AC coupled recommendation?

Ampster

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Ampster, how can I get the Skybox to have more charging capacity? Can it support an external charger that it will control to run in AC coupled mode... or is my only option to get 2 units?
I just tested mine and it will take 100 Amps as a charge setting so that is 4800 kW, Two Skyboxs will not AC couple so your only choice is to use an external charger. As far as I know that would have to be set up manually, There is no way that I know of having the Skybox trigger that, Years ago I did that with an Outback Radian. I just used a timer to turn it on and the voltage setting turned it off. I am still not convinced that you would need more than 100 Amps and it would not work in a grid down situation. When the grid is up you always have the option of extending the charge time by pulling from the grid if the solar is insufficient.
 

TexasSun

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I just tested mine and it will take 100 Amps as a charge setting so that is 4800 kW, Two Skyboxs will not AC couple so your only choice is to use an external charger. As far as I know that would have to be set up manually, There is no way that I know of having the Skybox trigger that, Years ago I did that with an Outback Radian. I just used a timer to turn it on and the voltage setting turned it off. I am still not convinced that you would need more than 100 Amps and it would not work in a grid down situation. When the grid is up you always have the option of extending the charge time by pulling from the grid if the solar is insufficient.

OK, just to echo things. It's a 5kW inverter (sufficient). 100 amp output, so at 48v, we're talking almost 5kW. His setup is just over 8kW, but it is several years old... so let's say it's closer to 6-7kW of peak output. It is easy to disable his solar in 1.5kW banks, so that may be his choice. I think a manual external charger will be too much hassle for him to consider.

Please explain what you mean by 'it would not work in a grid down situation'. With what we went through in February, that's the point of this setup! When the grid is up, all power (from old enphase and this Skybox) would go onto the grid, either self-consumed or sold back to the power company. When power is down, I expect the Skybox to work in AC coupled mode. It puts out the 240Vac. The enphase inverters all kick on. Power as needed will be consumed by the home. Excess power from the enphase inverters will be absorbed by the Skybox and dumped into the batteries (100 amp max). Excess power from the Skybox's solar panels will either get dumped into the batteries, or not consumed (if 100A limit reached). If batteries get full, the Skybox should frequency shift to turn off the enphase inverters. This is how I picture things working, what am I missing?
Thanks.
 

Hedges

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Sunny Island (not in love with 'used' units, but new units aren't that much more).

BTW, again, reading specs more indepth, I read where the Sol-Ark 12k only actually supports 9 kW of continuous output in inverter mode! Gotta read the fine print.

Looks like $6800 for two new ones. (There previously were bigger bargains, maybe most of the DC Solar inventory has been sold off?)


$3400 each is still $1400 off street price, $2300 off MSRP

https://www.altestore.com/store/inv...tts/sma-sunny-island-6048-us-inverter-p10458/

11.5kW continuous from battery at 25 degrees ambient, derated at higher temperature.
You'll need AC coupled (and/or DC coupled) PV to make a system. During the day, AC coupled contributes to available power.


I think Sol Ark can take 9kW of battery charge from either PV or AC coupling, generate 9kW of AC from either battery or PV. It can process 12kW of PV split between battery and AC. Supports AC coupling, but if accepting power from AC coupled PV, still limited to 9kW battery charging from all sources. (these may vary a bit with battery voltage if it is a charge current limit.) Seems like DC coupled PV is a way to have more charging.
 

TexasSun

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Thanks guys. OK, it looks like the Outback SkyBox is the recommendation I'm going to pass to my buddy. $3k. 5kW solar capable. 4kW absorption (from enphase in grid-down situation) to charge batteries. AC couples. Puts the 5kW back onto the grid in normal conditions for self-payoff over time.

Sorry Hedges, but zero warranty for a minimum of unneeded additional output and zero warranty vs 10 years is a losing proposition. And twice the price!
 

Hedges

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If it meets the need, that's all good.
The SMA model sold in U.S. is a better fit for larger systems, including starting larger motors. Doesn't make an economical small system.
Only reason I put in as big a setup as I did was the liquidation sale bargains available early last year. But I did have to spend a lot to save a lot.

💸💸💸
 

SolarPrep

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I did not know that. Where did you read that? There is no mention of that on the Outback site or forum.
Ampster: I reached out to Outback today to get an answer to this. I will post their answer if/or when I get an answer. As I stated in this thread, I've heard this from 3 different companies, all of whom I am working with on pricing of inverter/charge controller options. I've ordered a fair amount of equipment from two of them, so I cannot imagine why they would give me bad info. I believe they were doing me a service by fore-warning me.

It is an interesting piece of gear. I have no agenda regarding wanting to spread rumors. I highly value service after the sale, so the last thing I want to buy is a piece of important, expensive gear that is discontinued, and for which it would then be likely to be difficult to get parts for.
 

SolarPrep

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Thanks guys. OK, it looks like the Outback SkyBox is the recommendation I'm going to pass to my buddy. $3k. 5kW solar capable. 4kW absorption (from enphase in grid-down situation) to charge batteries. AC couples. Puts the 5kW back onto the grid in normal conditions for self-payoff over time.

Sorry Hedges, but zero warranty for a minimum of unneeded additional output and zero warranty vs 10 years is a losing proposition. And twice the price!
TexasSun: What about Radian, or XW-Pro?

By the way, I feel your pain on this. We are going through some of the same gyrations trying to find solutions for our system, and for a couple of friends.
 

fafrd

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Well fudge. In reading specs in more detail, I realized that the Sigineer model does NOT work with the grid. So it will not produce power onto the grid which is a problem. (I'm surprised nobody mentioned that!). OK, back to the list:
I did not understand if you are limiting yourself to UL-listed equipment only and what schedule is driving your request, but if you were ready to consider Sigineer, you may want to have a look at Huayu’s AC-coupled battery inverter as well: https://m.huayu-solar.com/Content/uploads/2021694206/PDF/AC-Coupled-Quick-Installation-Guide.pdf


My need is similar to that of your friend:

I am looking for an AC-coupled battery charger that will limit itself to charging only with excess solar energy from my legacy grid-tied system after loads have been served.

So (Wbc = battery charger energy):

Wpv > Wld, Wbc = (Wpv - Wld) so no PV energy exported

Wpv < Wld, battery energy is used to supply remaining load power to maintain zero-import (as long as battery energy remains)

With the CT sensors this Huayu AC-coupled charger uses, it appears to support this functionality.

For backup functionality, this 240V model will need to be paired with an Autotransformer and while they have some products with UL listing and are apparently working on getting these AC-coupled inverters listed, that will take some time (which you may not have).

But priced at under $1000 (and possibly under $700), these Huayu inverters are the best budget option I’ve found yet for those looking to convert existing grid-tied systems to zero-export or minimum-export using a battery to store unused solar energy during daylight hours to offset consumption after the sun has gone down..

Victron’s 240V Multiplus II is another option I’m analyzing - pricier than Huayu but top-quality and a fraction of the cost of Solark or Skybox.

And the Schneider Conext SW is another option in similar price range that I am analyzing to understand whether is supports this ‘only charge battery with excess AC-coupled-solar-energy’ functionality or not…

With the changes likely coming to California’s NEM program soon, I suspect that there are likely to be many, many solar NEM customers in California with existing grid-tied systems seeking to find cost-effective ways to store their excess solar energy in a battery for after-hours consumption rather than exporting it to the grid…
 

SolarPrep

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Fafrd: If you elected to buy the Victron, you would always be able to sell it in the future if your plans changed. They are very popular with the RV crowd. But, keep in mind they are not certified for use in the US.

I've gotten to the point where I don't trust any written or verbal statements from Chinese manufacturers about certification for use here. In the cases where they claim "Ul Listed" or "Compliant" most of them could not be found, were not tested by a NRTL, were "certified" internally, or "certified" by an unknown agency.

That may or may not matter to you. I do agree that the Huayu units look very appealing.
 

SolarPrep

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Well fudge. In reading specs in more detail, I realized that the Sigineer model does NOT work with the grid. So it will not produce power onto the grid which is a problem. (I'm surprised nobody mentioned that!). OK, back to the list:

$7k Sol-Ark 12k... full featured
$3k Outback Skybox... 5kW output, only 4kW charging capable
$5k Sunny Island used (2x units)... full featured but no warranty
$3.2k Sigineer M12040D . 12kW inverting, 120A solar charger plus 100A charger. (please verify, but I take that to mean it will charge off it's own panels at a 6kW rate, and additionally charge from the enphase inverters at a 5kW rate at the same time?)

Well that takes out the Sigineer. Next options are the Outback Skybox (yes Ampster) and the Sunny Island (not in love with 'used' units, but new units aren't that much more). OK, first, SolarPrep, can you point to evidence that it is being discontinued? And Ampster, how can I get the Skybox to have more charging capacity? Can it support an external charger that it will control to run in AC coupled mode... or is my only option to get 2 units? And for the Sunny Island system, I've heard where they need a transformer. Can someone point to where I can read more about that?

BTW, again, reading specs more indepth, I read where the Sol-Ark 12k only actually supports 9 kW of continuous output in inverter mode! Gotta read the fine print.
Thanks
Texas SUn: What about the 5k Sol-Ark? Under $4500
 

fafrd

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Fafrd: If you elected to buy the Victron, you would always be able to sell it in the future if your plans changed. They are very popular with the RV crowd. But, keep in mind they are not certified for use in the US.
I believe Victron does now have a Multiplus II certified for use in the US, but it is only a 12VDC model, which won’t work for me.
I've gotten to the point where I don't trust any written or verbal statements from Chinese manufacturers about certification for use here. In the cases where they claim "Ul Listed" or "Compliant" most of them could not be found, were not tested by a NRTL, were "certified" internally, or "certified" by an unknown agency.
Once they end up on California’s apt river list (like Growatt) there is little to be concerned about.
That may or may not matter to you. I do agree that the Huayu units look very appealing.
My plans are changing as I’m realizing the new crop of EV will essentially provide a whole-home generator.

So while I was interested in the Huayu or another brand AC-coupled battery charger to dump excess AC solar energy beyond that needed to serve loads onto my LiFePO4 battery, I’m now more interested to find a way to find a way to charge an EV only with excess solar generation (not sure that exists yet).

Using an EV as an on-demand generator to keep a house battery topped-off (or skating just above empty) looks like it is here now (and easy/cheap) so the only remaining piece of the puzzle is how to recharge an EV during daylight hours without importing from energy from grid…
 

TexasSun

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Thank you for all for the additional ideas.

SolarPrep, I tried contacting Huayu, and have not gotten a response from their US rep. I asked who are their distributors in the US. Do you know who to contact?

The Sol-ark 5k is quite appealing. But it's limitation is the AC coupling capacity, at 5kW, that leaves 3kW at risk or he disconnects it. I have the Sol-arc 12k and love it. Yes the 5k is more than the competitors, but I think it's worth it. But I know my buddy will have issues with the shortfall in AC coupling capacity.

And there is the 'flood' of new products due in Q1. No idea what will be available when or at what cost... and that will be when we have another freeze / power outage, so my buddy wants this in place before then. Ah well...
 

Hedges

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The Sol-ark 5k is quite appealing. But it's limitation is the AC coupling capacity, at 5kW, that leaves 3kW at risk or he disconnects it. I have the Sol-arc 12k and love it. Yes the 5k is more than the competitors, but I think it's worth it. But I know my buddy will have issues with the shortfall in AC coupling capacity.

A single Sunny Island could support all 8kW (up to 12 kW) with manual intervention.

One Sunny Island and a 120/240V transformer could have up to 6.8 kW of AC coupled GT PV downstream, and would serve as a UPS with solar. That automatically supports critical loads.
A second AC coupled GT PV inverter could be connected before Sunny Island so it also feeds grid, but doesn't go through the 56A 120V relay.

During a power failure, flip a couple breakers and Sunny Island feeds breaker panel like a backup generator would, and interacts with the second PV inverter as well. It can control up to 12 kW of AC coupled GT PV while off grid; current doesn't go through its relay.

A limit to watch when setting up system with transformer like this is that while power of second PV inverter is balanced across both grid phases, the first PV inverter going through transformer and Sunny Island puts all its power on one phase. Code limits main + PV breaker amperage to 120% of breaker panel busbar.

If both inverters go to grid connected breaker panel they would be balanced. When Sunny Island picks up load as a battery-backed UPS, no PV is automatically used. Once you flip breakers, PV would be available.
 

Cajunwolf

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I’m thinking, in a grid down gas lines down… winter weather situation… 100Ah isn’t unreasonable… the amount of energy electric resistive heaters use is STAGGERING…
Then again, the odds his will happen again is low. Likely whatever took down the gas mains has been corrected. I’m certain MANY homeowners in the area purchased standby generators after the fact…
I found a sweet 4350kw gas/propane 30 amp generator for $621 one month after that freeze. I've been offered $1000 for it. I have a friend out in Katy who tried what these gentlemen are talking about, and DCPower is correct. It's not worth it for "most people." There are always exceptions.
 

SolarPrep

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I believe Victron does now have a Multiplus II certified for use in the US, but it is only a 12VDC model, which won’t work for me.

Once they end up on California’s apt river list (like Growatt) there is little to be concerned about.

My plans are changing as I’m realizing the new crop of EV will essentially provide a whole-home generator.

So while I was interested in the Huayu or another brand AC-coupled battery charger to dump excess AC solar energy beyond that needed to serve loads onto my LiFePO4 battery, I’m now more interested to find a way to find a way to charge an EV only with excess solar generation (not sure that exists yet).

Using an EV as an on-demand generator to keep a house battery topped-off (or skating just above empty) looks like it is here now (and easy/cheap) so the only remaining piece of the puzzle is how to recharge an EV during daylight hours without importing from energy from grid…
fafrd: the Victron Multiplus and Quattro in 12v and 24v are UL listed. The 3000va units only.
 

SolarPrep

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Thank you for all for the additional ideas.

SolarPrep, I tried contacting Huayu, and have not gotten a response from their US rep. I asked who are their distributors in the US. Do you know who to contact?

The Sol-ark 5k is quite appealing. But it's limitation is the AC coupling capacity, at 5kW, that leaves 3kW at risk or he disconnects it. I have the Sol-arc 12k and love it. Yes the 5k is more than the competitors, but I think it's worth it. But I know my buddy will have issues with the shortfall in AC coupling capacity.

And there is the 'flood' of new products due in Q1. No idea what will be available when or at what cost... and that will be when we have another freeze / power outage, so my buddy wants this in place before then. Ah well...
TexasSun: And the 5k SolArk cannot be stacked. Darn.
 

fafrd

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fafrd: the Victron Multiplus and Quattro in 12v and 24v are UL listed. The 3000va units only.
Victron themself told me that only the 12V model of the Multiplus II was UL-certified for use in the US, but if you have other information on the 24V model, please share.
 

SolarPrep

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Fafrd: not the Multiplus 2; the original Multiplus in the old fashioned heavy box, and the Quattro. Look on the Northern AZ Wind site, and you will see them. 12v and 24v; not 48v. 3000va only. I was mistakenly told that the 3000va 48v Quattro was also UL, but after I bought it, found out is not. Now, that is an issue.

Victron always says they are coming out with listed models, and it never seems to happen. Too bad, because it is great equipment. Our market just isn't important enough to them. They still sell a lot to RV people. The Multiplus 2 is really popular for that. I understand that the primary reason for the new "2" versions is saving cost and weight on the cabinet, and the addition of the second input. The inverter is basically the same.
 
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