SMA inverters: Better reliability but no panel level monitoring. Good tradeoff?

[Seltos]

I'm shopping for a ballpark 7kw roof solar system in the sunny SoCal desert. No trees or other shading issues on our roof, except we may lose some sun before true sunset, due to nearby mountains to the west.

I can get a SMA Sunny Boy system for $2.50 per watt, before the federal tax credit is even deducted. My SolarEdge and Enphase system quotes range from $3.35 - $4.35 per watt.

Pros for SMA Sunny Boy as I understand them:
1. Notably better reliability, especially vs SolarEdge apparently.
2. Faster parts replacement processing.
3. String level monitoring from a cell phone. If a panel goes out, its string is impacted and the homeowner who checks can see this or (I think?) be auto-alerted to this via email.
4. Less expensive as noted.
5. Integrated Rapid Shutdown now available
6. SMA automatically notified if something fails (or is about to fail) and ticket created and replacement part shipped.

Cons:
1. No panel level monitoring.
2. Ten year warranty (vs 12 for SolarEdge or 25 for Enphase).

What are thoughts of professional installers (or homeowners for that matter) here who've worked with these inverter systems?

[Ampster]

I'm shopping for a ballpark 7kw roof solar system in the sunny SoCal desert. No trees or other shading issues on our roof, except we may lose some sun before true sunset, due to nearby mountains to the west.

I can get a SMA Sunny Boy system for $2.50 per watt, before the federal tax credit is even deducted. My SolarEdge and Enphase system quotes range from $3.35 - $4.35 per watt.

..................
What are thoughts of professional installers (or homeowners for that matter) here who've worked with these inverter systems?

I am a homeowner who has installed both SolarEdge and Enphase on some dwellings. Did that price include Rapid Shutdown if required in your jurisdiction? SMA equipment is considered rock solid and I would go with the least expensive option if the Sunny Boy includes RSD, if required.

[solarix]

What would you rather have?
A highly reliable, system using PV panels that virtually never fail and a less expensive, proven inverter with an honest warranty that is easy to service but can't see individual panel failures.
- or -
A more expensive system that gives you visibility into a less reliable system with a dishonest warranty because it has its electronics under the PV panels in a hot, hostile environment where they are hard to service.
Your choice....

[oregon_phil]

I have a 10.22 kW in three strings to an SMA 7.7 -41 inverter with Tigo TS4-R-O optimizers. My inverter is located inside my insulated pole barn. SMA is the only system I have owned. Whatever system you select, make sure you get INSTALLER privileges from day one.

Pro's

1. The thing is built like a tank. Just make sure all conduits are properly sealed with duct seal or equivalent.
2. The inverter can be run on a local network without the cloud. This means if the internet goes down, you still have full local access to your inverter. You do need an internet connection if you want the inverter to talk to the Sunny Portal application.

SMA let's you control when firmware updates happen. You can set firmware updates to automatically happen (not my choice) or you can download the updates from the web and update firmware at your discretion (my choice). In other words, you have control over your device; updates etc are not PUSHED onto your system without your knowledge.

3. SMA will email you if a fault like rapidshutdown happens, but the email will be the next day. I don't rely on the email. Since I have installer's privileges, I look at my production numbers and Events file daily to see what's going on.

I don't use the cell phone app. Maybe too much information but I set my SMA to a known IP address using DHCP reserve on my router. Then I just call up 192.168.xxx.yyy to get to the inverter web interface. For remote access, I use my routers VPN. I am cloud phobic.

The part about SMA automatically creating a ticket, sending parts before something fails.... that hasn't been my experience. I have a spare inverter and TIGO optimizers on hand for replacements. How many weeks is it going to take to determine a system failure with your installer, then weeks/months to convince SMA to send a replacement, another couple weeks to schedule installer to install replacements. For me in Oregon, that could be my entire summer's production window.

I did have an issue with my first SMA inverter. I got a Level 1 tech, then a level 2 tech, and finally four hours later spoke to a level 3 tech (I think I only got this far because I am a retired ME from a high tech electronics company and had reams of data/charts/Power point presentation).

An important thing to do is to pick a good installer that has a track record, that is easy to communicate with and responds in a decent time.

Good luck!

[J.P.M.]

What would you rather have?
A highly reliable, system using PV panels that virtually never fail and a less expensive, proven inverter with an honest warranty that is easy to service but can't see individual panel failures.
- or -
A more expensive system that gives you visibility into a less reliable system with a dishonest warranty because it has its electronics under the PV panels in a hot, hostile environment where they are hard to service.
Your choice....

Some of us have been chanting that mantra for long time and the manta is as correct and as sensible as it was back in the day. I'm fan of the KISS principle.

Add to that: It's also been my experience that most owners I talk to - and I talk to a lot more than my share - don't know about panel level monitoring and wouldn't give a crap about it even if they did understand what they were looking at.

Those who do know about it almost universally get bored with it after a half dozen or so looks at a screen.

As a result of not looking at output, and also because there's a higher probability of more problems in systems with more parts, one possible unexpected problem is what happens when one micro or optimizer drops out but goes unnoticed because the loss is small ? When a string inverter dies, I'd expect the problem gets noticed when the next electric bill arrives and it's a whopper compared to what it was before the inverter stopped functioning.

[sabersix]

Another drawback for SMA is that there is no easy way to upload data to PVOutput.org if that is of any interest to you.

I have SMA and had to build a custom database logger and uploader on a Raspberry Pi.

https://pvoutput.org/intraday.jsp?id=39485&sid=36066

[solarix]

The success of the microinverters and optimizer products seems to me due to the public's love affair with smart phones. "Oh - its like I have a smart phone under every solar panel....."
ya - and how long do smart phones last.

[Seltos]

Did that price include Rapid Shutdown if required in your jurisdiction?

Yes, I believe it did. I will be certain of this before moving forward.

[Seltos]

I don't use the cell phone app. Maybe too much information but I set my SMA to a known IP address using DHCP reserve on my router. Then I just call up 192.168.xxx.yyy to get to the inverter web interface. For remote access, I use my routers VPN. I am cloud phobic.

I have a spare inverter and TIGO optimizers on hand for replacements. How many weeks is it going to take to determine a system failure with your installer, then weeks/months to convince SMA to send a replacement, another couple weeks to schedule installer to install replacements. For me in Oregon, that could be my entire summer's production window.

I did have an issue with my first SMA inverter. I got a Level 1 tech, then a level 2 tech, and finally four hours later spoke to a level 3 tech (I think I only got this far because I am a retired ME from a high tech electronics company and had reams of data/charts/Power point presentation).

Good luck!

1. Good idea on the DHCP known IP address. And to get installer level access too. Thanks Oregon Phil!
2. It obviously takes more capital to keep a spare inverter around. One reason I wanted to go with SMA vs SolarEdge. Lower failure rate.
3. PowerPoints: I won't be able to match this but can make myself a thorn in the side if need be.

[Seltos]

Another drawback for SMA is that there is no easy way to upload data to PVOutput.org if that is of any interest to you.

I have SMA and had to build a custom database logger and uploader on a Raspberry Pi.

https://pvoutput.org/intraday.jsp?id=39485&sid=36066

Interesting! I need to dig into this further. Have not heard of PVOutput.org.

[Mike 134]

What would you rather have?
A highly reliable, system using PV panels that virtually never fail and a less expensive, proven inverter with an honest warranty that is easy to service but can't see individual panel failures.
- or -
A more expensive system that gives you visibility into a less reliable system with a dishonest warranty because it has its electronics under the PV panels in a hot, hostile environment where they are hard to service.
Your choice....

Been thinking about the electronics under a solar panel.
They have it pretty good compared to the electronics under your car hood. Those can go from below zero to over 150 degrees within an hour, then back down to below zero, depending on the season/location, in addition they are subjected to vibrations and shocks that the solar electronics do not experience.

Hopefully the solar engineers have studied the best practices that the auto engineers use to have long lived electronics in hostile environments.

[J.P.M.]

Interesting! I need to dig into this further. Have not heard of PVOutput.org.

PVOutout is a good source of info for a lot of stuff although you don't need to register to get all/most of the advantages. Like the old CSI database when it was still around, neither is widely known but both very useful in their own ways.

[J.P.M.]

1. Good idea on the DHCP known IP address. And to get installer level access too. Thanks Oregon Phil!
2. It obviously takes more capital to keep a spare inverter around. One reason I wanted to go with SMA vs SolarEdge. Lower failure rate.
3. PowerPoints: I won't be able to match this but can make myself a thorn in the side if need be.

On 3: I can be a PITA quite well with a string inverter, but because it's a string inverter, being a PITA to vendors and mfgs. is much less necessary.

[sabersix]

Interesting! I need to dig into this further. Have not heard of PVOutput.org.

This is the software I'm using on my Raspberry Pi to pull SMA data.

https://github.com/SBFspot/SBFspot/

[Seltos]

PVOutout is a good source of info for a lot of stuff although you don't need to register to get all/most of the advantages. Like the old CSI database when it was still around, neither is widely known but both very useful in their own ways.

Great to learn! Can it help me get a more accurate sense of what my estimated output might be (annually?). I'm seeing discrepancies in the estimated annual output for my proposed rooftop system, even with similarly sized systems, with panels all tilted similarly and on the same 200 azimuth. PVWatts seems to be higher than Aurora. I get no shading so not sure why this difference exists.
PVWatts has "System Losses" as one of its factors and has a default of 14%. Is that a realistic estimate? Dropping that to 10% raises the output quite a bit.