Proposed solar array install

[Mr. Kelly]

My system has the 250W Aurora-Power One microinverters installed on a ground mount system located about 250 feet from the main panel. 26 micros installed in 2013 and another 20 micros in 2015. One micro failed about a year after install, replaced under warranty. Two failed about two years ago, also replaced under warranty. Installing the replacements was not under warranty. Replacing a micro is extremely easy (I watched the electrician), takes about 10 minutes. My system has survived and performed well, both from summer heat into the +90F range and to -35F winter range.

When the system was installed I also had an ethernet cable buried to communicate with the micro data collection devices for the micros, although the micros also can communicate by WI-FI, the distance was too far for a reliable WI-FI connection. There are about 15 data points that each the micro has, and checking the micros involves a quick readout on the home computer. The key data is micro voltage, watts and frequency. Most if not all of the data is down-loadable, so it is easy to track performance over time,

FWIW, June 2021 will set a record for total June monthly power output for my system, now 8 years old: 1,890 kWh with one day to go, and I estimate today will produce about another 65 kWh. I have not been able to discern any panel/micro degradation in power output over this period of time.

Our system is grid-tied under MN net meter law, and it produces 100% of the electricity use in our household, including providing most of the power for our two BEV cars.

Thank you for your thoughts and your input.

when I thought about having to change out micro inverters, due to failure, I wondered if it would be a fairly easy job.

May I ask you, roughly, how much the guy charged you to swap them out? Was it a solar installer that swapped them out, or can a general electrician handle that?

Did you eventually take it upon yourself to switch them out yourself? I thought about that possibility for future consideration.

 

[peakbagger]

FYI, he has a ground mount, access to the panels is quite easy, probably a step ladder. Its just two MC connectors to disconnect using a special unlocking tool or some jiggling with a couple of screwdrivers, unplugging the trunk cable with another special tool and couple of screws holding the inverter to the frame. Its the same story on a roof mount except the inverter is under the panel. That means cutting a hole in your roof to get underneath it from the attic (decidedly impractical) or unbolting the panel and lifting it up from the array to get access to the connectors and screws. In the case of a large array with more than one or two rows there is also the problem of rigging to get to the panel in the middle of the array. Of this is assuming the manufacturer is still making that model microinverter.

Depending on the system, the new panels may need to be registered to inverter.

 

[begreen]

This thread has me thinking of adding DC optimizers to our system. We have temporary shading issues from tall trees in spring and fall as their shadow transits the panels. What kind of gain would one expect? What is the failure rate of these devices and how do you know if it has failed? Easy to replace in a field mount system?

 

[peakbagger]

My understanding from forum postings is you need a new string inverter with capability to talk to the optimizers to get all the benefits. Solaredge is one brand of string inverter that works. I think you still get some benefits without a smart inverter due to an panel level MPPT but no RSD and no module level monitoring . The Solaredge Inverters seem to have mixed reviews, I think a big issue is they only support service through dealers and will not talk to consumers. The existing MC connectors are unclipped and then the optimizer goes between the connectors. I dont think there is a easy answer to the benefit as it varies with the shading and how many MPPT channels you have on your existing array and how the strings are arranged.

They look like $80 to $100 each plus the possible inverter upgrade so they would really need a big benefit. Might be better to put in few new panels (or hire an arborist ? I think the big plus is if you need RSD its a lower cost solution to microinverters and a gateway.

The reports on the forums seem to be more reliable than microinverters since they are simpler but its slightly newer technology so less years in the field.

 

[begreen]

My understanding from forum postings is you need a new string inverter with capability to talk to the optimizers to get all the benefits. Solaredge is one brand of string inverter that works. I think you still get some benefits without a smart inverter due to an panel level MPPT but no RSD and no module level monitoring . The Solaredge Inverters seem to have mixed reviews, I think a big issue is they only support service through dealers and will not talk to consumers. The existing MC connectors are unclipped and then the optimizer goes between the connectors. I dont think there is a easy answer to the benefit as it varies with the shading and how many MPPT channels you have on your existing array and how the strings are arranged.

They look like $80 to $100 each plus the possible inverter upgrade so they would really need a big benefit. Might be better to put in few new panels (or hire an arborist ? I think the big plus is if you need RSD its a lower cost solution to microinverters and a gateway.

The reports on the forums seem to be more reliable than microinverters since they are simpler but its slightly newer technology so less years in the field.

Thanks. I don't want to hijack this thread so I will post concerns and details in a new thread.