Inverter replacement compatibility

[titan1021]

Hi all,

I have a client that has asked if I can replace their solar inverter for them. While I have been in the trade for over 22yrs I haven't dabbled in solar as of yet, so I am here hoping for a little input.
The client currently has a Sunny boy inverter that has failed, that inverter is 14yrs old. I have found a very similar Solar Edge inverter that appears to be a good replacement. I've attached the specs of each, just wondering if Solar Edge would be the correct replacement and if not is there a compatibility tool or chart etc.. out there to help locate a proper/equivalent replacement. The client doesn't want another Sunny Boy.
Shouldn't I just be able to swap the two or are there other considerations?

Thank you

 

[winnie]

It looks like the Sunny Boy can operate at higher DC input current. In other words it can get to full power on a lower voltage, higher current array.

The question is: what is the operating current of the existing array. If the existing array .

NB I don't do solar work.

Jon

 

[PWDickerson]

No, it won't work. SolarEdge inverters only operate in conjunction with SolarEdge optimizers installed at each solar panel. It is a complete proprietary system. I doubt you want to go through the trouble of removing the array and installing the optimizers. You might want to consider a Fronius inverter.

 

[titan1021]

No, it won't work. SolarEdge inverters only operate in conjunction with SolarEdge optimizers installed at each solar panel. It is a complete proprietary system. I doubt you want to go through the trouble of removing the array and installing the optimizers. You might want to consider a Fronius inverter.

Thank you so much for that insight! I will check out Fronius inverters.

 

[pv_n00b]

This is an old grounded PV array with a string Voc of 500V. There is no drop in replacement for this inverter with a modern inverter without doing some work on the PV array to make it compatible. Check out the Fronius Primo 3.8. It's as close to drop in as you can get for this application. It's still going to require that the array be changed to an ungrounded system.

 

[pv_n00b]

On a side note, the AHJ may require that the PV array be brought up to the current code for rapid shutdown. That's going to be more work and definitely something you want to know going in if there is a permit and inspection involved.

 

[ggunn]

This is an old grounded PV array with a string Voc of 500V. There is no drop in replacement for this inverter with a modern inverter without doing some work on the PV array to make it compatible. Check out the Fronius Primo 3.8. It's as close to drop in as you can get for this application. It's still going to require that the array be changed to an ungrounded system.

What's to change? The grounding of the DC negative (or, rarely, the positive) conductor in a grounded PV array happens in the inverter.

 

[titan1021]

This is starting to sound like I should refer this client to a Solar contractor as its getting out of my wheelhouse as a non-solar guy.
I was thinking it would just be a matter of swapping in a new inverter.

 

[ggunn]

This is starting to sound like I should refer this client to a Solar contractor as its getting out of my wheelhouse as a non-solar guy.
I was thinking it would just be a matter of swapping in a new inverter.

I think that's a great idea, especially seeing that it's an old system you would be dealing with. Solar tech has changed a lot since it was installed.

 

[solarken]

What's to change? The grounding of the DC negative (or, rarely, the positive) conductor in a grounded PV array happens in the inverter.

There is no GEC for DC in a modern inverter, there is for old grounded PV systems, so there could be changes needed.

 

[ggunn]

There is no GEC for DC in a modern inverter, there is for old grounded PV systems, so there could be changes needed.

But that GEC in older systems is only at the inverter; there would be no needed change to the array.

 

[electrofelon]

There is no GEC for DC in a modern inverter, there is for old grounded PV systems, so there could be changes needed.

But what changes? One could just not land it, or land it on the ground bar as a anxiliary electrode. It may NEED to be landed depending on code cycle installed under, structure details, etc, but I can't think of how one can go wrong just landing it on The ground bus in the inverter.

 

[jaggedben]

The only thing that would likely need to be changed on the array if changing to an ungrounded topology inverter would be the color or marking of the previously grounded DC conductor, if it was properly colored or marked white or gray when originally installed. Personally I would totally let that slide, although it'd be prudent to put a note somewhere explaining the situation for the next guy.

It's possible, though not exactly likely, that the solar modules are positively grounded Sunpower modules, in which case the situation would be more complicated.
In any case, personally I wouldn't replace any inverter without knowing the module model and choosing the inverter accordingly to the specs of the array.

 

[electrofelon]

The only thing that would likely need to be changed on the array if changing to an ungrounded topology inverter would be the color or marking of the previously grounded DC conductor, if it was properly colored or marked white or gray when originally installed. Personally I would totally let that slide, although it'd be prudent to put a note somewhere explaining the situation for the next guy.

It's possible, though not exactly likely, that the solar modules are positively grounded Sunpower modules, in which case the situation would be more complicated.
In any case, personally I wouldn't replace any inverter without knowing the module model and choosing the inverter accordingly to the specs of the array.

There is also some labeling that would need to be changed/added. The stupid "the DC conductors of this system are ungrounded and may be energized - do not lick" for example.

 

[kingpb]

Why not just call SMA, and ask them what the replacement would be?

 

[jaggedben]

Why not just call SMA, and ask them what the replacement would be?

Definitely worth a try, although there's no guarantee they're currently making one that works for that array.

 

[ggunn]

Definitely worth a try, although there's no guarantee they're currently making one that works for that array.

They don't make a 3800W grounded inverter any more but they do make these

https://files.sma.de/downloads/SB30-77-US-DUS184327W.pdf?_ga=2.141269554.1431969362.1689624639-136339688.1689624639

I believe the old one had a 600VDC upper limit as well, so the stringing should be the same. If all you are doing is replacing a dead inverter, then permitting/inspection should not be an issue.

 

[jaggedben]

Right, probably that's the one, but ya wanna check start voltage and MPPT window, not just nameplate output power.

 

[pv_n00b]

What's to change? The grounding of the DC negative (or, rarely, the positive) conductor in a grounded PV array happens in the inverter.

Technically we can't relable the white grounded conductor. But that has to be done somehow since it won't be grounded anymore. Some AHJs will allow an exception and mark the exposed ends but that's not guaranteed.

 

[ggunn]

Technically we can't relable the white grounded conductor. But that has to be done somehow since it won't be grounded anymore. Some AHJs will allow an exception and mark the exposed ends but that's not guaranteed.

Which white wire is that? Even in the days of grounded inverters I never had white wires out in the array.