question

Rasmus Mikkelsen avatar image
Rasmus Mikkelsen asked

Input current limit with dynamic ess

Hi all

I have a question about the input current limit. In my house, the input current from grid is fused with 3 25a fuses, one for each phase.

I'd like to avoid blowing those fuses, as they are not breakers. I have breakers for everything else after those 3 big fuses from grid.

This example as shown in the picture, I have set the input current limit to 25a in ve config, and no power assist (should I enable that?)

charging.jpg

You can see as an example here im charging batteries from grid (pulling 16a) when its cheap to use later.

But what happens if I apply another 10a load on the same L1 as inverter is on, could be vacuum cleaner. That fuse on L1 will most likely blow right ? I cant seem to limit the current the inverter wants to charge with, or did I miss something?


I want to try the dynamic ess thats why im curious on this (havnt tried beta) but from what I understand it will charge and discharge at any point duing the day. All my appliances are spread out on L1 L2 and L3 but, I could be unaware and tapping another 10a from L1 while system is charging from grid.

I hope you understand my confusion here :-) I guess im asking how the inverter will react to this, or will I blow the fuses not sure

/Rasmus


Edit: Now was a good example atm charging from grid, and wanted to cook dinner for later, but oven is on L1 aswell, will be pulling more than the 25a fuses. If I enable power assist, will multi supply that load ? Because it seems like all the load will be supplied from the grid when schedule charge is on?

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1 Answer
Alexandra avatar image
Alexandra answered ·

@Rasmus Mikkelsen

The input current limit will always be obeyed.

You should set it so that the fuses incoming are 1.25 times the input current limit. So 20A for a 25A fuse/breaker.

Do not enable power assist. ESS manages that.

The system will power assist anything above the input current limit. It is a hard limit.

The inverter can add its own inverting power ability to the input current limit.

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Rasmus Mikkelsen avatar image Rasmus Mikkelsen commented ·

Hi @Alexandra

Again thank you very much for your help and support here. I will change the limit to 20a, and see how it goes. But in your opinion I shouldnt worry about it then :-)

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Alexandra avatar image Alexandra ♦ Rasmus Mikkelsen commented ·
The one time I have seen the input current not obeyed is when there was a battery issue and it refused discharge as there was a (rather large) problem. You will see the system go into pass through though. You can always set an alarm.
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Rasmus Mikkelsen avatar image Rasmus Mikkelsen Alexandra ♦ commented ·

Hi @Alexandra thank you. I've testet a bit today, I set the input current limit to 20a like you said. Please see this picture when charging batteries from grid and charging car at the same time. Every load is beeing pulled from the grid.


Pulling 25.4a on L1, and im still kinda worried :-) Did not see inverter go into passthrough, I stopped pretty fast because I dont have a spare fuse hehe. I would expect what happens is inverter will supply load to car rightcurrent-limit.jpg

current limit.jpg

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current-limit.jpg (146.5 KiB)
current-limit.jpg (146.5 KiB)
Alexandra avatar image Alexandra ♦ Rasmus Mikkelsen commented ·

I am interested to know why the battery is only charging from L1 and L2+3 are not charging at all. If it was not charging then


Your AC loads are 2k and battery charging 3k.

If the other two phases were charging instead of the L1, then the AC load would be under the 20A limit.

What are you AC loads measured with?

Do all the inverters have ESS assistant configured and are all the input current limits on the inverters set to 20A?

What is the phase compensation set to?

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ronaldt avatar image ronaldt Alexandra ♦ commented ·

I am still a bit confused. As far as I can find out, the Input Current Limit is the input current measured at the Multiplus. And that is the one I can limit. But, as Rasmus, I have also a vacuum cleaner. And that adds up to the total current taken from the energy grid. So I would like the Multiplus look at the current from the grid where the EM540 is installed. Not all the power for the house goes via the Multiplus.

There is a way, I think.... You can set the Grid Setpoint. It will take (or give) the amount of energy from the grid specified. And that can be set on 20A. (actually on 20 * 230 = 4600W). But in a 3 phase system you can not set this per phase. Therefore it can not be used.
So is there a way to set the maximum current taken from the grid measured at the grid input (EM540)?

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