Finally going solar. I have a question about Enphase microinverters and Powerwall compatibility

[wwu123]

I installed in 2012 so it had to be the 4 wire. I remember putting on an end cap I bent 4 wires sticking out and placed the sealing cap on it.
I am pretty sure that when I got that warranty replacement, they said it was compatible with the M series. Perhaps a special IQ7 to mate with M series?
I just found my paperwork on the replacement IQ: M-21540-IQ7-S22-RMA and it looks like an IQ inverter and so stamped. This one works with my desktop
Envoy Comm Gateway.

Got it, thanks! Looks like since the time I inquired a few years ago, they've come out with these that are an IQ7 wolf in M215 sheep's clothing, i.e. innards are IQ7-based, but outwardly compatible with older 4-wire M-series.

I got curious about what the extra two wires are fore, besides L1 and L2 that carry 240V. It's the neutral and ground, and the main compatibility issue is how neutral is connected in the older micro's, and also which of two wires carries the PLC communications for the Envoy metering - the newer 2-wire use L1/L2 that they have, while the 4-wire uses neutral for one of the wires.

 

[charlesj]

Got it, thanks! Looks like since the time I inquired a few years ago, they've come out with these that are an IQ7 wolf in M215 sheep's clothing, i.e. innards are IQ7-based, but outwardly compatible with older 4-wire M-series.

I got curious about what the extra two wires are fore, besides L1 and L2 that carry 240V. It's the neutral and ground, and the main compatibility issue is how neutral is connected in the older micro's, and also which of two wires carries the PLC communications for the Envoy metering - the newer 2-wire use L1/L2 that they have, while the 4-wire uses neutral for one of the wires.

I believe that their 12 ga wire in their spaced setup may swap 120V from L1 in one plug to L2 in the next one. I think I read something like that reading the installation instructions in 2012.
May also read not to skip a plug but not sure anymore.

 

[swedge]

Do you know if your M215's were installed with the old 4-wire cabling, or the newer 2-wire cables? My M215's were installed in 2013 with the 4-wire cabling, and a few years ago when I looked with the original installer into adding more panels (and micro's), I was told that I couldn't just extend my existing strings with the newer IQ micro's as they used a 2-wire system, and would require a completely separate home run back to the panel - i.e. a completely separate new install with all the associated high fixed costs.

It would bring me great comfort to know that if one of my M215's failed, it could be swapped out part-for-part with a newer IQ-series micro without any compatibility issues. But I was given to understand they would still send out brand-new M215 replacements for warranty failures.

I do know my old Envoy for monitoring is not compatible with newer IQ micro's, while the newest Envoys are backwards-compatible - but I think I'd also have to have all of my existing micro's re-cabled to the 2-wire system possibly?

Yes, but... Yes, the M215240-IQ7 works with the old cabling and the old Envoy gateway. In Calif they are allowed as repair/replacements however, they are not allowed for system expansion. I learned this the hard way.

In 2022 we expanded our 14 panel M250 system with 6 new panels and M250240-IQ7-S22-US MicroInverters. Those plug into the old cable and work with the old Envoy. PG&E issued permission to operate, all OK. Till it wasn't.

Shortly later, PG&E rescinded our PTO! The new micorinverters are not compatible with the current rule 21, we were told. We had a spec sheet from Enphase which says they are compatible. So chaos ensued. It eventually turned out the Enphase had recently issued a new spec sheet, the current one, which says the M215-IQ7 and M250-IQ7 are " * Not recommended for Site expansion in California and Hawaii." and they are not on the list of approved inverters.

My understanding is that they can be used for replacement of old inverters as a repair, but not for new installations or expansions.

The proposed fix was to replace the 6 new inverters, the cable connecting those, and add an IQ gateway. The system would then have an old Envoy and a new "Gateway", but the monitoring system handles that OK.

And, yes, the system expansion forced us onto NEM2. Further expansion would force us onto NEM3. But that is a whole other issue, off topic but covered in a different thread.

 

[charlesj]

Yes, but... Yes, the M215240-IQ7 works with the old cabling and the old Envoy gateway. In Calif they are allowed as repair/replacements however, they are not allowed for system expansion. I learned this the hard way.

In 2022 we expanded our 14 panel M250 system with 6 new panels and M250240-IQ7-S22-US MicroInverters. Those plug into the old cable and work with the old Envoy. PG&E issued permission to operate, all OK. Till it wasn't.

Shortly later, PG&E rescinded our PTO! The new micorinverters are not compatible with the current rule 21, we were told. We had a spec sheet from Enphase which says they are compatible. So chaos ensued. It eventually turned out the Enphase had recently issued a new spec sheet, the current one, which says the M215-IQ7 and M250-IQ7 are " * Not recommended for Site expansion in California and Hawaii." and they are not on the list of approved inverters.

My understanding is that they can be used for replacement of old inverters as a repair, but not for new installations or expansions.

The proposed fix was to replace the 6 new inverters, the cable connecting those, and add an IQ gateway. The system would then have an old Envoy and a new "Gateway", but the monitoring system handles that OK.

And, yes, the system expansion forced us onto NEM2. Further expansion would force us onto NEM3. But that is a whole other issue, off topic but covered in a different thread.

Thanks.
So, I could just replace all of my 16 remaining M215s with the IQ7 ...RMA designation in the future. Not an expansion nor a new install.
May even get some increased production.

 

[swedge]

May even get some increased production.

You may not see much more production. Almost all of the time, actual production is limited by the angle between the panels and the sun rather than by the inverter. Panels produce their rated power only when the sun is exactly perpendicular to the panels, and then only at lower than typical temperature and when they are new. If your inverters do limit your production, it is probably only a small reduction for a short time on a few weeks.

You can run NERL's PVwatts (link) with your panel and inverter specs, array orientation and geographic location to estimate production with various inverter specs. In the System Info, Advanced Paramers you can set the DC/AC ratio where the typical setting is 1.2, e.g. a 258 W DC panel on a 215 W AC inverter. So you can estimate your annual production with the same panels but different inverter limits and efficiencies.

 

[cali8484]

Yes, but... Yes, the M215240-IQ7 works with the old cabling and the old Envoy gateway. In Calif they are allowed as repair/replacements however, they are not allowed for system expansion. I learned this the hard way.

In 2022 we expanded our 14 panel M250 system with 6 new panels and M250240-IQ7-S22-US MicroInverters. Those plug into the old cable and work with the old Envoy. PG&E issued permission to operate, all OK. Till it wasn't.

Shortly later, PG&E rescinded our PTO! The new micorinverters are not compatible with the current rule 21, we were told. We had a spec sheet from Enphase which says they are compatible. So chaos ensued. It eventually turned out the Enphase had recently issued a new spec sheet, the current one, which says the M215-IQ7 and M250-IQ7 are " * Not recommended for Site expansion in California and Hawaii." and they are not on the list of approved inverters.

My understanding is that they can be used for replacement of old inverters as a repair, but not for new installations or expansions.

The proposed fix was to replace the 6 new inverters, the cable connecting those, and add an IQ gateway. The system would then have an old Envoy and a new "Gateway", but the monitoring system handles that OK.

And, yes, the system expansion forced us onto NEM2. Further expansion would force us onto NEM3. But that is a whole other issue, off topic but covered in a different thread.

If you only added 10% more (allowed in the original interconnection agreement) then you could have avoided being forced into NEM2?

 

[swedge]

If you only added 10% more (allowed in the original interconnection agreement) then you could have avoided being forced into NEM2?

True. Actually the limit for retaining grandfathering is the larger of 10% or 1kW DC. But I ran the numbers and concluded that a still larger expansion worked out better economically. The only cost of NEM2 over NEM1 is about $.03 of NBCs per kWh exported. But we wanted the expansion to help cover charging our Model Y, which roughly doubled our total consumption. My goal was to keep the annual true-up to less than $100. In a few weeks we are coming up on our first true-up with the larger system and the car, so I'll get to see how good my estimates were. All the rain this year was not in my model and has not helped...

My installer, who shall remain un-named, actually suggested we do the expansion but not tell PG&E at all. My problem with that was that the NEM credit is limited by a month estimated maximum solar production, but only the production PG&E knows about. Their estimate is generous, but with the larger expansion it would have messed up the economics.

One mitigation of the NBCs which I did not consider is charging the car during the day to reduce the export/re-import which occurs when charging at night. I've seen recent rumors that Tesla is working on including this feature in the Tesla app soon, and others have implemented this in their own API scripts. Manually it is a pain to start slow car charging when the PW is full, and then stop when the export credit increases. This could only save less than $100 per year, but if it does come to the app, I will probably use it.

 

[wwu123]

Yes, but... Yes, the M215240-IQ7 works with the old cabling and the old Envoy gateway. In Calif they are allowed as repair/replacements however, they are not allowed for system expansion. I learned this the hard way.

In 2022 we expanded our 14 panel M250 system with 6 new panels and M250240-IQ7-S22-US MicroInverters. Those plug into the old cable and work with the old Envoy. PG&E issued permission to operate, all OK. Till it wasn't.

Shortly later, PG&E rescinded our PTO! The new micorinverters are not compatible with the current rule 21, we were told. We had a spec sheet from Enphase which says they are compatible. So chaos ensued. It eventually turned out the Enphase had recently issued a new spec sheet, the current one, which says the M215-IQ7 and M250-IQ7 are " * Not recommended for Site expansion in California and Hawaii." and they are not on the list of approved inverters.

My understanding is that they can be used for replacement of old inverters as a repair, but not for new installations or expansions.

The proposed fix was to replace the 6 new inverters, the cable connecting those, and add an IQ gateway. The system would then have an old Envoy and a new "Gateway", but the monitoring system handles that OK.

And, yes, the system expansion forced us onto NEM2. Further expansion would force us onto NEM3. But that is a whole other issue, off topic but covered in a different thread.

Could you not have "repaired" 6 of your old panels with new M250-IQ7's, and then added the 6 new panels, with "these old M250's found on eBay"...?

 

[charlesj]

Thanks.
...
May even get some increased production.

You may not see much more production. Almost all of the time, actual production is limited by the angle between the panels and the sun rather than by the inverter. Panels produce their rated power only when the sun is exactly perpendicular to the panels, and then only at lower than typical temperature and when they are new. If your inverters do limit your production, it is probably only a small reduction for a short time on a few weeks.

You can run NERL's PVwatts (link) with your panel and inverter specs, array orientation and geographic location to estimate production with various inverter specs. In the System Info, Advanced Paramers you can set the DC/AC ratio where the typical setting is 1.2, e.g. a 258 W DC panel on a 215 W AC inverter. So you can estimate your annual production with the same panels but different inverter limits and efficiencies.

What I meant was and you may have missed my post that my IQ7 replacement has been the number 1 producer of energy in the pack ever since.
Wish I had the data for that previous M215 to see if that place in the pack was also the best location and producer before it was replaced.

I think I have about a 6%-8% variance between the best and worst or something like that even allowing for late afternoon shaded panels.
Over a year and years it could add up.

 

[charlesj]

True. Actually the limit for retaining grandfathering is the larger of 10% or 1kW DC. But I ran the numbers and concluded that a still larger expansion worked out better economically. The only cost of NEM2 over NEM1 is about $.03 of NBCs per kWh exported. But we wanted the expansion to help cover charging our Model Y, which roughly doubled our total consumption. My goal was to keep the annual true-up to less than $100. In a few weeks we are coming up on our first true-up with the larger system and the car, so I'll get to see how good my estimates were. All the rain this year was not in my model and has not helped...

My installer, who shall remain un-named, actually suggested we do the expansion but not tell PG&E at all. My problem with that was that the NEM credit is limited by a month estimated maximum solar production, but only the production PG&E knows about. Their estimate is generous, but with the larger expansion it would have messed up the economics.

One mitigation of the NBCs which I did not consider is charging the car during the day to reduce the export/re-import which occurs when charging at night. I've seen recent rumors that Tesla is working on including this feature in the Tesla app soon, and others have implemented this in their own API scripts. Manually it is a pain to start slow car charging when the PW is full, and then stop when the export credit increases. This could only save less than $100 per year, but if it does come to the app, I will probably use it.

Let us know as I am interested.

 

[swedge]

What I meant was and you may have missed my post that my IQ7 replacement has been the number 1 producer of energy in the pack ever since.
Wish I had the data for that previous M215 to see if that place in the pack was also the best location and producer before it was replaced.

I think I have about a 6%-8% variance between the best and worst or something like that even allowing for late afternoon shaded panels.
Over a year and years it could add up.

Ah! That is interesting. Maybe the new MicroInverters are more efficient?

Back when installer put in my original 14 panels, I signed myself up with Enphase as in installer. The installer version of the Enlighten web site gives me access to data for each inverter individually, including history. I think maybe the trick to getting installer access was using a different email address and saying I was self-installing. This let me see, for example, that when my installer commissioned the 6 new panels, they mapped the inverter serial numbers backwards. On the web display, the shade swept right to left on the old row, and left to right on the new row. They fixed it, though I suppose I could have as well.

Anyway, Enphase does seem to keep the data, so you may still be able to get access to the M215 historical data.

 

[h2ofun]

True. Actually the limit for retaining grandfathering is the larger of 10% or 1kW DC. But I ran the numbers and concluded that a still larger expansion worked out better economically. The only cost of NEM2 over NEM1 is about $.03 of NBCs per kWh exported. But we wanted the expansion to help cover charging our Model Y, which roughly doubled our total consumption. My goal was to keep the annual true-up to less than $100. In a few weeks we are coming up on our first true-up with the larger system and the car, so I'll get to see how good my estimates were. All the rain this year was not in my model and has not helped...

My installer, who shall remain un-named, actually suggested we do the expansion but not tell PG&E at all. My problem with that was that the NEM credit is limited by a month estimated maximum solar production, but only the production PG&E knows about. Their estimate is generous, but with the larger expansion it would have messed up the economics.

One mitigation of the NBCs which I did not consider is charging the car during the day to reduce the export/re-import which occurs when charging at night. I've seen recent rumors that Tesla is working on including this feature in the Tesla app soon, and others have implemented this in their own API scripts. Manually it is a pain to start slow car charging when the PW is full, and then stop when the export credit increases. This could only save less than $100 per year, but if it does come to the app, I will probably use it.

Why is it a pain to charge the EV during the day when the PW's are full? i have been doing this, when needing to charge the EV, when we have some sun and I am sending back 20kw to pge. I just plug in the car, and when I see the batteries full, I say start charging. Has been real easy for me. And I do love my Model Y toy, and since been doing a lot of local driving lately, to charge for free is fun.

 

[swedge]

Why is it a pain to charge the EV during the day when the PW's are full? i have been doing this, when needing to charge the EV, when we have some sun and I am sending back 20kw to pge. I just plug in the car, and when I see the batteries full, I say start charging. Has been real easy for me. And I do love my Model Y toy, and since been doing a lot of local driving lately, to charge for free is fun.

I don't remember you having an EV. Yes, free go-juice is fun! In our case, with smaller solar, we depend on TOU credits to leverage our production, hopefully to keep our true up around $100. Hence grid charging and export everything (less 20% reserve). I do wish we had seen this coming and got 2 PW's back when SGIP was paying for them! With that we could export all of our solar at partial peak and true out to zero. Your case of many kW production and many PW's would be the way to go, except for the capital expenditure....

On NEM1, there was no penalty to export and then re-import, so start charging at midnight when the rate dropped. 48 A times 240 volts is 11 kW till up to 85% usually. Easy.

On NEM2, there is $.03 NBC penalty per kWh exported. We want to let the PW charge up, and depending on when the morning coastal stratus clears, the PW is full around 12:30. But watching for that to happen means paying attention instead of fixing lunch, so that is a pain. When PW gets to full, solar typically is around 4kW, depending on haze density or thin high clouds, and the house is using .3 kW, so it starts exporting 3.7kW, decreasing as the sun moves westward. The point is to charge to absorb the excess, so this has to be monitored and adjusted as the excess changes. At the start, 3.7kW / 240 volt is ~15 Amps, so set the car charge rate to 15 amps. Get out a calculator. Calculate the time in hours till 3 pm (when the kW rate goes up so we'd prefer export). Lets say today PW hit 100% at 12:45, so it is 2.25 hours till 3:00. At 3.7kW we need to stop after adding 3.7 X 2.25 = 8.35 kW. The model Y battery holds roughly 70 kWh, so this session will add 8.35 / 70 % = ~12%. Add the present SOC %, say 55%, and set the charge limit to 12 + 55 = 67%. The car will stop charging at 3 pm. And readjust if the solar or house change appreciably.

This saves about $0.25 per day, $7 per month, but only when we have excess solar, so maybe $50 per year. I figure that isn't worth the daily dance, but if the app can do it automatically, cool, we'll only charge after trips to 50% and plug the car in every time we get home. But at $50 per year I'll need to have little else to do before I try to write a script and leave a computer running to automate the process.

Sorry, long answer to a simple question. A bad habit on my part.

 

[BGbreeder]

Gosh, @swedge, that seems like a lot of effort and manual tweaking on your part for $0.25/day, or is it filed under "fun hobbies"? From the outside, it seems like no small amount of effort on your part...

All the best,

BG

 

[swedge]

Gosh, @swedge, that seems like a lot of effort and manual tweaking on your part for $0.25/day, or is it filed under "fun hobbies"? From the outside, it seems like no small amount of effort on your part...

All the best,

BG

I am hoping that Tesla's "Drive on Sunshine" feature is released soon and automatically does what I want. Way easier and more reliable than the monitoring and twiddling, I hope!

My solar is not Tesla, but my Power Wall should provide all the info needed to do this. Fingers crossed...

First Look at Tesla's 'Drive on Sunshine' Feature That Will Charge Your Tesla With Excess Solar Energy

Tesla is rolling out a new feature called 'Drive on Sunshine,' enabling Tesla owners to charge their vehicles using excess solar energy. Discover how this innov

www.notateslaapp.com

 

[h2ofun]

I don't remember you having an EV. Yes, free go-juice is fun! In our case, with smaller solar, we depend on TOU credits to leverage our production, hopefully to keep our true up around $100. Hence grid charging and export everything (less 20% reserve). I do wish we had seen this coming and got 2 PW's back when SGIP was paying for them! With that we could export all of our solar at partial peak and true out to zero. Your case of many kW production and many PW's would be the way to go, except for the capital expenditure....

On NEM1, there was no penalty to export and then re-import, so start charging at midnight when the rate dropped. 48 A times 240 volts is 11 kW till up to 85% usually. Easy.

On NEM2, there is $.03 NBC penalty per kWh exported. We want to let the PW charge up, and depending on when the morning coastal stratus clears, the PW is full around 12:30. But watching for that to happen means paying attention instead of fixing lunch, so that is a pain. When PW gets to full, solar typically is around 4kW, depending on haze density or thin high clouds, and the house is using .3 kW, so it starts exporting 3.7kW, decreasing as the sun moves westward. The point is to charge to absorb the excess, so this has to be monitored and adjusted as the excess changes. At the start, 3.7kW / 240 volt is ~15 Amps, so set the car charge rate to 15 amps. Get out a calculator. Calculate the time in hours till 3 pm (when the kW rate goes up so we'd prefer export). Lets say today PW hit 100% at 12:45, so it is 2.25 hours till 3:00. At 3.7kW we need to stop after adding 3.7 X 2.25 = 8.35 kW. The model Y battery holds roughly 70 kWh, so this session will add 8.35 / 70 % = ~12%. Add the present SOC %, say 55%, and set the charge limit to 12 + 55 = 67%. The car will stop charging at 3 pm. And readjust if the solar or house change appreciably.

This saves about $0.25 per day, $7 per month, but only when we have excess solar, so maybe $50 per year. I figure that isn't worth the daily dance, but if the app can do it automatically, cool, we'll only charge after trips to 50% and plug the car in every time we get home. But at $50 per year I'll need to have little else to do before I try to write a script and leave a computer running to automate the process.

Sorry, long answer to a simple question. A bad habit on my part.

I just bought a model Y toy last month, at 6K more than the price now

 

[jgleigh]

My solar is not Tesla, but my Power Wall should provide all the info needed to do this. Fingers crossed...

ChargeHQ will probably do what you want until Tesla adds their new features.

EV Charging from Home Solar

Start charging your EV from your home solar panels with a 60-day free trial. Works with popular solar inverters + Tesla EVs or compatible smart chargers.

chargehq.net

 

[charlesj]

...

Anyway, Enphase does seem to keep the data, so you may still be able to get access to the M215 historical data.

I will see if I can find the serial number of the old inverter but when I replaced it with the new IQ and asked Enphase to recognize it, they told me the old data of the old inverter will be gone. The overall total for the system didn't change.
Will see if this difference changes over the long run.

 

[swedge]

I just bought a model Y toy last month, at 6K more than the price now

We love our MY. It is a fine toy, and a nice car for us as well. Trying to wring our charging out of our small solar system is an engaging exercise.

I'm guessing you did not opt for FSD. I'm having fun with it, watching the development of machine vision driving autonomy. It is a little nerve wracking playing safety pilot for a novice AI, but truly amazing what it can do so far. It is sort of like a virtual reality game, but without the virtual bit. ;-)

 

[h2ofun]

We love our MY. It is a fine toy, and a nice car for us as well. Trying to wring our charging out of our small solar system is an engaging exercise.

I'm guessing you did not opt for FSD. I'm having fun with it, watching the development of machine vision driving autonomy. It is a little nerve wracking playing safety pilot for a novice AI, but truly amazing what it can do so far. It is sort of like a virtual reality game, but without the virtual bit. ;-)

Nah, got to draw the line some where. I do enjoy playing with autopilot. But, I have had AP freak out, and phantom breaking, so I still need to drive the car.
Now, would love to put an elevator in my house, so that is on my list to look at. EXPENSIVE!!