Solaredge Backup Inverter Generator Connection?

[bradeyboy]

I have a Solaredge Energy hub with a LG RESU 10H backup battery connected to a Backup Interface. The BUI has a generator connection, and has the latest firmware. What I still am unclear on is how this generator connection interacts with the generator connection. If I connect my whole house Generac to this connection, when does the contact closure turn send to the generator? The drawings I see show the Inverters and Generator connection is not isolated from each other. When the battery backup turns off, does the BUI close the contacts to provide a start to your generator? Then when the generator starts, how is it interacting with the Inverter? If at night, I don't see a problem. If during the day, it would appear that inverter solar output might feedback into the generator. Also, if the inverter is receiving power from the generator, would this provide charge to the battery? There is literally no documentation on the proper usage of this generator connection other than a footnote that it is available with the proper software. Has anyone used this setup and can provide some advice? I really don't need to burn up my inverter or my generator if they are not isolating.

 

[jaggedben]

Have you tried contacting Solaredge support to see if there's documentation that you can't find online?

Is this a DIY project or did a contractor install it? Contact the contractor?

It may be the case that they built the hardware into the equipment but are not actually supporting it yet.

I'm not familiar with the latest Solaredge stuff but I can tell you that generator integration is pretty particular to the equipment.

 

[bradeyboy]

I am the installer, so kind of a do it yourself. The difference is I am an Engineering Tech and went through the Solaredge and LG training. I contacted Solaredge support a few months ago when their firmware update came out that was supposed to support the generator. They were little to no help. Depending on who you get in touch with, they all have varying levels of knowledge. Documentation seems to be like a secret society. The more you dig, the more you find that even their support people do not know exists. I was hoping to find someone that already has installed and experimenting with the concept. I have the generator ATS, but do not want to add that into the mix if I can avoid it. That only gives me 16 circuits of backup instead of the whole panel. I have a 16K generator and have placed a soft start device on my AC. I have a fairly large house with many circuits, but do not draw a huge load because most things are not turned on at the same time. If on gen, will just have to decide what gets priority with the heavy hitters like AC, Range, or clothes dryer.

 

[ggunn]

I am the installer, so kind of a do it yourself. The difference is I am an Engineering Tech and went through the Solaredge and LG training. I contacted Solaredge support a few months ago when their firmware update came out that was supposed to support the generator. They were little to no help. Depending on who you get in touch with, they all have varying levels of knowledge. Documentation seems to be like a secret society. The more you dig, the more you find that even their support people do not know exists. I was hoping to find someone that already has installed and experimenting with the concept. I have the generator ATS, but do not want to add that into the mix if I can avoid it. That only gives me 16 circuits of backup instead of the whole panel. I have a 16K generator and have placed a soft start device on my AC. I have a fairly large house with many circuits, but do not draw a huge load because most things are not turned on at the same time. If on gen, will just have to decide what gets priority with the heavy hitters like AC, Range, or clothes dryer.

How important is it that the PV system runs during a power outage? The simple way to handle this might be to interconnect the PV inverter on the line side of the ATS.

 

[jaggedben]

How important is it that the PV system runs during a power outage? The simple way to handle this might be to interconnect the PV inverter on the line side of the ATS.

He already mentioned that he has a backup interface and battery.

 

[ggunn]

He already mentioned that he has a backup interface and battery.

OK, but couldn't he move the POI of the inverter to the supply side of the ATS to keep it from backfeeding the generator and let the backup interface arbitrate between the battery and the generator?

 

[analog8484]

I have a Solaredge Energy hub with a LG RESU 10H backup battery connected to a Backup Interface. The BUI has a generator connection, and has the latest firmware. What I still am unclear on is how this generator connection interacts with the generator connection. If I connect my whole house Generac to this connection, when does the contact closure turn send to the generator? The drawings I see show the Inverters and Generator connection is not isolated from each other. When the battery backup turns off, does the BUI close the contacts to provide a start to your generator? Then when the generator starts, how is it interacting with the Inverter? If at night, I don't see a problem. If during the day, it would appear that inverter solar output might feedback into the generator. Also, if the inverter is receiving power from the generator, would this provide charge to the battery? There is literally no documentation on the proper usage of this generator connection other than a footnote that it is available with the proper software. Has anyone used this setup and can provide some advice? I really don't need to burn up my inverter or my generator if they are not isolating.

Based on what I have seen, the generator interface is the BUI is not functional at this point (i.e. waiting for the not yet available firmware). It seems deceptive at best for SolarEdge to market/sell this feature before it's actually working and available. For now you have to connect generator to loads interface on the BUI via an external transfer switch before the loads panel.

 

[bradeyboy]

The firmware and application notes was released in July. The problem is they are not promoting it and have no specifics on how to best connect it and are pointing you towards using your generator ATS after the BUI. There is conflict in one release that talks about using an alternative power source setting in the Energy hub inverter. And a different path with utilizing the backup interface device. I just put in a request for assistance from support. I am a registered installer with them.

 

[analog8484]

I've seen that app note and it basically shows a non-functional generator interface in the BUI even with the most recent firmware hence my comment.

Alternative Power Source based generator solutions have been available for HDWave inverters without needing the BUI but you need to have a way to curtail/disable solar power production such as using the power reduction interface with an appropriate controller.

 

[bradeyboy]

Yes, that is exactly what I was seeing. If I could get some insight on the dry contact that is available on the BUI, I can start to figure things out. I am thinking the dry contact closes after the inverter on battery decides its going to shutdown the battery input as available power. I read somewhere to set the engine delay to allow for that to happen before calling for EG start. I guess if during the day and solar can take up the load, it would save battery until absolutely needed. I can experiment, but just have not had the right opportunity yet. My other issue is that the Generac has the battery charger built into the transfer switch. If not using that, going to have to put a smart battery charger in the generator and send some grid AC its way.

 

[bradeyboy]

I was thinking I could also add a second inverter circuit breaker to the BUI to feed the AC sense to the Generac. When that AC is lost, the Gen would start on auto. The problem would be when the grid comes back, the BUI would not be able to isolate the generator before transferring back. Maybe that is the oversight by Solaredge. They need to be able to turn off the gen set before transferring back to grid, otherwise might have mismatched phases and we all know what happens then!!

 

[ggunn]

I was thinking I could also add a second inverter circuit breaker to the BUI to feed the AC sense to the Generac. When that AC is lost, the Gen would start on auto. The problem would be when the grid comes back, the BUI would not be able to isolate the generator before transferring back. Maybe that is the oversight by Solaredge. They need to be able to turn off the gen set before transferring back to grid, otherwise might have mismatched phases and we all know what happens then!!

I know that this isn't exactly your situation, but the way we handle the limit on the amount of PV that can be connected to a PowerWall when it is running off grid is to insert normally open contactors into some of the PV circuits. The contactors are provided with activation voltage by a power supply connected to AC power on the grid side of the Tesla Energy Gateway (TEG). When the grid goes down and the TEG takes over supplying power to the residence, the power supply loses power and the contactors open, reducing the amount of connected PV. Perhaps you could do something similar when the power switches from battery to generator to turn off the PV so the generator cannot be backfed.

 

[ggunn]

I know that this isn't exactly your situation, but the way we handle the limit on the amount of PV that can be connected to a PowerWall when it is running off grid is to insert normally open contactors into some of the PV circuits. The contactors are provided with activation voltage by a power supply connected to AC power on the grid side of the Tesla Energy Gateway (TEG). When the grid goes down and the TEG takes over supplying power to the residence, the power supply loses power and the contactors open, reducing the amount of connected PV. Perhaps you could do something similar when the power switches from battery to generator to turn off the PV so the generator cannot be backfed.

I'll just add that we use microinverters for our resi PV systems, so the contactors allow us to trim the PV back to allowable levels in an off grid situation without completely shutting down the PV. Your situation is different; shutting down the PV completely when the generator is running will likely be what you need to do. It occurs to me that you could use normally closed contactors on the PV inverter output(s) that get their activation voltage from a power supply on the generator output so that when the generator starts up it shuts off the PV. Good luck.

 

[jaggedben]

I would not be trying to do any kind of direct generator connection to the BUI that isn't supported by Solaredge. Presumably the purpose here is to provide power to loads and recharge the battery a bit if the battery runs down overnight, to reduce generator on time. Compared to putting the generator ATS on the load side of the BUI to just power the loads, the risk/benefit ratio here is really bad, especially if you already have an ATS to use.

Seems like Solaredge needs to get their act together. Doesn't surprise me. Enphase did something similar where they first released their Enpower Switch with generator terminals marked 'future use.' (This was 2.5 years ago now.) But about 9 months later they released software support for generators along with tech briefs and announcements and webinars. About par for the course for the difference between those two companies in the last few years, in my experience.

 

[analog8484]

I was thinking I could also add a second inverter circuit breaker to the BUI to feed the AC sense to the Generac. When that AC is lost, the Gen would start on auto. The problem would be when the grid comes back, the BUI would not be able to isolate the generator before transferring back. Maybe that is the oversight by Solaredge. They need to be able to turn off the gen set before transferring back to grid, otherwise might have mismatched phases and we all know what happens then!!

I agree, SE most likely didn't fully think through what's really needed in a generator ATS (e.g. delays for generator startup, engine cool down, etc). Once SE realized the BUI can't do what's necessary they reverted back to Alternative Power Source based solutions which really needs a n external generator "plant controller" to do all the necessary things to safely transfer power between the grid and generator.

 

[RumRunner]

I was thinking I could also add a second inverter circuit breaker to the BUI to feed the AC sense to the Generac. When that AC is lost, the Gen would start on auto. The problem would be when the grid comes back, the BUI would not be able to isolate the generator before transferring back. Maybe that is the oversight by Solaredge. They need to be able to turn off the gen set before transferring back to grid, otherwise might have mismatched phases and we all know what happens then!!

The idea is not workable based on your concept. . . . and here’s why:

Adding a second inverter circuit breaker to feed the AC sense [sic] to feed the GENERAC sounds logical but what will happen when the grid is down and no power to the AC sensor for the GENERAC.
The root of the complexity lies on the nature of what you are trying to accomplish.
Normally-- power transfer is easily managed when dealing with two power sources.
But you are dealing with three sources to supply power (not simultaneously) to a common load (ie) Grid, PV and Generator.

Solaredge is a manufacturer-- they’re more adept in building the unit. Automation scheme is not their cup of tea. The reason they can’t give you a definitive answer --to get you out of this morass that you are mired in.

This scheme is generally used on high-end RV (motor home). I have mine that came with the manufacturer.
Your problem with transferring power back to or from the grid is handled by a lowly (cheap timer) that will allow the GENERAC to stabilize the voltage (during crank up) before the transfer is made.

This also ensures total isolation.
Above scenario is just one of many-- that needs specialized knowledge of controls to accomplish. . . not done by installers, salesmen and off-the-cuff mouth pieces belting out a bunch of baloney by hungry vultures.

Post a relay schematic diagram and allow us to examine the scheme and make corrections as necessary.

Good luck.

 

[solarken]

Here is a SolarEdge doc that describes a few scenarios that they support with generators and the BUI.

 

[synchro]

Here is a SolarEdge doc that describes a few scenarios that they support with generators and the BUI.

It doesn't look like charging the batteries from the generator through the BUI is supported with the approaches in this document.

The following is from a DIY forum, but it possibly may provide some useful information:
https://diysolarforum.com/threads/solaredge-daytime-solar-options-during-power-outtage.53089/

 

[Steve16]

I was under the assumption that the generator was to be used only as a backup to the backup... didn't think the batteries and generator were compatible in any way

Basically batteries get to too low of a level, the xfer switch shuts them down and changes to generator power until the grid is restored to either recharge the batteries or fire up the PV to recharge the batteries.

*just read the document confirming this

 

[solarken]

I would not be trying to do any kind of direct generator connection to the BUI that isn't supported by Solaredge. Presumably the purpose here is to provide power to loads and recharge the battery a bit if the battery runs down overnight, to reduce generator on time. Compared to putting the generator ATS on the load side of the BUI to just power the loads, the risk/benefit ratio here is really bad, especially if you already have an ATS to use.

Seems like Solaredge needs to get their act together. Doesn't surprise me. Enphase did something similar where they first released their Enpower Switch with generator terminals marked 'future use.' (This was 2.5 years ago now.) But about 9 months later they released software support for generators along with tech briefs and announcements and webinars. About par for the course for the difference between those two companies in the last few years, in my experience.

I agree it is aggravating when companies release promises that go years before fulfilling them, but SolarEdge anbd Enphase are not alone. Generac, who you would think with their long experience with generators has done the same or worse. They announced their DC generator years ago, PWRgen, and then it was delayed and delayed. And I am not sure they support AC generator integration even now. Sure seems like DC is the way to go however, since it eliminates the synchronization issue and can be made to look just like a solar array to hybrid inverters. I don't know why there are not more manufacturers coming out with DC generators to couple with modern inverters.