I've selected a vendor and they offer (2) 6.8Kw systems in SF Bay Area

[shade_tree]

Both use;
Q CELLS Q.PEAK DUO BLK ML?G10+-400 (17)
And I can either go with a central inverter;
SMA Sunny Boy 7.0-US $16K total
or
Enphase IQ7A-72-2-US (17) $18,150 total
Both estimate to produce 9350-9400kw which is about 40% more than I needed last year but I just bought one plug-in hybrid, plan to buy another EV in a couple years and plan to use A/C more often.

At least from where I am in CA both these pricings are very competative (both before any incentives or tax credits)

My roof is pretty well positioned and shading should not be an issue

Obviously the SMA is cheaper which is attractive but advantage for the microinverters that I can see are
25 year (no labor after an initial period) vs. 10 year warranty (looks like I can extend SMA warranty 5 years for $400 or 10 years for $800 including labor)
Individual panel monitoring for production/temp/etc
Panels are independent so one failure won't stop whole system and shading wouldn't impact a whole string (though as mentioned I have no shading issue)
I've heard microinverters are traditionally more efficient but estimate production from both systems is about the same

In theory the SMA could come with secure power backup plug but at least here in CA I'm hearing that has to be disabled to have the fast shutdown
Also looking at the SMA site it says because of current part shortage, they will be shipping inverters without wifi module (can't be added later) and I'm wondering will this impact their cloud monitoring/troubleshooting features?

My other question is if I add batteries in 10 years will there be an advantage to either?


Related question is I have a 1960 home with original 100A panel, I am upgrading that to 200A separately as from what I understand a 100A would never have the headspace to accommodate that panel. Solar installer is suggesting I even downgrade main breaker to 180A so I have more headroom for future batteries, does that sound right? . Electrician sounds a little hesitant to do that now and this is getting 5 quotes on the panel upgrade as it varied form $3-8K! "solar ready" panels don't seem common around here

I have a comp shingle roof that is at least 20 years old so I am also replacing that.

BTW I have PG&E for electricity who charges 35-60c/kwh so going solar is a no-brainer and payback shouldn't be a problem at least with current net metering regulations




Thanks

[Ampster]

Assuming they're both UL1741SA compliant you should be able to add batteries by adding a hybrid inverter with batteries to AC couple with them. it is not as simple as just connecting batteries to the inverter. I installed IQ7 micros nine months ago and AC coupled them to an Outback Skybox with batteries a few months later.

[shade_tree]

That's good to know. For me at least I live in an area with with redundant lines and I've never lost power more than an hour in many years of living here. I would only get batteries so I could store energy to use on my own time if the NET metering rules change in CA with NEM 3.0. I am hoping to get grandfathered in current rules for at least 10 years so batteries wouldn't be consider until then.

[SolTex]

Both use;
Q CELLS Q.PEAK DUO BLK ML?G10+-400 (17)
And I can either go with a central inverter;
SMA Sunny Boy 7.0-US $16K total
or
Enphase IQ7A-72-2-US (17) $18,150 total
Both estimate to produce 9350-9400kw...

Better look at those power estimates carefully. They sound a bit optimistic. I can't comment on the string inverter, but I have a Enphase system with micro inverters so I know how they work. Your maximum possible power output with the IQ7A micros, regardless of what panel you use, will be 17 times the peak output rating which is 366W. So 17 x 366 = 6.2 kW at which point they will start clipping.

https://enphase.com/sites/default/files/2021-04/IQ7A-DS-EN-US.pdf

[J.P.M.]

Better look at those power estimates carefully. They sound a bit optimistic. I can't comment on the string inverter, but I have a Enphase system with micro inverters so I know how they work. Your maximum possible power output with the IQ7A micros, regardless of what panel you use, will be 17 times the peak output rating which is 366W. So 17 x 366 = 6.2 kW at which point they will start clipping.

https://enphase.com/sites/default/files/2021-04/IQ7A-DS-EN-US.pdf

If the OP has a reasonably south facing array with not too much shade, a 6.2 kW system in PG & E territory ought to have no problem producing about 1,500 + kWh/yr. per kW., or ~ 9,300 kWh/yr. long term average.

OP: Do a PVWatts run using your inputs and see what you get.

[SolTex]

OK, my mistake. OP said "9350-9400kw" and I thought they were talking about system power output, not annual kWh production. Back to lurking...

[foggysail]

The OP mentions warranties of one vendor vs the other. Who knows which company will be around next year, forget about 10, 25 or whatever years! IMHO, warranties should have little value when it comes to panel selections

[oregon_phil]

Both use;
Q CELLS Q.PEAK DUO BLK ML?G10+-400 (17)
And I can either go with a central inverter;
SMA Sunny Boy 7.0-US $16K total
or
Enphase IQ7A-72-2-US (17) $18,150 total
Both estimate to produce 9350-9400kw which is about 40% more than I needed last year but I just bought one plug-in hybrid, plan to buy another EV in a couple years and plan to use A/C more often.

At least from where I am in CA both these pricings are very competative (both before any incentives or tax credits)

My roof is pretty well positioned and shading should not be an issue

Obviously the SMA is cheaper which is attractive but advantage for the microinverters that I can see are
25 year (no labor after an initial period) vs. 10 year warranty (looks like I can extend SMA warranty 5 years for $400 or 10 years for $800 including labor)
Individual panel monitoring for production/temp/etc
Panels are independent so one failure won't stop whole system and shading wouldn't impact a whole string (though as mentioned I have no shading issue)
I've heard microinverters are traditionally more efficient but estimate production from both systems is about the same

In theory the SMA could come with secure power backup plug but at least here in CA I'm hearing that has to be disabled to have the fast shutdown
Also looking at the SMA site it says because of current part shortage, they will be shipping inverters without wifi module (can't be added later) and I'm wondering will this impact their cloud monitoring/troubleshooting features?

My other question is if I add batteries in 10 years will there be an advantage to either?


Related question is I have a 1960 home with original 100A panel, I am upgrading that to 200A separately as from what I understand a 100A would never have the headspace to accommodate that panel. Solar installer is suggesting I even downgrade main breaker to 180A so I have more headroom for future batteries, does that sound right? . Electrician sounds a little hesitant to do that now and this is getting 5 quotes on the panel upgrade as it varied form $3-8K! "solar ready" panels don't seem common around here

I have a comp shingle roof that is at least 20 years old so I am also replacing that.

BTW I have PG&E for electricity who charges 35-60c/kwh so going solar is a no-brainer and payback shouldn't be a problem at least with current net metering regulations


Thanks

You mentioned that you would only get batteries so you can use energy on your own schedule. This is a very different solution than having whole house backup or critical loads backup. As an exercise to help you understand how such a battery solution would be implemented, I would get your installer to draw up a schematic for potential battery solutions for your situation. That way you can price things out and understand how pieces of equipment play together now instead of 10 years from now. Technology does change, but at least you would understand a baseline understanding. For example, SMA's battery inverter is more expensive than SMA's solar inverter for approximately the same wattage.

It might also influence what and how you are making changes to your panel upgrade.

I have an SMA 7.7-40 inverter. If you can hardwire ethernet to the inverter, then wifi doesn't matter. Like previous responses, I wouldn't bother with extended warranties. I would buy a spare inverter instead. RMA'ing an inverter will take weeks or months depending on installer availability and SMA turnaround.

SMA does use the cloud app Sunny Portal to collect and store data, but the SMA inverter does not require the cloud for operation or reporting purposes. You can run the SMA inverter entirely offline if you want. There is a post titled "Disgusted with new trends forcing equipment to internet cloud connected" that references Enphase microinverters. Only you can answer whether or not the requirement for cloud connection is important to you.

[shade_tree]

The OP mentions warranties of one vendor vs the other. Who knows which company will be around next year, forget about 10, 25 or whatever years! IMHO, warranties should have little value when it comes to panel selections

I'm not so worried about panels but i think enphase and sma will be around in 20 years

[shade_tree]

You mentioned that you would only get batteries so you can use energy on your own schedule. This is a very different solution than having whole house backup or critical loads backup. As an exercise to help you understand how such a battery solution would be implemented, I would get your installer to draw up a schematic for potential battery solutions for your situation. That way you can price things out and understand how pieces of equipment play together now instead of 10 years from now. Technology does change, but at least you would understand a baseline understanding. For example, SMA's battery inverter is more expensive than SMA's solar inverter for approximately the same wattage.

It might also influence what and how you are making changes to your panel upgrade.

I have an SMA 7.7-40 inverter. If you can hardwire ethernet to the inverter, then wifi doesn't matter. Like previous responses, I wouldn't bother with extended warranties. I would buy a spare inverter instead. RMA'ing an inverter will take weeks or months depending on installer availability and SMA turnaround.

SMA does use the cloud app Sunny Portal to collect and store data, but the SMA inverter does not require the cloud for operation or reporting purposes. You can run the SMA inverter entirely offline if you want. There is a post titled "Disgusted with new trends forcing equipment to internet cloud connected" that references Enphase microinverters. Only you can answer whether or not the requirement for cloud connection is important to you.

Thanks I'll take a look at the thread. I may go with sma and if that goes out after the 10 year warranty then upgrade to whatever is battery comparable then. I mean in 10 years there may be a more seamless way to use your EV as a home battery storage. For me the only purpose is to avoid paying peak power rates. A lot of that can be mitigated by using appliances and charging off peak so even one home battery would be enough. However the installed cost of battery integration is about a $1k per kWh which i would never get ROI within battery lifetime with at least current net metering credits in CA
edit: i did check out the cloud thread and I'm not too worried about tha from a security perspective. For me the main downside of cloud servicing is the manufacturer may charge for this in the future

[Ampster]

... However the installed cost of battery integration is about a $1k per kWh which i would never get ROI within battery lifetime with at least current net metering credits in CA

It is the erosion of Net metering credits that have improved the ROI of solar with batteries compared to just solar. Load shifting with batteries is where the leverage happens.

[J.P.M.]

It is the erosion of Net metering credits that have improved the ROI of solar with batteries compared to just solar. Load shifting with batteries is where the leverage happens.

I'd respectfully suggest the leveraging starts with using less electricity through lifestyle modification and conservation measures with load time shifting being one of the lifestyle adjustments.

[shade_tree]

It is the erosion of Net metering credits that have improved the ROI of solar with batteries compared to just solar. Load shifting with batteries is where the leverage happens.

Absolutely but if I can install my system now before NEM 3.0 passes in CA i should be grandfathered in at least 10 years with friendly net metering Already with TOU rates i have changed my usage as much as is reasonably possible. But if we are all away for school and work, gotta cook dinner and do homework during peak TOU

[Ampster]

Absolutely but if I can install my system now before NEM 3.0 passes in CA i should be grandfathered in at least 10 years with friendly net metering Already with TOU rates i have changed my usage as much as is reasonably possible. But if we are all away for school and work, gotta cook dinner and do homework during peak TOU

I have been on TOU rates for ten years with solar. I have become a pessimist because even under current NEM plans thea rate changes and the time periods for those rates have eroded the benefits of solar. I am also in an area where outages create some value for backup. Therefore it is easier for me to justify batteries when I include value of a hedge against further erosion of benefits. You are wise to a least be seeing batteries as a possibility in the future. There was some talk during the NEM 3.0 discussions about further incentives for batteries.