Failing panels or optimizers?

[brian.c]

Today I finally had my Tesla solar installed. After they completed wanted to check the output of my older system (Sunrun) to compare with what the new system was generating. To my surprise, 3 additional panels are no longer generating.

One panel (A6) has not been generating now for a while, that specific optimizer was replaced in 2017, worked for a couple years and then again stopped working. I will be putting in a call to Sunrun to see if I can get someone out for warranty.

Last time took a couple months, then another month or so for Tigo to approve a warranty replacement. What are the signs of failing panels? They seem to work in the morning, then after a couple hours those 3 panels drop off to 0. I went up and cleaned them just to be sure that was not the issue, but still nothing after the fact.

Looking over the last couple weeks they all seem to be pretty erratic. When the optimizer failed both times, seemed to completely drop to 0 one day, so thinking this may be a panel issue. If panels fail after 10 years, whats the chance of finding a similar matching panel?

(moderator note: added line spacing to improve readability. no other change made)

 

[wwu123]

I'm not sure what type of optimizers and inverter you have, and how it reports, but wondering if it possibly a communications issue rather than an actual production issue.

I have a similar behavior on one panel on my system, which uses Enphase micro-inverters. One panel works fine starting in the morning, then often drops out in late morning. Usually in the late afternoon/evening, it'll start reporting again til the end of the day, though sometimes it doesn't start reporting until the next morning. For several months, I didn't know if there was no production when it wasn't reporting or not. Also on many other days, it seemed like it would get stuck at a certain wattage til end of day.

Turns out in my case, it's mainly a communcations issue. Each micro-inverter gathers data itself and sends it via some powerline comm protocol to a central monitoring box. When it is not able to communicate, it comtinues to record data, and then sends it when it next re-establishes communication. The monitoring system then receives the accumulated energy and then spreads the production evenly across the previous hours where there was no reporting. Thus in my case, creating the flat stuck wattage in retrospect, since it apparently doesn't have the entire power curve for the day. Also if it doesn't establish comms til the next morning (the micro's are self-powered and can't report at night), the flat stuck wattage is spread the next day from midnight to the morning when comms are re-established. All of which makes for some odd-looking production graphs, but at least I know my troublesome panel is still producing.

 

[brian.c]

I'm not sure what type of optimizers and inverter you have, and how it reports, but wondering if it possibly a communications issue rather than an actual production issue.

I have a similar behavior on one panel on my system, which uses Enphase micro-inverters. One panel works fine starting in the morning, then often drops out in late morning. Usually in the late afternoon/evening, it'll start reporting again til the end of the day, though sometimes it doesn't start reporting until the next morning. For several months, I didn't know if there was no production when it wasn't reporting or not. Also on many other days, it seemed like it would get stuck at a certain wattage til end of day.

Turns out in my case, it's mainly a communcations issue. Each micro-inverter gathers data itself and sends it via some powerline comm protocol to a central monitoring box. When it is not able to communicate, it comtinues to record data, and then sends it when it next re-establishes communication. The monitoring system then receives the accumulated energy and then spreads the production evenly across the previous hours where there was no reporting. Thus in my case, creating the flat stuck wattage in retrospect, since it apparently doesn't have the entire power curve for the day. Also if it doesn't establish comms til the next morning (the micro's are self-powered and can't report at night), the flat stuck wattage is spread the next day from midnight to the morning when comms are re-established. All of which makes for some odd-looking production graphs, but at least I know my troublesome panel is still producing.

The inverter is a SMA4000, Tigo optimizers and panels are REC 230w (REC230PE).

I checked output on the inverter and its matches pretty closely to what the Tigo reports, so I think that rules out reporting errors. The Tigo works independently from the inverter from my understanding.

It appears all 3 panels starting having issues in the last month or so. I am also wondering if its maybe the Tigo controller. Whats the odds of having 3 panels, or 3 optimizers start failing within a month. Then again, if it was the controller I would expect all panels to act up.