Battery inverter with controlable output

Polle

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Feb 9, 2021
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Hello,
I have been reading a lot on this forum and i am looking for a battery inverter with the possability to control the output power.
Because i already have a solar grid tie inverter (growatt, 3 phase 6kwp) i just need a battery inverter.
The goal is controle the outpus power of the inverter to load match so i have 0 usage from the grid.
i have a plc and communicate with my existing growatt inverter.
I also know the load at all times (in the house, used from grid or sent back to grid) so that way i can calculate how much the battery inverter needs to generate.
I can communicate through RS485, Can, or give a 0-10V signal, PWM, 4-20mA,...

The only big problem is that finding the battery inverter capable of doing this is not easy..

This one looks like a possability https://www.aliexpress.com/item/400...7#7559#56_668#3164#9976#773_668#3468#15607#32
But apparently no one figuted out how to communcate in a decent way. Also it looks like it is forbidden in belgium :)

I also saw this one: https://www.aliexpress.com/item/327...#7559#56_668#3164#9976#773_668#3468#15612#355
But not clear how it is possible to tell the inverter how much to output without the CT. (I want to control it myself, not via the CT)

Can anyone point me in the right direction, or even better, knows the solution for my problem?

Thanks!
 

Roland W

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Oct 9, 2017
Messages
106
But not clear how it is possible to tell the inverter how much to output without the CT. (I want to control it myself, not via the CT)
[/QUOTE]

Why would you want to control the output by yourself? An inverter with a CT is just designed to do what you want. No communication needed with wharhowever....

If you don't want the inverter to do it at certain times, then just cut the DC to the inverter when power is not needed using a timer switching a DC contactor...
 

Polle

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Feb 9, 2021
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But not clear how it is possible to tell the inverter how much to output without the CT. (I want to control it myself, not via the CT)

Why would you want to control the output by yourself? An inverter with a CT is just designed to do what you want. No communication needed with wharhowever....

If you don't want the inverter to do it at certain times, then just cut the DC to the inverter when power is not needed using a timer switching a DC contactor...
[/QUOTE]

well, i have a 3 phase system. (3x380V +N) so if i use the CT clamp, i can only compensate 1 phase..
As the "reversing power meters" are to be replaced by digital ones in belgium (in my home not yet, but i want to be ready when it is), i want to compensate all 3 phases..
I know i will probably need more than 1 inverter but that is not the question right now :)
 

Roland W

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Oct 9, 2017
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106
well, i have a 3 phase system. (3x380V +N) so if i use the CT clamp, i can only compensate 1 phase..
As the "reversing power meters" are to be replaced by digital ones in belgium (in my home not yet, but i want to be ready when it is), i want to compensate all 3 phases..
I know i will probably need more than 1 inverter but that is not the question right now :)

There are already several threads on the forum where people say exactly this with 3 phase systems. But there is absolutely no problem with zeroing out only one phase. Why do you think it would be?
Is somebody telling you that that would crash the grid or something? That is a myth, and the utility does not care. For the power provider there is no difference in one phase being zero while others have lets say 2000W draw, or one phase have 4000W draw (because you are cooking your chicken in the oven), while others 2000W. Its is the same imbalance. Grid imbalances are dealt on a much higher level.
There will no worker from your utility knock on your door because of that, same they will not send anyone when you switch on your cloths dryer.
When your house was built, the electrical company which made your installations was instructed to separate your circuits according estimated draw, by best practice and knowledge. But your 3 phases will always be out of balance as you never do things the same time. Those imbalances are equalizing out through all houses in your Neighborhood.
No need to get scared, and your phase will not be zero all day. Or will it :)
 

daromer

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Then 3 1phase inverters with ct clamps on each or 1x3phase inverter with a 3phase meter attached to it.

You dont need to controll it your self as such
 

Polle

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Feb 9, 2021
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Then 3 1phase inverters with ct clamps on each or 1x3phase inverter with a 3phase meter attached to it.

You dont need to controll it your self as such
Hello daromer,
Do you have a good sugestion what inverter and meter i need then?
 

daromer

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Most hybrid inverters can do it. i run the MPI 10kW from MPP for this basically. Though im not using the 0 feed function built in personally but controll it but thats due to other reasons. But i know many other people that have it and run an SDM630 to it.
But some people use the GTIL version but note that they aint legal in many places.
I think victron have units and Growatt to but never used them myself

Note that no matter what version or brand you buy you will have to have permit to install such a device. No matter if you feedback more than you use or not you have a device hooked up to grid that still need to follow proper functionality :)
 

Polle

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There are already several threads on the forum where people say exactly this with 3 phase systems. But there is absolutely no problem with zeroing out only one phase. Why do you think it would be?
Is somebody telling you that that would crash the grid or something? That is a myth, and the utility does not care. For the power provider there is no difference in one phase being zero while others have lets say 2000W draw, or one phase have 4000W draw (because you are cooking your chicken in the oven), while others 2000W. Its is the same imbalance. Grid imbalances are dealt on a much higher level.
There will no worker from your utility knock on your door because of that, same they will not send anyone when you switch on your cloths dryer.
When your house was built, the electrical company which made your installations was instructed to separate your circuits according estimated draw, by best practice and knowledge. But your 3 phases will always be out of balance as you never do things the same time. Those imbalances are equalizing out through all houses in your Neighborhood.
No need to get scared, and your phase will not be zero all day. Or will it :)
I know that, if possible, i would buy a battery inverter capable of doing this but i just don't know which one is.
All inverters is see are MPPT ones, but i don't want to connect solar panels to it, only a battery to zero out. I know it is possible zeroing a 3 phase system on just 1 phase..
 

Polle

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Joined
Feb 9, 2021
Messages
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Most hybrid inverters can do it. i run the MPI 10kW from MPP for this basically. Though im not using the 0 feed function built in personally but controll it but thats due to other reasons. But i know many other people that have it and run an SDM630 to it.
But some people use the GTIL version but note that they aint legal in many places.
I think victron have units and Growatt to but never used them myself

Note that no matter what version or brand you buy you will have to have permit to install such a device. No matter if you feedback more than you use or not you have a device hooked up to grid that still need to follow proper functionality :)
the mpp solar looks nice but i am not going to connect the solar panels to it because i want to place the battery and the inverter in another building. is that a problem? Will it work the way i want it? Also, my load and supply cable are the same.. I don't know if it is clear but what i mean is that i only have 1 cable (5G10mm²) from my house to the place where the battery an inverter will be placed.
 

Roland W

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Oct 9, 2017
Messages
106
I know that, if possible, i would buy a battery inverter capable of doing this but i just don't know which one is.
All inverters is see are MPPT ones, but i don't want to connect solar panels to it, only a battery to zero out. I know it is possible zeroing a 3 phase system on just 1 phase..

I only know those 2 inverters which you have linked already. I am using the SUN2000 and it works great. There is no 3-phase battery inverter like those for DIY to my knowledge.
 
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daromer

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Polle yes it would work then but its expensive for it. And still note you need approval for the devie you connect like that.
 
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