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njordan avatar image
njordan asked

Multiplus 3~ | 6x US2000 - AC coupled - DC charging Limit not as set....please help

Dear all,

i tried many things but at this point i would like to ask for help.

I have a 3 phase system of Multiplus2 3000VA that work per individual phase not in group. So each phase compensates itself via EM24 to zero Watt going out side. The PV Inverters are all AC coupled. So my MP2 work as intelligent Charger taking any power per phase that would go out of my house.

I set VDCC as follows:

1709459395677.png

In addition the MP2s are limited to the max of 32A, but i HOPE this means each of them is limited to 32Amps.

Else i could not find any place in VenusOS to set any limit. In Pylontech Menu i see the 150A limit as a parameter that anyhow cannot be changed.

My PV is rather small with 2500Wp, and varies per phase....

So like now i have 1200W on L2|| and 800W on L3|| and 200W on L1|| coming from PV.

On EM24 i see a Power of 400W going out of my house......on L2 i see a charging of arround 800W going to the Pylontechs, and on L3 i see also 800W going into Pylontechs...so overall its DC 50V / 30A......

Which of course is not as planned. I would have expected the 50A to be possible, so WHY does the L2 inverter not take all the 1200W??? going into my battery.

Is anyone here who can tell me PLEASE what i could have set wrong? or forgot to set at all.

Thanks a lot,

Norbert

charge current limit
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7 Answers
njordan avatar image
njordan answered ·

is there anyone able to help. i already tried to find something blocking in VEconfigure. but the only CHARGE-related page is limited by 35A...which is the limit of each MP2.

But i guess and hope that this does not mean that all 3 MP together are limited to 35A (together). my believe in engineering was that 3 MPs would charge back to the battery from AC via 3 times 35A......

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mjs500 avatar image
mjs500 answered ·

are you using GX device using an MK3-USB in between your 3 MPs and your GX device ?


GX device using an MK3-USB, are not controlled by DVCC and will charge and discharge according to the configuration made in those units.

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njordan avatar image njordan commented ·
Thanks for the reply. I'm using a VenusGX via EM23 smart meter + the three inverters connected via the BUS. not sure what you mean with the MK3 cable. I only used it for the configuration.
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mjs500 avatar image mjs500 njordan commented ·

not sure what you mean with the MK3 cable. I only used it for the configuration. good then is not the problem then

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Duivert NL avatar image
Duivert NL answered ·

hi, did you follow the manual on pylontech battery setup:

https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom

i have a similar setup but DVCC is forced on, so i can not adjust the charge limit

the pylontech's BMS control this

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njordan avatar image njordan commented ·

Thanks for the reply. YES i did check this page before/while i was configuring via VEconfig. My DVCC is also forced ON.


1709650480812.png

1709650519006.png

From Pylontech Parameters it should be 150A possible.

1709650718178.png


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1709650480812.png (26.1 KiB)
1709650718178.png (15.5 KiB)
Duivert NL avatar image Duivert NL njordan commented ·
ok that looks similar to mine, i have far more solar (9600W) and 15kW pylontech's but they also dont charge at max current, i think because the pylontech BMS controlls it

it's at max around 3000kW (60A)

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njordan avatar image njordan Duivert NL commented ·

yes but in my case it stops at ~32A, which is the max of a single inverter max charge current. But the current is split in between the MP2s, like it does not go ahead ~30A in total charging current.

Maybe worth mentioning, i'm not using MPPT controller, but all DC current is coming from the MP2s...and from the AC side.

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Duivert NL avatar image Duivert NL njordan commented ·

in the victron pylontech docs it says the same:

2. Minimum Battery Sizing Recommendations

Once DVCC is enabled on the GX device, the charge and discharge rates are managed by the Pylontech battery.

https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom

the pylontech won't charge at the maximum to keep the battery healthy, the higher the SOC the lower the charge current

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njordan avatar image
njordan answered ·

after some more reading, could it be related to battery temperature? its located in the basement and we have 17-19°C right now.

I could not find any chart, but maybe this is a reasoning? not sure if 6x US2000C could limit the charging current to "only" ~30A for that temp conditions....hard to believe but still try to make this understandable.

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Duivert NL avatar image Duivert NL commented ·
i dont think so, mine are in a lower temp 13-15 right now
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njordan avatar image
njordan answered ·

UPDATE:

I have an update that i do not understand and like as well. As soon as i change from "individual phase" to "total of all phase" the charging current goes up to 50Ams and the overal grid Power is almost zero, so nothing going out of my house.

For me its hard to understand and not believe that this is on purpose.

Why should a "inidivual phase" not take all available AC power per Phase and take all it can to the battery. Why should it stop at ~32Amps OVERALL current, not per inverter....


Strange, any place i can discuss with Victron directly to see if its really some situation that nobody had before, as not many use "individual phase".

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Duivert NL avatar image Duivert NL commented ·

info on it is here, you will find how it works, default setting is "total of all phases"

https://www.victronenergy.com/media/pg/Energy_Storage_System/en/multiphase-regulation---further-information.html#UUID-3b4a9fa7-d9e3-c1cc-8da3-924588a1e4ba

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njordan avatar image njordan Duivert NL commented ·

Thanks a lot for your link. I read it again, but still i do not see any other information than what i thought it would be.....

>>>> "Individual phase" mode selected

>>>> ESS balances the power of each separate phase to 0 W.

For me this means that each phase would take all available power that would go out of my house else. But this is not the case. works like mentioned as far as like 30Amps is not reached. but when reaching this "limit" the inverter do not DC charge anymore.....~30Amps is the overall DC current, so with 900W, 1200W on L2/L3 i'm FAR from the per inverter Amps limit.

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Duivert NL avatar image Duivert NL njordan commented ·

yes, but it also says this about individual phase:

Beware: using the system this way causes significant losses as power will flow from one AC phase to another via the DC connections. This incurs losses caused by converting from AC to DC on one phase, and then back again from DC to AC on the other phase.


so if you calculate your example, it maybe makes more sense?:

"So like now i have 1200W on L2|| and 800W on L3|| and 200W on L1|| coming from PV.

On EM24 i see a Power of 400W going out of my house......on L2 i see a charging of arround 800W going to the Pylontechs, and on L3 i see also 800W going into Pylontechs...so overall its DC 50V / 30A......"


L1 200W pv

L2 1200W pv

L3 800W pv

total is 2200W pv

house takes 400W

2200-400=1800W

you said it charged with around 800W+800W=1600W so that looks ok to me with the individual phase setting

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njordan avatar image
njordan answered ·

First i'm aware of single phase is not very much recommended, but i need to do so in my case to not balance over phases, even though it would be better for the inverters and everything......but still, it should work as its written that way in Victron Docs.s

Maybe for clarification:
My situation is like the following coming from the house AC side as PV

L1 200W
L2 1200W
L3 800W

on the grid total i see -300 to -400W....so not all is going into the battery

looking at the inverters i see:

L1 = 200W
L2 = 800W
L3 = 800W

on the Pylontech side i see 50V * ~30A...which would be the ~1800W / 30A
of course not talking about any losses.

So i'm far from the charging limit that would be possible.
if i say (total all phases) I see 50A easiliy.
BUT on individual phase it leaves part of the Watts unused going to the network, and this does not happen as long as i'm not close to the 30Amps. Never checked the exact breaking point but at maybe overall 1000W its no issue and the grid SUM is zero.
And the SOC is maybe at 70%, so far from absorption.

Maybe this explains it better.

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Alexandra avatar image Alexandra ♦ commented ·
Is the AC PV single phase as well or three phase?
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njordan avatar image
njordan answered ·

@mvader (Victron Energy)

maybe you can comment on this, please.

Summary:

* 3~ MP2-3000 (L1,L2,L3) - 6xUS2000C

* VenusGX on 3.22

* EM24 SmartMeter
* Single Phase Hoymiles 1600Wp on AC-IN side


If Phase compensation = Total ALL the DC charging current reaches 50Amps easily when PV is ON.

As soon as o choose Individual Phases (i know its more loss,....not recommended for that reason) the maximum possible DC charging is ~30/32Amps. Even though the power is split between two phases, meaning that each inverter only covers ~ 800W / 16Amps.


How can that be? Is this on purpose/bug?

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