that came out couldn't get it to work (he wasn't an HVAC guy). I told him to remove the SureStart and rewire the compressor per the factory diagram until they figure it out. Then the AC wouldn't start at all. He said the outside unit must be bad and it could be just a coincidence that problems started happening when they installed the SureStart. He said that I need to call a HVAC repair service and get it fixed. He said the HVAC repair service would have to state that the SureStart caused the problem if I wanted to get reimbursed. I called a local HVAC service and asked them what they would do (while the tech was still here). They said they would diagnose what the bad component(s) was but wouldn't state what caused the problem.

I compared the factory wiring diagram to what the tech rewired and noticed that there was a wire missing going to the start capacitor. I asked the tech why he didn't install that wire. He said he rewired it per a picture that was taken by the first tech prior to installing the SureStart. I looked at the picture and noticed that there was a disconnected wire so it couldn't be before the first tech started the job. The tech said that was all he could do and needed to get to another job. I made a wire up after the tech left and connected per the wiring diagram. The unit now runs like it did before Tesla touched it.

I don't know if I could get Tesla to install a 3rd Powerwall since I'm getting a SGIP incentive and that might not comply with the terms of the agreement.
I thought I'd give an update and I'm a little miffed.
I got an automated email yesterday from PG&E notifying me that they just received a request for interconnect for my system. Tesla told me this was done weeks ago so it annoyed me (and the fact that they put an incorrect mailing address on the form).
I called Tesla for an update on my SureStart status. Turns out the reason I got the interconnect notice from PG&E was because Tesla had changed my building permit to remove my AC from the backup panel and they resubmitted the PTO request with the new permit number. There was no communication with me about their plan or my concurrence that I agreed to have the AC removed from the backup panel.
Additionally, it isn't that simple to remove my AC from the panel. My service meter, solar, powerwalls, gateway, backup panel, everything, is mounted on my shop. The power for my house comes underground in conduit 250' from the backup panel. There isn't enough room left in the conduit for another set of wires to relocate the backup panel at my house. They would have to trench and I don't know if that is practical. There is landscaping, my lawn, concrete patio, etc over the original trench path. And, to go around, they would have to go a long way around since there is a septic system, pond, and other stuff in the way. I don't think that length would be acceptable.
There may be enough room in the conduit to pull just the wires for the AC and put it in the backup panel but I don't know if I want that (I don't want to have to go down to my shop to reset that breaker).
The bottom line is the agreement is the AC would be part of my backup and they changed this without even discussing it with me.
And if they think they are going to send me a bill for the modifications they have another think coming (I have already paid for the install in full).
 

BIC1

Member
Feb 19, 2020
90
16
Missouri USA
This guy says he's the one that partners with Tesla to provide the SureStart. Even though the generic wiring instructions should be sufficient, he said he would mark up the factory compressor wiring diagram for any customer to remove any chance for error, which seems to be common, reading this thread.

Jeff Solak
Owner | Premier Components Supply LLC
7108 W. Belmont Ave, Chicago, IL 60634
1-802-342-5727 | [email protected]
 

niveknow

Member
Jul 7, 2020
81
42
Houston, TX
I have 2 AC units and appear to have Sure Starts listed in my equipment list details:

EE-009508-016 Soft Starter, 230V, 60/50Hz, 08-16 RLA Sure-Start # SS1B08-16SN
EE-009516-032 Soft Starter, 230V, 60/50Hz, 16-32 RLA Sure-Start # SS1B16-32SN
 

RKCRLR

Member
Apr 13, 2020
480
199
Garden Valley, CA
This guy says he's the one that partners with Tesla to provide the SureStart. Even though the generic wiring instructions should be sufficient, he said he would mark up the factory compressor wiring diagram for any customer to remove any chance for error, which seems to be common, reading this thread.

Jeff Solak
Owner | Premier Components Supply LLC
7108 W. Belmont Ave, Chicago, IL 60634
1-802-342-5727 | [email protected]
I'll give him a try but Hyper Engineering said the SureStart isn't compatible with reverse running compressors.
 

BIC1

Member
Feb 19, 2020
90
16
Missouri USA
I have 2 AC units and appear to have Sure Starts listed in my equipment list details:

EE-009508-016 Soft Starter, 230V, 60/50Hz, 08-16 RLA Sure-Start # SS1B08-16SN
EE-009516-032 Soft Starter, 230V, 60/50Hz, 16-32 RLA Sure-Start # SS1B16-32SN
Yep, those are the same two part numbers Hyper gave me for my 2-ton & 3-ton. Make sure they don't get mixed up.
 

Left coast

Member
Apr 11, 2019
37
31
Ventura
I thought I'd give an update and I'm a little miffed.
I got an automated email yesterday from PG&E notifying me that they just received a request for interconnect for my system. Tesla told me this was done weeks ago so it annoyed me (and the fact that they put an incorrect mailing address on the form).
I called Tesla for an update on my SureStart status. Turns out the reason I got the interconnect notice from PG&E was because Tesla had changed my building permit to remove my AC from the backup panel and they resubmitted the PTO request with the new permit number. There was no communication with me about their plan or my concurrence that I agreed to have the AC removed from the backup panel.
Additionally, it isn't that simple to remove my AC from the panel. My service meter, solar, powerwalls, gateway, backup panel, everything, is mounted on my shop. The power for my house comes underground in conduit 250' from the backup panel. There isn't enough room left in the conduit for another set of wires to relocate the backup panel at my house. They would have to trench and I don't know if that is practical. There is landscaping, my lawn, concrete patio, etc over the original trench path. And, to go around, they would have to go a long way around since there is a septic system, pond, and other stuff in the way. I don't think that length would be acceptable.
There may be enough room in the conduit to pull just the wires for the AC and put it in the backup panel but I don't know if I want that (I don't want to have to go down to my shop to reset that breaker).
The bottom line is the agreement is the AC would be part of my backup and they changed this without even discussing it with me.
And if they think they are going to send me a bill for the modifications they have another think coming (I have already paid for the install in full).
This is very concerning. I’m in the same boat though it will be much easier to remove my ac from the backup. I’ve asked if they will reimburse me for hiring an electrician to find a solution to keep my ac in the 2pw backup panel rather than sending an electrician to remove my ac out of the backup. I have my doubts, no hurt in asking though.
 

RKCRLR

Member
Apr 13, 2020
480
199
Garden Valley, CA
Theoretically, one could add external switching (relays) and use two units, one for each direction.
Or possibly one unit if the reverse direction doesn't require the soft start.
I asked EasyStart if 2 units could be used. They said no because the logic for monitoring wouldn't work. I suspect SureStart would be similar.
EasyStart said their unit would work on the forward (high) stage. But it wouldn't have an effect on the reverse (low) stage. They estimated low stage start requires about half the LRA. My LRA is 130 so it would be marginal for 2 Powerwalls.
I wonder if 2 "dumb" units like Schneider Electric's Altistart would work. Or perhaps a mixture of both.
 

bob_p

Active Member
Apr 5, 2012
3,728
2,922
Depending upon the size of the HVAC systems, it may be tight to run 2 units off 2 PowerWalls, especially if there is additional load in the house.

We have 3 HVAC systems in our house with 4 PowerWalls, and after "hard starts" were added to all 3 units, we're able to run everything in our house (3 HVAC, 2 full-size refrigerators, pool pumps, lights, computers, ...) off grid with the 4 PowerWalls, as long as we aren't running the electric ovens (which pull a lot of power while heating up).

With 2 HVAC units, it may be better to add a 3rd PowerWall, along with the easy starts...
 

RKCRLR

Member
Apr 13, 2020
480
199
Garden Valley, CA
Depending upon the size of the HVAC systems, it may be tight to run 2 units off 2 PowerWalls, especially if there is additional load in the house.

We have 3 HVAC systems in our house with 4 PowerWalls, and after "hard starts" were added to all 3 units, we're able to run everything in our house (3 HVAC, 2 full-size refrigerators, pool pumps, lights, computers, ...) off grid with the 4 PowerWalls, as long as we aren't running the electric ovens (which pull a lot of power while heating up).

With 2 HVAC units, it may be better to add a 3rd PowerWall, along with the easy starts...
I only have 1 unit but it has 2 stages. That is what is causing the problem. The low stage runs in reverse.
 

ArizonaJon

Member
May 29, 2020
97
37
Tucson, AZ
Care to share a bit more about this? Is this a universal device? How is it different than the sure start Tesla installs? What did it cost to install? I have the same issue and want to have an alternative ready. Although they did misrepresented my install as well I doubt they’ll gift me another powerwall. Maybe I can get them to cover this device?

thanks!
The device is a Micro-Air EasyStart. Link to product below. Looks like they are a little less than $350. Mine was included with the system installation.
EasyStart™ 368 Soft Starter
 

RKCRLR

Member
Apr 13, 2020
480
199
Garden Valley, CA
I did some playing around yesterday with a simulated power outage.

Running off Powerwalls with no solar:
The low stage AC start was hit and miss. I didn't try turning off all of the breakers so there were still some automatic loads (refrigerator, etc.) that would be there (between .5kW and 1kW). The Powerwalls would come back after a few seconds after being tripped due to the AC trying to start. I think the AC is it's own worst enemy since the outside and inside fans are commanded to run before the compressor starts. The thermostat is computerized so there is no way to directly control when the compressor tries to start. It can take several minutes (or longer if it has a fault stored) before it will try to start again. And I can't lock out the high stage so it will trip the Powerwalls if it thinks it needs high stage.

Running off Powerwalls with solar generating:
Everything works as normal. I even started my well pump with the AC running on high stage.

The problem is there is a small window between when the Gateway commands the solar to start generating and when the Powerwalls get full enough to stop charging.

Is there a way to command the Gateway to let the Powerwalls drain down to a lower level when in backup mode and then command the solar to start charging again?
This would give me enough time to get the AC running in high stage to "supercool" the house and then turn it off.
 

cali8484

Member
Jul 8, 2018
282
161
California
I did some playing around yesterday with a simulated power outage.

Running off Powerwalls with no solar:
The low stage AC start was hit and miss. I didn't try turning off all of the breakers so there were still some automatic loads (refrigerator, etc.) that would be there (between .5kW and 1kW). The Powerwalls would come back after a few seconds after being tripped due to the AC trying to start. I think the AC is it's own worst enemy since the outside and inside fans are commanded to run before the compressor starts. The thermostat is computerized so there is no way to directly control when the compressor tries to start. It can take several minutes (or longer if it has a fault stored) before it will try to start again. And I can't lock out the high stage so it will trip the Powerwalls if it thinks it needs high stage.

Running off Powerwalls with solar generating:
Everything works as normal. I even started my well pump with the AC running on high stage.

The problem is there is a small window between when the Gateway commands the solar to start generating and when the Powerwalls get full enough to stop charging.

Is there a way to command the Gateway to let the Powerwalls drain down to a lower level when in backup mode and then command the solar to start charging again?
This would give me enough time to get the AC running in high stage to "supercool" the house and then turn it off.

Just curious, did you ask Tesla for a 3rd PW? If so, what was their response?
 

RKCRLR

Member
Apr 13, 2020
480
199
Garden Valley, CA
Just curious, did you ask Tesla for a 3rd PW? If so, what was their response?
I haven't asked Tesla about a 3rd Powerwall. Would that require another Gateway?
I'm getting a SGIP incentive and I don't want to jeopardize that. I'm hoping Tesla can come up with a solution. I know that any storage system that exceeds 10kW is a whole another set of hoops you have to jump through for the incentive I'm getting. If I were to get a 3rd Powerwall it would have to be outside of the SGIP approval loop.
 

mongo

Well-Known Member
May 3, 2017
13,486
42,178
Michigan
I haven't asked Tesla about a 3rd Powerwall. Would that require another Gateway?
I'm getting a SGIP incentive and I don't want to jeopardize that. I'm hoping Tesla can come up with a solution. I know that any storage system that exceeds 10kW is a whole another set of hoops you have to jump through for the incentive I'm getting. If I were to get a 3rd Powerwall it would have to be outside of the SGIP approval loop.

Still one gateway.
It would cross the 10kW boundary, but check with your installer, 3 PWs might actually get you more per battery.

SGIP with Large Scale Energy Storage (3 x PowerWalls) with Tesla or Individual
 

RKCRLR

Member
Apr 13, 2020
480
199
Garden Valley, CA
Still one gateway.
It would cross the 10kW boundary, but check with your installer, 3 PWs might actually get you more per battery.

SGIP with Large Scale Energy Storage (3 x PowerWalls) with Tesla or Individual
My SGIP incentive allocation has already been approved and reserved. I applied under the Residential Equity Resiliency program. That program is currently out of funding so there is no going back to the well for more money. I'm waiting for PTO so Tesla can submit the final paperwork. Also, as I remember, Tesla didn't even want to do applications for anything greater than 10kW (it would need to be a 3rd party developer).
And I'm not even sure 3 Powerwalls would be enough. My LRA is 130 for high stage. Low stage is about half that and it is hit and miss for it starting. It's quite possible I'd need 4 Powerwalls to start the high stage. Tesla would need to measure the actual inrush current to be sure.
 
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holeydonut

Supporting Member
Supporting Member
Jun 27, 2020
2,236
1,624
East Bay NorCal
Another thing to consider for adding soft starts is that they could void your warranty.

I have Dual Stage Lennox XC21s and had a Licensed/Trained/Certified/whatever Lennox technician on site to install soft-starts. But he called HQ and Lennox told him that they would not allow soft starts to be installed on my equipment otherwise I would void the warranty on the condensers. They added that:

1) Lennox Industries had no documented instance of anyone ever installing a Soft Start on their current generation of residential compressors (includes all of their current Merit, Elite, and Signature lines).

2) Soft starts are not recommended on Lennox's older, dual stage equipment since the soft start cannot properly learn the in-rush current demands of both the single and dual stages
 

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