EG4 18KPV A/C Coupling

[wondersparrow]

I have a micro inverter based grid tied solar system. I would like to both expand it and add batteries. The problem is that my current array is hooked up to a sub-panel in my shop. Does the EG4 18k support A/C coupling on the load side (not hooked up to the Gen terminals)? The manual doesn't imply that it does. I tried asking Signature Solar, but they just sent me a screenshot of the manual even though I asked about A/C coupling on the load side.

 

[Supervstech]

@SignatureSolarJess

 

[SignatureSolarJess]

I have a micro inverter based grid tied solar system. I would like to both expand it and add batteries. The problem is that my current array is hooked up to a sub-panel in my shop. Does the EG4 18k support A/C coupling on the load side (not hooked up to the Gen terminals)? The manual doesn't imply that it does. I tried asking Signature Solar, but they just sent me a screenshot of the manual even though I asked about A/C coupling on the load side.

Hi @wondersparrow No, the EG4 18k inverter can not support A/C coupling on the load side. It only supports A/C coupling through the Gen ports.

 

[SignatureSolarJess]

@SignatureSolarJess

Thank you

 

[kennyb]

I have a micro inverter based grid tied solar system. I would like to both expand it and add batteries. The problem is that my current array is hooked up to a sub-panel in my shop. Does the EG4 18k support A/C coupling on the load side (not hooked up to the Gen terminals)? The manual doesn't imply that it does. I tried asking Signature Solar, but they just sent me a screenshot of the manual even though I asked about A/C coupling on the load side.

It doesn't. It's highly annoying since it requires an additional feeder essentially. If you need to backfeed your panel your best bet is the old guard of Schneider/outback/sma.l

 

[wondersparrow]

The Sol-ark 15k specifically says it can do it. You lose the detailed solar power stats, but it works. You would think it would be mostly a software limitation of having UL1741SA working on the load as well as Gen.

 

[kennyb]

The Sol-ark 15k specifically says it can do it. You lose the detailed solar power stats, but it works. You would think it would be mostly a software limitation of having UL1741SA working on the load as well as Gen.

I've talked to sol-ark about it. They reeeeeallly don't want you to use it and they want it on the gen port as well.

I'm in the same boat as you. I've got 2 Ac coupled arrays 300ft from my inverter. I've had to rewire and go DC couple.. it's just not realistic to run a second 3/0 aluminum feeder to make it work.

 

[wondersparrow]

Is there a better product if all you want is to add battery to an a/c coupled system? Running new cables isnt really an option for me. So many other utilities need to be crossed, that cost would more the 18k itself.

Having the logic for the various interconnection agreements and time of use sure is nice built in to the inverter sure is nice. The string inverter is handy for expansion but can easily be replaced by more a/c coupled micro inverters.

 

[kennyb]

Schneider, outback, sma.

The problem you'll come across is the CEC (Canadian electrical code)requires ul9450 now for batteries. That means a massive exspense on batteries for those systems. So even with the additional feeder you're better off with the LuxPower/eg4.

I just got 2 LuxPower from the Canadian distributor at an amazing price (pm for contact) And the maple/gsl 14.3 kwh batteries are ul9450 with the lux(pm for contact at gsl). Your other option is the eg4. Same same but different...and more expensive in Canada.

 

[ksmithaz1]

Enphase Encharge. For a mere $6000...

 

[kennyb]

Enphase Encharge. For a mere $6000...

And be limited in surge. The encharge 10 is limited to surge of <6kva and continuous is <4kva. And for the low low retail price of 12k cad.

Don't even know pricing on the new 5s. But I do know that local retail pricing on the controller is 4500 cad.

 

[ksmithaz1]

This is really why you don't want micro-inverters if you plan on having storage. Also once you have storage you always want MORE (and MORE and) storage. So much easier with a component or AIO setup just expand the bus. I'd probably just transition away from them if I went battery.

 

[kennyb]

This is really why you don't want micro-inverters if you plan on having storage. Also once you have storage you always want MORE (and MORE and) storage. So much easier with a component or AIO setup just expand the bus. I'd probably just transition away from them if I went battery.

Its a pain with the new rules.You can't have any lithium >1kwh in a dwelling unit, >40kwh in an attached garage or 80Kwh in a detached structure.

Dc couple with its own feeders just doesn't make alot of sense in the remote building, especially if you're retrofitting. Back feeding the panel and using the existing Ac lines does. The problem is the way all these aios implement Ac couple. If they allowed backfeed like the old guard does this wouldn't be an issue.

In my case I already had a 3/0 feeder to the house from the other building. I had intended to backfeed 90A through that and be fine. But now I've got to run a parallel 6/4 acw90 cable to feed DC to the inverter that's already going to send out Ac to that location.

 

[wondersparrow]

This is really why you don't want micro-inverters if you plan on having storage. Also once you have storage you always want MORE (and MORE and) storage. So much easier with a component or AIO setup just expand the bus. I'd probably just transition away from them if I went battery.

The problem is micro inverters are quite cost effective and efficient. Most new grid-tied installs use them by default. In my area, that is probably over 80% of new installs. Eventually many of them will want to make upgrades. If we don't want to be wasting money and generating literal tonnes of e-waste, we need a solid a/c coupling solution that allows for storage and intermittent off-grid scenarios.

 

[solar8484]

What is the reason that eg4 doesn't support AC coupling on the inverter output port? Frankly it's misleading to claim AC coupling capability when it's not supported on the inverter output port. AC coupling is inherently about connecting AC power sources to the inverter output port in parallel.

 

[kennyb]

What is the reason that eg4 doesn't support AC coupling on the inverter output port? Frankly it's misleading to claim AC coupling capability when it's not supported on the inverter output port. AC coupling is inherently about connecting AC power sources to the inverter output port in parallel.

I'm just guessing here, but I believe it has to do with the relay on the gen port being used as a redundant safety for charging and possibly stoping backflow to an attached generator. Also people like seeing production. If you backfeed the load terminals you won't see production, just what's left over going to your battery.

My xw+ has been Ac coupling via the load side for 5 years flawlessly. I just need a bigger system now. If it wasn't for the new regulations on batteries I'd be still using Schneider going forward.

 

[solar8484]

I'm just guessing here, but I believe it has to do with the relay on the gen port being used as a redundant safety for charging and possibly stoping backflow to an attached generator. Also people like seeing production.

That makes sense for a generator but doesn't really explain why AC coupling to grid-tied PV inverters is only supported on the generator port. It's fine to have a PV shedding relay for extra safety but that should not preclude AC coupling on the inverter output port. As you may know, Schneider has a dry contact for driving optional external PV shedding relay for such purpose. Has anyone tried AC coupling on eg4 output port? Is it really different from the generator input port besides the relay?

 

[Gubman]

I'm just guessing here, but I believe it has to do with the relay on the gen port being used as a redundant safety for charging and possibly stoping backflow to an attached generator. Also people like seeing production. If you backfeed the load terminals you won't see production, just what's left over going to your battery.

My xw+ has been Ac coupling via the load side for 5 years flawlessly. I just need a bigger system now. If it wasn't for the new regulations on batteries I'd be still using Schneider going forward.

Do you mind detailing how you got the XW to AC couple? I have tried with the XW Pro with DC batts to Enphase with AC batts and the XW was growling at me. I wasn't very comfortable with the setup. Tried several options including: https://diysolarforum.com/attachments/3master-wiring-schneider-off-grid-gif.123909/ from https://diysolarforum.com/threads/h...-xw-pro-6848-w-rack-batteries-off-grid.50433/

 

[Gubman]

That makes sense for a generator but doesn't really explain why AC coupling to grid-tied PV inverters is only supported on the generator port. It's fine to have a PV shedding relay for extra safety but that should not preclude AC coupling on the inverter output port. As you may know, Schneider has a dry contact for driving optional external PV shedding relay for such purpose. Has anyone tried AC coupling on eg4 output port? Is it really different from the generator input port besides the relay?

I agree on the idea in principle. If you think about it, each Enphase IQ# AC couples to an existing AC voltage all day long with millions of units in operation and a DC input, like an inverter. Its an implemented SOLUTION - granted an inverter has much more to deal with, but the core idea has been handled very well.

 

[kennyb]

Do you mind detailing how you got the XW to AC couple? I have tried with the XW Pro with DC batts to Enphase with AC batts and the XW was growling at me. I wasn't very comfortable with the setup. Tried several options including: https://diysolarforum.com/attachments/3master-wiring-schneider-off-grid-gif.123909/ from https://diysolarforum.com/threads/h...-xw-pro-6848-w-rack-batteries-off-grid.50433/

Iq7a to main panel 15A breaker. Ac out of xw feeds lugs on the main panel.


Enable Ac couple in Schneider software

Set grid profile to frequency watt profile in Enphase. The only issue I ever had was the battery coefficient setting needed to be set to 0 or there was a weird offset and frequency shifting on the xw would begin 1v or more late.