What I'm learning about DIY Enphase and Hoymiles Microinverters

[ncsolarelectric]

It has been brought up here as a "bad idea" to put 2 microinverters together as Enphase did with the D380 from 11+ years ago. It was 380W in one package. It had dimensions of 12.25" x 6" x 1.33".

Currently, the Enphase IQ8H is 380W in one package. It has dimensions of 8.3" x 6.9" x 1.2". Smaller and denser than its dual predecessor. So even Enphase learned from their mistakes.

The latest Hoymiles HMS-1000-2T-NA is 958W. It has dimensions 10.27" x 7.09" x 1.22", which is about 24% larger than an IQ8 and it's all heatsink, not plastic.

The Quad HMS-2000-4T-NA is 1918W. It has dimensions of 13.03" x 8.58" x 1.44", and again it's all heatsink, not plastic.

Given the reliability data they shared on the HM and HMS inverters, I'm convinced they will be reliable and far more so than a D380 from 11 years ago.

 

[fromport]

You forgot to mention that if you provision IQ7's without the IQ Gateway, the Enphase warranty is voided. Hoymiles has no such clause, their DTU is optional, and the internet is optional.

You forgot to mention it is illegal to hookup those Hoymiles here in california when the Rule21 grid config is not configured.
So here in Cali you will need (at least once) to hookup a DTU.

There are plenty of alternative off-grid inverters like an AIMS inverter/charger or EG4 to provide battery backup microgrid, and some of them can even work without batteries like an IQ8.

If you have Time-of-Use and you have storage you could during high rate times use your battery to select "zero usage" from the grid.
Eg: if your home uses 1000 watt, 1000 watts will be provided by the batteries zo make the meter show zero.
And we are talking about a whole house solution with the IQ8 & batteries.
Afaik the EG4 and aims are not grid tied as it they can deliver back to the grid. They have a load side that you can hook essential loads to that can be fed from the battery, but not the whole house.

 

[fromport]

Hoymiles makes a 300W and 350W single microinverter that is cheaper than an IQ7, and temperature rise shouldn't be a concern there but they test them underwater at 85C, so I'm not too worried about it. Also, as an engineer, just because Enphase got it wrong with the D380 12 years ago, doesn't mean it can't be done right. 12 years ago the most popular inverter was a SATCON. You forgot to mention that if you provision IQ7's without the IQ Gateway, the Enphase warranty is voided. Hoymiles has no such clause, their DTU is optional, and the internet is optional. After speaking with them a week or so ago, They said that had no plans for a microgrid forming microinverter. There are plenty of alternative off-grid inverters like an AIMS inverter/charger or EG4 to provide battery backup microgrid, and some of them can even work without batteries like an IQ8. What I like most about Enphase is the design and concept of their IQ Batteries and the ability to control them to maximize self-consumption. Now that I've got it working, it's slick! But compared to EG4, it's way too pricey and I wish I had waited until I had learned more. I jumped the gun, but y'all get to benefit from my learning experience. Why gripe? I share to help others, not "just" to vent my frustration, but that too. Happy 4th!

From:

Hoymiles Microinverter Review | Hoymiles vs Enphase Showdown

Hoymiles vs Enphase Microinverter Showdown | Technical Review - After huge growth in the USA solar market, they set their sites on Australia.

www.mcelectrical.com.au

Hoymiles got up to 77 degrees internally. (celsius)
It was only a 1 to 1 power ratio, on tilt frames, on a 25-degree spring day. If that little black box lasts past its warranty period, I’ll be mighty impressed.
Now compare that to the Enphase microinverter which continually ran at least 10 degrees cooler. So the rule of thumb in Electronics, aka “Arrhenius’s Equation” would say that the Enphase microinverter will last twice as long. If you’re concerned about longevity, the Hoymiles inverter runs ridiculously hot. I think I’s reasonable to be concerned about the Hoymiles inverter failing.

So on a day with 40C ambient, I am pretty sure the temperature of the microinverter will go over the 85C you mentioned in water.
The water prevents spot heat build up, so in hot air the temp will be even worse imo.

 

[ncsolarelectric]

So on a day with 40C ambient, I am pretty sure the temperature of the microinverter will go over the 85C you mentioned in water.
The water prevents spot heat build up, so in hot air the temp will be even worse imo.

Hoymiles specs say these can operate at up to 65C ambient temperature, and the warranty is intact. Enphase is only 60C. I've done a lot of projects in the California central valley in desert areas like Lost Hills and Dos Palos, on the ground and on metal roofs. I've monitored temperatures there inside closed metal boxes in direct sunlight and the maximum I've ever seen inside the box was 70C. Outside, it could be 40C, but these inverters are rated for that.

Are you aware of the ratings for SiC Diodes and MOSFETs? Or are you still thinking in terms of silicon from 15-20 years ago? Those things can have junction temperatures approaching 200C!

 

[ncsolarelectric]

You forgot to mention it is illegal to hookup those Hoymiles here in california when the Rule21 grid config is not configured.
So here in Cali you will need (at least once) to hookup a DTU.

I'm not sure that's true. I'll be taking the 30-minute training for setting up a DTU, but I've done over 300 sites in CA, and "grid-config" is product specific. Rule 21 requires certain behaviors that are already built into the inverter. It's not external software that controls them with any inverters. Enphase uploads the data to the inverter, but most inverters my crews have installed don't require an upload to meet Rule 21, and I don't think Hoymiles does either. They are CEC Approved for use in CA, and a DTU is not required.
Even if you're correct, so what? The DTU-Pro is less than half the cost of the Envoy + Comm module, and Hoymiles has a DTU-Lite that is a very low-cost USB stick as an option too. If an installer needs to carry a USB stick in his pocket to finish an install, that sounds pretty easy to me.

If you have Time-of-Use and you have storage you could during high rate times use your battery to select "zero usage" from the grid.
Eg: if your home uses 1000 watt, 1000 watts will be provided by the batteries zo make the meter show zero.
And we are talking about a whole house solution with the IQ8 & batteries.
Afaik the EG4 and aims are not grid tied as it they can deliver back to the grid. They have a load side that you can hook essential loads to that can be fed from the battery, but not the whole house.

EG4 and AIMS "can't" deliver power to the grid, they are not grid-tied. That is correct, but that does not prevent them from supplying power to the whole house. Both of them are a better option for a whole-home inverter because they can output 50A. In most small homes, 50A is the size of the largest breaker in the panel, and that's (technically) what is required for sizing a whole-home inverter per code. With an Enphase IQ system, you would need 3 x Battery 10T's + 1 x Battery 3T to get 50 Amps of inverter output for a whole-home backup PLUS it requires the Envoy, a cell modem, and the System Controller 2.

At my cost, the Enphase battery for a 50A inverter would be over $27,000 wholesale. That's 53.6 kWh of energy storage.
An equivalent EG4 battery system would be $2600 (2 inv) + $15,500 for 10 batteries (51.2 kWh) and racking, and a few other parts comes to around $18,000. With EG4 however, I could choose to have only 4 batteries, or 6. With Enphase, you have no choice in the size of the battery relative to the inverter. It's $27,000 no matter what you do if you want to size the inverters to run a whole-home backup system at 50A. They gotcha by the tail, their whole business model is designed to rope you in and then require you to buy things that you don't need. I like choice!

IMO and I admit it openly, their Sunlight Backup System is a lure (gateway drug) that hooked me like a fish into buying everything but the battery to save cost, which then locked me into using their batteries in the future at the expensive cost I just mentioned. Smart business acumen for sure.

 

[ncsolarelectric]

Marketing is an instrument.
You are doing the same by posting your pricelist here.
Everything for a buck it seems.

And what's your point of being here, pointing out flaws in others for fun and practice?

First off, I haven't installed a system in CA since 2018, so I see things have changed. My bad, I was not aware of it. Oo no, another flaw. Crap.

 

[ncsolarelectric]

"deny deny deny, not sure, oh what if ..."
Make up your mind...

It's never going to happen! My boss beat into me "be flexible Todd", so I have a very open mind that changes often, regardless.

 

[Cubedweller]

Another sunny day was lost. I spoke to Enphsae today. It seems that I don't need to go to hands-on training after all. Yeah! But, I need to submit a design review of my single line. I already finished all of the Installer Certification training courses including storage. However, I can't submit a design review! First, I need to pass their Storage "Design" Certification course. A 4th certification is still required to turn on my system. AFTER another 2+ hours of courses, then I have to submit a design review and wait for their approval before I can proceed to turn on my system. If anyone ever suggests using Enphase to me again, I may explode. They own the system, not me. I have no control and someday, maybe they will allow me to operate the $12k solar system I purchased.

This is exactly what happened to me. I have a System Controller 2 hanging on the house, uncommissioned until I submit my SLD and other miscellany. I'm still steaming about that.

 

[ncsolarelectric]

This is exactly what happened to me. I have a System Controller 2 hanging on the house, uncommissioned until I submit my SLD and other miscellany. I'm still steaming about that.

Try to cool off. It's like going through an airport. Just give them the details they want and you're on your way. It's just time consuming and frustrating. Next time, Hoymiles. I've already got mine on order.

 

[Cubedweller]

Try to cool off. It's like going through an airport. Just give them the details they want and you're on your way. It's just time consuming and frustrating. Next time, Hoymiles. I've already got mine on order.

Thanks. I still have another 14 microinverters or one string inverter to purchase. I have 14 IQ8+s at the moment, but deciding to buy 14 more is problematic. And I hope the AT&T provisioned modem they are sending me works here in Western NC. It's all they had, so that's what they are sending me, no option to backorder until Verizon or T-Mobile units get back in stock. But hey, I have 30 days (from order date) to return it. So really 21 days if it arrives when it's supposed to.

 

[ncsolarelectric]

Update, my Enphase system has been running flawlessly since turning it on. No complaints. Other than the weather because it's been overcast or thunderstorms nearly every day. However, today my system hit a new production record, 25.19 kWh, or 2.52 kWh per solar panel, per day. It is outperforming. Hopefully, the weather will cooperate for a little while so I can see what it can really do.

 

[svetz]

Hopefully, the weather will cooperate for a little while so I can see what it can really do.

Have you run SAM to get the expected max for your setup for various times of the year?

..., today my system hit a new production record, 25.19 kWh, or 2.52 kWh per solar panel, per day. It is outperforming.

The 1000 W/m² at sea level depends on "average" air mass, but it's not always constant and changes seasonally (SAM has a graph for your area). This is the output from my solar sensor the other day, note the max was 1187.5.
And yes, my inverters clipped out the solar bonus dag nab it! ; -)

.......

WOOT! ~41% to that first megawatt hour! Planning a party? Or are all your friends already sick of hearing how great solar power is? ; -)

 

[ncsolarelectric]

Have you run SAM to get the expected max for your setup for various times of the year?


The 1000 W/m² at sea level depends on "average" air mass, but it's not always constant and changes seasonally (SAM has a graph for your area). This is the output from my solar sensor the other day, note the max was 1187.5.
And yes, my inverters clipped out the solar bonus dag nab it! ; -)
View attachment 102726

WOOT! ~41% to that first megawatt hour! Planning a party? Or are all your friends already sick of hearing how great solar power is? ; -)

According to my simulation, July should average 18 kWh per day. So far, July is averaging 19.2 kWh. Outperforming the estimate.

 

[svetz]

According to my simulation, July should average 18 kWh per day. So far, July is averaging 19.2 kWh. Outperforming the estimate.

My setup consistently "overperforms" too. I've also noticed that while none of my microinverters run under 285W (their rated continuous max) it's not uncommon to see some around 305W for extended periods. Enphase has a top-of-the-line pricetag, but they don't inflate their specs.

Have you decided the layout for Hoymiles yet? Is it a testbed, going on a different house, or will it be on the same microgrid as Enphase?

 

[ncsolarelectric]

My setup consistently "overperforms" too. I've also noticed that while none of my microinverters run under 285W (their rated continuous max) it's not uncommon to see some around 305W for extended periods. Enphase has a top-of-the-line pricetag, but they don't inflate their specs.

Have you decided the layout for Hoymiles yet? Is it a testbed, going on a different house, or will it be on the same microgrid as Enphase?

My Hoymiles inverters and cables should arrive on Thursday. I can't afford to buy any solar panels for myself right now, so I'm thinking of replacing one of the IQ8+ with an HM-350NT, on a separate branch and see how it performs. It has a 319W continuous output with a 350W peak, compared to the 290W / 300W peak of the IQ8+. Then I can set up the DTU and see how well that works as well.
I need to make some videos!

 

[ncsolarelectric]

I ordered the Chint Din-rail meter used with Hoymiles DTU-Pro to control the Export current. The inverters can be configured for zero-export. My first experiment is to connect the meter to the output of an off-grid inverter and then control the microinverters so they do not backfeed into the off-grid inverter. Then they should run in parallel with the microgrid and be stable, without shutting down randomly.

My second experiment is to connect the microinverters to a 48Vdc battery instead of solar panels and see how well they perform electrically and thermally.

If both experiments are successful, we will be able to create our own AC-coupled batteries with a backup microgrid. Who wants to donate an inverter and battery for this test? Or just buy a pallet of solar panels, that would help me out immensely!

 

[BiduleOhm]

You (all people in this thread) may find that video interesting:

 

[Cubedweller]

You (all people in this thread) may find that video interesting:

Thanks. This really has me thinking to forego the Enphase batteries and just using something else for the remaining 14 panels. SolarEdge or just plain string stuff with EG4 or SOK batteries.

 

[ncsolarelectric]

Thanks. This really has me thinking to forego the Enphase batteries and just using something else for the remaining 14 panels. SolarEdge or just plain string stuff with EG4 or SOK batteries.

I'm not sure I understand your reasoning based on what was in the video. He clearly showed that for 14 microinverters, the nighttime power consumption was only 8 watts, or less than 0.6 watts per microinverter, or less than 0.2%.

 

[Cubedweller]

I'm not sure I understand your reasoning based on what was in the video. He clearly showed that for 14 microinverters, the nighttime power consumption was only 8 watts, or less than 0.6 watts per microinverter, or less than 0.2%.

He said 18 watts apparent power, each, or 280VAr for 14, which is no problem with the grid, but using batteries at night instead, could be an issue. This explains some Enphase customers with batteries that have been discharging at night with no loads on them. Especially in winter this could be an issue. Those batteries also have IQ8s strapped on top of them. Dave doesn't have batteries yet, so that should be interesting if he does.