Are Microinverters Reliable?

[thejq]

This was a lesson I learned many years ago in the space industry, instead of building backups to the backup circuits, was to design a better, robust circuit with fewer parts to go bad.

If a gadget has a 1% failure rate, having 2 gadgets gives you a 2% failure rate.

Not to dispute your conclusion, but your example is little off. Having a backup is to make sure the system still works in case the primary mode fails. So a failure is when both fails. So if failure rate is 1% each, system failure rate is 0.01% (not 2%). Of course, in the context of solar, there's no backup, so if any component fails, the system (panel + micro) fail, which agrees with your conclusion.

[JCP]

Enphase growth reduced because of warranty losses
http://seekingalpha.com/article/1888...igation-growth
The stock market review is telling:

They are screwing with the numbers !

According to Enphase latest 10-Q, their warranty cost estimates increases had to do with their 2nd generation (190). They actually reduced the warranty accrual on the 3rd generation (215). Obviously, only time will tell what the actual failure rate is.

[wantons0up]

Obviously, only time will tell what the actual failure rate is.

Yep, but who wants to be another guinea pig...

[JCP]

Yep, but who wants to be another guinea pig...

At least, they're making money now, so they should be able to cover their warranties.

[russ]

I think that if the catastrophic microinverter failures were really happening we would have members bitching - we have heard little first hand in the way of complaints.

A lot of the complaints are of the "heard in the barber shop" variety.

[wantons0up]

I think that if the catastrophic microinverter failures were really happening we would have members bitching - we have heard little first hand in the way of complaints.

A lot of the complaints are of the "heard in the barber shop" variety.

I wouldn't assume that a lack of complaints here means anything. This is an extremely small sample size.

[sdold]

I He says it hasn't cost him or the customer anything, but it's bordering on a 50% failure rate in the last 2-3 years.

50% of what, did he say? Is he saying that in that time, 50% of the systems have had a bad inverter, or 50% of the inverters have gone bad? I can live with the former because replacement is so easy.

[wantons0up]

50% of what, did he say? Is he saying that in that time, 50% of the systems have had a bad inverter, or 50% of the inverters have gone bad? I can live with the former because replacement is so easy.

Failure after they were in service for 1-3 years.

[sdold]

Failure after they were in service for 1-3 years.

Sounds like something other than current production Enphase. At any rate, I wouldn't assume his complaints mean anything, that's a pretty small sample size.

[wantons0up]

He admitted they weren't the current generation, I thought I had mentioned that in my first post. They scared him off enough though that he's been recommending central inverters for the last 6-12 months until he hears how the newer gen micros last.

[sdold]

It's hard to blame him then.

[russ]

I wouldn't assume that a lack of complaints here means anything. This is an extremely small sample size.

Wrong - over the course of a year a lot of people come through here and they know a lot more people. The guy was blowing smoke up your buddies backside to sound important. If the problem was that big Enphase would be in deep yoghurt!

[wantons0up]

Wrong - over the course of a year a lot of people come through here and they know a lot more people. The guy was blowing smoke up your buddies backside to sound important. If the problem was that big Enphase would be in deep yoghurt!

I like and appreciate this forum but it is not a useful data point to prove reliability. 21,000 members total. 10,200 have zero posts. 3,400 have one post, and 1,800 have two posts. That leaves about 5,000 members over 6 years of forum life with 3 or more posts. And you'd admit many of those visited to learn something, or ask a question, or whatever, and may not have a PV system. Great forum, but not a large sample size.

And you may not have read a few posts in this thread that back up the massive warranty claims I've alluded to:
• From 2011 to 2013 Enphase sales increased by 55.7% compared to the increase of warranty accruals of 248%
• Enphase growth reduced because of warranty losses

[russ]

What to say? No one has reported problems like this and some members are using the microinverters - for years.

I guess our members are just lucky -

Several are installers and Naptown in particular has used the microinverters since they became available.

The one link (the contrarian) says in full disclosure he is short in Enphase stock. The annual report I am not bothering to go through. If I had PV on the roof it would be using a string inverter - the "show and tell" of the Enphase has never interested me. I consider it a gimmick unless one actually has a shade problem

[wantons0up]

Enphase has laid out lots of money on warranty claims. That says everything you need to know, at least about early generation inverters. Hopefully the newer models are more reliable. Not sure why you're acting like you have a dog in the fight, a forum is supposed to be people sharing information altruistically to help each other. It seems like you're taking it personally if microinverters are unreliable.