Looking for opinions on Enphase Inverters

It certainly is an interesting concept where conceivably one could build a PV system 200 watts at a time without having any redundant or underused equipment. Its a bit like not having all of your eggs in one basket so to speak.

The inverters themselves have a 10-year warranty, and if one fails then your power only falls by 200 watts and not an entire system failure that you might have with a single large inverter.

By converting the 24V DC to 240V AC right at the panel the run back to the main AC panel can be done with much smaller and cheaper wire. They have also eliminated the expense of DC disconnects, inverter programming etc.

Enerphase is currently offering incentives to installers, so that might be one reason the solar company is recommending them, but overall it looks to be a system that can be installed rather quickly and quite easily.
http://www.enphaseenergy.com/products/moreinfo/faststart.cfm

The only con that I can see, and this is from my personal point of view only, is that they want you to sign up to monitor the output of the system. I don't want to have to ask someone else what the output of my system is, but perhaps other less technical people prefer that route. Its hard to tell if they are looking to make money from the sale of the product, the after sales service, or both.

John

Hi John,
We (a few of us from AltE) recently had a chance to see Enphase's product at the Solar Power 2008 show. If it's an indication of the interest in their product, their booth more than any other I saw had the largest crowd of folks oozing out into the aisles. It has clearly generated a lot of excitement in our industry and it was the highlight for most our folks that went to the show as well.

Personally, this is a product that I have been bugging manufacturers to come out with for the US market (but apparently Enphase stayed off our radar until now) after Trace let go of their Microsine inverter series.  Our retail division, AltE Store, focuses on helping Do-It-Yourselfers install RE systems safely & successfully. However, grid-tie solar electric systems have almost always involved playing with very high and very dangerous DC voltages - something that only the most skilled DIYer should consider installing and, of course, with the assistance of a licensed electrician for final hookup and code review. So, what impressed me about the Enphase product was how they not only made the install simpler (and simpler to meet code requirements) but that it allows DIYers to play with DC voltages that won't stop their heart. I.e. under 48VDC. 

The other big point is that so many green DIYers are working on a budget that doesn't necessarily allow them to afford the upfront cost of a 5-10kW PV system. A micro grid tie inverter allows folks to add capacity as their budget affords. You add one inverter & one panel at a time. And whether you live in a state that has an aggressive rebate program for RE systems or not, the 2008 or 2009 tax credit makes this small of a system even more financially attractive.

We're hoping to get one of these units into our AltE "Labs" to test and play with soon.  So with any luck, our guys will be able to provide you and other folks out there with some of our test results. Stay tuned!

Indeed, this turned me off initially, too.  I'm just getting started and was reading the EMU manual this morning.  It turns out the monitoring unit has a built in web server that will display all the vitals for each inverter.  There's even an lcd display telling you how many inverters are reporting, what the current output is, and the cumulative output.  Enphase isn't doing themselves any favors by neglecting to advertise this- sure the monitoring and alerts by a third party website is nice, but the way they're talking about it makes it seem like you have an inaccessible black box doing who-knows-what on your local network.

I've also wondered about using 2 12v or 16v modules.  I would guess that as long as the combined wattage was at or under the rated maximum, it would work just fine.  Not much sense in doing it though- the sweet spot of $/W is up around 180W these days.  Maybe if you had a bunch of old 100W-120W modules sitting around, though.

i think two 12v should work.  i wonder if enphase cares for warranty or anything else.  only issues i see is you would have to add MC solarline 1 connectors, and that may not fit well with the j box and inverter. 2nd issue, if you have two in series, the ends may not reach the inverter forcing somebody to buy or make 3 or 6ft extensions which may get crowded under the modules.

james
altE staff

or you can have your solar/electrical pro install a dumb old analog meter between the output of the inverters and the point of interconnection.  i kid about this, but I employ this method with a string inverter and prefer it to having to pay a subscription.

low tech, granted, but should be able to track production old school style.  if you want daily numbers, go outside every day after sunset and write it down.  fire up a spreadsheet and go town. I settle for monthly data. 

http://www.altestore.com/store/Meters-Communications-Site-Analysis/Meters-Battery-Monitors/Power-Meters/GE-Solar-KWHR-Meter-240V-100A-EZ-Read-Meter/p3918/

http://www.altestore.com/store/Meters-Communications-Site-Analysis/Meters-Battery-Monitors/Power-Meters/Kilowatt-Hour-Meter-Base-NEMA-3R/p4227/

james
altE staff