Looking for an AC coupled battery inverter with output power control

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MrAlfabet

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Does anyone know of battery inverters that can feed back to the grid, but with a controlled output? I want to DIY control the power output so that my home energy meter stays at zero. Modbus / PWM / 0-10V, whatever. Preferably on the cheaper side. I've seen the Victron MultiPlus, but they're on the expensive side.
 
Yeah, it's called a hybrid inverter. They aren't cheap

There are some that are called "Grid-Tie Inverters" that are cheap, but they are not really to be trusted. And in some places, they are absolutely illegal to use, regardless if there's a feed-back tariff or not.
 
Korishan said:
Yeah, it's called a hybrid inverter. They aren't cheap
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I thought 'hybrid' meant you could couple both batteries and solar to the same inverter?
 
MrAlfabet said:
I thought 'hybrid' meant you could couple both batteries and solar to the same inverter?
Click to expand...

Some are, yeah. But not all.
 
That's probably a different version of the AIMS inverter. Are you wanting to back-feed the grid, or only supplement what comes into your home?

If "not" back-feeding, then most of them will work. They won't back-feed when the grid is offline, which is what you want.

If you want to feed back into the grid for tariff offset, then you need to get an inverter that can do that. And there are very few that can do that and they aren't cheap.
 
Korishan said:
That's probably a different version of the AIMS inverter. Are you wanting to back-feed the grid, or only supplement what comes into your home?

If "not" back-feeding, then most of them will work. They won't back-feed when the grid is offline, which is what you want.

If you want to feed back into the grid for tariff offset, then you need to get an inverter that can do that. And there are very few that can do that and they aren't cheap.
Click to expand...
I'm not going off-grid so I only want to back feed into an online grid, this is for an energy storage system. Storing cheap energy during the low hours (with a separate charger), using it grid-tied with an inverterduring the peak hours.
 
MrAlfabet said:
I'm not going off-grid so I only want to back feed into an online grid, this is for an energy storage system. Storing cheap energy during the low hours (with a separate charger), using it grid-tied with an inverterduring the peak hours.
Click to expand...

There is a difference between grid-tied and grid-tied, unfortunately. This can be very confusing.

First off, you say you want to feed back into the grid for energy storage. I'm not sure what you mean here. Are you meaning you are using the utility grid as a storage device and you send power back to the power company and get a reduction on your power bill. Then use that power during off-peak hours to get a cheaper rate?

Or are you meaning you will be merging battery storage with your in-house electric so that you use primarily battery and then have the utility grid to supplement anything above what the battery can handle surge or time wise?

If you are doing the first option, then options are limited. And you need to verify with your power company if they will accept that device. They can be very picky about what devices they allow on their network
If you are doing the second option, there is a lot more leeway here as there are plenty of inverters that will do this merger.

The inverter you posted from Aliexpress doesn't feed back into the grid. It just limits how much comes from the grid to be merged with battery/solar input. This is why I'm asking these questions because you said you want to back-feed, but at the same time you aren't. So this confusion needs to be cleared up before you go and purchase something you don't need.
 
First of and dont want to be grymou but do you got approval even to tid such a system in? IF not i highly recommend to do a subpnael instead and regular inverter....
 
Korishan said:
MrAlfabet said:
I'm not going off-grid so I only want to back feed into an online grid, this is for an energy storage system. Storing cheap energy during the low hours (with a separate charger), using it grid-tied with an inverterduring the peak hours.
Click to expand...

There is a difference between grid-tied and grid-tied, unfortunately. This can be very confusing.

First off, you say you want to feed back into the grid for energy storage. I'm not sure what you mean here. Are you meaning you are using the utility grid as a storage device and you send power back to the power company and get a reduction on your power bill. Then use that power during off-peak hours to get a cheaper rate?

Or are you meaning you will be merging battery storage with your in-house electric so that you use primarily battery and then have the utility grid to supplement anything above what the battery can handle surge or time wise?

If you are doing the first option, then options are limited. And you need to verify with your power company if they will accept that device. They can be very picky about what devices they allow on their network
If you are doing the second option, there is a lot more leeway here as there are plenty of inverters that will do this merger.

The inverter you posted from Aliexpress doesn't feed back into the grid. It just limits how much comes from the grid to be merged with battery/solar input. This is why I'm asking these questions because you said you want to back-feed, but at the same time you aren't. So this confusion needs to be cleared up before you go and purchase something you don't need.
Click to expand...
I'm sorry for not being more clear.
Right now I have solar panels with a solar inverter that feeds back into the grid all the power that is not used in the home. I'd like to store the excess energy, since I pay more for what I draw from the grid than I get for what I feed back into the grid.
Since I have 3 phase, it is very possible that I'm pulling power from 1 leg, wile the battery is feeding it back to the grid on another leg to keep the total at 0. Also since I'm doing this DIY, it might be possible that I or the algorithm I'm working on will DUCK up and actually feed power back to the grid (on total over 3 legs).
I'll give my power company a call to see what's allowed.
Maybe I've misread something, but the inverter link I posted is meant to keep the home energy meter at 0 (for 1 leg though). Could you explain to me how this is not 'feeding back into the grid'? I understand the intention is that the inverter output is always equal to (or lower than) the power usage in the home (on that leg), but if I'm controlling this manually, set it to 2000W, and only use 100W, am I not feeding back into the grid?

daromer said:
First of and dont want to be grymou but do you got approval even to tid such a system in? IF not i highly recommend to do a subpnael instead and regular inverter....
Click to expand...
Tesla powerwalls and Victron products are legal here. I'm trying to do the same, but DIY.
 
MrAlfabet said:
Maybe I've misread something, but the inverter link I posted is meant to keep the home energy meter at 0 (for 1 leg though). Could you explain to me how this is not 'feeding back into the grid'? I understand the intention is that the inverter output is always equal to (or lower than) the power usage in the home (on that leg), but if I'm controlling this manually, set it to 2000W, and only use 100W, am I not feeding back into the grid?
Click to expand...

Energy meter at 0. This is not feeding back into the utility grid. It's limiting how much is used "from" the utility grid. If your house uses 3000W, and you have 3000W of battery power, it will use the battery "before" it uses utility grid. But if your power requirements go above what the battery can give, it'll start to use the utility grid to supplement the battery.

An inverter voltage is always "higher" than utility grid. Otherwise it couldn't push power out. Think of two batteries, one at 10V and the other at 9V. The 10V will push into the 9V until they are balanced at 9.5V (actually less due to losses in heat). And as far as feed-back grid-tie inverter, the inverter would output to the utility at a slightly higher voltage to push power back up the line.
So house grid voltage would be slightly higher than utility grid if you were to measure before and after the inverter.
 
Korishan said:
MrAlfabet said:
Maybe I've misread something, but the inverter link I posted is meant to keep the home energy meter at 0 (for 1 leg though). Could you explain to me how this is not 'feeding back into the grid'? I understand the intention is that the inverter output is always equal to (or lower than) the power usage in the home (on that leg), but if I'm controlling this manually, set it to 2000W, and only use 100W, am I not feeding back into the grid?
Click to expand...

Energy meter at 0. This is not feeding back into the utility grid. It's limiting how much is used "from" the utility grid. If your house uses 3000W, and you have 3000W of battery power, it will use the battery "before" it uses utility grid. But if your power requirements go above what the battery can give, it'll start to use the utility grid to supplement the battery.
Click to expand...
Alright, but I'm assuming there's always a delay between the read value and the output. If i'm running my 2kW space heater, the inverter supplies 2kW, and I shut the heater off, will I not be (very briefly) feeding back into the grid?

Could you explain to me the difference in technology between the inverter I have (which feeds solar back into the grid) and the inverter I'm looking at?

The
 
MrAlfabet said:
Korishan said:
MrAlfabet said:
Maybe I've misread something, but the inverter link I posted is meant to keep the home energy meter at 0 (for 1 leg though). Could you explain to me how this is not 'feeding back into the grid'? I understand the intention is that the inverter output is always equal to (or lower than) the power usage in the home (on that leg), but if I'm controlling this manually, set it to 2000W, and only use 100W, am I not feeding back into the grid?
Click to expand...

Energy meter at 0. This is not feeding back into the utility grid. It's limiting how much is used "from" the utility grid. If your house uses 3000W, and you have 3000W of battery power, it will use the battery "before" it uses utility grid. But if your power requirements go above what the battery can give, it'll start to use the utility grid to supplement the battery.
Click to expand...
Alright, but I'm assuming there's always a delay between the read value and the output. If i'm running my 2kW space heater, the inverter supplies 2kW, and I shut the heater off, will I not be (very briefly) feeding back into the grid?

Could you explain to me the difference in technology between the inverter I have (which feeds solar back into the grid) and the inverter I'm looking at?

The
Click to expand...

Yes, there is a delay, on the order of milliseconds. So you wouldn't really see the changes unless you were using a 16-bit or better ADC monitoring changes.

I was updating my post when you replied so maybe the second paragraph partially answered your question.
The inverter you currently have pushes back out to the utility grid, so it's possible to get backward rolling on your power meter. ie means that the meter will actually count down, backwards, as excess power generated via Solar/Wind/Hydro is fed into the utility grid. A net 0 inverter is not "intended" to back-feed into the grid pushing the meter in reverse
 
Korishan said:
Yes, there is a delay, on the order of milliseconds. So you wouldn't really see the changes unless you were using a 16-bit or better ADC monitoring changes.

I was updating my post when you replied so maybe the second paragraph partially answered your question.
The inverter you currently have pushes back out to the utility grid, so it's possible to get backward rolling on your power meter. ie means that the meter will actually count down, backwards, as excess power generated via Solar/Wind/Hydro is fed into the utility grid. A net 0 inverter is not "intended" to back-feed into the grid pushing the meter in reverse
Click to expand...
Edit: Something went wrong when posting, let's try this again.

If I understand you correctly, the solar inverter (feeding back into the utility grid) creates a voltage higher than the utility grid. The battery/net-0 inverter creates a voltage equal to the grid (slightly higher than the outlet, but basically the same as the utility grid). What happens when I hook the amp-clamp of the net-0 meter up to the wrong leg? Or my algorithm fucks up and tells the inverter to deliver 2kW while I'm only using 1kW in my home? If I understand you correctly the net-0 inverter will then feed back into the utility grid. I get that that is not the intended use of a net-0 inverter, I'm just wondering if it breaks things. Is the power produced by my solar inverter 'cleaner' than the power produced by the/a battery inverter?
 
I would call the delay alot more than mS. I dont know how often they run the loop but i guess we talk about 100-500ms between cycles. So no you can not hide that you are doing this if you have somewhat new type of meter. They can sense it. No its not legal just because you are close to 0 ;)

If you hook the clamp wrong it can not sense what it should sense and it either dont do anything or it try to max it out. It should be on the hot leg going to grid.
 
daromer said:
I would call the delay alot more than mS. I dont know how often they run the loop but i guess we talk about 100-500ms between cycles. So no you can not hide that you are doing this if you have somewhat new type of meter. They can sense it. No its not legal just because you are close to 0 ;)

If you hook the clamp wrong it can not sense what it should sense and it either dont do anything or it try to max it out. It should be on the hot leg going to grid.
Click to expand...
If I am allowed to feed back to the grid with the solar inverter, am I not automatically allowed to do this as well with batteries? The energy company is not going to see adifference, right?
 
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