- 8pm: PW's at 99% capacity
- 8pm: manually switched off the main (grid) to house, grid-down notification received
- 8pm-7:30am: house runs on PW's
- 7:30am: PW's at 80% capacity
- 7:30am: solar comes on-line and begins charging PW's while PW's power the house
- 9am: solar production increases to the point that it is both powering the house and charging PW's
- 10:30am: PW's reach 98% capacity
- 10:30am: solar shuts off
- 10:30am-11:30am: PW's power the house
- 11:30am: PW drops to 96% capacity
- 11:30am: Solar comes back on-line and begins powering the house and charging PW's
- 11:35am: manually switch main to the house back on
- 11:42am: solar comes back on-line and system resumes normal operations with excess power going to the grid
- 11:42am: grid-up notification received
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Just completed a 16 hour grid outage simulation. I'm very pleased.
- Thread starter nyprepper
- Start date
Not at all... no blip, no nothing. Seamless.
I've done a few prior grid-down simulations but this is my first time simulating a scenario where solar production exceeds home consumption with the PWs being fully charged.
I was also very pleased to see that the PW's only had to drop to 95% before solar came back on-line. I had heard that was potentially more like 70%.
I've done a few prior grid-down simulations but this is my first time simulating a scenario where solar production exceeds home consumption with the PWs being fully charged.
I was also very pleased to see that the PW's only had to drop to 95% before solar came back on-line. I had heard that was potentially more like 70%.
Which firmware version does your system have? Are you still on 1.34.3? What was the ambient temperature? I'm still concerned about the Powerwalls failing to charge from solar during outages when the temperature is low, but I'm waiting until there's a new firmware version to re-test. (We still have cool/cold mornings through most of May and June.)
it was 50 to 60 Fahrenheit outside temp over the course of the test. Powerwalls are in my garage and about the same temp range. I am on 1.34.2 right now.
hodad66
Member
Wow!! Sounds like my (possible) system. They quoted me with 6.62 KW and one PW
although I asked for two. I have some morning shade.
woferry
Member
My system's only been online since this past Sunday, last night was the first time I tried throwing the main breaker. I got home well after sunset and my single PW had already drained from 100% to ~89% so I couldn't test the >60Hz part, but I was surprised to find that with the PW already providing 100% of the house power (~600W), when I threw the main breaker I still saw CCFL lights flicker and my Vizio TV turned off, though it seems everything else (Dish DVR, AV amp, 2 Mac Minis, digital clocks, etc) survived without hiccup. So I didn't expect that, I expected it to be seamless when the PW was already sourcing. Maybe there's still some latency switching from following the grid's frequency to the PW actually driving the frequency itself, not sure. I think I can come up with a way to see the actual line AC signal (240FPS camera watching the screen of an analog oscilliscope I have), have to give it a shot and see if it works.
Other things I ran into was that both of my inverters remained powered, even though one of them sits between the main breaker and gateway, so it seems like there was enough voltage leaking through to keep the inverter powered (I threw its breaker and it turned off, threw it back and it turned on again), and my CTs clearly freaked-out, as the app suddenly started reporting ~0.3kW of solar production (even though the sky was black and the inverters were in Night Mode), and the gateway also reported energy coming from (or maybe to, I'd have to double-check) the grid even though it reported itself as islanded and the main breaker was off. When I turned the main breaker on again it seemed like only a few seconds before I heard the 'clunk' from the gateway and it was back to fully on-line (synchronization didn't take long at all), and of course the transition back to grid was seamless (I'd turned the TV back on to make sure it didn't glitch again).
Other things I ran into was that both of my inverters remained powered, even though one of them sits between the main breaker and gateway, so it seems like there was enough voltage leaking through to keep the inverter powered (I threw its breaker and it turned off, threw it back and it turned on again), and my CTs clearly freaked-out, as the app suddenly started reporting ~0.3kW of solar production (even though the sky was black and the inverters were in Night Mode), and the gateway also reported energy coming from (or maybe to, I'd have to double-check) the grid even though it reported itself as islanded and the main breaker was off. When I turned the main breaker on again it seemed like only a few seconds before I heard the 'clunk' from the gateway and it was back to fully on-line (synchronization didn't take long at all), and of course the transition back to grid was seamless (I'd turned the TV back on to make sure it didn't glitch again).
DrGene
Member
NYPrepper thanks for the PW info. I have been trying to determine if its possible to charge the Model 3 off the PW system? Tesla rep said no because the PW is limited to 5 kW. However it's important to be able to charge my model 3 off the PW because I do grid studies and Im seeing some Puerto Rico kind of long outage events possible in locations throughout the US mostly associated with coal and gas plant retirements and an over dependence on large auto transformers which are no longer manufactured in the US and can take up to a year to repair or replace. Gunmen can take down an entire town in minutes and the town can be without power for months. Southern Company sees more equipment failures from gunfire than any other cause. Here is their web page article: The Subtle Art of Making Substations Bulletproof I hope the embedded link gets through the TMC server. We really need those PW's to power our cars as well as our homes. Dr Gene Preston www.egpreston.com
Uhm, this may be dumb but, if a 6.6KW system is powering house and charging a battery, couldn't you plug in the tesla on 110?
Excellent! I have a 10.5kW system with 2 powerwalls. My problem is when we have experience an outage (we have had 3) all of the arc fault interrupter (AFI) circuit breakers trip and none of the other breakers trip. Tesla Power has been working on a solution since September 2018. They admit there is a problem. I cannot replace the AFI's with non-AFI's due to the local electrical codes. I suspect (being an engineer) that the the quality of electricity (amplitude, noise, etc) from the inverter (DC to AC) is not withing the requirements for the AFI's. If I was not retired I would get an oscilloscope form work and record the grid data and then simulate an outage and record the powerwall/inverter data.
On a side note: Since I have the solar panels, 2 powerwalls and the Tesla wall charger (set for 80 amps) it would be nice if I could plug my car in and use the 90 kWhr batteries as additional backup for the house, especially in the summer when we have to use the AC. This would be a relatively easy engineering backfit and during extended outages I could also run over the a supercharger outside the outage area and recharge the car giving me essentially an infinite amount of time for the grid to come back.
On a side note: Since I have the solar panels, 2 powerwalls and the Tesla wall charger (set for 80 amps) it would be nice if I could plug my car in and use the 90 kWhr batteries as additional backup for the house, especially in the summer when we have to use the AC. This would be a relatively easy engineering backfit and during extended outages I could also run over the a supercharger outside the outage area and recharge the car giving me essentially an infinite amount of time for the grid to come back.
There is no reason you can't have a NEMA 14-50 on the backed up side if you have two Powerwalls. Even with one Powerwall, you could probably get a 30 amp dryer outlet installed and use the appropriate adapter to charge from that. The important thing to realize is that the Powerwall only holds about 13.5 kWh. If you need to do serious charging, you'd want to do it during the daytime when solar power is available.
The Model 3 allows you to set the charge current to lower than the default, which is either 48A or 32A depending on which model you have. If you were to set the current to 20A, your charging power would be about 4.8 kW (240V x 20A = 4800W) which a single Powerwall could handle with no other loads. The only thing is, when installing just a single Powerwall, Tesla doesn't allow any circuit breaker above 30A to be backed up. As @cwied suggested, you could install a 30A dryer outlet just for charging during outages. Or, if you buy two or more Powerwalls, you can simply install a Tesla Wall Connector on a backed-up 60A breaker.
In our case, our EV charging stations are not backed up by our Powerwalls. I don't want the Powerwalls to get drained by our EVs overnight if there should happen to be an outage. Instead, we added a backed-up 120V outlet in our driveway. During an extended, widespread outage, I don't expect we would be driving much, so just being able to charge slowly at 120V should be fine. If the geographic scope of an outage is more limited, then we can use Superchargers. Alternatively, in a real pinch, we could also unplug our electric stove or dryer and charge using one of those outlets, as they are backed up and I have a couple of 240V extension cords.
By the way, more on topic here, I just noticed that our Powerwalls have been updated to version 1.35.2, and the ambient temperature is in the 40s (Fahrenheit). Might be a good time for another outage test!
Nice, I do not have mine set to backup. I have a 8.54 kW system and 2 PWs. As the sun comes up, I run the house and replenish the PWs. I usually throw a charge on the car at 4:30 am. Totally seamless switching even when there was a power outage. I have not pulled from the grid in 2 months. I live near Pittsburgh PA and went live on 3/1 and produced 1.6 mWh in the first 2 months.
The Arc Fault breakers should only trip at the moment the power goes out and the Backup Gateway's switch opens. I have a similar problem with my APC ATS when it switches between sources.
If you really want to take power out of an EV, you can use a grid-tied inverter connected to the 12V system to inject about 1,000W into your house to support the Powerwall system. This will act as a runtime extender. I did a proof of concept with a cheap 600W inverter and I still have it for disaster use.
Powerwall 2.0 Backup Runtime Extender
This morning, from about 10 AM to 11:20 AM, I performed an outage test (by flipping our main breaker) on version 1.35.2 of the Powerwall software. Our electric induction range worked during the outage, for the first time, but our solar array still didn't produce any energy.
When I started the test, the weather was cloudy and cool (roughly 45F / 7C), our two Powerwalls were at 82% (according to the app) and discharging to match our home consumption (don't know why), our solar array was generating a bit less than 1 kW, and our home consumption was minimal. Shortly after starting the outage, we ran our electric oven and stovetop, and our home's power consumption exceeded 4 kW at times. Our Powerwalls were down to about 77% charge when we turned the main breaker back on. Within minutes, our solar array started producing again, at roughly only 1 kW due to cloud cover.
Unfortunately, I had an issue with our multimeter and couldn't get good line frequency readings. Obviously, the frequency during the outage was closer to 60 Hz than in previous outages, as we got no errors from our induction range, a small victory. But it was apparently still too high for our SunPower/Enphase micro-inverters to turn on.
Could this failure to charge from solar during an outage have been related to the cool ambient temperature? I'll need to call Tesla again. If there was any solar production immediately prior to the start of an outage, the Powerwalls should definitely condition themselves as necessary to accept solar charging!
When I started the test, the weather was cloudy and cool (roughly 45F / 7C), our two Powerwalls were at 82% (according to the app) and discharging to match our home consumption (don't know why), our solar array was generating a bit less than 1 kW, and our home consumption was minimal. Shortly after starting the outage, we ran our electric oven and stovetop, and our home's power consumption exceeded 4 kW at times. Our Powerwalls were down to about 77% charge when we turned the main breaker back on. Within minutes, our solar array started producing again, at roughly only 1 kW due to cloud cover.
Unfortunately, I had an issue with our multimeter and couldn't get good line frequency readings. Obviously, the frequency during the outage was closer to 60 Hz than in previous outages, as we got no errors from our induction range, a small victory. But it was apparently still too high for our SunPower/Enphase micro-inverters to turn on.
Could this failure to charge from solar during an outage have been related to the cool ambient temperature? I'll need to call Tesla again. If there was any solar production immediately prior to the start of an outage, the Powerwalls should definitely condition themselves as necessary to accept solar charging!
If you know the IP address of your Gateway on your local network, you can get the Powerwall's own frequency readings from /api/meters/aggregates (e.g., https://192.168.1.46/api/meters/aggregates).
Is it possible your solar is connected outside the backup gateway, and had no power when the main breaker was open? Have you ever seen the solar work with the grid down?
Very interesting. Your system is almost exactly what I'll have. I say "I'll have" because I've been waiting for the 2 PWs for over 2 years. I paid the deposit for the 2 PWs over 2 years ago.
What day/month did you run your experiment?
Similar threads
