AC Coupling with the Schneider XW Pro: It Does Work... BUT!

What is AC Coupling?

XW Pro AC Coupling Solutions Guide

Equipment:

Schneider XW Pro
Conext 100a 600v Charge controller
Mini PDP
Battery Monitor

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[garymeissner]

I added a Schneider XW-Pro to my Enphase PV Solar power system a while back, and I ran into the same issues with Schneider. They just don't seem to understand what "Time of Use" is all about. When I read their web site, they sure made it sound like it would do it, but as you found out, it just doesn't work with their existing built in software. It is a shame, because it is one of the best inverters as far as the hardware goes. It is a beast with a very clean output that does not break a sweat, even running up to 12, 000 watts. I ended up programming a smal PLC that monitors the solar production and my house consumption and it commands the XW-Pro to go into charge mode and adjusts the charge rate every 5 seconds to keep my grid power near zero. This is working great now. I have managed to keep my grid power to virtually zero for several months. I have sent Schneider data and screen shots of what I am doing and trying to get them to just add this simple code into the Gateway (Insight home or facility now). It has all the data it needs to control charging and the loads on the output side. If you also want to run the loads back in the main panel, it needs a power meter on the grid side. They already support that with a Watt-Node device. So with that, it should be able to do everything I am doing with my add on PLC. When my A/C kicks on, it pulls 3, 000 wats from my main panel. It takes about 10 second for my PLC to see the load and adjust the "Sell Current" to cover the load and get the power meter back to zero power. And when the A/C shuts of again, there is a few seconds of export as the PLC commands the XW-Pro to dial back the sell current again and get the power meter back to zero. And if the solar is making more than the house is using, it will even go back into charge mode and adjust the charge current to get the grid power back to zero again.

It sounds like Schneider may actually be starting to listen as people like us and a few others are pointing out this dumb limitation. I really hope they put this functionality in a future firmware update, but I am not holding my breath. If they don't get it right, I still have my PLC working now.

I am still on an older firmware for a few reasons. I hope to update it soon, because there is a bug in the version 1.03.00 that I am still running. When I was off grid during a power failure, it was causing 11 of my Enphase iq7 microinverters to cycle on and off, and the frequency kept changing. The battery bank was not full, and I was well below my charge current limit settings, so it should have been running a solid 60 Hz. But with any big surge current, like starting the microwave, the frequency would bump. And at one point, it dropped to just 57 Hz. At that point, all of the Enphase micros shut down due to a bad grid frequency error. Without the solar input, the power was more stable again, but everything with an AC motor was running slow. The refrigerator even sounded off, but it stayed running without a problem. Shutting the inverter down and starting it again, did restore the frequency back to 60 Hz, but the sun had gone down, so it did not go back to AC coupling. The grid came back up in the middle of the night. Schneider says the frequency error problem was fixed in version 1.11 and later. The only reasons I have not done the upgrae, is I need to make sure my PLC will still work with the new code, and I have to shut down my critical loads to do the update.

[DavidPozEnergy]

Thank you for this video. I love that you are pushing it through its paces.

[nawiribrahim]

In Africa we have tried tested a combination of Victron and Fronius and it works perfectly. The manufacturers worked together to perfect it.

[DavidHalko]

I am waiting for my GenetrySolar 12k to arrive, and plan on doing A/C coupling with an array. It will charge batteries from the A/C coupled grid tie, can be programmed to shut off the array by frequency shifting & shut off the grid tie, run the house from batteries when the grid tie is too low, and use the grid as a last resort power for a whole house UPS.

[russael]

Found your channel by searching for XW Pro in YouTube. :)

I had a Sunpower install done last year; 18, 420w panels with microinverters with their new Sunvault, 26kwh battery solution. I don't know if you've seen their Sunvault system or not, but the inverter they use in the system is the XW Pro with the conext gateway. The way it's all interconnected is done by something called a Sunpower Hub+, which basically acts like a router for electricity and tells it where to go, and also contains an automatic transfer switch. It's all grid tied through the Hub+ which measures power at all three points - solar production, grid usage or sell, battery discharge and charge. The XW Pro only has power lines from the Hub+ and the battery cables. It doesn't rely on the inverter for AC coupling.

They include 1 inverter with either the 13kwh or 26kwh size, and 2 inverters with the 52kwh solution (I upgraded to that capacity last month along with 6 additional panels, so now I have 24.) My power company doesn't do net metering. They do something called distributed generation instead. Basically, there's no way to get a zero bill. Closest you can get is $7.50, which is the generic service charge, and there's no way to get to that dollar amount without batteries and running in self supply.

One thing I've noticed about the battery system in off-grid or microgrid mode, is that the lights will flicker about once a second for around 5 minutes, and then it may smooth out for 10 - 15 minutes, and then it'll start the pulsing again. When it flickers the lights, you can hear the inverter pulsing along with it. Kind of weird. Was wondering if you've seen this behavior.


If you have any questions about the Sunpower system I had installed, I'd be happy to answer any questions.

[JimLarsen]

On the DIYsolarforum a lot of Schneider owners have been unable to fix the xw pro leaking power back to the grid when it is not supposed to. Since last year Schneider hasn't fixed this. Some have said their smart meter reports this back to their utility company and without having authorization to feedback to the grid it could cause them problems.

[rowlandcrew]

Hi Ben, great update. what is your balancing transformer wiring hookup (~schematic for the transformer that is on your solar edge inverter)? Is there any load on that transformer or is it just coupling the split phase? Schneider has recently released a contactor package, BCS, that you put at your meter to isolate from the grid. Does this BCS enable a method to get the time of use function you mention? My main interest for the schneider BCS is that I want to have my solar, batteries, generator, hybrids out in my utility shed. the idea is to keep the flammable stuff away from the house and close to the solar panels. My AC bus runs throughout the property, has most loads by the meter and the meter is 200' away from the shed. therefore, disconnecting from the grid (when it is down and when I run a generator or AC coupled) means having the schneider control the BCS "remotely". schneider says it "just needs to be wired to the XWPRO". In short, I think if you get a BCS and demo it, that would be interesting. Eric bensen has a powerpoint that has tons of info but no "Ben smoke test". thank you

[bentleyjarrard]

I'm using the older XW+ in an AC coupled fashion with an existing grid tie system, actually 2 grid tie systems in the State you mentioned, CA. Haven't had any problems in over 4 years. I have to agree with you 100% on the mediocre TOU and basically nonexistent Battery Charge Control settings. It was short video but would have been nice if you went into a little more detail about specifics of the issues. If the Pro is the same as the older XW+ here are the 2 BIG problems. 1) Time of Use is based on a 24 hour clock instead of a 7 day clock. This is important because the higher rates usually do not apply on weekends so there is no reason to cycle your batteries and shorten their life on days you don''t need TOU like Sat & Sun. 2) This is the really stupid one. The inverter is hard programmed in the firmware to Exit Peak Load Shave mode when the battery voltage reaches the setting for "Recharge Volts" + 0.5V, which means it will stop discharging the batteries BEFORE a recharge cycle is triggered so the batteries will not be ready for self consumption the next day. Also, there is no way to set the inverter to automatically start a charge cycle later that evening when rates drop so the batteries are topped up for the next Peak Load Shave session. Just to make it even more convoluted, theoretically its possible to get a compatible PLC with ModBus RS485 to send a 1 or 2 to the appropriate register to manually trigger a Bulk or Float recharge cycle but it apparently takes a team of engineers to figure out how to actually use the RS485 function on the Schneider.

[flyingjeff]

Ben, I have a very similar (same?) Solaredge DC coupled system. Have you ever updated the software on the Solaredge? Just curious—I haven’t tried that.

[chrisolofson]

Do not replace your old Solaredge type A inverter with anything made by SolarEdge in the last 2 years. Solaredge 1ph failure rates are over 50% right now. I have over 300 SE systems out there and will likely never install another one. At least until I see a tremendous improvement in quality and customer service.

[josedurand]

The reason why a normally closed relay is needed is to cut the AC coupled PV supply when the generator is in used to avoid back feed currents to the generator stator. Back feed currents will damage the generator stator.

[CRsolar]

Total agree- pain in butt - I am not a fan of AC coupling these - I helped someone that purchased 3 of these XWs - Schneider needs to wakeup - they have the $$$ to do amazing things..

[silverbackag]

AC coupling is just not for grid tied. Works like a peach for off grid too…at least with SMA. But the Sunny Islands control the Sunny Boys’ outputs as part of a system.

[brentjohnson]

Another good video! Maybe this is why they say the Schneider is for pro installers since there are so many nuances to it. I am needing a off-grid supply for a couple of HVAC and water heater and saws and welders in the shop. Interesting that AC coupled doesn’t automatically charge the batteries.

[mikluck]

Your reviews on the XW pro have been great. I have an AC coupled system and learning about some of the quirks up front is beneficial for sure. I also have a 20kw whole home generator with an ATS (where the AC coupled micro inverters tie in). I've been doing some research on how to hook everything up so when you mentioned the extra external contactor it firmed up some of the ideas i was working on. Any chance you have a generator to demonstrate some of those features? I'm assuming you could use the generator to charge the batteries, then use the batteries to create the 'grid' to get the AC coupling going again. However, when I was looking in the setting in the manual I can't say I'm 100% on that being in there.

[dangoras]

Ben i never seen anyone mount a breaker box to a refrigerator i guess it keeps it cool 😂... Good information brother keep it

[yankey]

Thanks for sharing brother. Keep up the good work. God Bless

[fisherus]

Where's everybody? C'mon, Ben's coming!

[sitechca]

One year later and the latest XW Pro firmware is v2.04 dated 03/2023. So no improvement in AC-coupled, on grid, TOU support.

[chukwunedugeraldonuchukwu]

Hi Ben, where can I buy the Schneider 6848 and they would also install the unit ( yes, we'll pay for installation).
I'm in Bethesda, MD.