Hooterville Co Op noticed my EG4 Solar A/C with 2700W ground mount panels - need advice on response?

[Plum Crazy Rob]

Is the situation that EG4 A/C has a rectifier supplying DC bus and PV supplying DC bus, so the only inverter involved is 3-phase BLDC motor-drive?

Sounds like an "on-line UPS", which has no AC backfeed.

Yep. I literally discussed this with them basically verbatim. Need UL1741 saying something about isolation testing AC - DC to convince them, as well as no backfeed per whatever text.

 

[Hedges]

Turn off AC breaker, or disconnect AC wires going to A/C. That makes it DC powered, not connected to grid.

Later add an extension cord for it.
If you ever need AC power - do you run A/C when sun is down?

 

[50ShadesOfDirt]

This is one of the reasons why we never hooked up to the grid ... the grid police.

If you read the billion-page contract between yourself and the grid provider in your area, AND, you read your state's billion-page PUC document covering that grid provider, you'll find that there is all kinds of wording in there allowing them to come onto your property and verify whatever they want. When you hooked up to the grid, or signed a contract to utilize the existing connection, you've signed away your rights.

You can choose to not allow them on, but the wording covers that, and they disconnect you until the situation is resolved, usually in their favor. If your neighbor on the same transformer is causing grief, they can shut the transformer down causing you to lose power, and they'll point to the neighbor for some peer pressure.

I encourage everyone to read these documents for your state and grid provider, and then ... either go off-grid (if you can, and once on-grid, it usually is no longer possible to boot them out), or if on-grid, put in a parallel system in such a way that there is no connection back to the grid, even to the point of separate wiring throughout.

If you do have a grid connection, you can have a charger "appliance" that plugs into the grid, and supplies charging to the off-grid piece (such as a chargeverter).

Couldn't quite tell if OP has a fully separate & parallel system for the A/C unit, but if it was fully independent wiring, the inspection would be pretty quick. Unfortunately, the wording in the billion-page document(s) does allow this inspection.

Hope this helps ...

 

[Q-Dog]

James, I actually THOUGHT about tagging you at this point. They are doing their own due diligence and while I am having a polite discussion with them, they will not simply take my word for it.

Edit, I gave them the EG4 Cutsheet / links to Signature Solar and Deye website.

They came and physically checked it for backfeed (0, of course)

This right here makes zero sense to me. They physically checked it, found nothing wrong, still giving you grief? I guess I would pull the grid power connection until things quiet down.

 

[Mattb4]

Friday update. They know it's connected to A/C - THEIR POWER. I don't want to go into why I'm not able to give them the "THESE ARENT THE DROIDS YOU ARE LOOKING FOR" - let's move forward.

Also both guys involved here are current or former linemen now responsible for the onesey twosey volume of Solar instls the Co op has to deal with. Neither had heard of Sol Ark when I name dropped Deye makes those AND my EG4 Air Con.

Interestingly options are:
1) Do nothing. About 0.001% chance of this by my estimate
2) Have me sign a (more or less) STANDARD SOLAR INTERCONNECT AGREEMENT (!)
3) Ask me to disconnect the breaker. I'll be 60 next month - when does short term memory loss start?? Why is that breaker disconnected??

Discuss. Especially option #2, interconnect. Crazy, yes or no. I'm an Engineer, and I say export is not possible, it's NOT AN INVERTER is not an adequate explanation . I'm not sure saying it's UL1741 would help - they do know about grid down inverter disconnect - and they want to lump it in as an inverter - saying it complies with "an inverter standard" may make things worse.

Well dang it. I had hopes that they would not prove obstreperous.

It is hard to convince people that are not open to the idea. You might just have to go with option #3.

 

[Zwy]

Friday update. They know it's connected to A/C - THEIR POWER. I don't want to go into why I'm not able to give them the "THESE ARENT THE DROIDS YOU ARE LOOKING FOR" - let's move forward.

Also both guys involved here are current or former linemen now responsible for the onesey twosey volume of Solar instls the Co op has to deal with. Neither had heard of Sol Ark when I name dropped Deye makes those AND my EG4 Air Con.

Interestingly options are:
1) Do nothing. About 0.001% chance of this by my estimate
2) Have me sign a (more or less) STANDARD SOLAR INTERCONNECT AGREEMENT (!)
3) Ask me to disconnect the breaker. I'll be 60 next month - when does short term memory loss start?? Why is that breaker disconnected??

Discuss. Especially option #2, interconnect. Crazy, yes or no. I'm an Engineer, and I say export is not possible, it's NOT AN INVERTER is not an adequate explanation . I'm not sure saying it's UL1741 would help - they do know about grid down inverter disconnect - and they want to lump it in as an inverter - saying it complies with "an inverter standard" may make things worse.

Forget #2, option #1 probably won't work.

Use option #3. Add in an off grid system with batteries for when it needs AC power.

Unless they can sign off on it if they do research it. I would have just installed an off grid system from the start and powered the mini split off it. They couldn't do a thing about it.

 

[Plum Crazy Rob]

Use option #3. Add in an off grid system with batteries for when it needs AC power.

Yup I was mentally planning this in the back of my head. Probably in my future. Had to make sure my "Pirate" Solar Air Conditioner and/or System were reasonably legit first ?‍

 

[Plum Crazy Rob]

This is one of the reasons why we never hooked up to the grid ... the grid police

You aren't wrong. Even though I live in the sticks, the Co op GM lives a few miles from me on a shitty dirt road. I live on a very nice paved road I'm sure he takes when it's muddy. He must have 20-10 vision but he spotted the panels from the road, and according to linemen thought hmmm I didn't see that "system" cross my desk for PTO (remember what I say about tiny size of co op, and tiny volume of Solar). This led to investigation and I'm sure, wow his usage is way down! GO LOOK!

Even more fun, the confusion about an APPLICATION came from, someone else with the same name ( my name is not common like "John Smith") - applied in the same general timeframe- unbelievable. Different address of course but once they saw the name, pulled it out for review.

 

[timselectric]

The best way to deal with a bully, is to take away their leverage against you.

 

[Johno1066]

I have real difficulty understanding the story about an inverters feeding back into the lines and electrocuting anyone. When I was much younger I was involved with power distribution and most power lines were isolated and grounded before anyone was allowed to work on them, 3kv dc overheads were worked on in a live state just as most lower voltage AC transmission lines are at the moment. There is more chance of the linesman getting into trouble working on live transmission line than grounded de- energised lines that is for sure.

 

[Hedges]

Not isolated from source unless they unplug every single utility meter on the branch.
And more likely to get into trouble when it is thought to be dead, even tested dead, vs. is hot and you know it.

Linemen are getting electrocuted from generators. Not likely from UL1741 GT PV inverters, but easily done with grid-forming inverters if backfeeding the house without proper interlock or transfer switch.

Grounding works, but what has somtimes happened is they grounded one end, then later discovered a break somewhere in the other direction.

In the case of OP, I think PV system and AC are isolated by diode input to capacitors. I wouldn't actually consider that a safety circuit, failed diode could backfeed DC. What could work is an AC powered relay. Except DC backfeed might keep it closed. And most relays aren't "Isolators", which I think are supposed to have 1" opening. Or low frequency transformer isolation.

 

[740GLE]

Again, it’s not just linemen it’s also public safety.

It’s about minimizing risk and anyone with an illegal set up, could back feed a transformer could cause 4kv-34kv energized line sitting on the ground. Sometimes lines don’t arc and spark, so no tell tale sign someone should stay alway.

 

[MrM1]

They came and physically checked it for backfeed (0, of course)

I'm confused by this. If it's not back feeding , where's the problem? Do you have a digital meter? I back fed once for about 30 seconds on a weekend, it was less than 100w (OK it happened a few times that weekend, but still 10-15 seconds and then less than 100w).

I had an official from the CoOp here that following Monday. Although oddly once he saw I had solar, he didnt seem to care.

My point, if you have a digital meter they know your not back feeding, and if they checked, and you're not, what's the problem?

 

[cs1234]

Again, it’s not just linemen it’s also public safety.

It’s about minimizing risk and anyone with an illegal set up, could back feed a transformer could cause 4kv-34kv energized line sitting on the ground. Sometimes lines don’t arc and spark, so no tell tale sign someone should stay alway.

How does a grid tied inverter that syncs to a working grid signal backfeed a transformer if it's off because there is no working grid to sync to? Are we talking about non grid tied inverters here? Or do we think the illegally grid tied inverters with limiters are somehow making up their own grid signal to sync to and exporting to a dead ac input?

 

[Hedges]

We don't expect a proper UL-1741 listed grid-tie inverter with anti-islanding to backfeed a dead grid.
But there is lots of other equipment that could.
If the utility detects backfeeding from someone who doesn't have approval from them including equipment model they know about, who knows what is connected?

 

[DIYrich]

What do you have between the panels and the eg4 air conditioner? Ul1741 is for inverters. You can't get that for the air conditioner.

 

[MrM1]

What do you have between the panels and the eg4 air conditioner? Ul1741 is for inverters. You can't get that for the air conditioner.

There is nothing between the panels and the eg4 A/C. This EG4 A/C unit is direct connect to solar panels. It has a built in MPPT.

It has the option to be supplied by AC power at the same time, and if so, the A/C unit prioritizes solar input 1st.

 

[cs1234]

We don't expect a proper UL-1741 listed grid-tie inverter with anti-islanding to backfeed a dead grid.
But there is lots of other equipment that could.
If the utility detects backfeeding from someone who doesn't have approval from them including equipment model they know about, who knows what is connected?

I'm just curious how any grid-tie only inverter (with or without limiter), whether listed or not, would backfeed a dead grid? Do they not all have to *constantly* analyze the incoming AC signal and sync up to it in order to output anything? Do they have the ability in their internal circuitry design to just keep going, bypassing the sync requirement? If that's the case, they are essentially regular off grid inverters internally as well, and you would think they would be marketed as being able to do both grid-tie and off grid. I figured it was inherent in their design that the analyzing of the incoming AC signal was pretty hard coded / gated and not really able to be bypassed.

I suppose one could say anything is possible with unlisted grid-tie inverters, but do we have any examples/evidence of simple grid-tie only inverters that aren't listed doing such?

 

[Plum Crazy Rob]

What do you have between the panels and the eg4 air conditioner? Ul1741 is for inverters. You can't get that for the air conditioner.

And you certainly understand exactly why I didn't point THIS out to them. That's why I want a copy of UL1741. What IS it then that might apply to the A/C?? Or is Deye simply verifying by Design and / or having an AC current powered relay/contactor it complies.

 

[xtrorion]

Hi all. I have an EG4 24K Solar Air Conditioner connected to 240v AC Power and 2700W of ground mount panels. See pics. Recently received the following letter from my PoCo (edited identifiable info).

So in other words, we noticed the 50% reduction in your usage and sent someone to investigate. This is muddled somewhat as *I* talked to them about net metering and interconnect of a full blown Solar Instl, but they had a wait list so I blew that off. They have me confused with someone who DID submit an application and likely called and emailed wrong guy.

Unlike an Inverter, the EG4 Air Conditioner of course does not have the capability of converting DC to AC so I assume the anti islanding stds and so forth are irrelevant?? Of course it DOES invert AC to DC..

What is your response?? As I say, they think I've run an end around on them on a full blown Solar Instl - not just the EG4 A/C.View attachment 161628View attachment 161631View attachment 161632

This is really simple, just tell them there is no interconnection to the grid. You have installed a solar AC that works in much the same way as solar lights next to the driveway....end of discussion. They are asking a very reasonable question....Even if you have an off grid system not connected...this is all they care about.

 

[xtrorion]

Hi all. I have an EG4 24K Solar Air Conditioner connected to 240v AC Power and 2700W of ground mount panels. See pics. Recently received the following letter from my PoCo (edited identifiable info).

So in other words, we noticed the 50% reduction in your usage and sent someone to investigate. This is muddled somewhat as *I* talked to them about net metering and interconnect of a full blown Solar Instl, but they had a wait list so I blew that off. They have me confused with someone who DID submit an application and likely called and emailed wrong guy.

Unlike an Inverter, the EG4 Air Conditioner of course does not have the capability of converting DC to AC so I assume the anti islanding stds and so forth are irrelevant?? Of course it DOES invert AC to DC..

What is your response?? As I say, they think I've run an end around on them on a full blown Solar Instl - not just the EG4 A/C.View attachment 161628View attachment 161631View attachment 161632

Just let them know that these panels are shade for your new chickens......

 

[Plum Crazy Rob]

Just let them know that these panels are shade for your new chickens......

I think you just won this thread even over the @SeaGal edit of their letter?? Wait, what?? Those are SOLAR PANELS?? I found them in the dumpster...

 

[Plum Crazy Rob]

Keep in mind while this is not connected intentionally "bi directionally " at the Mains like a GT inverter, it is connected to AC power - herein lies their problem. It's still potentially a "Solar system Interconnect" worthy of review / potentially backfeeding.

 

[Madcodger]

The best way to deal with a bully, is to take away their leverage against you.

Good point. Or hand it over to a decent attorney, if you're willing to spend a few bucks.
Their concerns about back feeding to the grid were reasonable. But when that was shown to be not an issue, they're just being unreasonable.

 

[Madcodger]

Oops - replied to wrong post. Fixed that below.