Paralleled EG-4 6500EX on a 120V single phase system?

[zanydroid]

There is no "double negative" , whatever that means.
It's just two 120v inverters connected in series.
Each one provides 120v. And together, they provide 240v.

The 120V inverter have a common neutral. Let’s label these the top inverter and bottom inverter, corresponding to L1 and L2.

If you configured both inverters to output with no phase difference with each other, the L1 to L2 voltage is 0, this is the config that OP wants

You need to set a 180 degree phase difference to get split phase

BUT. The way the double negative comes into play is that the top and bottom inverters are not in series in the same direction. If they were in the same direction then the bottom inverter would be set to 0 degrees.

What would you configure the degree difference between inverters for two parallel 120v based on your notation?

In a Wye setup would you program the inverters to be 120 degrees apart or 30 degrees?

 

[apctjb]

SRNE makes some 5kW 120V units that can be stacked in parallel for 120V only or 120V / 240V

Had not heard of this brand but took a look and you are correct. Does EG4 make there own stuff or are they private labeling/repacking the electronics?

 

[zanydroid]

Had not heard of this brand but took a look and you are correct. Does EG4 make there own stuff or are they private labeling/repacking the electronics?

Private label + extra layer of support / local regulation handling.

EG, if there is a regulatory problem, EG4 has a slightly higher chance (they've filed paperwork/updated their processes in response to issues) to solve it than LuxPower (zero based on what I've seen on this forum, beyond getting the original listing certs).

 

[apctjb]

Your understanding of current flow is flawed.

No doubt, its flawed on most things these days. That said this is my understanding...

 

[zanydroid]

Notice how the bottom one goes - + and the top one goes + -

That was what I was trying to explain earlier.

Tim’s assumed measurement axis for his writeups (consistent across his post history on this forum) has + - on the bottom one.

No doubt, its flawed on most things these days. That said this is my understanding... View attachment 210728

 

[apctjb]

Private label + extra layer of support / local regulation handling.

Thanks, that is what I thought but not 100% sure.

 

[timselectric]

You need to set a 180 degree phase difference to get split phase.

Incorrect
If they were out of phase, any amount of degrees. They wouldn't be able to produce 240v , combined.

In a Wye setup would you program the inverters to be 120 degrees apart or 30 degrees?

A WYE system is 3-phase. (3 separate phases) the 3 phases are placed equally around a 360° axis of time. Which is why they are 120° of separation.

But that has nothing to do with this conversation.
We are only talking about a single phase.
A WYE system is 3 individual split-phase systems, with a common connection between the 3 neutrals.

 

[timselectric]

What would you configure the degree difference between inverters for two parallel 120v based on your notation?

There is noo degree difference.
They are connected in parallel.

 

[42OhmsPA]

Had not heard of this brand but took a look and you are correct. Does EG4 make there own stuff or are they private labeling/repacking the electronics?

Private label, lately Lux Power (which was a great move imo) prior Voltronic, Megarevo, maybe some others.
You do get US based support, it's seems to be getting much much better based on feedback here.

 

[zanydroid]

In a Wye setup would you program the inverters to be 120 degrees apart or 30 degrees?

For 120 degrees I believe all the inverter - will be connected to the neutral. For wye the other choices are confusing.

For split I believe either polarity is plausible to use

 

[zanydroid]

There is noo degree difference.
They are connected in parallel.

But if you say the two inverters are configured to 0 degrees, why does connecting the L1/L2 in 120/240V mode cause magic smoke?

 

[zanydroid]

Incorrect
If they were out of phase, any amount of degrees. They wouldn't be able to produce 240v , combined.

If you look at OP’s picture where both inverters have - output connected to neutral, does this still apply?

Anyway I think we both understand this and haven’t agreed before in other threads on the notation difference explaining why some people insist on 180 degrees so we can agree to disagree again

 

[timselectric]

No doubt, its flawed on most things these days. That said this is my understanding... View attachment 210728

That drawing is also incorrect.
The positive and negative markings are shown opposite of how they actually are.

 

[timselectric]

But if you say the two inverters are configured to 0 degrees, why does connecting the L1/L2 in 120/240V mode cause magic smoke?

That would be a dead short. (Which could cause "magic smoke")
But they are not at zero degrees (except for once every second)
They move through the full 360 degrees.

 

[zanydroid]

The positive and negative markings are shown opposite of how they actually are.

IMO this depends on how the inverters are connected and programmed. I don’t understand how your point of view on configuring phase angles generalizes to handle both split phase and wye configurations in the same 120V inverter

 

[timselectric]

If you look at OP’s picture where both inverters have - output connected to neutral, does this still apply?

Anyway I think we both understand this and haven’t agreed before in other threads on the notation difference explaining why some people insist on 180 degrees so we can agree to disagree again

That drawing is incorrect.

 

[zanydroid]

That would be a dead short. (Which could cause "magic smoke")
But they are not at zero degrees (except for once every second)
They move through the full 360 degrees.

OK, so what is the difference that causes no magic smoke in a proper parallel config to double 120V capacity?

(And I’m assuming the inverters are frequency synchronized)

 

[timselectric]

IMO this depends on how the inverters are connected and programmed. I don’t understand how your point of view on configuring phase angles generalizes to handle both split phase and wye configurations in the same 120V inverter

Let's try a simpler explanation.
If you place two 12v batteries in series.
You can still measure 12v at each battery. But together, you will measure 24v.
Multiply the voltage by 10, and reverse the current flow 60 times per second.
That is split-phase.

 

[timselectric]

OK, so what is the difference that causes no magic smoke in a proper parallel config to double 120V capacity?

I don't understand your question.

(And I’m assuming the inverters are frequency synchronized)

Always synchronized. (In perfect phase with each other)

 

[zanydroid]

I don't understand your question.

In two different configurations, you say it is 0 degrees.

(Config 1 - two in parallel, to give 120V)
(Config 2 - two in series, to give 120/240 or 240V)

There is something different in config 2, such that if you connect the hot terminals together, magic smoke goes out. If Config 1 and Config 2 are identical, giving identical 0 degree configuration will result in same behavior. But we know it is not the same, because they behave very differently

It should be because one of these configs will have one inverter flipped in the wiring.

 

[timselectric]

In two different configurations, you say it is 0 degrees.

0 degrees from each other.

(Config 1 - two in parallel, to give 120V)
(Config 2 - two in series, to give 120/240 or 240V)

Correct

There is something different in config 2, such that if you connect the hot terminals together, magic smoke goes out. If Config 1 and Config 2 are identical, giving identical 0 degree configuration will result in same behavior. But we know it is not the same, because they behave very differently

The only difference is in how they are connected together.
If you connect two ends of a power source , it's a dead short.
Same goes for two sources in series or parallel.

It should be because one of these configs will have one inverter flipped in the wiring.

Yes, the connections are different for series and parallel.
Just like every other power source. (Batteries and solar panels, for instance)

 

[zanydroid]

OK, so in the series split-phase configuration, if the inverter manufacturer insists on measuring voltage and interpreting configuration settings with the - probe at neutral, I feel we should follow their terminology and call one of those 0 degrees and one of those 180 degrees. (EG V1 = L1 - N, V2 = L2 - N). Otherwise stuff will not work. (I've been trying to find an example EG from victron on how they interpret this, but I was not able to in the allotted time).

If the inverter manufacturer insists on measuring / interpreting the settings the same direction on both legs (EG V1 = L1 - N, V2 = N - L2) then it should be 0 degrees.

What would you call (series or parallel) a split-phase inverter that can be configured in either L1/L2/N, or L1/L1/N (120V) mode, without changing any wiring inside the inverter (and it may not even be possible to change if the neutrals are bonded together on a busbar and can't be swapped). I'd prefer to refer to one of the inverters as configured in 0 degree mode for 120V and 180 degree mode for split phase because we have not done any physical rearranging of how the inverters are wired up.

 

[timselectric]

OK, so in the series split-phase configuration, if the inverter manufacturer insists on measuring voltage and interpreting configuration settings with the - probe at neutral, I feel we should follow their terminology and call one of those 0 degrees and one of those 180 degrees. (EG V1 = L1 - N, V2 = L2 - N). Otherwise stuff will not work. (I've been trying to find an example EG from victron on how they interpret this, but I was not able to in the allotted time).

If the inverter manufacturer insists on measuring / interpreting the settings the same direction on both legs (EG V1 = L1 - N, V2 = N - L2) then it should be 0 degrees.

What would you call (series or parallel) a split-phase inverter that can be configured in either L1/L2/N, or L1/L1/N (120V) mode, without changing any wiring inside the inverter (and it may not even be possible to change if the neutrals are bonded together on a busbar and can't be swapped). I'd prefer to refer to one of the inverters as configured in 0 degree mode for 120V and 180 degree mode for split phase because we have not done any physical rearranging of how the inverters are wired up.

You can call it anything you want. (And would be wrong)
I'm just trying to help you (and anyone else reading) understand what it is, and should be called.
Split-phase is really simple.
But for some reason people try to over complicate things.

 

[zanydroid]

You can call it anything you want. (And would be wrong)
I'm just trying to help you (and anyone else reading) understand what it is, and should be called.
Split-phase is really simple.
But for some reason people try to over complicate things.

The reference you've sent out on YouTube I believe is clear about the measurement polarity of the probes (if he doesn't say it explicitly, it can be seen with how he puts them on the lines). I'm not sure why that measurement direction is better than the other one.

I think it's super helpful for people to know that the 180 degree viewpoint merely happens because the measurement or programming polarity is flipped. And then they can move on / understand it more deeply.

And I think even if programming is "wrong" on how an inverter interprets the phase angle configured into it, you have to enter it wrong too to match.

 

[timselectric]

The reference you've sent out on YouTube I believe is clear about the measurement polarity of the probes (if he doesn't say it explicitly, it can be seen with how he puts them on the lines). I'm not sure why that measurement direction is better than the other one.

I think it's super helpful for people to know that the 180 degree viewpoint merely happens because the measurement polarity is flipped. And then they can move on / understand it more deeply.

I don't mention that, because it just confuses people more.
Unless someone brings up using a scope.
This is the only time that how measuring leads are connected, matters.
A scope is the only time that an individual half cycle is displayed on a screen.