Sol-Ark 12K + Enphase IQ8 microinverters

[sgturner]

Hi All,

I'm wondering if it would be possible to supplement a PV DC system connected to a Sol-Ark 12K with a few more panels with Enphase IQ8 microinverters connected to the Sol-Ark's generator inputs?. What do the IQ8s need for them to turn on?. How do you turn them off for RSD requirements?.

thanks, Steve

 

[timselectric]

The Sol-ark is designed for AC coupling.
It can be programmed for what you want to do.

 

[sgturner]

So my question is - if I connect say 4 panels to 4 Enphase IQ8s and connect that 240VAC output to the Sol-Ark, does it just work?. The IQ8 needs no signal from somewhere to say turn on? (or for RSD - turn off).

 

[timselectric]

The Sol-ark will control them, by adjusting the frequency.

 

[fafrd]

So my question is - if I connect say 4 panels to 4 Enphase IQ8s and connect that 240VAC output to the Sol-Ark, does it just work?. The IQ8 needs no signal from somewhere to say turn on? (or for RSD - turn off).

I don’t own a Solark inverter, but in general, the only ‘signal’ Microinverters need to ‘turn on’ is a suitable 60Hz grid signal.

With grid present, the Solark should just pass-through the grid signal and your Microinverters will produce exactly as if they were directly connected to the grid.

When the grid goes down, the Solark should be able to output a suitable PSW grid signal to get the Microinverters to begin producing.

As long as loads + battery charger can consume everything the Microinverters are producing, the operation of that off-grid backup power system is straightforward, but the ‘magic’ happens when the Microinverters are producing more that total consumption (including any power being used by the Solark to charge the battery).

In that case, I believe the Solark supports ‘frequency shift’ whereby Microinverter production can be throttled-back smoothly / linearly by ‘shifting’ the 60Hz PSW frequency (grid emulation frequency) off of 60Hz.

If the Microinverters support frequency shift, they will reduce output generation accordingly.

If they don’t, the Solark will continue to shift frequency until it is beyond the limits of what the Microinverters require in order to detect ‘grid present’ and they will shut down.

Either way, the Solark + Microinverter system should operate properly and safely (both on-grid and off).

 

[timselectric]

I don’t own a Solark inverter, but in general, the only ‘signal’ Microinverters need to ‘turn on’ is a suitable 60Hz grid signal.

With grid present, the Solark should just pass-through the grid signal and your Microinverters will produce exactly as if they were directly connected to the grid.

When the grid goes down, the Solark should be able to output a suitable PSW grid signal to get the Microinverters to begin producing.

As long as loads + battery charger can consume everything the Microinverters are producing, the operation of that off-grid backup power system is straightforward, but the ‘magic’ happens when the Microinverters are producing more that total consumption (including any power being used by the Solark to charge the battery).

In that case, I believe the Solark supports ‘frequency shift’ whereby Microinverter production can be throttled-back smoothly / linearly by ‘shifting’ the 60Hz PSW frequency (grid emulation frequency) off of 60Hz.

If the Microinverters support frequency shift, they will reduce output generation accordingly.

If they don’t, the Solark will continue to shift frequency until it is beyond the limits of what the Microinverters require in order to detect ‘grid present’ and they will shut down.

Either way, the Solark + Microinverter system should operate properly and safely (both on-grid and off).

Yes, exactly.
I studied the Sol-ark deeply, earlier in my planning. But, decided that it just wasn't worth the money to me. Especially sence, I was going to need a transformer to get full rated power out of it.

 

[Ellis Redding]

So this is directly in the Owner Manual.
This way doesn't seem to be using the MPPTs.
I would be very hesitant to not follow this for AC Coupling as if you could do both, they probably would have listed it.
Basically this just replaces the Enphase Smart Switch with the Sol Ark which is a super expensive trade off. But it might let you use a real battery. Rather than the Enphase 10x battery. 10x being the cost.

 

[timselectric]

So this is directly in the Owner Manual.
This way doesn't seem to be using the MPPTs.
I would be very hesitant to not follow this for AC Coupling as if you could do both, they probably would have listed it.
Basically this just replaces the Enphase Smart Switch with the Sol Ark which is a super expensive trade off. But it might let you use a real battery. Rather than the Enphase 10x battery. 10x being the cost.
View attachment 87401

You can do both, AC and DC coupling simultaneously.

 

[sgturner]

Thanks for all your comments, and I did see that diagram also. I'm referring to this section in the Sol-Ark install manual:

I'm assuming, but can someone confirm, that this is talking about using Panels+microinverters connected to the "Gen input"

 

[timselectric]

Thanks for all your comments, and I did see that diagram also. I'm referring to this section in the Sol-Ark install manual:
View attachment 87404
I'm assuming, but can someone confirm, that this is talking about using Panels+microinverters connected to the "Gen input"

Yes, it is.

 

[sgturner]

So, if this is an Input, how does the Sol-Ark signal the IQ8?. Is it sending some sort of low power 240VAC "sync" signal out the input to enable the microinverter?. Its all very mysterious....

 

[timselectric]

So, if this is an Input, how does the Sol-Ark signal the IQ8?. Is it sending some sort of low power 240VAC "sync" signal out the input to enable the microinverter?. Its all very mysterious....

It changes the frequency of its output, to control the micr inverters. They only output, if they see a clean power, already on the line.

 

[Ellis Redding]

From Sol Ark Sales:

Hi Aaron,
Yes, we can do AC coupling and DC coupling through the MPPT.

• a. 7.6 to Gen breaker
• i. If you have more than 7.6kW of AC coupling please see (b).
• b. 9.6 in Critical Load panel
• i. If you have greater than 7.6kW, you can Input the power of the AC coupling into a breaker in the Critical Loads Panel.
  MAx Allowed PV Power + 13000 W
• 
  
  Then I asked:
  
  Ahh yes, ok
  
  
  So the SolArk can handle 12k DC and 9.6k AC simultaneously?
  
  If there were no loads in the critical and all the coupled power went back to the SolArk, it would be able to handle it?
  
  Thanks,
  
  Aaron
• 
  
• Response from Sol Ark
• The reason that we recommend more DC than AC connected to the system is that in a grid down situation, the AC coupled panels are utilized only when the batteries need to be charged. This is done because controlling the amount of power produced by the AC coupled panels is a slow process and could potentially over charge the batteries or damage the system/devices due to not having anywhere to send excess power. The system can curtail DC coupled power quite easily and thus we recommend more DC coupled power than AC. When there are more AC coupled panels than DC coupled panels connected to the system, the system will cycle the batteries more frequently and the batteries may not get fully charged in a grid down scenario. In a grid up situation, this is not an issue as power generated by the AC coupled panels is passed through to the grid.
  
  

So basically, if the AC going into the Critical Panel exceeds the loads and flows into the Sol Ark, it's going to reduce DC production when it maxes out.
I think it would be intelligent not to connect enough this way that the AC would overwhelm the Sol Ark, but that seems unlikely.

 

[timselectric]

Exactly

 

[Ellis Redding]

Do you have to use a combiner box with the enphase? or can you just wire a short string directly to a breaker?

 

[timselectric]

Should be able to go directly to the breaker. But, I would check the manual.

 

[fafrd]

From Sol Ark Sales:

Hi Aaron,
Yes, we can do AC coupling and DC coupling through the MPPT.

• a. 7.6 to Gen breaker
• i. If you have more than 7.6kW of AC coupling please see (b).
• b. 9.6 in Critical Load panel
• i. If you have greater than 7.6kW, you can Input the power of the AC coupling into a breaker in the Critical Loads Panel.
  MAx Allowed PV Power + 13000 W
• 
  
  Then I asked:
  
  Ahh yes, ok
  
  
  So the SolArk can handle 12k DC and 9.6k AC simultaneously?
  
  If there were no loads in the critical and all the coupled power went back to the SolArk, it would be able to handle it?
  
  Thanks,
  
  Aaron
• 
  
• Response from Sol Ark
• The reason that we recommend more DC than AC connected to the system is that in a grid down situation, the AC coupled panels are utilized only when the batteries need to be charged. This is done because controlling the amount of power produced by the AC coupled panels is a slow process and could potentially over charge the batteries or damage the system/devices due to not having anywhere to send excess power. The system can curtail DC coupled power quite easily and thus we recommend more DC coupled power than AC. When there are more AC coupled panels than DC coupled panels connected to the system, the system will cycle the batteries more frequently and the batteries may not get fully charged in a grid down scenario. In a grid up situation, this is not an issue as power generated by the AC coupled panels is passed through to the grid.
  
  

So basically, if the AC going into the Critical Panel exceeds the loads and flows into the Sol Ark, it's going to reduce DC production when it maxes out.
I think it would be intelligent not to connect enough this way that the AC would overwhelm the Sol Ark, but that seems unlikely.

This tells me that Solark has much less confidence in their ability to throttle / regulate an AC-coupled array compared to the ease with which MPPTs can easily and quickly throttle/regulate a DC-coupled array by increasing string voltage.

Victron essentially told me the same thing (DC-coupled control 100% ready for prime-time, AC-coupled control still on the bleeding edge and not yet as reliable / fool-proof).

 

[sgturner]

So, I still don't feel like I have gotten my question answered - can you connect a panel+IQ8 directly to the Sol-Ark 12K "gen input" and have it work. Has anyone actually done this?.

 

[timselectric]

So, I still don't feel like I have gotten my question answered - can you connect a panel+IQ8 directly to the Sol-Ark 12K "gen input" and have it work. Has anyone actually done this?.

Yes, it will work. But, check the manual for their specific requirements for connecting. So that you don't void the warranty.

 

[timselectric]

It's been a while since I read the manual. I do remember that it is suggested that you connect the Micro's to the critical loads panel. And then to the Sol-Ark. But, I think that this is just for maximum efficiency.