Not sure if you had the job as lineman you would have that opinion.
Utility company visited me for exporting from my solar Off-grid growatt LVM-ES SPF 3000TL
- Thread starter vallesj
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Do you mind posting a wiring diagram on this setup? I mean the connections of your dry contact relay to the chargeverter.
cs1234
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I would probably follow the standard procedures to check that a line wasn't being backfed when working on it. More things than a grid tied / synced inverter can cause a line to be live in a power outage.
More and more people are getting prebuilt AIO solar generators with batteries in them and using them as UPS's. I would imagine almost every one of those devices is like this growatt and does spurious backfeeding as they are probably using the exact same hardware inside. They are getting bigger and bigger, many of them are up to 3-4k output already.
The power companies aren't concerned about the lineman. They are concerned about their gravy train.
The lineman, I am certain, ARE concerned about the lineman.
You can hate the "power companies" all you desire. Real people are working the lines and back feed is dangerous.
ricardocello
Watching and Learning
That would be super aggravating, as net exported power is still 0W.
Now we have to prevent imbalanced loads in the house?
Seems to me that would happen in a normal non-solar house with the hairdryers all running on L1 (paraphrasing from another thread).
Maybe not.
hwy17
Anti-Solar Enthusiast
I understood any AIO that can do SUB/SBU grid mixing is paralleling to the grid, whether it allows for intentional export modes or not.
I could be wrong, but I believe it is inherently necessary.
Brucey
Solar Wizard
So my understanding is a Victron quattro or multiplus had a double throw, double pole internal switch to avoid this kind of problem of unexpected export. Do the aios not have this?
cs1234
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Tell that to the European countries that allow grid tied balcony solar of 800 watts or more with no inspections or permits, or, at most requiring a simple form that says you have one dropped off in the post. Do you honestly think they aren't as concerned or more about lineman safety in Europe than we are here in the States?
We aren't talking about a gas powered generator hooked up with a suicide plug here. We are talking about devices that either do no significant exporting, or do exporting / syncing to UL1741 standards and turn off the export when power goes out. Devices literally being used in the manner for which they are designed and sold. The lineman need to get legislating quick and outlaw all these EcoFlow and Bluetti power stations before something bad happens, because they are rapidly growing in popularity as the consistent quality of utility services goes down.
I'm not even arguing that they should accept significant intentional backfeeding. I'm only stating that there should be a tiny amount of spurious backfeeding that is allowed without question, because it just happens. If the backfeeding happens for a few seconds or less, and then goes away, it's obviously not a generator hooked up with a suicide cord. I believe certain regular devices and appliances can even cause spurious backfeeding.
cs1234
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I'm not sure the Victron inverter/chargers are immune to it either.
42OhmsPA
What's in a title?
automatikdonn
Becoming Offgrid
dougbert
Solar Addict
since mine are V1 I understand, but they are deep in the basement
now my son bought a V2 and it is quieter
dougbert
Solar Addict
UL1741 certification is meant to provide that "no feedback" to grid occurs. are these inverters certified, or is the listing lacking something?
dougbert
Solar Addict
LVM-ES SPF 3000TL does not have that UL1741 certification from its spec sheet
timselectric
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In SUB mode, they do run in parallel with the grid. Similar to a grid-tied inverter.
They usually draw a set amount (200 to 500w) from the grid as a buffer.
But sometimes that's not enough buffer, and a little bit sneaks through.
Today's utility meters are getting very sensitive and can detect this small amount.
It's only an issue in SUB mode. So if it's giving you problems, don't use it in SUB mode. Or run the double conversion, like the rest of us.
zanydroid
Solar Wizard
I thought SUB/SBU meant it does NOT mix and does NOT do grid assist/peak shaving and does NOT have the necessary inverter control to achieve this. Just a transfer switch to lock out the grid vs the inverter
And when I say SUB/SBU I mean only one AC source can carry the load, with no blending. If the inverter cannot carry the load then the full grid can carry the load.
Otherwise, how the heck is everyone getting away with parallel operation?
However since these are inverter/chargers, when charging from grid the inverter hardware is connected albeit configured in charging mode
cs1234
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The issue is that spurious feedback occurs regardless on many/all of these inverters if they are connected to the grid, UL1741 cert or not. Anything synced up with the grid for either UPS mode, power assist or intentional backfeed, leaks a tiny bit back onto it. UL1741 protects with anti-islanding which pretty much just cuts power export on grid down.. but it would still likely export for a second or a fraction of a second anyway when the grid fails.. it's nearly impossible not to.
The power companies just want to make sure everybody bows down and kisses their butt, hoping the customer does not get anything that will cause them to gain any bit of power independence. Do they actually do anything different when doing line maintenance when they know there is a small permitted residential solar system in an area they are working on? I can't imagine they do. They probably check for lack of electricity as they always do, and proceed to do their work. If somebody gets zapped, it's probably because they skipped/rushed some necessary safety check they were supposed to do, be it on the line or their PPE.
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timselectric
If I can do it, you can do it.
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I don't have a diagram, but it's pretty simple.
The Dry contacts control the relay. And the relay controls the AC feeding the chargeverter.
dougbert
Solar Addict
my XW Pro contact provides 250mA @ 12v, that is why I do the 1st level Bosch relay, then the 2nd level SSR. Then I stay within limits
what are the limits with your contactor and your relay? which relay?
zanydroid
Solar Wizard
Ah, I see some slides showing growatts that can turn on their inverter while on utility power. Not sure how this can be marketed as an off grid inverter 
timselectric
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These are two different modes.
SBU keeps grid and inverter separate. (Either grid/ or inverter)
SUB runs the inverter in parallel with the grid. (Without battery) (Either grid and solar inverter/ or battery and solar inverter)
timselectric
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I don't mind the noise because it's rarely on.
And when it is, I am already annoyed about the fact that I am using grid. lol
Then he would have to replace it with https://us.growatt.com/products/spf-3500-5000-us
This model is specific to USA and have UL 1741 certification.
I solved this one when I first set my system up. I picked out 250 watts worth of load that never goes away and left it on the grid side. That amount eats anything that might get "leaked" by my tp6048. Its not supposed to but it won't matter if it did since that load is there all the time.
If you can't do that then chargeverters would be my go to method. Run on battery only and have the chargeverters come up with missing power as needed. It will take a few of them depending on how much you might need but it would work.
If you can't do that then chargeverters would be my go to method. Run on battery only and have the chargeverters come up with missing power as needed. It will take a few of them depending on how much you might need but it would work.
OffGridInTheCity
Solar Wizard
Wow. Getting on the power company radar can be difficult. I had a fly-by-night AC installation company swap out my 100a main panel with 200a as part of the central furnace/AC install and cut the meter tag and failed to get power company approval... After a while I got a notice and the power company required I trench and conduit out to the street due to the 200a to get my 'tag' back. Nightmare + expensive. This was 20yrs ago.
So early on (7 yrs ago) I went UL listed ATSs for off-grid with grid-assist. ATSs are mechanically linked relays and this prevents back feed to the grid from my solar powered inverters mechanically (no surprise electronics or settings) but default to grid when my solar power runs out. While this approach has it's challenges, I'm confident I'll stay off the power company radar.
So early on (7 yrs ago) I went UL listed ATSs for off-grid with grid-assist. ATSs are mechanically linked relays and this prevents back feed to the grid from my solar powered inverters mechanically (no surprise electronics or settings) but default to grid when my solar power runs out. While this approach has it's challenges, I'm confident I'll stay off the power company radar.
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