Enphase announces sixth-generation product line

[RegGuheert]

As expected, Enphase is moving to a new family of plastic-enclosed inverters which utilize a new two-wire AC wiring system know as the IQ family. The specifications for the new plastic inverters roughly match those of their fifth-generation products with the exceptions that the higher-power unit supports 72-cell PV modules and they are not compatible with Engage.

The new two-wire cabling system should prove to be both cheaper and more flexible than Engage.

Finally, it appears that the new inverters and wiring system require the use of yet-another new Envoy to function properly. I assume this is due to the lack of a neutral line in the new wiring system.

I have to believe that this major chage is aimed squarely at trying to make Enphase' product offerings cost-competitive in the market. At the same time, making a full line of products which has little in common with their previous products leaves the door wide open to departures to competing technologies. While I don't think they really have a choice, it seems that Enphase will need a flawless rollout and rapid market acceptance of their new line in order to survive.

[GetOffYourGas]

I really hope that, whatever Enphase is trying to accomplish, they are successful. My entire system is depending on their staying in business so they can honor their warranty.

I'm not sure how much the lack of backwards compatibility hurts them wrt new installations. I'm sure that's where they get most of their revenue, and not in selling replacements which are still mostly under warranty.

It seems like Enphase is teetering on the edge of existence. Or am I just misreading the situation?

[ltbighorn]

I was kind of surprised that they had a three-line system for so long, but then I haven't looked at all into why that might be.

Lack of backwards compatibility hurts a bit on the expansion side, but that's probably a small part of their business too. Ultimately though with micros, there's not as much "sunk" investment, so it doesn't hurt as much to switch technologies. But it's very much true that if my new Envoy-S Metered won't even work with them, then I might as well consider competitors at the same time as I evaluate them.

GetOffYourGas, certainly looks like they're in a difficult spot, confirmed by their recent taking of somewhat more expensive than usual debt. I wouldn't quite say edge of existence, as there's a lot of value there, and it could be resolved by a heavy-handed restructuring or acquisition.

But if things go badly I guess I'll need to stock up on a few M250s or S280s.

[GetOffYourGas]

I've had three of 16 inverters fail (naturally, all under warranty). Each one took longer than the one before it to get a replacement from Enphase. I was getting concerned about this latest one, as it took about 2.5 months. I just got confirmation from my installer that he has the inverter in hand, and will get out hopefully early next week to replace it. It's a shame, too. That particular panel lost one of the sunniest Syracuse summer's I've ever seen.

It is somewhat assuring to 1) have finally received the replacement and 2) hear that they are sitting on a large amount of assets. I hope their leadership has the will power needed to make those tough decisions. It's never easy to do, and many companies go down in flames rather than admit they are in trouble, and make the necessary cuts.

The silver lining: Enphase has a decent installation base. Even if the company went under, it is highly likely that someone would buy their IP and build compatible replacements. You and I may lose our warranty, but at least we would be able to purchase a replacement inverter. Of course, I would much rather see them survive the full duration of my 25-year warranty (which runs through 2036).

[RegGuheert]

I was kind of surprised that they had a three-line system for so long, but then I haven't looked at all into why that might be.

There are actually four wires (what electricians call three-wire plus ground): L1, L2, N and ground. The ground is required because the structure is metal. By going to plastic, they eliminate the need for the ground wire (IIUC). The neutral was used in the past to carry the powerline communications signals. That allowed the Envoy to communicate with the microinverters even though it was only wired to 120 VAC. I assume the future Envoys will need to be connected to 240VAC in order to communicate with the sixth- and later-generation microinverters.

But it's very much true that if my new Envoy-S Metered won't even work with them, then I might as well consider competitors at the same time as I evaluate them.

It is very doubtful that your Envoy will be able to communicate with the new inverters UNLESS the S-series inverters and the Envoy-S already communicate over L1 and L2 only.

But if things go badly I guess I'll need to stock up on a few M250s or S280s.

If the S-series microinverters are as reliable as the fourth-generation inverters, then I doubt you will need very many spares.

I need to try to calculate an MTBF for the fourth-generation microinverters which excludes the original M215s, since they apparently include third-generation power electronics. (Sorry, GetOffYourGas!)

[RegGuheert]

It looks like Enphase has now started production of these sixth-generation inverters. Here is a listing for a few IQ+ inverters on eBay. The seller is charging about $190 for each 290-W inverter.

[Durandal]

Interesting. Something I never considered until today, is if I have a pure sinewave inverter that can output say, 4,000w, and it is doing so on my off-grid circuit, and I want to use these guys to make additional strings to put extra AC power onto my off-grid circuit, I could probably do so, which would reduce the load on the battery connected inverter? (Essentially reducing the charge controller size needed, assuming I can make use of that extra AC power when it is being generated, which I can surely do by some thermal storage.)

[RegGuheert]

The IQ6 inverters (hard limit at 240 VA) are going for US$0.50/watt on eBay (local pickup).

The IQ6+ inverters (hard limit at 290VA) are going for US$0.59/watt on eBay shipped.

I'm not sure what the cabling costs, but it has to be cheaper than Engage.

[RegGuheert]

I was looking at the released datasheet for the Enphase IQ-series inverters yesterday and I noticed the following entries which are non-existent in both the preliminary datasheet for the IQ-series inverters and in the datasheets for Enphase' previous products:

Overvoltage class DC port: II

and

Overvoltage class AC port: III

Even though I have designed and tested lightning-suppression equipment in the past, I had not hear of this type of rating. An internet search revealed this National Instruments webpage which has the following to say:

The amount of insulation required in the isolation barrier depends on several factors:

- Working Isolation Voltage (voltage across the isolation barrier) -- larger isolation voltages require more insulation.
- Transient Voltage (temporary voltage spikes across the isolation barrier) -- insulation strong enough to withstand the normal working voltages of the circuit can break down under large transients. Therefore larger transients will require more insulation.
- Air Pollution -- insulation can be reduced by contaminants in the air. Dirtier environments require more insulation.
- Single-Fault Current Path -- if the insulation breaks down, can the shorted current go through a human body? If so, a larger amount of insulation is required.

The IEC has covered these issues in Section 6 of the IEC 1010 standard. The commission has defined things such as overvoltage categories, pollution degrees, and double insulation.

That page also includes a table indicating the transient voltage which must be withstood for each overvoltage class. The National Instruments webpage also lists these descriptions for IEC "installation categories":

Category II -- Energy-consuming equipment to be supplied from the fixed installation.

Examples: Appliances, portable tools, and other household and similar loads. Measurement equipment intended to measure the voltage levels of these loads must be rated at this overvoltage category.

Category III -- In fixed installations and for cases where the reliability and the availability of the equipment is subject to special requirements.

Examples: Switches in fixed installation and equipment for industrial use with permanent connection to the fixed installation; measurement equipment intended to measure the voltage levels of these fixed installations must be rated at this overvoltage category.

I suppose what is implied by all of this is that BOTH the DC section AND the AC section of the new IQ 6 and IQ 6+ inverters are galvanically isolated from something (the metal tab on the unit?) and have the following minimum insulation breakdown voltages: DC section: 500V, AC section 4000V (or is it 2500V?). And I suppose the transient is common-mode on top of the two wires connected to each section.

Is this the proper understanding of what those specifications mean? If not, what then is meant by "overvoltage class"? Also, is this new requirement something that comes about because of the elimination of both the ground and the neutral wires in these new inverters?

[RegGuheert]

The IQ6 inverters (hard limit at 240 VA) are going for US$0.50/Watt on eBay (local pickup).

The IQ6+ inverters (hard limit at 290VA) are going for US$0.59/Watt on eBay shipped.

I'm not sure what the cabling costs, but it has to be cheaper than Engage.

Here's an IQ 6+ for US$0.48/Watt shipped.

That's still 41% more than the US$0.34/Watt I paid for M250s over the weekend. I suspect the IQ-series inverter prices will come down a lot more as time goes on.