Need new inverter - Looking for recommendation

[tom3096]

My old Fronius inverter is out of warranty so I need to replace it. Any opinions on the best inverter to choose? My array is 6kw, but the panels are old and I typically max out around 3900-4100 of output. Any suggestions are much appreciated!


My panel specs are:

- Kyocera 200GT (30 panels)
- Max power: 200w
- Max voltage: 26.3v
- Open circuit voltage: 32.9v
- Max power current: 7.61a
- Short circuit current: 8.21a



My inverter specs are:

Fronius Model Number IG 4000
AC output 4000 watt
Max. DC Power (STC) 4800 W
Max DC Voltage 500 V
MPPT Voltage Range 150V - 450V
Max. Input Current 26.1 A
Inverter Efficiency 95.2%

[J.P.M.]

Why not a simple replacement ? Seems like IG 4000's may still be available if maybe a bit small for the full output of the original, new array.

BTW, just because it's out of warranty doesn't mean it's worth scrapping just yet.

I bought an exact replacement for my Sunpower rebadged PowerOne inverter and it's sitting in the garage next to the original which is close to warranty expiration but won't get changed out until it finally takes a dump.

[peakbagger]

I agree with JPM, Fronius equipment is quite robust (as long as the house has a quality surge suppressor). Many of the new inventers have all sorts of functionality but require "talking to the mothership" IE communications over the internet. The data seems to be hoovered out of the inverter and then stored out on the web instead of in the equipment so its a matter of the owner begging to get back data that rightfully should be stored locally. Memory is dirt cheap these days. This seems to be the biggest issue folks are having these days is getting the communication to work and keeping it working. Plus there are issues that the owners do not always get access to the full functionality of the inverter, rather they have to talk to their installer assuming their installer is even still in business. My 10 plus year old Fronius's seem to work quite well cut off from the world with basic error codes and error code diagnostics in the back of the paper manual supplied with the equipment. It only has a basic two line display but everything I need to know is not that hard to find. I think the KISS approach is the way to go with equipment that may still be around 15 or 20 years in the future. If I want data logging I would far prefer to have it on site safe from a vendor deciding to abandon it on their end.

One major hassle is that Fronius appears to have been hit hard by the chip shortage or maybe the war in Ukraine, so long delivery times.

[tom3096]

I see. Thanks for your input. I'll check into getting a refurbished Fronius.

[J.P.M.]

This is not meant as a plug, but others here mentioned "Solar Cowboys", also DBA as YouLoveSolar (I know, sounds like a real rinky dink operation) a couple of years back as a go to place for string inverters that are compatible w/ the old style Sunpower panels. I took a leap of faith and bought a refurbished twin to my still operating inverter from them and it came in what looked like a factory sealed box that was identical to the one my original inverter came in.
Customer service was good, fast and knowledgeable. They even met a rather unusual requirement of holding the inverter for about 3 months until I requested shipment. Price was ~ $700 w/ freight. I paid my original installer $250 to check it out on arrival and it came up clean, including being OK to use w/ my Sunpower 327 panels. It even smelled new.

FWIW, their website shows a refurbished IG5100 in stock which is listed on/using the same spec sheet and manual as the IG4000 for about $900. Just sayin'.

[bcroe]

I have had similar good service from a pair of Fronius IG7.5 for a decade,
pushed about as long and hard as possible. They keep it simple, no
software or communications to foul up. I did manage to pick up a brand
new spare set just in case, at a huge discount because someone thought
they were obsolete.

This simple meter is installed in the system to keep track of annual energy.
Bruce Roe
BiDirMtr.JPG

[peakbagger]

I wonder if we looked at the solar system "half life" of the various respondents to this thread if someone would come to the conclusion that the KISS principle seems to be the recommendation from those who have had systems for awhile

I have a spare Sunny Island inverter stashed away and one of the Solarcity 6 KW inverters stashed away. I guess I should store them in galvanized trash cans sealed with aluminum duct tape for an EMP event to fully cover my bases.

[J.P.M.]

I wonder if we looked at the solar system "half life" of the various respondents to this thread if someone would come to the conclusion that the KISS principle seems to be the recommendation from those who have had systems for awhile

I have a spare Sunny Island inverter stashed away and one of the Solarcity 6 KW inverters stashed away. I guess I should store them in galvanized trash cans sealed with aluminum duct tape for an EMP event to fully cover my bases.

FWIW, such training and experience as I've been fortunate to receive over my life have convinced me that KISS is usually the better path in system design and probably a life philosophy.

I read and respond to (some) threads while often wondering if a lot of what I'm reading - which is more often than not - about system access problems or restrictions to system information access imposed by manufacturers and think to myself what B.S. it all is.

For starters, if what I read is representative of perhaps what some of the more knowledgeable (?) residential PV owners/users think they know, I'd conclude most residential users are clueless about the information they think they need and wouldn't know what to do with it anyway.

Still, and kind of like a junk knot tease, making system operating information and output "semi" available (maybe), and so playing "I've got a secret" with system information seems like too much control for too few - if any - reasons that make sense to me, particularly with respect to what seems to be restrictions or hurdles/hoops that manufacturers seem to want to impose. That too is simple B.S.

To your conjecture about recommendations/conclusions, I can respond/add : I designed my system with KISS as an up front design philosophy.
The system uses a dual MPPT string inverter and simple layout and was assembled by an old and established electrical contractor that was also an early PV peddler.
I largely credit KISS in system design and monitoring for having pretty much 100 % system availability with trouble free operation over 10+ years of system use with not much more than the usual and necessary system maintenance - which isn't much.
I've got the simple system monitor that Sunpower provided 10 years ago that, even though Sunpower has cheapened and scaled back the available system parameters available for monitoring, and while their support otherwise and always has and continues to suck, still gives me more information than I need - and I've got a lot of system information and operational data.

IMO only, a lot of the stuff I see/read here about system problems comes from up an up-front violation of the KISS principle partly brought on by ignorance as well as the idea that a lot of folks have no idea what they bought or how things actually work. If they did (have a clue), they might well have not got sucked into the peddler's and their media shills trap about PV being the solution to all their energy problems.

Rant mode off.

[bcroe]

I read and respond to (some) threads while often wondering if a lot of what I'm reading - which is more often than not - about system access problems or restrictions to system information access imposed by manufacturers and think to myself what B.S. it all is.

AMEN. Bruce Roe

[tom3096]

Thanks for the suggestions about where to find refurbished interverters. It surprises me that my past Google searches for "refurbished solar inverter" yielded no usable links. You would think that there would be quite a market for legacy/refurbished equipment. Much like you see in the computer world. Hard to justify ponying up for a brand new inverter when you are hooking it up to an 18 year old system mounted on a 23 year old roof! I'm finally at the point where my current system is starting to pay off...

[J.P.M.]

Thanks for the suggestions about where to find refurbished interverters. It surprises me that my past Google searches for "refurbished solar inverter" yielded no usable links. You would think that there would be quite a market for legacy/refurbished equipment. Much like you see in the computer world. Hard to justify ponying up for a brand new inverter when you are hooking it up to an 18 year old system mounted on a 23 year old roof! I'm finally at the point where my current system is starting to pay off...

For anything I may have added that was useful, you're welcome.

The common string inverter warranty is/was about 10 or 12 years. That's about the same time in the past when residential PV really started to take off, at least in the U.S. So, I'd expect a lot of 10 to 12 year old inverters to start failing about now or soon, depending on where they are mounted and treated.
We may see more searches as well as a lot of weeping and gnashing of teeth when owners find out their vendors are out of business and, for a lot of probably good and valid reasons, the remaining vendors won't/don't want to service equipment they did not install.

BTW, 18 years is a pretty long payback - maybe the price for being an early adopter.

As for searches, try "refurbished grid tie inverters".