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grid tied inverter recommendations

davis mounger

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Aug 9, 2020
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My students put up a 2K system that had Enphase micro-grid tied inverters (M215) for eight 72 cell modules about 8 years ago- donated stuff from the power company. Three of the inverters have failed over the last year or so. had an early Envoy out the field logging the performance someone had donated- it went out too recently. Was planning to get a new envoy and we've recently run an ethernet connection out there- and the current students were going to raise some funds to replace the dead micro inverters. However, Enphase refuses to take a purchase order from our school district (not the point of the post-that's how the district operates, and how Enphase operates- it is what it is). Since they aren't interested in taking our money, I'm going to need to look for another company for a data logger that can post to the cloud. And since I can't get replacement micro inverters and I bet the others are probably not long for the world, also open to changing the inverting structure. Open to either a new set of micro-grid ties, or just bite the bullet and get a 3000W inverter (room for a bit more expansion)- with a datalogging/cloud combo. I'm familiar with the pros and cons of micro-grid vs single inverter- just would like to hear what's new on the market that seems to be doing well and doesn't break the bank. I haven't really kept up with new products lately. The logger would preferably be one with a link we could make publicly available for education purposes.
 
Do you know why the Enphase died? People expect those to be reliable.

I'm happy with SMA Sunny Boy high voltage string inverters.
Older models can be found fairly cheap (sometimes $0.10/W) either used or new old stock.
There are a couple logging devices, and either RS-485 or "Speedwire" Ethernet. Sunny Boy Control, Sunny Web Box, Sunny Explorer software on a PC.
 
Do you know why the Enphase died? People expect those to be reliable.

I'm happy with SMA Sunny Boy high voltage string inverters.
Older models can be found fairly cheap (sometimes $0.10/W) either used or new old stock.
There are a couple logging devices, and either RS-485 or "Speedwire" Ethernet. Sunny Boy Control, Sunny Web Box, Sunny Explorer software on a PC.
Nope. They've just stopped. I think at least some of them were used when we got them. Since these were donations, whatever warranty they had doesn't apply.

Can these logging devices read any inverter make as long as they're working properly?
 
I was wondering if it was AC power line transients, temperature, panel volts/amps/watts, lightning surges, etc.

Those devices are only for the language of SMA inverters. I've built up a nice collection of older SMA equipment, and it isn't grid tied even where that is available.

They have a new product Data Manager that talks to all inverters with SunSpec protocol. I have no experience with it.
Features include participating in spot markets for power.


 
Hard to say. All of the micoinverters lasted for about 6 years. Then one died, then another, etc. So no one event.
 
In comparison, I had five 2500W SMA inverters for 17 years. One died within 5 year warranty and they swapped a PCB. One blew a transistor and I uninstalled it. All told, I figure 35 operating years per failure. 35 year MTBF? Perhaps they would have started reaching end of life and I would calculate a lower MTBF if I kept using them, but I swapped for other models with features I wanted.

The newer units are warranted 10 years standard, 15 or 20 years optional. The Sunny Island battery inverters are warranted 10 years (difference is they would operate 24/7. In both cases I think warranty period is lesser of years or kWh processed.

Microinverters, in a hot area under a panel, have a tough environment.
 
How is the array mounted? How far is the array from the service panel? What else is shared with the service panel/interconnect?

Converting from micro inverter to string inverter may require some good amount of rewiring. Would be a great project for students to compare the systems and show highlights of both.

Another great opportunity for learning would be troubleshooting the current system. Verify line voltages/currents at various points. Disassemble part of the system compare it to another. See if you can verify the “bones” of the system and interconnect are solid so you feel better knowing the emphase units are headed to greener pastures.

Troubleshooting is an amazing process that is tough to teach from books. Hands on learning and reasoning into why to look here, or check this because it interacts with that, takes some time and is a great skill that can be applied to various fields, not just electrical stuff.

It seems everyone wants to know the quick solution for the problem they currently face but it seems few want to know why that’s the solution, or the reasoning that’s the solution.
 
How is the array mounted? How far is the array from the service panel? What else is shared with the service panel/interconnect?

Converting from micro inverter to string inverter may require some good amount of rewiring. Would be a great project for students to compare the systems and show highlights of both.

Another great opportunity for learning would be troubleshooting the current system. Verify line voltages/currents at various points. Disassemble part of the system compare it to another. See if you can verify the “bones” of the system and interconnect are solid so you feel better knowing the emphase units are headed to greener pastures.

Troubleshooting is an amazing process that is tough to teach from books. Hands on learning and reasoning into why to look here, or check this because it interacts with that, takes some time and is a great skill that can be applied to various fields, not just electrical stuff.

It seems everyone wants to know the quick solution for the problem they currently face but it seems few want to know why that’s the solution, or the reasoning that’s the solution.
"How is the array mounted? How far is the array from the service panel? What else is shared with the service panel/interconnect?"

On a steel frame. Everything's well grounded. The array is about 80 feet from the service panel. There's a dedicated double breaker for the feed in the service panel. The service panel is for the outdoor stadium: lights, receptacles, etc.
 
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