Replacement for Fronius IG 4000

hmbay

New Member
Joined
Jan 15, 2021
Messages
13
Just looking for suggestions and recommendations... my misbehaving IG 4000 (it's the third one - 2 were replaced under warranty years ago) is going crazy (see post about power output reduced by 1/3 - now its just stuck in various error modes).

The Primo 3.8 would appear to be the logical plug compatible solution (I'm trying to minimize hassle) but I know at the time Sunny Boy was a big competitor. Goal is to get another 10 years out of the system. The panels have a 25 year warranty and we're at 15 years now so we figure we've got a good 10 years left on the panels and the roof. In 10 years the solar industry will probably look a lot different that it is now (batteries and inverters built into panels?)

I've got 3 strings of 9 Kyocera KC175GT panels (175W, MPV 23.6V, OCV 29.2V, SCC 8.09A, MPC 7.42A). It fits under the specs for the Primo 3.8 and the price is reasonable. The panels are in good shape and produced over 3200W after we reinstalled the panels with new leak-proof mounts a few months ago. Each string is producing roughly the same amount of power so we don't have any dead panels.

We just did a full removal and reinstall of the panels to address a terrible installation job from 15 years ago so PLEASE do not suggest throwing everything out and starting over. The property is a rental and we already dismissed that option.
 

mopat

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Joined
Jun 22, 2020
Messages
545
Fronius

Fronius Primo 3.8-1 Inverter​


3800W, 208/240VAC, 60Hz, 600VDC, DC Disconnect, Transformerless, 2 Unfused Input, 2 MPPT, Wi-Fi/Ethernet Datamanager, Arc-Fault Protection, UL 1741 SA Compliant​




  • Item # 1430-198
  • (0)



Price: $1,280.00

Too much??
 

hmbay

New Member
Joined
Jan 15, 2021
Messages
13
Absolutely, the price is great compared to what the IG 4000 cost 15 years ago. But is it the best solution? I think so but I wanted to get some validation before moving ahead.

On the IG 4000, I've been speaking to a service tech who thinks the AC boards in the IG are dead so rather than fix it, he said buy a new one and get the latest features like WiFi monitoring. Unfortunately my configuration doesn't fit into the Primo MPPT well since I've got an odd number and we already re-wired them as 3 strings of 9 instead of 2 strings. But I didn't have MPPT before so WTF.
 

mopat

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Joined
Jun 22, 2020
Messages
545
I bought the IG4000 August 2011 for $2,233. it's still going strong.

That Sunny Boy 3.8US is about the same price as Fronius.
 

hmbay

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Joined
Jan 15, 2021
Messages
13
Sunny Boy 5.0US gives me 3 MPPT inputs and is $200 cheaper than the Primo 3.8 from the same vendor. Having had 3 Fronius failures in 15 years I think I'm going to change brands. Any reason to pick the Fronius over the Sunny Boy? $200 buys a lot of nachos.
 

hmbay

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Joined
Jan 15, 2021
Messages
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I went through the configurator and it looks like my 3 x 9 Kyoceras fit better with a Sunny Boy 5.0US than the comparable Fronius products.
 

wattmatters

Photon Sorcerer
Joined
Apr 16, 2021
Messages
1,399
my misbehaving IG 4000 (it's the third one - 2 were replaced under warranty years ago) is going crazy.
Is there something about the physical location of the inverters which may have contributed to reduced life? They are pretty solid units. The Primo is a very good inverter. As in SMA Sunny Boy.

see post about power output reduced by 1/3 - now its just stuck in various error modes
When I read this and see you have 3 equal strings, it does make me wonder about one of the strings being the issue.

I've got 3 strings of 9 Kyocera KC175GT panels (175W, MPV 23.6V, OCV 29.2V, SCC 8.09A, MPC 7.42A).
Unfortunately my configuration doesn't fit into the Primo MPPT well
Yes it does. Fits perfectly.

since I've got an odd number and we already re-wired them as 3 strings of 9 instead of 2 strings. But I didn't have MPPT before so WTF.
The Primo 3.8 (USA) has 2 x MPPT inputs, each with a max current capacity of 18A. That's more than ample for your array.

There are two simple configurations which will suit your set up:

1. You can connect two of the strings in series and have one string of 18 panels and a second of 9 panels:
Screen Shot 2021-11-14 at 6.06.22 am.png

2. Another option is to connect two strings of 9 panels in parallel to one MPPT and connect the other string of 9 into the other MPPT. The Primo has internal terminals specifically for connecting strings in parallel. This is the layout info:
Screen Shot 2021-11-14 at 6.06.51 am.png

Even if the paralleled arrays are facing different directions it will perform just fine.
 

DCPower

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Joined
Oct 6, 2021
Messages
18
Location
Sweetwater Lake, CO
I installed several IG4000’s about 15 years ago. I found they had no tolerance for heat - they’d fail within a year or two if they are mounted in an enclosed space that’s not fully ventilated (garage, etc).
 

wattmatters

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Joined
Apr 16, 2021
Messages
1,399
I installed several IG4000’s about 15 years ago. I found they had no tolerance for heat - they’d fail within a year or two if they are mounted in an enclosed space that’s not fully ventilated (garage, etc).
Interesting. yes, heat will be the the death of any inverter so heat management is important. You may well have found the same problem with other models/brands if your space has inadequate ventilation for dissipating heat.

The Primo snapinverter has active cooling (fans) which will help.

The newer Primo Gen24 has a different design, with one larger lower speed fan. A bit quieter I believe.

Some people hook up external fans to blow over their inverters when output and temps are high. I'm considering just this - I have an off-grid system as well as my grid-tied Fronius system. My off-grid has a load of unused capacity so hooking up a fan pointed at my Fronius Symo is not going to cost anything. Mine is mounted on an external wall, under a wide eave so sees very little direct sun but we do get very hot days here (can exceed 40°C).
 

hmbay

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Jan 15, 2021
Messages
13
I'll try to answer all the questions.

We tested all 3 strings independently and they were all performing within 1-2% of each other. These are 15-year-old Kyocera 175 panels.

The IG 4000 was now stuck in standby - it looked like both AC stages had died - and my friendly repair guy just said to replace it.

The IG 4000 has 2 big fans so you would figure that would be enough. We're not talking Palm Springs or Las Vegas so not excessive heat in enclosed space. I think it had just gotten old and tired since it was probably around 10 years old. I took it apart to separate the e-waste from the metal and found no obvious problems (e.g. melting or burn marks) so probably some components just died. BTW, this was our third IG 4000. One just plain died and one took a hit from a super rare for the area lightning strike - both were under warranty. So this latest one had lasted the longest of the 3. I'm OK with 15 years.

As for Fronius Primo - I had considered reconfiguring my panels into 2 strings. But since I have very nice wiring with 3 clean string inputs, the Sunny Boy 3x MPPT solution works out really fine. We installed the Sunny Boy 5.0 last weekend and it was a snap. Also like the monitoring and service solutions as well as the packaging. Performance appears to be better than the IG 4000 but then it did not have 3x MPPT or ShadeFix.

Also the Sunny Boy SPS was an added bonus that you get with the 5.0 unit. (Please let's not start a flame war on the merits of SPS vs installing batteries - it's a rental property so nullo batterio). And it was $200 cheaper.

No one is suggesting these inverters popping up on YouTube so that's reassuring. The prices are crazy but who knows what the hell you are getting.

Altogether our PV renovation project cost under $2,500. For that we got:
  1. New roof mounts & flashing (the idiots had used tile mounts on a shingle roof) - we had to repair and seal 34 old roof penetrations!
  2. New grounded rack splices
  3. New grounded panel clamps
  4. New grounding hardware
  5. and finally New Inverter
The previous installation was all ProSolar so we used ProSolar hardware just to make it easier. The new FastJack E standoffs and flashings survived the epic atmospheric river storm we had a few weeks ago so we're looking good. I also preferred the old school separate flashing approach as opposed to the integrated solutions and rackless mounts. Finally, I had used ProSolar FastJacks on our own house when I did a self-install 11 years ago. That also has never leaked and it uses conventional roof jacks like for plumbing vents.

Also in the process of pulling and replacing the panels we had discovered 2 possible ground-shorts and fixed those on the historic MC1 cables.

The only things carried over from the old system were the panels, racks, wiring, and AC & DC disconnects. We did have to run a new neutral wire from the main panel to the Sunny Boy which turned out to be really easy because the electricians had done a good job on the original install - as opposed to the clowns who f'd up the roof installation.

The goal was to buy 10 more years of operation since the panels have a 25-year warranty and appear to be ahead of projected performance and for the price (compared to $20K+ for a new system) was well worth it. We'll probably sell the house in the next 10 years as we're close to retirement age.

Now a local electrician and roofer - both quite respectable - had estimated $11K to do the same thing (except no new inverter - so we're probably talking closer to $15K with inverter and maybe more like $20K as we probably would have insisted in replacing the MC1 connectors with MC4s - rewiring every panel).

Our real estate agent said that it wasn't worth doing the repairs at that price and she would have stripped the system off and just fixed the roof leaks. Furthermore, she said that a whole new PV system would have had Zero impact on sales price (we're talking about a house valued now at $1.5M so a $20K solar installation is noise).

Anyway, that's the whole story... it took 11 months from when the inverter started misbehaving - that was after the tenants moved out - and then we identified that the roof leaks had gotten much worse even in a relatively dry winter - to having the renewed system commissioned last weekend and we've already generated 62kWh in less than a week.

We were still agile and mobile enough to do the work ourselves on a low-roof (single-story house) so we were fortunate. Given other circumstances, we might have just pulled the panels, sold them off, and fixed the roof. So we consider this a very happy ending!
 

wattmatters

Photon Sorcerer
Joined
Apr 16, 2021
Messages
1,399
As for Fronius Primo - I had considered reconfiguring my panels into 2 strings. But since I have very nice wiring with 3 clean string inputs, the Sunny Boy 3x MPPT solution works out really fine. We installed the Sunny Boy 5.0 last weekend and it was a snap.
The Sunny Boy is a good inverter. As I said before the Primo would also have managed the 3 strings perfectly well.

Glad you got a good outcome and especially fixed roofing issues, ground faults and are going to get good extra life out of the system. Win win win.
 

wattmatters

Photon Sorcerer
Joined
Apr 16, 2021
Messages
1,399
The only things carried over from the old system were the panels, racks, wiring, and AC & DC disconnects.
If you haven't, I would check your disconnects for age related issue, especially the DC ones.
 

mopat

Solar Addict
Joined
Jun 22, 2020
Messages
545
I'll try to answer all the questions.

We tested all 3 strings independently and they were all performing within 1-2% of each other. These are 15-year-old Kyocera 175 panels.

The IG 4000 was now stuck in standby - it looked like both AC stages had died - and my friendly repair guy just said to replace it.

The IG 4000 has 2 big fans so you would figure that would be enough. We're not talking Palm Springs or Las Vegas so not excessive heat in enclosed space. I think it had just gotten old and tired since it was probably around 10 years old. I took it apart to separate the e-waste from the metal and found no obvious problems (e.g. melting or burn marks) so probably some components just died. BTW, this was our third IG 4000. One just plain died and one took a hit from a super rare for the area lightning strike - both were under warranty. So this latest one had lasted the longest of the 3. I'm OK with 15 years.

As for Fronius Primo - I had considered reconfiguring my panels into 2 strings. But since I have very nice wiring with 3 clean string inputs, the Sunny Boy 3x MPPT solution works out really fine. We installed the Sunny Boy 5.0 last weekend and it was a snap. Also like the monitoring and service solutions as well as the packaging. Performance appears to be better than the IG 4000 but then it did not have 3x MPPT or ShadeFix.

Also the Sunny Boy SPS was an added bonus that you get with the 5.0 unit. (Please let's not start a flame war on the merits of SPS vs installing batteries - it's a rental property so nullo batterio). And it was $200 cheaper.

No one is suggesting these inverters popping up on YouTube so that's reassuring. The prices are crazy but who knows what the hell you are getting.

Altogether our PV renovation project cost under $2,500. For that we got:
  1. New roof mounts & flashing (the idiots had used tile mounts on a shingle roof) - we had to repair and seal 34 old roof penetrations!
  2. New grounded rack splices
  3. New grounded panel clamps
  4. New grounding hardware
  5. and finally New Inverter
The previous installation was all ProSolar so we used ProSolar hardware just to make it easier. The new FastJack E standoffs and flashings survived the epic atmospheric river storm we had a few weeks ago so we're looking good. I also preferred the old school separate flashing approach as opposed to the integrated solutions and rackless mounts. Finally, I had used ProSolar FastJacks on our own house when I did a self-install 11 years ago. That also has never leaked and it uses conventional roof jacks like for plumbing vents.

Also in the process of pulling and replacing the panels we had discovered 2 possible ground-shorts and fixed those on the historic MC1 cables.

The only things carried over from the old system were the panels, racks, wiring, and AC & DC disconnects. We did have to run a new neutral wire from the main panel to the Sunny Boy which turned out to be really easy because the electricians had done a good job on the original install - as opposed to the clowns who f'd up the roof installation.

The goal was to buy 10 more years of operation since the panels have a 25-year warranty and appear to be ahead of projected performance and for the price (compared to $20K+ for a new system) was well worth it. We'll probably sell the house in the next 10 years as we're close to retirement age.

Now a local electrician and roofer - both quite respectable - had estimated $11K to do the same thing (except no new inverter - so we're probably talking closer to $15K with inverter and maybe more like $20K as we probably would have insisted in replacing the MC1 connectors with MC4s - rewiring every panel).

Our real estate agent said that it wasn't worth doing the repairs at that price and she would have stripped the system off and just fixed the roof leaks. Furthermore, she said that a whole new PV system would have had Zero impact on sales price (we're talking about a house valued now at $1.5M so a $20K solar installation is noise).

Anyway, that's the whole story... it took 11 months from when the inverter started misbehaving - that was after the tenants moved out - and then we identified that the roof leaks had gotten much worse even in a relatively dry winter - to having the renewed system commissioned last weekend and we've already generated 62kWh in less than a week.

We were still agile and mobile enough to do the work ourselves on a low-roof (single-story house) so we were fortunate. Given other circumstances, we might have just pulled the panels, sold them off, and fixed the roof. So we consider this a very happy ending!
Glad you got it figured out. Best of luck.
 

hmbay

New Member
Joined
Jan 15, 2021
Messages
13
The DC disconnect (a triple blade switch with fuses - one for each string) was installed indoors so it is clean and looks new. The AC disconnect (outdoors) is also in good shape. We visually inspected and tested all of the components since we quite literally took the whole system apart in the end. We have had corrosion issues since we're close enough to the ocean for aluminum to dissolve but things looked pretty good.

Interestingly, we could not get any local electricians or solar providers to come out and do a safety/technical review of the system (e.g. to verify that the disconnects, wiring, etc was up to par for another 10 years). All they wanted to do was look at the system on Google Earth and quote a new one. They basically viewed the existing system as landfill and all recommended total replacement (except for the guy who wanted $7K to just remove and reinstall the panels). I even argued with one of the outside sales people that they should seriously consider servicing people with first generation systems since they are all going to need guidance to either evolve or replace their systems. Nope, not interested. I'm talking about some really sincere green people but at the end of the day, new system installs generate a lot more profit for them. Inheriting another installers problems is just too much of a headache. Since most of the new guys are providing 25 year warranties, I kind of understand where they are coming from. They would have to cut a new kind of service agreement for customers like me with mixes of old and new components.

Obviously our weak links are the MC1 connectors but we're mounted on a steady roof, not an RV or vibrating/tracking metal frames, and we've never observed any connectors wiggling out. Each panel has a junction box so if we were AC we could have replaced each junction box and installed new MC4s but the cables were in good shape so we decided to stick with the MC1s. We also were not sure whether we would damage the panels if we fiddled with the junction boxes and 1 damaged panel would have kind of screwed us.

Finally, I am very impressed with the inverter performance given the low angle of the sun and a wide variety of weather conditions since we installed it. We've generated 120 kWh much faster than I had expected so the per string MPPT and ShadeFix are definitely doing their thing.
 
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