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Growatt 12k passthrough

Yes it is a low frequency inverter. Ian was also wrong in his description of the inverter board putting out 240vac. It puts out 28vac at 60hz which is stepped up by the transformer. Xantrex/Schneider works the same way. While it is a fact that the transformer is indeed placed across the grid when in bypass mode(not a great thing), it's not a bad inverter when used off grid. I've been running the 8kw model for a year and a half without a single problem. It's been a trouble free, reliable inverter. No flickering lights. No stray AC voltage appearing on the solar panel frames or any of the other issues that plauge many of the other inverters on the market. Starts and runs everything I've thrown at it, and believe me I've tortured it. Spot welder, mig welder, table saw, mill, lathe etc., all while powering the entire house.

In Will's latest video about the new EG4 battery someone commented about this inverter and Ian's video. Will's reply was brutal and uncalled for, in my opinion. Telling someone their inverter is junk and that they should get a new one is easy to do when manufacturers give you everything for free. Not everyone can afford to drop $5k or more on the latest and greatest inverter that comes along. That comment severely lowered my opinion of Will as well.
 
Quattrohead said:
I used to respect Ian's cowboy style but I've lost it, it is obviously a low frequency inverter. It's high frequency because of the way it steps the voltage to the primary of the transformer and they all do that. Have any of you seen an engine run without a flywheel, it's as rough as fuck, stick a flywheel on it and it smooths right on out. A V6 will run smoother and a V8 will run even smoother still, equivalent of the amount of steps per cycle for the transformer drive. The way the growatt drives the transformer is the equivalent thing.

My bullshit detector ramped up when he started slagging off the luxpower unit and doing that iffy listing on his website, now he's slagging growatt because he doesn't sell them anymore. Nope off my vendor list.
Click to expand...
Watch this video, I think what happened is Growatt sold this as a low frequency inverter. Over time, Ian found he was getting requests for support for problems people were experiencing. He did some research and testing and found there were problems related to having the unit connected to grid. Watch the whole video, maybe then you might understand. This unit is fine in an off grid situation.

 
shopman said:
Yes it is a low frequency inverter.
Click to expand...
Read thru the comments on the video and found this:

Ok I own one.I just ran the experiment.Your missing the point.Even when u don't loose a leg when in bypass your inverter transformer is trying to balance the neighborhood transformer. What I just did is this.I put it in bypass mode without grid charging. With would be the same. But I don't charge from grid ever. Solar charging only.I took off all load from inverter. Inverter onIn bypass due to low battery.I had current on my grid neutral and hots....So this transformer is balancing in parallel with the pole transformer. Now being properly breakered for the wire will prevent damage. My biggest issue is thisnow I'm pulling power through my utility meter that I'm not using. I'm now paying for power my neighbor is using and so is he. This is absolutely unacceptable! The point of solar is to reduce my electric bill not pay for my neighbors when my batteries go low and it enters bypass mode.... I'm going to have to isolate the neutral somehow... I'm pissed.

It is an autotransformer.
 
It's both.
A low frequency inverter, and using the secondary of the transformer as an autotransformer for bypass.
 
timselectric said:
They work very well.
Just don't connect the grid to it. That's when it becomes a problem.
Click to expand...
Even then it is only a problem if you do not use the correct circuit breakers in the correct locations.
Yeah you can end up being the auto transformer for everyone on your pole pig but what Ian was saying is rather wrong.
 
Quattrohead said:
Even then it is only a problem if you do not use the correct circuit breakers in the correct locations.
Yeah you can end up being the auto transformer for everyone on your pole pig but what Ian was saying is rather wrong.
Click to expand...
Connecting to the grid brings two issues. Proper grounding and balancing the utility transformer.
Both can be delt with, but it's not in any manual. And requires some internal reconfiguration. ;)
 
timselectric said:
It's both.
A low frequency inverter, and using the secondary of the transformer as an autotransformer for bypass.
Click to expand...
It is a 240V HF single-phase inverter that uses an auto-transformer on the output to generate split phase.

1691970006821.png

I was confused by the transformer for a while too.
 
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timselectric said:
Just don't connect the grid to it. That's when it becomes a problem.
Click to expand...
While I am not a fan of the architecture of this, it may or may not be a problem when connected to the grid. However, the user needs to understand what it does and how it works in order to determine if it works well for them.
 
FilterGuy said:
It is a 240V HF single-phase inverter that uses an auto-transformer on the output to generate split phase.

View attachment 162609

I was confused by the transformer for a while too.
Click to expand...
Where did you find this information? There is no neutral input terminal.
In a teardown video, I counted too many connections to the transformer to be an autotransformer in inverter mode. But it's definitely using the load side for pass through.
 
It is a wildly misunderstood inverter and in my opinion, unless people have one in front of them to derive their comments from, they should refrain from making misguided assumptions as to its operation. As Tim said, it can be reconfigured for safe use in bypass mode but that option should be left to those of us with extensive electrical and electronics knowledge which is the reason I will never detail that modification here. The only time the transformer functions as an auto transformer is in bypass mode as configured from the factory.
 
I'm not an electrician, but I am an electrical engineer, and I find it hard to believe that it meets code to connect the neutral of the output circuit to the neutral of another (what someone should assume IMO) independent circuit. Also, a transformer has an input and an output, both figures above seem to be assuming the neutral is connected to the input. I have to assume the neutral is on the output side of the transformer, so not connected to the input coil.

In any case, I appreciate not wanting to detail how someone might hack the internals of such a device, assuming that's what's required, but just saying "don't connect it to a grid", when the device is clearly intended to be connected to the grid doesn't seem much better. Not knowing exactly what the problem is, I don't know what information would do more help than potential harm, but if the product is unsafe in it's default configuration, used for it's intended purpose, and wired to code, then that should be spelled out in bold letters.
 
webbbn said:
I'm not an electrician, but I am an electrical engineer, and I find it hard to believe that it meets code to connect the neutral of the output circuit to the neutral of another (what someone should assume IMO) independent circuit. Also, a transformer has an input and an output, both figures above seem to be assuming the neutral is connected to the input. I have to assume the neutral is on the output side of the transformer, so not connected to the input coil.

In any case, I appreciate not wanting to detail how someone might hack the internals of such a device, assuming that's what's required, but just saying "don't connect it to a grid", when the device is clearly intended to be connected to the grid doesn't seem much better. Not knowing exactly what the problem is, I don't know what information would do more help than potential harm, but if the product is unsafe in it's default configuration, used for it's intended purpose, and wired to code, then that should be spelled out in bold letters.
Click to expand...
This unit does not meet code.
Which is why it's not UL listed.
 
webbbn said:
I'm not an electrician, but I am an electrical engineer, and I find it hard to believe that it meets code to connect the neutral of the output circuit to the neutral of another (what someone should assume IMO) independent circuit. Also, a transformer has an input and an output, both figures above seem to be assuming the neutral is connected to the input. I have to assume the neutral is on the output side of the transformer, so not connected to the input coil.

In any case, I appreciate not wanting to detail how someone might hack the internals of such a device, assuming that's what's required, but just saying "don't connect it to a grid", when the device is clearly intended to be connected to the grid doesn't seem much better. Not knowing exactly what the problem is, I don't know what information would do more help than potential harm, but if the product is unsafe in it's default configuration, used for it's intended purpose, and wired to code, then that should be spelled out in bold letters.
Click to expand...
Using a 3 pole automatic transfer switch would allow AC input where the neutral could be switched from grid to inverter output. There is a relay contact on the unit to control the transfer switch. https://diysolarforum.com/threads/growatt-12k-passthrough.37359/post-472116

If you go back to the beginning of this thread, you can see how this discussion progressed concerning this unit.
 
All this is rather surprising, but based on what I paid, I guess not... You get what you pay for with Growatt. So I have this unit and have been running it for over 2 years Solar/Battery/utility. In Ohio, you dont get good sun all year, so mainly in the winter months, it will goto bypass alot. I have not "seen" an issue, but that does not mean it's not there. I do have an electronics background, but that's not the same as Electrical engineering. I live in a rural area, where there's only 2 houses on the road. Transformer on the post coming into my house. Nobody else on it AFAIK. Not sure I would have an issue, but it's not clear to me how I would know.
 
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