I always call the main number and one of the options is 'Energy' or 'Storage' (as opposed to Solar). They do seem to tinker with the options often, though....
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pdxgibby
Software Engineer
That appears to work just fine. However, when there is an outage, the house is powered by the powerwalls and the panels turn off. Once the powerwalls discharge to 97% (I think), they will re-enable the micro inverters / PV and re-charge the powerwalls from solar. This cycle continues while the panels are generating power.
What I am told, is that the iQ6 and newer micro inverters from enphase support dynamic output based on demand. This means that the micro inverters can produce the same output as the load demands, thus eliminating the need to repeatedly cycle production and discharge exclusively from the Powerwalls. Theoretically, this avoids the loss in efficiency by charging and discharging the PWs and also avoids the repeated power cycling of the PV system.
Of course....I could be wrong. But this is my understanding. If someone knows better than me, I'd love to know.
No, you're correct. This is an excerpt from the document I linked.
The following settings define the IQ Microinverter over frequency power limit
• Start frequency in Hz (min 60, max 65)
• Start delay in milliseconds (min 0, max 10)
• Ramp down rate in %/Hz (min 40, max 83.33)
However, I don't belive the PW curtails. I think it simply spikes high and disables the GT output rather than tell it to pump out less
The following settings define the IQ Microinverter over frequency power limit
• Start frequency in Hz (min 60, max 65)
• Start delay in milliseconds (min 0, max 10)
• Ramp down rate in %/Hz (min 40, max 83.33)
However, I don't belive the PW curtails. I think it simply spikes high and disables the GT output rather than tell it to pump out less
pdxgibby
Software Engineer
Got it...so, once the Powerwall can curtail properly by dynamically adjusting the frequency this would be possible with the iQ6 and newer enphase micro inverters. Very smart...saves ~10-15% efficiency loss in charging / discharging the PW.
I'm actually right in the middle of my first simulated grid outage (2 hours planned). It looks like once the PW capacity decreases to 97%, it re-enables solar production. My micro inverters take about 15 minutes to start producing. They are now producing, and my house is consuming from the solar and the PWs are charging from excess solar.
So. Freaking. Awesome.
Today I tried charging 2 PWs off-grid from solar (enphase IQ7 microinverters). When the charge got to be around 92-95%, the microinverters where turned off and the powerwall began discharging. After 5 minutes, the inverters would come back online, and then supply power for a short period of time, and then they would be turned off again.
Interestingly, not all of them were turned off at the same time, so at any given time, a few inverters would be supplying power, so the power never went completely to zero. When look at the frequency in the Enphase application, it tells me that the frequency that tripped them to go off was 60.5Hz. How can it be 60.5? Does the powerwall first try 60.5 and then gradually ramps it up to 65?
Interestingly, not all of them were turned off at the same time, so at any given time, a few inverters would be supplying power, so the power never went completely to zero. When look at the frequency in the Enphase application, it tells me that the frequency that tripped them to go off was 60.5Hz. How can it be 60.5? Does the powerwall first try 60.5 and then gradually ramps it up to 65?
The answer to your question very much depends on how Tesla has your Powerwall configured. From my understanding they have fairly fine grained control of how the frequency changes based on multiple factors such as Powerwall charge, load, and input.
Check out Utility outage simulation data dump. In there I share the test I did while sampling the data every 0.5s. It shows that the frequency slowly changes over time based on those factors and there isn't a "spike" or some magic.
What's cool about that is that is if your inverters support the float down (like the Enphases do) and the inverter + Powerwall settings are aligned you can get really close to optimal use of solar during an outage.
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So I call Enphase support. They told me:
1. There is a separate grid profile for working with Tesla Powerwall.
2. The support tech sent me this attached Technical Brief on how to make them work. Still reading it.
1. There is a separate grid profile for working with Tesla Powerwall.
2. The support tech sent me this attached Technical Brief on how to make them work. Still reading it.
Yes, you're above the continuous 5000W sink capability (@ 6960W) of one PW at maximum panel generation with no other loads.
However, for the majority of instances you're not going to be a max-generation, there are loads, and the PW should be able to signal to the IQ6's to curtail if necessary.
Yes, I think this will be a problem only if all of the following happen to coincide:
1. Running in off-grid mode
2. Solar output is close to the max (6.9 kw)
3. There is not enough demand in the house to soak up 1.9kw.
If this happens, the Powerwall will turn-off the inverters for 5 minutes, then they will come back again, and the cycle will repeat.
You can work around the problem by manually turning off some of the inverters (circuit switch). I think you should have 3 branches, so you can turn off one, and the other two will be under 5kw.
You can also work around by adding an additional electrical load in the house (turning down the AC, plugging in electrical car, roasting a turkey in the oven). So just have an extra frozen turkey in the freezer, it's cheaper than getting a second PW.
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Ok, so today I was able to achieve ramp-up/ramp-down with 2 PWs and Enphase IQ7 and IQ7+ microinverters. When the state of charge approached 95%, PWs gradually increased the frequency, and the Enphase microinverters gradually decreased the power, without turning off. When the house load increased, the PWs started supplying power, and then the frequency started decreasing (although there was a couple of minutes of delay there), and the Enphase power started to ramp back up.
This avoids the constant cycling of - turning off solar, discharging batteries, turning back on, charging batteries - when running in off-grid mode with a full battery.
As an additional bonus, this grid profile allows the microinverters to restart within 5 seconds (instead of the usual 305s), so when the PW tries to restart with a low state of charge, the microinverters start up quickly and send power to PWs quickly, before it can be further discharged.
instructions:
1. Download Installer Toolkit app.
2. Put Envoy in AP mode by pressing the button (left button on my Envoy).
3. Connect to EnvoyXXXXX wifi.
4. Open Installer Toolkit, and connect to the Envoy.
5. Change grid profile to PREPA off-grid frequency-watt 83 /Hz
6. Click continue. Then you wait for the new grid profile to propagate, and you can exit.
This avoids the constant cycling of - turning off solar, discharging batteries, turning back on, charging batteries - when running in off-grid mode with a full battery.
As an additional bonus, this grid profile allows the microinverters to restart within 5 seconds (instead of the usual 305s), so when the PW tries to restart with a low state of charge, the microinverters start up quickly and send power to PWs quickly, before it can be further discharged.
instructions:
1. Download Installer Toolkit app.
2. Put Envoy in AP mode by pressing the button (left button on my Envoy).
3. Connect to EnvoyXXXXX wifi.
4. Open Installer Toolkit, and connect to the Envoy.
5. Change grid profile to PREPA off-grid frequency-watt 83 /Hz
6. Click continue. Then you wait for the new grid profile to propagate, and you can exit.
My installer said that my system doesn't have the PREPA profile - any idea how to get it?
Let me follow up too with a question around the frequency settings @Dan123.
In the profile you attached the "Slow Overfreqency" is set to 61.8hz which is not UL 1741 compliant which requires 60.5hz. Seems I need some sort of hybrid profile.
- Keep frequency and voltage settings from IEEE 1547 profiles
- Adjust "Reconnect" to allow faster reconnect allows for off-grid restart in an emergency
- "Over Frequency Power Limits" to align with the Powerwall frequency adjustments during off grid operation on very sunny days
In the profile you attached the "Slow Overfreqency" is set to 61.8hz which is not UL 1741 compliant which requires 60.5hz. Seems I need some sort of hybrid profile.
- Keep frequency and voltage settings from IEEE 1547 profiles
- Adjust "Reconnect" to allow faster reconnect allows for off-grid restart in an emergency
- "Over Frequency Power Limits" to align with the Powerwall frequency adjustments during off grid operation on very sunny days
It is for Puerto Rico, but I looked at its parameters, and there is nothing abnormal there. Also, it says in their technical paper, that when the enphase is on the load side (there is a powerwall behind the grid and solar), then the Powerwall is responsible for complying with IEEE 1574 standard, and the Enphase inverters don't need to comply.
I was able to scroll down through that list. Maybe try calling Enphase support directly.
If the Powerwall is installed between the grid and your Enphase inverters, than the Powerwall should take care of UL 1741 compliance, and the inverters don't need to?
Doesn't sound right. UL1741 SA is about grid interactivity with the frequency source grid-side
PWs are just pass-through until it islands, so until then Enphase still has to respect grid-rules. The PREPA profile probably allows Enphase to be flexible with the crazy frequencies from the PW in the micro-grid.
1574 governs interconnection itself, things like grounding, disconnections, etc. When the micros are controlled by the PW sinewave it then becomes the responsibility of the gateway to decide when to island. 1741 inherits 1574 as far as electrical is concerned then adds fire ratings, physical aspects like construction and product aspects that may hurt installers/owners.
Pic below might help
