Solark inverter with Solaredge DC optimizers

[629658]

Enphase and APSyestems micros take less then a second to shut down and the Enphase has a variable reduction and feathers nicely when AC coupling.

I dont think the issue is the panel/Micro response time it is the HF inverter (Sol Ark) response time is the issue. The forum is full of off grid people with issues going strictly AC Coupled. Not saying it wont work but I do not think they will be happy with the results. Add some DC coupled with the AC couple and now you have something.

 

[timselectric]

The best way to get your money's worth from the Sol-Ark is to use your existing system for AC coupling.
Without AC coupling, you're limited to what the Sol-Ark can produce itself. If you are going to pay that much for it, you should try to get the most out of it. (IMO)

To clarify
I'm recommending both, AC and DC coupling.
Not one or the other.

 

[BlueMarblePA]

To clarify
I'm recommending both, AC and DC coupling.
Not one or the other.

My solar installer here recommends exactly this. Since I have 9.6kw panels with 34 solaredge optimizers and 7.6kw solaredge optimizer (not yet roof installed), he runs commends installing these into the Gen input of the solark 15k and then additional 3kw DC input. This gives me two more mppt that I can bring in DC solar later!

 

[Hedges]

I just looked at my Solaredge inverter, and I am concerned that it is not UL 1741-SA compliant. It only says UL - 1741 which I guess means it will not be able to be frequency shifted or controlled by the Solark?

See if a firmware update gives -SA
If not, you may not get permission to install and operate, because -SA is required in most if not all areas.

AC coupling with SolArk, we here it is best to do two things:
1) Connect the GT PV inverters to "generator" input, so SolArk and disconnect them instantly by relay
2) Have DC coupled production > AC coupled, so SolArk can ramp DC up/down, and connect/disconnect AC coupled.

Don't know how well it does frequency shift, utilizing -SA. If that works, DC > AC wattage shouldn't be as important.

Solar Edge we're reading & hearing of reliability issues. Good you got a deal, since you may end up removing it.
Lay out enough parts on the driveway to operate and test the equipment, make sure it is good before installation (including all optimizers.)
The optimizers implement RSD, and inverters of recent years implement arc-fault.
With DC coupled, I suppose SolArk supports both (would require RSD module per panel) but I don't know the details.

SolArk many people are happy with, and some can start some motors (e.g. A/C) but at least one thread here reports not starting some 1.5 HP and 3 HP shop tools, although other model motors do start. (He said his Outback had started them fine.) So consider your needs, and don't believe everything your read in the data sheet.

 

[Ampster]

Don't know how well it does frequency shift, utilizing -SA. If that works, DC > AC wattage shouldn't be as important.

Just to clarify, AC coupling only uses frequency shift when the grid is down or not connected. During normal operations the grid is passed through and the grid can act as the buffer when the batteries are full. The concern @jfpetesn raised is only an issue if the grid is down.

 

[GregTR]

What is the benefit here running the Solar Edge at all? The optimization? I'd recommend you sell the Solar Edge and re-string your panels for the Sol-Ark for DC coupling. If you're using a battery then you may be losing as much in efficiency with AC to DC charging as you're gaining with optimization.

If you want optimization you can always get Tigo with Sol-Ark which would be cheaper than running a whole other inverter.

You may have weird and obscure string configuration where with the Solar Edge the installer cared little to none to lay it out optimally while with Sol-Ark you may have to put more thought into it and/or add the Tigo optimizers.

I personally would not do AC coupling on Sol-Ark unless you already maxed out your DC side. There is no benefit to it.

 

[629658]

What is the benefit here running the Solar Edge at all? The optimization? I'd recommend you sell the Solar Edge and re-string your panels for the Sol-Ark for DC coupling. If you're using a battery then you may be losing as much in efficiency with AC to DC charging as you're gaining with optimization.

If you want optimization you can always get Tigo with Sol-Ark which would be cheaper than running a whole other inverter.

You may have weird and obscure string configuration where with the Solar Edge the installer cared little to none to lay it out optimally while with Sol-Ark you may have to put more thought into it and/or add the Tigo optimizers.

I personally would not do AC coupling on Sol-Ark unless you already maxed out your DC side. There is no benefit to it.

I think you are 100% accurate.

 

[Ampster]

I personally would not do AC coupling on Sol-Ark unless you already maxed out your DC side. There is no benefit to it.

While it does not apply in this case, AC coupling is a cost effective way to add batteries and additional DC solar to an existing GT system

 

[629658]

While it does not apply in this case, AC coupling is a cost effective way to add batteries and additional DC solar to an existing GT system

I don’t disagree may add some too. If your in an off grid or grid down situation AC coupling can cause issues.

 

[Ampster]

If your in an off grid or grid down situation AC coupling can cause issues.

The most likely scenerio is that the AC coupled GT solar may go offline.
I did have one issue on a sunny morning when my hybrid batteries were fully charged that the hybrid inverter went offline because of overvoltage when the grid dropped. I had to manually restart it. Apparently it could not modulate the AC coupled solar fast enough. There was no buffer available from the batteries and the AC coupled solar was going at capacity. Typically I have not had issues during frequent power outages.

 

[GregTR]

While it does not apply in this case, AC coupling is a cost effective way to add batteries and additional DC solar to an existing GT system

The problem is, what is available on the market besides buying a full blown Sol-Ark hybrid or the Sunny Boy to add batteries to an AC coupled grid-tied solution? At that point you might as well just DC couple the panels and eliminate the old grid-tie inverter. Only time that makes less sense if you're stuck with Enphase microinverters in which case you might just want to leave the cabling and AC coupling in place.

This is the saddest part of PV lifecycle today; it's almost cost prohibitive to enhance an existing basic grid-tied system with battery backup. You're either tied to the existing product and pay for their expensive battery solution (Enphase) or you're buying a new hybrid inverter to go along with your battery backup.

 

[Hedges]

I don’t disagree may add some too. If your in an off grid or grid down situation AC coupling can cause issues.

People have said low-frequency battery inverters are able to deal with AC coupling better (swallow excess power for a few seconds.)
My system with Sunny Island & AGM seems fine in that regard, AC coupled works great.

The two things it has had trouble with are poor power factor of some loads (VFD) upsetting the GT PV inverters,
and an unrelated issue that paralleled inverters bypassing grid to load sometimes disconnect, shutting down system.

 

[629658]

The most likely scenerio is that the AC coupled GT solar may go offline.
I did have one issue on a sunny morning when my hybrid batteries were fully charged that the hybrid inverter went offline because of overvoltage when the grid dropped. I had to manually restart it. Apparently it could not modulate the AC coupled solar fast enough. There was no buffer available from the batteries and the AC coupled solar was going at capacity. Typically I have not had issues during frequent power outages.

Yes that is the issue micro inverters are too slow to modulate. I think enphase take minutes to modulate. In my opinion the best approach is to have a little of both DC and AC couple

 

[Ampster]

Only time that makes less sense if you're stuck with Enphase microinverters in which case you might just want to leave the cabling and AC coupling in place.

Or you do not want to disturb your existing NEM agreement.

This is the saddest part of PV lifecycle today; it's almost cost prohibitive to enhance an existing basic grid-tied system with battery backup. You're either tied to the existing product and pay for their expensive battery solution (Enphase) or you're buying a new hybrid inverter to go along with your battery backup.

I see a hybrid with AC coupling as a much more cost effective solution to adding batteries to a GT inverter than that offered by Enphase and some pthers. It allows one to leverafe and existing GT inverter. It is essentially what Tesla did with the Powerwall. Depending on configuration a hybrid with DIY batteries can be much more cost effective than a Powerwall. And a Powerwall may be more cost effective than the equivalent Enphase system. It is not how one would design a system from the ground up.

 

[Hedges]

The problem is, what is available on the market besides buying a full blown Sol-Ark hybrid or the Sunny Boy to add batteries to an AC coupled grid-tied solution? ...

This is the saddest part of PV lifecycle today; it's almost cost prohibitive to enhance an existing basic grid-tied system with battery backup.

Or Schneider, or Outback Skybox (now replaced by new model)

AC coupled means you get battery inverter + PV inverter supplying AC during daylight hours. That is a good fit for A/C.
SolArk has a similar "feature" of more inverter power available when sun is on its DC coupled PV panels, because they are HV DC coupled.

Hybrids are going to hit lower cost price-points than component systems, especially the tier-1 component systems. But those do give superior surge capabilities.

If it doesn't bust the budget, I'd do 2x Sunny Island (while they're still being liquidated for a bargain).

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[Ampster]

Yes that is the issue micro inverters are too slow to modulate. I think enphase take minutes to modulate. In my opinion the best approach is to have a little of both DC and AC couple

Micros and string inverters are slow to modulate because of the UL 1741SA standard and the algorithm in the grid forming inverter. I do not think there is a distinction between micros and string inverters in that scenerio. The older UL1741 standard just dropped the GT inverters with no modulation. that might be why observed some newer micros being slow.

. I agree if you have DC solar on the hybrid that can react instantaneously giving your system some time to modulate the AC coupled inverters.

 

[629658]

Well I just did an upgrade from an 8 yo SMA GT to a Sol Ark and storage. It’s not cheap but I now have the solar system that I alway wanted. We are lucky Illinois has a rebate program starting up giving $300 per kWh of nameplate rating on new installs. And another $300 per kWh of installed storage.