Utility company visited me for exporting from my solar Off-grid growatt LVM-ES SPF 3000TL

[automatikdonn]

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.

I have a static 1000 watt load and somehow mine still "leak"

 

[Crowz]

I have a static 1000 watt load and somehow mine still "leak"

Is that load on the grid side aka not connected to the inverter at all?

This is what I have
grid > 250w stuff > inverter > rest of the house

This wont work
grid > inverter > 250w stuff and rest of the house

 

[automatikdonn]

Is that load on the grid side aka not connected to the inverter at all?

This is what I have
grid > 250w stuff > inverter > rest of the house

This wont work
grid > inverter > 250w stuff and rest of the house

Yea you are right. It's load side, not grid side. I see what you are saying now.

 

[underdog5004]

Wow, this makes me a lot happier about my decision to use a chargeverter instead of conext 5548 charger to charge my batteries!

 

[hwy17]

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

I think if we're using isolating relays for SBU mode there would be a significant transfer time.

How everybody's getting away with it, I guess not all smart meters are as smart as these ones.

I have an AXR-SD, OP's is an AXRe-SD. I don't know what the difference is but maybe the AXRe is a net metering meter and OP's utility is using them for all customers.

 

[timselectric]

I think if we're using isolating relays for SBU mode there would be a significant transfer time.

10 ms in SBU mode.
I didn't even notice the lights blink.

SUB mode is mostly used for batteryless or small battery systems.

 

[dougbert]

Wow, this makes me a lot happier about my decision to use a chargeverter instead of conext 5548 charger to charge my batteries!

it really is a better model

most use the charger side of the inverter because.....it is there and they save the $500 of the CV, but frustration and issues are there. Well, for those of us who do not netmeter it works

those who netmeter need to get the grid contract anyway and the issue goes away

my PoCo grid circuit here for my service is at capacity and they are NOT allowing any new netmetering to that circuit

 

[zanydroid]

I think if we're using isolating relays for SBU mode there would be a significant transfer time.

The inverter could be kept pre-synchronized, in which case it would just be the time for the relay to flip.

 

[timselectric]

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.

1 chargeverter can provide approximately 120kwh in a day.
I would never need that much.

 

[AshleyL]

I think if we're using isolating relays for SBU mode there would be a significant transfer time.

How everybody's getting away with it, I guess not all smart meters are as smart as these ones.

I have an AXR-SD, OP's is an AXRe-SD. I don't know what the difference is but maybe the AXRe is a net metering meter and OP's utility is using them for all customers.

My grid provider is a bit special.
My utility smart meter registers the export as "consumption".
In the past when I still using Growatt MIN-TLX 4200 (a grid-tie inverter), I forgot to connect the RS485 cable to the Eastron SDM230 CT sensor for zero export.
I ended up exporting around 18kWh and my grid provider smart meter consumption reading increased by the same amount.
Meaning I am being charged for exporting.

 

[hwy17]

The inverter could be kept pre-synchronized, in which case it would just be the time for the relay to flip.

Interesting. I had never even considered any of these inverters might be isolating like that. How would they deal with overload in Solar or Battery mode then? Recognize it and transfer?

 

[timselectric]

Interesting. I had never even considered any of these inverters might be isolating like that. How would they deal with overload in Solar or Battery mode then? Recognize it and transfer?

Yes

 

[Skid]

Full idiot who has never had a solar grid connected house but possibly going this direction soon, but is something that could allow current to the house only in one direction, like a supersized diode?

 

[cs1234]

My grid provider is a bit special.
My utility smart meter registers the export as "consumption".
In the past when I still using Growatt MIN-TLX 4200 (a grid-tie inverter), I forgot to connect the RS485 cable to the Eastron SDM230 CT sensor for zero export.
I ended up exporting around 18kWh and my grid provider smart meter consumption reading increased by the same amount.
Meaning I am being charged for exporting.

That's better than them saying they are going to turn off your power.

 

[mciholas]

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

I'm surprised that isn't enough to directly control the SSRs and eliminate the failure prone mechanical relay.

Here is an AC SSRs that switches 40 amps and needs 4 volts and 15 mA to turn on:

RSS-TD1A140ZP

https://selec-product.s3.ap-south-1.amazonaws.com/Data+Sheet/Temperature+Controllers+/RSS-TD1A125ZP.pdf

$14.79 at DigiKey.

Mike C.

 

[dougbert]

I'm surprised that isn't enough to directly control the SSRs and eliminate the failure prone mechanical relay.

Here is an AC SSRs that switches 40 amps and needs 4 volts and 15 mA to turn on:

RSS-TD1A140ZP

https://selec-product.s3.ap-south-1.amazonaws.com/Data+Sheet/Temperature+Controllers+/RSS-TD1A125ZP.pdf

$14.79 at DigiKey.

Mike C.

thank you, I will revisit my implementation

always accepting new input

 

[hwy17]

Full idiot who has never had a solar grid connected house but possibly going this direction soon, but is something that could allow current to the house only in one direction, like a supersized diode?

Unfortunately no such thing as an AC diode.

 

[dougbert]

Unfortunately no such thing as an AC diode.

and Mr Fusion maker

 

[Crowz]

1 chargeverter can provide approximately 120kwh in a day.
I would never need that much.

I was referring to those with small battery banks and needing more than 100 amps to keep the batteries charged and power loads. How I started out with a single battery that wasn't hard to do

 

[dfw_dude]

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.

The 6000XP I'm using has the UL1741 cert, while I've only had my system online for a few weeks and very confident there's no reason to be on power companies radar, I do like knowing I Have a bit of buffer with the idea you described above.

I Have my 6000XP pushing it's output to 9 circuits in a transfer switch (8 single pole, 1 double pole) for all the main stuff in my house. Electric oven and central HVAC are still 100% grid though. Nice to know I won't be getting a nasty visit with my new system installed

 

[Crowz]

Just remember you need something that pulls constant to act as a sponge power wise. If the ac's blower is on that counts but a turned off stove and completely off hvac isn't going to help any.

 

[timselectric]

Full idiot who has never had a solar grid connected house but possibly going this direction soon, but is something that could allow current to the house only in one direction, like a supersized diode?

No
AC stands for Alternating Current.
Diodes can stop Current from flowing in one direction. (Turning it into DC)
Two Diodes in opposite directions would stop flow in both directions. But at that point it's just off.

 

[timselectric]

I was referring to those with small battery banks and needing more than 100 amps to keep the batteries charged and power loads. How I started out with a single battery that wasn't hard to do

I see.
At that point, you're better off leaving the loads on the grid.
And saving the small system for emergency use.

 

[kolek]

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.

I've been testing my Deye (maker of Sol-Ark & Sunsync) looking for ways to solve this problem. There's a setting:

System Work Mode > Work Mode1 > Zero export power

Default is 020.

If you set it to 100, it draws 100 watts continuous from the grid to suppress feedback.
I've found that by setting it to 200 watts, I'm not seeing any feedback.
I believe it's similar to what @Crowz is doing above.

Can't be 100% sure there's no feedback now, but if the display is to be trusted, feedback/exporting has stopped.

 

[ricardocello]

Can't be 100% sure there's no feedback now, but if the display is to be trusted, feedback/exporting has stopped.

Unless you have equipment to measure backfeed current with sufficient time resolution, you can't really be sure.
The new fancy digital utility meters apparently can detect even the briefest instant of feedback.

I have an EM530 Energy Meter watching at about 10Hz, which is at least 10 times faster than most others.
Here is what happens with my Victron ESS when my HVAC load turns off.

Victron ESS Response Time Measurement

Does the meter "turn backwards" for a split second? Only with the ESS running, verified. And in my case, it really does physically go backwards, I've been paranoid watching it.

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