Typical canned response, what are you supposed to do in a PG&E outage? roast in your home during summer?
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2xPowerwall whole house backup - HVAC sure start problem
- Thread starter af88
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Jump in neighbor's pool!
We actually looked into this with the PSPS. The power outage seem to occur in the late fall when the winds reverse and we get red flag conditions. By then the days are shorter. And looking our bills we hardly use the A/C after mid October
I presume that the point was that when the sun is shining the panels are running the A/C. After the sun goes down the Powerwalls will drain fairly fast, so just be aware of that. If you need to run A/C at night during a power failure, you need more Powerwalls.
The problem is, most
I agree with you that they were trying to make someone aware, but the home won’t run the ac full blast all night.
This isn’t a sure start issue for most of us, Tesla energy employees in the sales / tech support /engineering side do not know how to properly size a powerwall+PV system for an HVAC system, they frequently forget that the traditional compressor or heat pump and air handler will often run at the same time. Crazy concept, I know!
I agree with you that they were trying to make someone aware, but the home won’t run the ac full blast all night.
This isn’t a sure start issue for most of us, Tesla energy employees in the sales / tech support /engineering side do not know how to properly size a powerwall+PV system for an HVAC system, they frequently forget that the traditional compressor or heat pump and air handler will often run at the same time. Crazy concept, I know!
aesculus
Still Trying to Figure This All Out
The worst of it is heat pumps. When they are in defrost mode or when they are loosing ground they turn on resistive heating in addition to the regular load. This is often a bigger draw than all the other aspects combined so you can see huge loads.The problem is, most
I agree with you that they were trying to make someone aware, but the home won’t run the ac full blast all night.
This isn’t a sure start issue for most of us, Tesla energy employees in the sales / tech support /engineering side do not know how to properly size a powerwall+PV system for an HVAC system, they frequently forget that the traditional compressor or heat pump and air handler will often run at the same time. Crazy concept, I know!
Yep! 1000000%. They have zero understanding of the photos and information they have you send them.
blatantly disregarded multiple attempts to get them to understand what the datasheets say for the pw.
At this point, it’s laughable. I’ve had a leaking SGv3 install for 4days with zero interaction from my acct manager despite every attempt to reach him from every angle possible.
Absolute COMEDY at this point.
Once a system is installed, the Tesla app can help considerably to determine how much power each device uses by watching the Home power increase and decrease as a single device is turned on and off.
With the hard start upgrades to our 3 HVAC air compressors, we have enough power with our 4 PowerWalls to run all 3 air conditioners at the same time, and still have sufficient power to run everything else in the house (except for running our double electric ovens).
We were concerned about two off-grid scenarios:
With the hard start upgrades to our 3 HVAC air compressors, we have enough power with our 4 PowerWalls to run all 3 air conditioners at the same time, and still have sufficient power to run everything else in the house (except for running our double electric ovens).
We were concerned about two off-grid scenarios:
- Short un-planned outages that might last a few minutes to a few hours, possibly when we aren't at home. For these outages, we want the system to run without any intervention on our end. We were able to test and verify this once the system was operating.
- Multi-day anticipated outages (after a hurricane) when we would manually turn off non-essential systems to stretch our solar and PowerWall power as long as possible (assuming the PowerWalls would be in Storm Mode and full when the outage hit). Excluding EV charging, we ran for 5 days recently without using any grid power for the house - so we're confident we can survive multi-day outages, as long as there is some sun.
Yes, you can do a whole home back up with two powerwalls but you will absolutely need the sure starts installed to prevent failure if you don't have a newer energy-efficient unit. It is recommended that you have 3-4 Powerwalls if you are backing up your A/C because most A/C units will drain your battery very quickly.
It also depends upon the size of your air conditioners. We have 3 units (one small for the master bedroom area and two large for the rest of the house). The smaller unit uses about 2KW while the larger units use around 4KW. 2 PowerWalls would be tight to support two large (4 or 5 ton) air conditioners, since the PowerWalls can only sustain 5KW each.
Could you share more information about the soft start device you used?
Spent 6 hours yesterday with an HVAC guys... the SureStart device went in, compressor started making a huge amount of noise... the contractor tried to debug... he tried a new capacitor that almost blue in my face, then compressor died... after more debugging found it overheated.., cooled it down with water... removed the SureStart, and an hour later compressor restarted... I have a very quiet carrier unit single phase compressor 17.9RLA/LRA 112... SureStart ss1b16-32n - Solar glass roof - 2PW.
I wish I had searched this forum earlier... Wasted time and money without talking about what might be the long term impact on my AC unit.
Seeing the number of threads about this issue, it is difficult to understand how Tesla would not provide better support for this... They should at least learn from all the cases they encountered with their customers and provide a KPNS for HVAC installers. It will damage the brand and slow adoption.
I wish i could give you some good news. But you are right in that Tesla has dropped the ball on this along with the installers. Tesla has a calculator that my installer used which showed 2 PW would be enough but it clearly is not. The Surestart never did work, in fact it caused more harm and it is now completely removed. Believe it or not 6 months later I'm still waiting for the installer to tell me how they are going to resolve this issue. The solution is simple, add a 3rd powerwall, however I'm not willing to pay for it since they promised me based on my budget this system would work with the AC and its in my contract. The right thing to do would be for them to install a 3rd powerwall and make the customer happy which is what all their Techs who came onsite also agreed with but still waiting to hear back from management. I could have easily purchased a Honeywell Generac generator with built in transfer switch and load shed module for AC for half the price of this system and I would have my whole house and 5 ton AC working just fine.
Back to the sure start after multiple tests the last round of tests with the HVAC company, Tesla on the phone and installer representative, it gave an error (lack of voltage/not enough power) so clearly 2 PW is not sufficient to even allow the surestart to operate properly. The other times it didn't give an error and seemed to not even operate. For all we know it could have put the surestart in a recovery mode according to hyper engineering when the surestart does not get enough power to operate it attemps to powercycle itself multiple time. The surestart is just not a real solution when there is just simply not enough current, I would go as far as to say it can cause damage to the compressor motor like what you experienced. The HVAC company cautioned against using it in my situation. Even though they also advertise its compatible with all scroll compressors i also question if that is the case.
Back to the sure start after multiple tests the last round of tests with the HVAC company, Tesla on the phone and installer representative, it gave an error (lack of voltage/not enough power) so clearly 2 PW is not sufficient to even allow the surestart to operate properly. The other times it didn't give an error and seemed to not even operate. For all we know it could have put the surestart in a recovery mode according to hyper engineering when the surestart does not get enough power to operate it attemps to powercycle itself multiple time. The surestart is just not a real solution when there is just simply not enough current, I would go as far as to say it can cause damage to the compressor motor like what you experienced. The HVAC company cautioned against using it in my situation. Even though they also advertise its compatible with all scroll compressors i also question if that is the case.
Thanks for this information. I wanted to get a soft start adapter for my A/C, but could not find someone to install one. The electrician who installed my whole-house surge protector was going to do it for me, but then never got back to me on it and didn't respond when I left him a message.
Sounds like I'm better off that he never got back to me. Maybe he didn't think it would work and didn't want to get involved.
My realtor told me that there are A/C units that are designed to be soft-start, but junking a perfectly good A/C unit just to have A/C during our rare power outages seems wasteful. Especially since we don't get life-threatening heat here.
Adding a referral powerwall at their old forum pricing would be the perfect solution. Or EVTV’s solution of more than 75kWh for 20k.
CrazyRabbit
Active Member
You are better off without it as it would likely cause more damage than good. The problem is even though Hyper claims it "will" work with all single stage scroll compressors they don't mention anything about the controller in the attic or better yet test it with the most common single stage scroll compressor Carrier which most cookie cutter homes in the USA use b/c of cost. If it was as simple as swapping out the compressor alone some might do it but its not that simple and requires removal of the heating unit and controller all costing upwards of 25K to convert to a multi-stage compressor which does not even require a sure start.
My advice to anyone who is talking to a solar company sales person who will tell you what you want to hear to make a quick buck is to put it in your contract like I did what you are expecting and document eveything. When they tell you the system they design will work with your AC unit ask them to remove the softstart out of the equation because there is a good chance it will not work and you will go through the same headache i'm going through to get the company to do the right thing and honor the contract. If the number of PW they sell you is on the border of coverage get another PW or do yourself a favor and go the Generator route which is half the cost of PWs without all the AC headache.
Just talking through my hat here, but I think the perfect solution would be if the car could provide the additional amperage to start the A/C compressor. My solar + Powerwalls provides all the power I need for everything I do, but just doesn't have the amperage to start the A/C compressor. I'm skeptical about the advisability of using the car as the sole house backup, but just for those brief amperage peaks it would be great.
But I think that's just a fantasy at present, and probably for the rest of my life.
But I think that's just a fantasy at present, and probably for the rest of my life.
The system should be designed properly from the start with all the loads taken into consideration. Relying on a third party device "surestart" which will likely not work or depending on a EV which some may or may not have is just Poor Engineering, you have to wonder most of these companies who design the systems likely do not have an EE on staff and use some chart possibly to size systems. If they have historical data that may be fine, but when a company is just getting into the battery business that is poor practice. In my case the company was around for a while and I think they have an EE, but they just simply relied too much on a device they had only installed once prior to my install which was apparent when they sent 3 different crews to install it and they burned up my AC cap and fried the first surestart. Live and learn
Thanks. My solar installer told me the system I was getting would not start my A/C. He mentioned that soft-start A/C systems exist but didn't say anything about the cost. He also mentioned that soft-start kits exist but never said that I'd be able to get one for my A/C. My realtor said that I could replace my A/C but didn't think it was a very practical idea. Unless my A/C died of old age and I needed to replace it anyway. Considering my age and the age of my house, the A/C will probably outlive me. In a year and a quarter, we've had one power outage that lasted long enough, at the wrong time of day, for me to notice the effects of not having A/C. I cranked up the ceiling fans to high and I was okay. There are advantages to living in paradise.
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