Sol-Ark 12K showing power pushing to grid when on generator

[SolarHead]

Last week we had a wind storm, grid was down for 4 hours. My ATS worked as it should, removed home from grid, started generator and all was well and worked as tested. Let me explain my configuration before I get into what happened next. My generator is a Generac 22KW and it was installed years ago, long before I ever thought I would install a solar system. Knowing the gen is big (22kw and 96A) I figured leave it alone, leave the ATS as is (no changes). I was tempted at first to move the generator over to the GEN port on the Sol-Ark but the 12k model can only handle like 37A or maybe more on gen port but either way, it would not utilize all 90A that my generator has to give so I figured why waste some of the generators capacity, things were working good so why change stuff. My configuration is where I have a 60A breaker in my 200A panel and that feeds the Sol-Ark its AC power, whether is grid power or generator power, that 200A panel is powered pretty much in any scenario. So, the grid was down, ATS did its job and generator was started and running and it was covering my 200A panel, my batteries at 100% SOC, sun shining and PV producing about 9,000 W. All was good I thought.




Being that the grid was down, my cable internet was down so PowerView would not connect (the dongle wouldnt get wi-fi). So I looked at my Sol-Arks screen and to my surprise, it was showing power pushing to grid when on generator (arrows going towards the tower icon). It scared me because I thought oh crap I'm backfeeding my generator. I was thinking okay I'm disconnected from the grid via the ATS. Was I back-feeding to my generator perhaps? If I was, I imagine my generator would be trash right now, or maybe the ATS has intelligence to know not to accept power, and only push/generate power I don't know. My mind is still blown by this, not sure why it was showing power pushing to the grid (the arrows were pointing to the tower icon). So, I called Sol-Ark. A tech called me back, we ended up texting pictures of my Sol-Ark screen, inside my ATS, inside my 200A panel to show CT location, sent him the line diagram of my entire system design. He said looks like everything was set up properly and CT's in correct location. Then while on phone the grid come back up, then he logged into my inverter from his end and looked around. He said he would discuss and get back with me. The following day the only thing they could suggest was changing the grid power setting from like UL1741SA to be set on "General Standard" which I did. He said that MIGHT help but wasnt sure. I have not tested it. I figured wait for sunny day when battery at 100% SOC , then flip disconnect on outside of my house to simulate a grid down and let the ATS do its job and fire the gen, then see if its showing power going to the tower icon. I am out of thoughts and ideas on why it was doing that. If it was pushing back to the 60A breaker in the 200A panel box, then I think it would have been pushing back towards the ATS and maybe the ATS has a way of not allowing power to back feed to the generator I dont know. Got any ideas? Really, the Sol-Ark did not know it was on generator I guess. I mean it was getting clean AC power from that 60A breaker thats in my panel box. The guy at Sol-Ark said they hardly ever had any experience with a customer having such a big generator, and its pretty clean power, I think less than 2 or 5% THD. If the GEN port on the Sol-Ark is empty (nothing connected to it), then not sure how the Sol-Ark can detect its on generator power. So, generator running, grid down, the Sol-Ark looks like it's pushing power back to that 60A breaker but its not going to the grid because the ATS has me disconnected from the grid. I'm lost. Not thinking clearly or not understanding what is happening. The guy at Sol-Ark didn't seem to know what else it could be but was trying and very much wanted to help. I will wait and run a test soon as conditions are right.

 

[RCinFLA]

There is a difference between SolArk gen input and grid input. Gen AC input will not allow any back feed export. Grid input cannot tell the difference between grid, which it allows back feed to, and generator sourced power into grid AC input of SolArk. That means it will back feed to generator.

You cannot allow export from SolArk to grid input port when generator is feeding grid input.

You either have to move generator to gen input on SolArk or disconnect SolArk grid input when feeding your panel from generator. You could set SolArk to no export but that would have to be done before allowing generator to power up.

If you are using an external CT sensor to prevent push to actual grid while allowing loads in main AC panel to be supplemented by SolArk back feed, you could put another CT sensor between panel A input and ATS switch and use a relay with coil powered from actual grid on panel B or generator output to switch SolArk CT sensor input between the actual grid input CT sensor and the second CT sensor between ATS and panel A.

The second CT sensor between ATS and panel A would then prevent any back feed into ATS switch, and therefore generator.

If you never care about supplementing panel B during normal grid operation you can get by with just the one CT sensor between ATS and panel A.

This assumes your use of external CT sensor is to prevent actual grid push. If you want grid push then you have to go to the first suggestion.

 

[cm119]

Did you get this worked out? The wiring diagram shows this setup, but the instructions are a little light on details. It just says when using a whole home gen and ATS to select ‘gen on grid input’ and disable grid sell. I guess this just means that gen ATS and grid sell back aren’t supported simultaneously?

Maybe a workaround is to disable auto-start of the generator, then in the event of an outage, you change the gen on grid input setting in the sol-ark then start it manually. Then after you are back on grid again change the settings back. In addition to correct CT placement as mentioned above.

 

[mgdean]

I have my Generac set up pretty much the same way. Are your CT's in Panel A and have you checked box that says Gen power is connected to your grid input?