I figured this would be a good place to ask and didn't find a conversation started on the subject. I am looking for people's experience with Micro vs. String inverters with residential solar arrays. Would anyone be willing to share their reliability record with either/both? I am familiar with the shading, expansion flexibility, advantages, and ease of replacement, controlled temps, cost disadvantages of micro inverters. What I am really focusing on is reliability. I've read that some of the early micro inverters had more failures, but that they have improved? Thanks all!
I'm not sure you can quantify "reliability" that way. Micros and central inverters each have thier own sets of advantages and disadvantages as I'm sure you well know. For a more thourough discussion, I hold pose the question here: Http:/forum.solar-electric.com/forum. (sorry, my paste function is not working properly, so if this link doesn't work, search NAWS forum and it will find it.) Icarus
I suspect that reliability is too granular to extrapolate to micro vs macro, or even by manufacturer. I suggest the following questions instead: How long is the warranty Likelihood that the manufacturer will be around when the device breaks Costs involved in taking advantage of the warranty It is number #3 that has attracted me to micro inverters since I've figured I can switch out that part, unlike a macro-inverter that most certainly involves the cost of an electrician.
Thanks for the resource! Great questions! While the micro inverters do have a longer warrantee, my main concern is system down time. Although, with the micros, the whole system, or half or a third, doesn't go down with a single failure.
Thanks again Icarus! This thread, My 7.5kWh micro Inverter (Build In Progress) - Page 7 was exactly what I was looking for.
Enphase. Enphase Micros have a 25 year warrantee. If they don't work like they should … you get them replaced … Enphase will send someone out to replace them AND give you a rebate for the lost power. You can check out my system at Going Green. Using American Made SolarWorld panels [that is udderly the only reason I got them my particular panels were made in Cowifornia…solar world is no longer manufacturing panels in my home state]. Enphase is a Cownadian company but I think they do the builds someplace else. Full disclosure: I own 100 shares of Enphase stock. Not a huge amount nor is it going to make me rich. I think it is making a good product so I purchased some just to be a part of it. Over the life of the system, micro inverters are probably going to save you money…but it will cost you a small amount more upfront.
For me it is a pretty simple choice. If you have no undue shading issues, and no local manufacturer incentive (like they do in WA I would go with a central inverter. If you have the above issues, then micros make sense. Icarus
Over the long hall Microinverters are more reliable than central inverters. Also you don't have that box on the side of your house on in your utility closet. Whatever you choose, going solar is great. Costs have come down that it is competitive with gas, and in some places coal. I'm not sure Minnesota is the best place for solar but you do have the nice long summers. Solar works good when it's cold, if you can keep the snow off of the panels it could work out well.
^That may...or not be true. Enphase, the earliest, oldest micro inverter hasn't been around terribly long, at least compared to some of the major players in conventional inverters. (SMA, Fronius, Outback etc) There are lots of these that have been in regular service for many years. I think Enphase builds a good product, but it lives in a harsher environment than a central inverter, subjected to weather, and most especially heat. Time will tell if on balance they are as reliable as central inverters have become. Additionally, central inverters can be replaced or repaired without getting on the roof, without removing any PV. As I said before, all issues address, I would go with central. Central in tears tend to be a bit less expensive per watt, but the price differential is fairly slight. Icarus
Oh I love solar, have it now. We have the same number of sun hours as Miami. Not as good as Arizona or California, however still quite a bit. The Enphase micros we are looking at have a 25 year warrantee, so I supose it is more of a concern for them. We have very low production in Nov, Dec, Jan, however, the micros should help out with the partial coverage of snow as well. Considering the 10 vs 25 year warantee, I think we are going to go that route. Thanks all!
My DIY system is also assembled from Enphase and SolarWorld components. Tree shading drove me to micros instead of string inverters, and rumored reliability problems (at that time) kept me away from the local micros. PV choice was very strongly driven by a 'too good to be true' price anomaly, in hindsight most likely a late-night web pricing error at a regional distributor. That anomaly vanished a bit after midnight, reverting to a normal price, but the anomalously low price remained in my online 'Shopping Cart'. I bit, and the low price (not equivalent to theft, but zero margin for them) was honored. The made-in-a-nearby-state feature was a plus, and was part of the reason I was pricing them. I have had no failures or system-related outages, but the sample is too small and brief to mean much -- 6 panels & inverters for 19 months, and 10 more for 15 months. One position runs noticeably lower than the rest in weak light, but fine in strong light. This is much more likely to be caused by the PV module than the inverter.
