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Need help : want to ac couple to a Enphase grid tied.

X propane

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Michigan
We have a small 6kw array on our barn with the IQ7 micro's combiner box. No Enphase Batteries.
We are in the process of building a 48volt Eve battery.
We are kinda lost with what inverters will work with the IQ7 based system.
Solark is not in our price range.
The shnieder xw pro, maybe , but I doubt we will have enough battery (at first) for it to unload into.
Was also looking at the Megarevo, Eg4 8k unit.


A little more information, our solar equipment is attached to our pole barn. This feeds into a 100 amp panel, then back feeds to our main house panel. We want to keep any new hybrid equipment in our barn as well.

Thank You for your help and experience.
Eric.
 
The schnieder xw pro, maybe , but I doubt we will have enough battery (at first) for it to unload into.
Was also looking at the Megarevo, Eg4 8k unit.
Perhaps I misunderstood the wording in your post. For AC coupling the battery does in fact have to be large enough to take 100% of expected excess PV production such that the charge rate is within the battery specs. Usually 0.5C or less. This issue has nothing to do with the XW Pro vs. an EG4.

I've not had any problems with AC coupling to a Schneider XW+ with Enphase M250's and a Fronius IG Plus. However, recently there are several posts on the Forum regarding the newer Enphase microinverters being much more sensitive and not accepting AC power from the back up inverter. As I understand it Enphase does have optional alternative firmware versions that can be used.
 
Are you planning to feed the enphase combiner into the generator input of the megarevo so that you can run the megarevo off-grid and provide power into the barn? Or is this a peak shaving battery and not really for battery backup? Haven't messed with ac coupling a lot. As I think you already know mine's got a battery and panels running to it and just the grid wires are connected so I can do peak shaving. No backup loads currently.
 
Perhaps I misunderstood the wording in your post. For AC coupling the battery does in fact have to be large enough to take 100% of expected excess PV production such that the charge rate is within the battery specs. Usually 0.5C or less. This issue has nothing to do with the XW Pro vs. an EG4.

I've not had any problems with AC coupling to a Schneider XW+ with Enphase M250's and a Fronius IG Plus. However, recently there are several posts on the Forum regarding the newer Enphase microinverters being much more sensitive and not accepting AC power from the back up inverter. As I understand it Enphase does have optional alternative firmware versions that can be used.
So 100%of what we do not consume? According to the smart utility meter, there are times when we push back 4 kw. our first battery will only be 300 amp hours. That's not going to be big enough for all that we don't use on sunny days?

Are all these inverters like this? I was thinking some had charge parameters that would allow for charging rate or stop charging when the battery was full again?
Thanks for the info, Eric.
 
Our Enphase system is all attached to our pole barn. It was installed by a company. The outbound solar power from the combiner box feeds into the 100 amp breaker panel in our barn. The barn is fed by the 150 amp panel in the house withe a breaker. Essentially back feeding from the bar to the house , and back through the meter. Barn and house have 125 feet between them.
I'm pretty certain there are not any ct's in the main house panel that is fed directly from the meter. If needed I could pull a set of wires through the conduit for ct's that come directly of the meter. Not sure how the Enphase system is measuring our usage to sift the frequency?

Back to the hybrid inverters, I was thinking to feed the hybrid inverter from the barn panel. yes I could feed the inverter with the Enphase solar, and ac input. To do the peek time shaving.
Eventually I would like to run off batteries through the night.
I hope this answered your questions.
Thanks for helping! Eric.
 
So 100%of what we do not consume? According to the smart utility meter, there are times when we push back 4 kw. our first battery will only be 300 amp hours. That's not going to be big enough for all that we don't use on sunny days?
Let's do some math. Using 5,000 watts just because I don't know the actual size of your system and I'd rather be cautious.

5,000 watts / 48 volts = 104 amps (theoretical max charging from PV)
300 ah at 0.5c = 150 amp cell charge rate limit

300 ah cells look fine to me.
Are all these inverters like this? I was thinking some had charge parameters that would allow for charging rate or stop charging when the battery was full again?
The problem isn't the inverter, it is the battery. Your PV production needs to go somewhere when you aren't using it. If the battery inverter tried to limit wattage in an off grid situation there would be bad consequences.
Thanks for the info, Eric.
 
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This is what the panels made today. It was a exceptionally clear sunny day. Unfortunately this is all I can view and share right now, the system isn't reporting correctly (go figure) . I can't really tell you how much we consumed. I was at work, my wife was home. We try to run laundry and dish washa... Heavier loads on the good days! I'm sure like most of the people on this site. I hope the screen shot loads, and gives a better idea of what the little system can produce.
Thanks again for sharing your experience,
Eric
 

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Sunny Island is a battery inverter that should AC couple most GT PV inverters. You can get surplus around $3000
It is best if yours do frequency-watts power modulation.

With just one of these 120V battery inverters you would need an auto-transformer to make 240V.
The power to-from grid would go though a single phase, so twice the current of your present system, unless you also had an isolation transformer between it and the grid.




 
Sunny Island is a battery inverter that should AC couple most GT PV inverters. You can get surplus around $3000
It is best if yours do frequency-watts power modulation.

With just one of these 120V battery inverters you would need an auto-transformer to make 240V.
The power to-from grid would go though a single phase, so twice the current of your present system, unless you also had an isolation transformer between it and the grid.




Just to be clear. This will work but would only be for an off grid customer only. The utility will not allow the use of an auto transformer. Consequently it would never be allowed in a grid tied system. Using an isolation transformer is a grey area in residential service and as I see it a 50/50 proposition passing inspection. Could it be hidden from the utility? Possibly but if discovered it would be an immediate red tag and meter pull. If it malfunctioned and caused any line damage your going to have to pull out the big checkbook.
 
??

There are UL listed transformers and auto-transformers.
You can use an isolation transformer instead of the auto-transformer (but many are not nice loads on an inverter, have to know what to look for.)

If you use two Sunny Island, then no transformers needed.

Transformers and auto-transformers are very commonly used. Especially buck-boost, e.g. to operate a 208V device on 240V or vice versa.
I can't imagine why utility would object or have any say on use of transformers. Auto-transformer to power 240V European appliance on 120V and vice versa is very common.
 
??

There are UL listed transformers and auto-transformers.
You can use an isolation transformer instead of the auto-transformer (but many are not nice loads on an inverter, have to know what to look for.)

If you use two Sunny Island, then no transformers needed.

Transformers and auto-transformers are very commonly used. Especially buck-boost, e.g. to operate a 208V device on 240V or vice versa.
I can't imagine why utility would object or have any say on use of transformers. Auto-transformer to power 240V European appliance on 120V and vice versa is very common.
Auto transformer usage in the USA will not pass inspection. Many threads on this subject. Those that advocate their use in these forums 100% of the time fail to mention this to the newbies. So they buy the stuff install it and then fail inspection and lose the money they spent. Sad but happens all the time.
 
Auto transformer usage in the USA will not pass inspection. Many threads on this subject. Those that advocate their use in these forums 100% of the time fail to mention this to the newbies. So they buy the stuff install it and then fail inspection and lose the money they spent. Sad but happens all the time.
I don’t write the rules but they are what they are. Perhaps in the old days but not allowed today. The use of the isolation transformers is common in industrial applications but not common in residential applications. That’s why I say your chances are 50/50 getting that approved. I just went through a re-inspection and the utility engineers went through everything with a fine tooth comb. One wasn’t fully onboard with a Sol Ark but finally approved it. If I went your route absolutely zero chance of approval. It’s their sandbox and you won’t be allowed to play in it without their approval.
 
??

There are UL listed transformers and auto-transformers.
You can use an isolation transformer instead of the auto-transformer (but many are not nice loads on an inverter, have to know what to look for.)

If you use two Sunny Island, then no transformers needed.

Transformers and auto-transformers are very commonly used. Especially buck-boost, e.g. to operate a 208V device on 240V or vice versa.
I can't imagine why utility would object or have any say on use of transformers. Auto-transformer to power 240V European appliance on 120V and vice versa is very common.
Also correct me if I’m wrong but single phased are not UL? My best advice is to pick equipment from the California Solar Equipment List. If it’s not on the list you’re going to have issues. Unfortunately it’s becoming the de facto standard across the nation.
 
There are several 120V single-phase inverters with UL listing. Some that do AC coupling, some not.
Some can be wired single or split phase, which might be a good fit for this smaller system.

SMA, Outback, Schneider, others.

You're probably thinking of 220V single phase European models.
I think the cheap import brands include single phase and split phase that aren't UL listed or on CEC list. I agree best to go by those lists.

Maybe something like Outback Radian would be a good fit. I think it is split-phase. I think it is high-frequency, so need to consider how well it works AC coupling, and starting motors. One forum member AC coupled Enphase to previous model Outback Skybox.


I like Sunny Island, but because it is 120V would either need two (11.5kW output) or transformer(s)
It works great, is UL listed but is NOT on the current CEC list (because it doesn't do Rule 21).
 
There are several 120V single-phase inverters with UL listing. Some that do AC coupling, some not.
Some can be wired single or split phase, which might be a good fit for this smaller system.

SMA, Outback, Schneider, others.

You're probably thinking of 220V single phase European models.
I think the cheap import brands include single phase and split phase that aren't UL listed or on CEC list. I agree best to go by those lists.

Maybe something like Outback Radian would be a good fit. I think it is split-phase. I think it is high-frequency, so need to consider how well it works AC coupling, and starting motors. One forum member AC coupled Enphase to previous model Outback Skybox.


I like Sunny Island, but because it is 120V would either need two (11.5kW output) or transformer(s)
It works great, is UL listed but is NOT on the current CEC list (because it doesn't do Rule 21).
I’m not an electrical engineer by any means. I do think the isolation transformer has merit. Auto transformers are a no go in my book.
 
Thank you for all your suggestions, really think we would be better off with a hybrid inverter for our situation, we're more interested in peak time shift than battery backup.
 
Thank you for all your suggestions, really think we would be better off with a hybrid inverter for our situation, we're more interested in peak time shift than battery backup.
IMO that’s why we chose Sol Ark it does both very well. We didn’t have to choose either or.
 
For time shifting, the battery inverter doesn't have to carry starting surge. Most of the shifting can be accomplished without carrying peak loads. But if you can get enough surge to start A/C that would be nice.

This is what PowerWall and Sunny Boy Storage are sold for. With wimpy backup as an option, using external transfer switch. But they (or the attached batteries) aren't cheap.

A hybrid or battery inverter that works with economical server rack batteries is probably the way to go. I haven't kept track of which models have the time shift features. I would think SolArk, Schneider, Outback Radian, but possibly some low cost ones too.
 
we're more interested in peak time shift than battery backup.
If you are not interested in backup and expect to always have the grid then that makes it much simpler. AC coupling gets more complicated when the grid is down with limits on how much GT inverter the hybrid grid forming inverter can handle. As also mentioned battery size matters.
You would just need a battery inverter that is UL listed and size for the loads you want shift. This inverter could be connected in parallel to the GT inverter. The battery inverter could use the AC generated by GT inverter to charge the batteries.
 
If you are not interested in backup and expect to always have the grid then that makes it much simpler. AC coupling gets more complicated when the grid is down with limits on how much GT inverter the hybrid grid forming inverter can handle. As also mentioned battery size matters.
You would just need a battery inverter that is UL listed and size for the loads you want shift. This inverter could be connected in parallel to the GT inverter. The battery inverter could use the AC generated by GT inverter to charge the batteries.
Yes this is exactly what looking for.
Being able to do both peak time shift and off grid would be great, but the extra expense doesn't seem worth it to me at this time. we have a portable generator that got us through 7 days of power outage.
Sol ark is out of my price range.
I need at least an 8 kw unit to power our well pump and a few small loads at the same time.
Any suggestions?
 
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