Current Microinverters -- Opinions?

lunarpower

SMA vs. Power One vs. Enphase vs. Enecsys vs. ....

What do people see as significant differences between these?

I'm thinking microinverters might be the way to go for installing panels at home, for various reasons.

jaggedben

Re: Current Microinverters -- Opinions?

Enphase is the only one where it's going to be easy to find people who have experience with it. They jumped out on this technological limb way before anyone else and have probably 95% or more of the micro-inverter market share. I've installed thousands of them. The current generation (M215) seem to be quite reliable, I've seen only 3 failures out of more than 1000 installed since 2011. The M215 will be replaced by the M250 towards the end of this year, which will allow higher power panels.
The Enphase monitor, known as the Envoy, plugs into the wall and sometimes has trouble communicating with the inverters.

SMA is arguably the most reputable inverter manufacturer on the planet. I'd have a lot of confidence in trying their micro-inverter, but no one has had that opportunity yet. They are finally just shipping them now, after having first announced them over a year ago. The SMA monitor will be wired in series with the inverter output and should not suffer the communication issues that the Envoy does. However, the SMA design will allow less power on a circuit. (15A instead of 20A).

Power-One is also a very reputable inverter manufacturer, I've installed a lot of their string inverters. But I haven't seen a reason to use their micros instead of Enphase, either on pricing or product design. It's my understanding, based on a thread here, that the inverters will not work if the monitoring unit is not plugged in. That strikes me as a bad design. Other than that, I don't know much about them.

Enecsys only does micro-inverters. I would say they suffered by not getting their original product out as early as Enphase. The one advantage they have is that their pricing seems to be significantly cheaper. Personally I think going with them would be a gamble, but it could pan-out to saving money and getting the same production. Good luck finding someone who has actually installed them; you'd probably have to call Enecsys themselves and ask for a reference.

Enphase and Power-One use a separate trunk cable with connectors for each inverter. Unplug an inverter and all the others remain plugged in.
SMA and Enecsys have the inverters daisy-chained. Unplug the chain at any point and all the downstream inverters go offline. This does make it easier to expand.

All of them can connect to online monitoring software. The Enphase software is probably the most developed in terms of available features, because they have the most customers. But IMHO their web design department has gone downhill and screwed up the usability in various ways. I have no experience with the others, I've only seen screenshots.

kenza

Re: Current Microinverters -- Opinions?

I have 15 Enecsys micros. Have been working fine since I installed them (6 months). It was the only 50Hz micro inverter I could buy in US back when I was buying. They were a looooot cheaper than anything you can find on a local market down here in Chile.

OliverHevvy

Re: Current Microinverters -- Opinions?

I've heard that the Enecsys micro inverters have a DC leakage problem, in other words, there is a significant DC voltage present on the AC terminals when the
AC power is off, or the inverter is not connected.

Also, their monitoring system uses wireless, not carrier-current or powerline. Not inherently bad, but not very secure, and if you are in a brick or concrete house, or have a metal roof (e.g. standing seam) you're gonna have trouble with reception.

jebatty

Re: Current Microinverters -- Opinions?

I have Power One, system active since Oct 2013, one issue likely fairly unique to me. The monitor connects to the micros either by wi-fi or ethernet. My ground mount install was too far from the house to use wi-fi, so I needed to install it in a weatherproof box at the ground mount site and connect via ethernet cable. No issue there. But, the monitor is spec'd at minimum temp of -5F. It actually works well down to about -15F, but somewhere between that and -30F it fails to connect and it fails to pickup or communicate with the panels and my computer, and it needs to be rebooted to work, sometimes several times. My solution was to install in the weatherproof box a small wattage incandescent light bulb as a heater, snap disc thermostat, to keep the monitor warm.

I've read posts saying that the inverters will not work without the monitor plugged. At the times when it fails to work in extremely cold weather, my production meter shows that the micros still are working and solar output continues. But I can't say that the monitor was unplugged at those times, although it did show that it was not connecting to the micros.

Suniva panels are rated at 265W, the monitor regularly reports output as high as 268W/panel.

BB.

Re: Current Microinverters -- Opinions?

I would be pretty surprised if the micro inverters shutdown/lost actual power output if the monitoring connection/black box went down.

In general, you just need the monitoring to make sure every micro inverter is producing (full) power. Because they do not have any displays (and are mounted under panels on a roof typically), you cannot see if any one inverter is working or not.

Enphase is known that the monitoring system can reprogram a parameter or so (like maximum working AC voltage) on the micro inverters--But that is a special (password protected?) service menu.

But, I do have any information on their monitor otherwise--So anything is possible. You may have to call Power One and ask the question.

-Bill

inetdog

Re: Current Microinverters -- Opinions?

BB. wrote: »

I would be pretty surprised if the micro inverters shutdown/lost actual power output if the monitoring connection/black box went down.

+1
However, unlike a microinverter, solar optimizers (controllable DC to DC converters) that are designed to work with a particular inverter will generally not produce any power until they have established a combined monitoring and control connection with the inverter.

brasche

Re: Current Microinverters -- Opinions?

You might find the links at this site informative: http://matter2energy.wordpress.com/2013/annual-report/

(WARNING: site has not been checked thoroughly by forum moderators; proceed at your own risk. -'Coot)