Adding a DC Server Rack to my Enphase System

[marcs]

I watched the video of Will on the Server Rack of LifePower. It made me very enthusiastic as it always pained me that I have a large Solar System but have to purchase power for overnight consumption and charging the EV when dark. I looked at brand (Enphase) battery options but the price per kW is just horrific. The EG4 Server rack with 30.72kwh (6 Batteries 100ah 48v) is a great value option for me. FYI I can sell back to the grid at ~70% of purchase price.

An Enphase Battery solution of 30kW is $26k (payback period ~80 years)
A 30kW DC Server Rack with Hybrid Inverter 6-8kW is $15k (payback period ~50 years)

I have a 16kW, REC 410 Alpha Pure, IQ8A Micro Inverter Enphase grid tied solar system. I do not plan to add a Generator as the power grid in my area is extremely stable.

I believe I need to add an AC coupling/hybrid inverter with variable frequency to make this possible, but this goes way beyond my knowledge. Can one of you let me know what inverter and diagram (etc?) I would need to integrate a lifepower EG4 server rack to my Enphase system (or if it is a pipedream)?

The Schneider Conext is (I believe) not compatible with Enphase and I got mixed info on the Solark. However, I have very little knowhow in this field and skilled advice is much much appreciated.

https://signaturesolar.com/eg4-ll-lithium-battery-48v-100ahd

-------------#-_----------
I did some research on the Forum and found these posts which are similar to my question. I don't believe they fully explained the solution to my challenge.
------------#-------------
Bart1080 Asked
I've a Enphase micro inverter solar system 240v grid tied 12.7Kw Enphase system, Shed Roof mounted. We've had it for 8 months but lots of excess solar power going to waste and would rather self utilize it more with battery backup for power outages to run critical loads with the help of my gen set.

Todd answered:
The Enphase IQ8 inverters can form a microgrid, in combination with their System Controller, which has the automatic transfer switch, the neutral-forming transformer, and the brain of the system. A Sunlight Backup System requires 2 Load controllers, "OR" an Enphase IQ Battery.

The Enphase Sunlight Backup with the Empower switch can do exactly what you want, but it's very expensive relatively speaking. And, Enphase requires the installer to be Enphase Storage Certified, which means their full training program.

No matter what system you decide to go with, the inverter must be sized per code to be equal to or larger than the largest load posted by the system it's connected to. In the case of Enphase, their microinverters are built into their Encharge battery products. They are the inverter. The IQ Battery 3T is limited to 1.28kW continuous, so you're limited to about 5.33A @240V. In your backup-loads sub-panel, the largest load must be < 5.33A. You can add more Battery 3Ts to reach 10.66A, 15.99A, etc. 3 of the IQ Battery 3Ts is equal to 1 IQ Battery 10T, which is 10.05kWh, and installed they run over $10k just for the battery/microinverter box, and cover. To make it all work requires a cellular modem, a Wifi comms adapter, and an Envoy that transmits data from the microinverters and the system controller to the cloud. The cloud connection is a requirement for their Warranty, it won't work without it.

To do what you'd like to do you need to add a backup-loads sub-panel and move the loads you want to run on the battery over to that panel. Just a few of them that you need as critical. If you don't do this, then the sizing of the inverter and the number of panels required will be prohibitively expensive, even when doing it DIY, in order to meet the code.

Best,
Todd

Todd D.
CEO, NC Solar Electric LLC, Statesville NC
-------#--------
I found another comment by Todd on adding DIY batteries to an Enphase system.

Todd answered:
It is possible with inverters certified to UL 1741SA, the "SA" part matters, and they program them with the same type of grid profile as the Enphase.

------#------
I also found this thread which is very close to what I'm looking to achieve and goes more in depth on the SolArk. The SolArk 8K is UL 1741SA compliant. Not sure if the 12k/15k are. It is a long read...

Sol-Ark 12K + Enphase IQ8 microinverters

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...

diysolarforum.com

 

[Samsonite801]

Yeah, when you put in DC batteries, you need to have a way to charge them, and a way to convert that DC power back to AC power (inverter), so you need an all-in-one (which has a AC-grid-to-DC-battery charger, and PV inputs in case you add more DC solar panels), or you'd need some standalone inverter, and an AC-to-DC battery charger (if they were separate components)...

The other question is whether you'd consume that DC battery power by pumping it back to the grid feed (with grid tie hybrid inverter), or if you will have an auxiliary AC loads panel wired to the inverter AC output and consume the power off the output. Most of the grid-tie inverters will not operate if grid power feed from power company goes down, so it would be better (for best uptime) to run the house loads off your own all-in-one inverter loads output.

I suppose too, there are some companies making special AC batteries now, which might have all the parts within them to convert AC-to-DC, and DC-to-AC, etc... I don't know if any of those solutions are fully developed into a consumer purchasable product yet.

 

[marcs]

The AC batteries are 100c/Watt. An Enphase T10 would give me the same price performance ratio.

Shop - SAX Power

1. Wählen Sie Ihren Speicher Informationen zu den verschiednenInstallationsvarienten finden Sie hier: Im Lieferumfang enthalten: 1 St. SAX Homespeicher (je nach Konfiguration) 1 St. Smartmeter (je nach Konfiguration) 1 St. Wandhalterung pro Speicher, mit 2 St. Sicherungsschrauben Benötigte...

sax-power.net

So how do I structure the diagram if I want to add the DC batteries? My system is not equipped with the Enphase sunlight backup with the empower switch which ensures the system keeps operating when the power company goes down (1 occurrence in 3 years). The battery would mainly be used for overnight power consumption and EV charging (Winter).

The idea to use the battery setup as an 'off grid' circuit, while the solar panels with their inverter are grid tied sounds great.

 

[ncsolarelectric]

The AC batteries are 100c/Watt. An Enphase T10 would give me the same price performance ratio.

Shop - SAX Power

1. Wählen Sie Ihren Speicher Informationen zu den verschiednenInstallationsvarienten finden Sie hier: Im Lieferumfang enthalten: 1 St. SAX Homespeicher (je nach Konfiguration) 1 St. Smartmeter (je nach Konfiguration) 1 St. Wandhalterung pro Speicher, mit 2 St. Sicherungsschrauben Benötigte...

sax-power.net

So how do I structure the diagram if I want to add the DC batteries? My system is not equipped with the Enphase sunlight backup with the empower switch which ensures the system keeps operating when the power company goes down (1 occurrence in 3 years). The battery would mainly be used for overnight power consumption and EV charging (Winter).

The idea to use the battery setup as an 'off grid' circuit, while the solar panels with their inverter are grid tied sounds great.

Just so happens, that's exactly what I've built here. I'm using Hoymiles HM-350NT and HM-700NT inverters, PowerQueen 12.8V, 50Ah batteries, a DTU with an RS485 zero-export meter, and a new PCBA of my own making that is a DC Limiter, to limit the battery short circuit current to 12A constant current, just like a solar panel. This will protect the microinverter and allow it to operate normally. I'm still tweaking the design, and I need to get it UL Listed for the application, eventually.

I'm available to discuss this anytime.

Added: This is showing my home's daily consumption, import/export, and production. The production shown is ONLY the portion coming from my HM battery-powered inverters. The export shown is coming from my Enphase solar system, not from the battery.

 

[400bird]

Do you want to have back up when the grid is down? In that case, you'd need something with an internal transfer switch (or add an external one)

16kW of solar and a 30kWh battery leaves you very light on battery when compared to the solar. What are your overnight loads? Charging the car isn't going to get much with 30kWh of storage.

Are you going to permit the system? If you're in the US, you're need to use a listed inverter, as in UL listed. Most of the low cost inverters are not.

Schneider XW and SW series are compatible with AC coupling to a capable grid tie inverter (including Enphase micros) but, there's a software deficiency where it won't automatically charge from excess solar without building a DIY controller.

I'd be looking into the Outback Radian series. SMA also has an offering (I'm not familiar with their models to know what's what there)

If you don't have any pumps or motors (air conditioning) to start you could look at something like the Sol-Ark, but they are transformerless (high frequency) and don't do motor starting well. Also, Sol-Ark has some weird restrictions on the amount of AC coupled vs DC coupled solar.

Also, with 16kw of solar, you're probably going to need 16 kw of battery inverter to allow off-grid operation.

 

[timselectric]

You basically need to build another system for battery features. Some can work together with micro inverters. Some can work as grid-tied also. But, it's too complicated for me to bother with. I personally would start over with an offgrid system and just reuse the panels.

 

[marcs]

Hi Todd. Looks really impressive. How would this enable me to incorporate an Server Rack into my system (sorry that I need that extra explanation)?

Hi 400bird.
Do you want to have back up when the grid is down? In that case, you'd need something with an internal transfer switch (or add an external one)
Not my driver for the battery upgrade. I'm mainly wanting to use this for power consumption during the night, which would include the EV.

Are you going to permit the system? If you're in the US, you're need to use a listed inverter, as in UL listed. Most of the low cost inverters are not.
I'm in the US and yes absolutely.

Schneider XW and SW series are compatible with AC coupling to a capable grid tie inverter (including Enphase micros) but, there's a software deficiency where it won't automatically charge from excess solar without building a DIY controller.
I don't have the skills to build my own Controller and would not be confident to trust a DIY to build one for me.

I'd be looking into the Outback Radian series. SMA also has an offering (I'm not familiar with their models to know what's what there)
OK THX I will ping them. Would you be able to advice how the circuitry would look?

If you don't have any pumps or motors (air conditioning) to start you could look at something like the Sol-Ark, but they are transformerless (high frequency) and don't do motor starting well. Also, Sol-Ark has some weird restrictions on the amount of AC coupled vs DC coupled solar.
I have two heat pumps so I guess solark is out. Schneider informed me their stuff doesn't work with Enphase.

Also, with 16kw of solar, you're probably going to need 16 kw of battery inverter to allow off-grid operation.
2xOutback Power Radian GS8048A => $9,000 USD 30kw EG4LL $10,500 (maybe 2??) Oeff it almost starts making sense to get 3 T10 at $22,800.

Which brings me to Tims post which discourages me a bit as he understands this a 100x better....this is a Pipedream?

 

[ncsolarelectric]

Hi Todd. Looks really impressive. How would this enable me to incorporate an Server Rack into my system (sorry that I need that extra explanation)?

When I'm done, you'll be able to drop the inverters into your EG4 rack, hookup the battery, and plug them in with a 30A 10/3 line cord. The only difficult part is finding a LiFePo4 battery charger that's AC input and not a charge controller.

 

[400bird]

You basically need to build another system for battery features. Some can work together with micro inverters. Some can work as grid-tied also. But, it's too complicated for me to bother with. I personally would start over with an offgrid system and just reuse the panels.

Too complicated? Just wire the new inverter between the main panel and sub panel/AC coupled inverters. If you don't want to have battery back up, you don't even need to do that. Just add it into the main panel.

Redoing everything and building it all off grid seems more complex to me.

 

[400bird]

Hi Todd. Looks really impressive. How would this enable me to incorporate an Server Rack into my system (sorry that I need that extra explanation)?

Hi 400bird.
Do you want to have back up when the grid is down? In that case, you'd need something with an internal transfer switch (or add an external one)
Not my driver for the battery upgrade. I'm mainly wanting to use this for power consumption during the night, which would include the EV.

It's getting easier, no need for using the internal transfer switch in the inverter.

Are you going to permit the system? If you're in the US, you're need to use a listed inverter, as in UL listed. Most of the low cost inverters are not.
I'm in the US and yes absolutely.

Good! That will sort of force you out of most of the cheeper products, hopefully into something proven and higher quality.

Schneider XW and SW series are compatible with AC coupling to a capable grid tie inverter (including Enphase micros) but, there's a software deficiency where it won't automatically charge from excess solar without building a DIY controller.
I don't have the skills to build my own Controller and would not be confident to trust a DIY to build one for me.

So, Schneider is out, I'd lean towards the Outback Radian.

I'd be looking into the Outback Radian series. SMA also has an offering (I'm not familiar with their models to know what's what there)
OK THX I will ping them. Would you be able to advice how the circuitry would look?

It's just AC coupling, connect the AC wiring (L1, L2, N, G) and DC to the battery.
You'll need to do some research with Outback on what current sensors they require or if they are provided. The current sensors would need to go on near your utility meter so it can charge from solar without pulling from the grid and discharge to cover loads.

If you don't have any pumps or motors (air conditioning) to start you could look at something like the Sol-Ark, but they are transformerless (high frequency) and don't do motor starting well. Also, Sol-Ark has some weird restrictions on the amount of AC coupled vs DC coupled solar.
I have two heat pumps so I guess solark is out. Schneider informed me their stuff doesn't work with Enphase.

"Doesn't work" isn't true, but that's besides the case if you're not going to add a controller.
If you aren't looking for grid down power the motor starting concern is an issue, you'll be connected to the grid to start the AC.

Also, with 16kw of solar, you're probably going to need 16 kw of battery inverter to allow off-grid operation.
2xOutback Power Radian GS8048A => $9,000 USD 30kw EG4LL $10,500 (maybe 2??) Oeff it almost starts making sense to get 3 T10 at $22,800.

If you're not concerned with grid down power, you don't need to match your battery inverter to you PV. You could probably run one 8k Radian. But you really should run an energy audit to see if 8kw of inverter is enough. Along with verifying you are planning enough storage. Depending on your driving/mileage needs, 30kwh may not be enough.

Which brings me to Tims post which discourages me a bit as he understands this a 100x better....this is a Pipedream?

 

[marcs]

Thx 400 bird!

 

[Samsonite801]

When I'm done, you'll be able to drop the inverters into your EG4 rack, hookup the battery, and plug them in with a 30A 10/3 line cord. The only difficult part is finding a LiFePo4 battery charger that's AC input and not a charge controller.

Some people have used the Sig Solar 48v 18a battery chargers, and a couple other AliExpress chargers. I purchased two AIMS 48v 18.75a battery chargers for mine, which I haven't plugged in yet.

Examples:

Sig Solar:

EG4 Battery Charger | 48V 18A

Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL

signaturesolar.com

AIMS:

https://www.amazon.com/Power-CON120AC3648VDC-Converter-Battery-Charger/dp/B08KKNK4L9

 

[marcs]

Got this from Enphase.

It seems they have profiles which make it work with Tesla, SMA, Victron and Schneider (so much for Schneider's customer service feedback).

I'm not sure if they thereby confirm that adding a frequency shift enabled AC Coupling from either of these 4 brands would mean I could add a DC Server Rack to my system.

 

[marcs]

Good morning,


The Schneider Conext XW Pro 6.8kW inverter has had issues with Enphase microinverters, and I cannot recommend the two to be used in the same system. Due to this, I would recommend either replacing your microinverters with charge controllers or searching for another hybrid inverter to use with your microinverters.


Mars Hurtado

Signature Solar LLC

903-441-2090 Ext-141

 

[GVSolar]

Good morning,


The Schneider Conext XW Pro 6.8kW inverter has had issues with Enphase microinverters, and I cannot recommend the two to be used in the same system. Due to this, I would recommend either replacing your microinverters with charge controllers or searching for another hybrid inverter to use with your microinverters.


Mars Hurtado

Signature Solar LLC

903-441-2090 Ext-141

Completely disagree.
I've been AC coupling with Schneider/Enphase equipment for over three years now. As long as you follow installation guidelines it's relatively seamless and highly reliable. Many others on the forum have as well.

 

[marcs]

Completely disagree.
I've been AC coupling with Schneider/Enphase equipment for over three years now. As long as you follow installation guidelines it's relatively seamless and highly reliable. Many others on the forum have as well.

Enphase also indicates this. No feedback from Schneider yet. Do you have an advice which Hybrid Inverter/AC coupling would be best for a 16kW system with IQ8A microinverters to link an DC 48v 30kW Server Rack to my system. Somebody already pointed out that 30kW might be light but I can always upgrade later (I assume).

THX

 

[GVSolar]

Not familiar with the iq8 series. @GXMnow @400bird @Ampster are all well versed in AC coupling - as are many others on the forum.

 

[Ampster]

Do you have an advice which Hybrid Inverter/AC coupling would be best for a 16kW system with IQ8A microinverters to link an DC 48v 30kW Server Rack to my system. Somebody already pointed out that 30kW might be light but I can always upgrade later (I assume).

16kW AC coupled to anything but a large Hybrid with lots of batteries might be a challenge. The issue is when the grid is down the Hybrid has to modulate the GT micros and the only buffer it has is the battery pack. I am pushing the limit with my 8kW of AC coupled micros and my 5kW Skybox with 42kWh of batteries. I want to add more IQ7s so I will wire them to the main panel instead of to the critical loads panel. When the grid is down I won't get the benefit of their generation but they will sell to the grid and power my loads including charging my EVs just fine when the grid is up.

Similarly, depending on your needs, you could wire only some of the micros to your critical loads panel depending on which Hybrid you choose. I would recommend the Outback Mojave which is just coming out and is an improvement over my Skybox which is reportedly being discontinued. Others have used SolArks and the latest one may have greater capacity for AC coupling if you need that large of a Hybrid.

 

[400bird]

Not familiar with the iq8 series. @GXMnow @400bird @Ampster are all well versed in AC coupling - as are many others on the forum.

?‍ Seems like an odd recommendation from Signature Solar and likely a misunderstanding of how the XW works. I don't have enphase, but I do AC couple to an XW.
The issue comes from Schneider not including any way to automatically initiate AC charging when on grid and have it charge following PV output.

Both myself and GXMnow have created different solutions to this. Both involve a 3rd party controller and programming to make it work.

 

[marcs]

I hope I don't sound crazy, but my battery addition is not targeted for off grid (my grid has been down once in 3 years). I would like to use solar energy during the night (stored in my battery) for my house needs and charging the EV when it is early dark in the winter (50miles 17kW~).

I'm still looking for somebody to say. go with that inverter, connect it like this and enjoy!

What I understand is:
- It can be done
- I need a standalone inverter to charge the battery, a way to convert that DC power back to AC power (inverter), and a DC battery charger (if not in the hybrid inverter
- The hybrid inverter doesn't need to be full system cap (16kW) if I do not want to use it off grid
- Enphase supports Tesla, SMA, Victron and Schneider inverters with freq. shift, but outback was not on the list nor is solark
- It's just AC coupling, connect the AC wiring (L1, L2, N, G) and DC to the battery
- Signature Solar Tech support is not very good. Schneider simply doesn't respond
- And Todd is building some cool stuff

...anybody?