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

[Vines]

Vines,

Below are the specs of the 2 I was recommended, plus the one you mentioned. I called Enphase and they think the 8A is overkill for my panels, not wrong, just overkill. They say in the Bay Area and the panel specs of what was proposed to me, most installers use the 8M or the 8+. Enphase says that if they had to pick one they would recommend the 8M. One installer explained to me to pay attention also to the input power. The number on the low end indicates if it will still be getting power when the sun is lower in the sky. The 8A has a low end of 295 which is much higher than the others. Any thoughts on that? Also, the installer that recommended the 8+ says that between the 8M and 8+ the difference in energy I'd get over a year is about 2kW according to whatever solar calculator it is that they use.

IQ8M specs:

• Peak output power: 330 VA
• Input power: 260 - 460 W
• Maximum continuous output power: 325 VA

IQ8+ has these specs:

• Peak output power: 300 VA
• Input power: 235 - 440 W
• Maximum continuous output power: 290 VA

IQ8A specs:

• Peak output power: 366 VA
• Input power: 295 - 500 W
• Maximum continuous output power: 349 VA
• Operating range: 16 – 58 V

I might be too conservative with my DC/AC ratio, so take that for what it is worth.

I know plenty of people use higher DC/AC ratios than I do. Currently the inverters we use output 384W continuously, and are paired with 415W or 425W modules. This is about 1.1 DC/AC ratio. I think Tesla allows up to 1.7, and it is common to see around 1.3.

As far as the startup voltage, all the IQ8 microinverters we are discussing have a startup voltage of 30VDC and a minimum voltage of 25VDC. They will all perform equally well in low light conditions. The number you are quoting as lower is "commonly used module pairings"

 

[charlesj]

Vines,

Below are the specs of the 2 I was recommended, plus the one you mentioned. I called Enphase and they think the 8A is overkill for my panels, not wrong, just overkill. They say in the Bay Area and the panel specs of what was proposed to me, most installers use the 8M or the 8+. Enphase says that if they had to pick one they would recommend the 8M. One installer explained to me to pay attention also to the input power. The number on the low end indicates if it will still be getting power when the sun is lower in the sky. The 8A has a low end of 295 which is much higher than the others. Any thoughts on that? Also, the installer that recommended the 8+ says that between the 8M and 8+ the difference in energy I'd get over a year is about 2kW according to whatever solar calculator it is that they use.

IQ8M specs:

• Peak output power: 330 VA
• Input power: 260 - 460 W
• Maximum continuous output power: 325 VA

IQ8+ has these specs:

• Peak output power: 300 VA
• Input power: 235 - 440 W
• Maximum continuous output power: 290 VA

IQ8A specs:

• Peak output power: 366 VA
• Input power: 295 - 500 W
• Maximum continuous output power: 349 VA
• Operating range: 16 – 58 V

To add what @Vines stated, or didn't state, the lower sun arc angle will produce X Watts depending on panel capability, not inverter ability.
Also, to consider or be informed is that Enphase uses 20A breakers, 240VAC. So, depending on which IQ you get your panel numbers and inverters allowed on each breaker will vary to not exceed 16A continuous.
As an example from past research, a 20A breaker can have 16 IQ7s or 11 IQ7As, roughly 3840W per breaker.

So, one combination may be less expensive over an another. But, with a higher DCtoAC ratio you may produce more as it will produce more earlier in the day and to later in the day even though the max is around 3840W.

 

[cali8484]

What is the point of iQ8 instead of iQ7 when you plan to pair with Tesla Powerwall?

 

[jrmnet]

What is the point of iQ8 instead of iQ7 when you plan to pair with Tesla Powerwall?

This is what I see online about the difference:

Compared to the Enphase IQ7, the IQ8 enables your solar system to generate power during an outage (kit required). Furthermore, if you are adding an Enphase battery now or in the future, you may want to consider the IQ8 series because they offer more scaling flexibility to your backup capacity.

 

[holeydonut]

What is the point of iQ8 instead of iQ7 when you plan to pair with Tesla Powerwall?

If you're pairing with a Tesla Powerwall, I can't imagine there being any difference. The Powerwall only cares what AC lands on the generation panel and that could be coming from Solar Edge, Delta, Enphase, or any other solar inverter.

Apparently the IQ8 min start DC voltage is 30 but the IQ7 is 33. And the IQ8 can go up to 60. So maybe you'll get more juice with an IQ8? Like one ounce of juice per 100 gallons.

Also, according to the spec sheet the IQ8 conforms with C22.1-2018 Rule 64-218 Rapid Shutdown. But my IQ7A only conforms with C22.1-2015 Rule 64-218 Rapid Shutdown. Are they the same thing? Only wwhitney knows. Eeeeekkkkkk.

 

[cali8484]

This is what I see online about the difference:

Compared to the Enphase IQ7, the IQ8 enables your solar system to generate power during an outage (kit required). Furthermore, if you are adding an Enphase battery now or in the future, you may want to consider the IQ8 series because they offer more scaling flexibility to your backup capacity.

Yes, I know the differences and that's why it doesn't make sense to me why you would want the iQ8 with Tesla Powerwall since the extra iQ8 features and Enphase batteries won't work with Powerwall. You will just be paying extra for features you won't be able to use.

 

[jrmnet]

Yes, I know the differences and that's why it doesn't make sense to me why you would want the iQ8 with Tesla Powerwall since the extra iQ8 features and Enphase batteries won't work with Powerwall. You will just be paying extra for features you won't be able to use.

So my current plans are to install 405 watt panels and no batteries at this time. I plan to install either a Tesla power wall or Enhphase batteries in the future. The 2 micro-inverts that installers have suggested are the iQ8M and the iQ8+. Another user on this thread also suggested that I look at the iQ8A. Are you suggesting that I should be considering something other than those?

Also, I didn't quite get this part of your statement "Enphase batteries won't work with Powerall". I would either get 1 type of battery or the other, I wouldn't be trying to combine batteries from both vendors.

 

[swedge]

Compared to the Enphase IQ7, the IQ8 enables your solar system to generate power during an outage (kit required).

PowerWalls will also let you generate solar during a grid outage.

It does this by creating the 60 Hz power as needed to keep the MicroInverters running, by making them think they are still connected to the grid. The PW charges with any excess above what the house draws till the PW approaches fully charged. Then it shifts the frequency above 60 HZ, which causes the MicroInverters to shut down immediately. At this point, the PW begins to discharge to power the house. When the state of charge has fallen somewhat, the PW shifts back to 60 Hz which, after 5 minutes or so, will restart the MicroInverters and top up the PW again. Lather, rinse, repeat.

I am not certain of this, but the latest Enphase systems may be able to run the house off of solar when the grid is down but without a battery. Older inverters (I have M250's) are either on or off, but the new ones can throttle their output as needed. I think. Maybe.

I am a fan of having a battery, but the economics can be disadvantageous. I am also a fan of consumption monitoring, which can enable better power use and hence better economics.

 

[cali8484]

So my current plans are to install 405 watt panels and no batteries at this time. I plan to install either a Tesla power wall or Enhphase batteries in the future. The 2 micro-inverts that installers have suggested are the iQ8M and the iQ8+. Another user on this thread also suggested that I look at the iQ8A. Are you suggesting that I should be considering something other than those?

The iQ8 would make more sense if you want to have sunlight only backup (i.e. island grid forming) without batteries. However, your plan is to install a battery system (Tesla or Enphase) then the sunlight only backup feature won't work anyway. The iQ7 series (iQ7,iQ7+,etc.) makes more sense to me when you plan to have batteries. I think installers have a lot of profit motive to propose iQ8 as the default.

 

[Vines]

The iQ8 would make more sense if you want to have sunlight only backup (i.e. island grid forming) without batteries. However, your plan is to install a battery system (Tesla or Enphase) then the sunlight only backup feature won't work anyway. The iQ7 series (iQ7,iQ7+,etc.) makes more sense to me when you plan to have batteries. I think installers have a lot of profit motive to propose iQ8 as the default.

There isnt a plentiful supply of IQ7 at a reasonable price, many of them are back-ordered. Therefore many people go to the IQ8 just to get projects done.

I think with chip shortages, Enphase is prioritizing the production of their most profitable microinverters.

 

[CrazyRabbit]

PowerWalls will also let you generate solar during a grid outage.

It does this by creating the 60 Hz power as needed to keep the MicroInverters running, by making them think they are still connected to the grid. The PW charges with any excess above what the house draws till the PW approaches fully charged. Then it shifts the frequency above 60 HZ, which causes the MicroInverters to shut down immediately. At this point, the PW begins to discharge to power the house. When the state of charge has fallen somewhat, the PW shifts back to 60 Hz which, after 5 minutes or so, will restart the MicroInverters and top up the PW again. Lather, rinse, repeat.

I am not certain of this, but the latest Enphase systems may be able to run the house off of solar when the grid is down but without a battery. Older inverters (I have M250's) are either on or off, but the new ones can throttle their output as needed. I think. Maybe.

I am a fan of having a battery, but the economics can be disadvantageous. I am also a fan of consumption monitoring, which can enable better power use and hence better economics.

Iq8 requires enphases gateway, which includes a auto transformer. Iq7 can curtail power, either thru the envoy or by frequency.
Both enphase and tesla inverters are 240v, no neutral for inverter. So powerwall, if you have 4000 watt inverter, and a 120v, 1000w load on L1; then the battery can charge on 1000w on L1 and 2000w on L2. 3000w load on L1, then the battery would be outputting 1000w on L1 and charging 2000w on L2.
I still wonder how big of a imbalance the powerwall can handle?

 

[holeydonut]

There isnt a plentiful supply of IQ7 at a reasonable price, many of them are back-ordered. Therefore many people go to the IQ8 just to get projects done.

I think with chip shortages, Enphase is prioritizing the production of their most profitable microinverters.

Yeah a few months ago I tried to get 12x iq7+ or iq7A. Had a helluva time finding any, and an installer struggled too.

If I ever had a warranty failure, I wouldn’t expect a speedy replacement since iq7 don’t work alongside iq8.

 

[swedge]

I still wonder how big of an imbalance the powerwall can handle?

The spec sheet says:
Imbalance for Split-Phase Loads 100%

But the breaker on each leg is 30A if memory serves, so 120V to is 3.6 kW as the max. I would describe that as 50% imbalance.

 

[BGbreeder]

The spec sheet says:
Imbalance for Split-Phase Loads 100%

But the breaker on each leg is 30A if memory serves, so 120V to is 3.6 kW as the max. I would describe that as 50% imbalance.

I guess it depends on your point of view. 3.6 out of 3.6 is 100%. Granted that is 50% of the total 240V power output.

Perhaps if one is trying for an off grid application, with an expected highly imbalanced load, adding an autotransformer would be prudent. Vikron makes some good ones.

All the best,

BG

 

[cali8484]

If I ever had a warranty failure, I wouldn’t expect a speedy replacement since iq7 don’t work alongside iq8.

That would be a huge mistake for Enphase since easy and prompt warranty replacement is one of the few remaining good things about Enphase.

 

[charlesj]

...

If I ever had a warranty failure, I wouldn’t expect a speedy replacement since iq7 don’t work alongside iq8.

Did that come from their tech support or tech papers?
I had an M215 go out a few years ago and they sent an IQ7 and works great. In fact, it seems to produce more than any of the other16 I have.
I would hate to wait for a replacement in the future if needed.

 

[swedge]

I guess it depends on your point of view. 3.6 out of 3.6 is 100%. Granted that is 50% of the total 240V power output.

Perhaps if one is trying for an off grid application, with an expected highly imbalanced load, adding an autotransformer would be prudent. Vikron makes some good ones.

All the best,

BG

The PW is spec'ed at 5 kW continuous, 7 kW short term peak.

I suppose there could be an autotransformer in the PowerWall Gateway, in which case the entire 7kW (58A) could be drawn from one leg, returned via the neutral. The breakers from the gateway to the house are 70 Amp on each leg. Who knows...

 

[BGbreeder]

The PW is spec'ed at 5 kW continuous, 7 kW short term peak.

I suppose there could be an autotransformer in the PowerWall Gateway, in which case the entire 7kW (58A) could be drawn from one leg, returned via the neutral. The breakers from the gateway to the house are 70 Amp on each leg. Who knows...

I'm not saying that you are wrong, but I don't think that one could draw all power on a single leg, or the specification for the breakers would be different. I believe that the 100% imbalance specification means zero on one leg and full (half the rated total output) on one 120V leg.

As I noted above, unless you are off grid, I don't think that it has any impact. Off grid is definitely a different case.

Autotransformer - Victron Energy

Use the Autotransformers for step up, step down and split phase output balancing purposes. Find a Victron Energy dealer near you.

www.victronenergy.com

All the best,

BG

 

[wwu123]

Did that come from their tech support or tech papers?
I had an M215 go out a few years ago and they sent an IQ7 and works great. In fact, it seems to produce more than any of the other16 I have.
I would hate to wait for a replacement in the future if needed.

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?

 

[charlesj]

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?

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.