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kiwi35 avatar image
kiwi35 asked

Multiplus in parallel + Pylontech battery = phantom charge.

Hello,

I have successfully setup parallel Multiplus : 48/5000/70 GX + 48/5000/70 (firmware 506, gw firmware 3.10) in ESS with BatteryLife
Problem appear that I have phantom charging that appears since 3 days... despite of discharging the battery (a little bit eg no less than 60%). Eg like pic 1A or 2A all the day when ESS is stopped.

Last night I had a battery overvoltage... which is bad and should not appends.

So :

- I didn't designed the thing like this. When I remove the paralell setup this never exist.

- Overvoltage... is not a good idea even I have setup the limit of charge of my pylontech to 52V on DVCC.

So I really like to see if there is a bug somewhere ? of if I can debug this to fix the problem.

Do you have any hints ... or is there any hardware issue I can debug ?

Regards

capture-decran-2023-10-06-a-193434.png

ESSPylontechmultiplus in parallel
capture-decran-2023-10-06-a-193434.png (52.0 KiB)
3 comments
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iammotorhomeless avatar image iammotorhomeless commented ·

@kiwi35 what size is your battery. ?

with two Multiplus 48/5000, you can now push a lot more power into it, you might need to lower your max charge Amps


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kiwi35 avatar image kiwi35 iammotorhomeless commented ·

@IamMotorHomeless Battery size is 8 US2000C. Aka 19kWh.

The problem is not the power of charging (that is scheduled on the night), is the fact, like screen shot, it continue to charge (low power between 40W up to 200W) when it should not... Not on some days (well I know the Pylontech BMS ask some charges sometimes) but EVERY days...


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iammotorhomeless avatar image iammotorhomeless kiwi35 commented ·

@kiwi35 umm, 19kWh that should take anything, so don't know why you are getting Overvoltage alarms. I was getting them when I only had 8kWh but it stopped when I added another 8, to 16kWh BYD

and the charge... this might sound mad, but I get a 5W up to 40W... but it's not real, it's just ghosting from the grid fluctuation.
have you tried a clamp meter to see if it is really charging
this is a known issue with paralleling MP 2's
I can't find the post I was looking for, but if you search for "cannot reach ZERO consumption", you might find some helpful stuff.


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8 Answers
Thierry Cortassa (Victron Energy Staff) avatar image
Thierry Cortassa (Victron Energy Staff) answered ·

after adjusted some parameter and swap the master/slave (there's a smal ardware difference betwen both multiplus), it's look working corectly now, we wait more few days to confirm and closed the problem !

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Alexandra avatar image
Alexandra answered ·

@kiwi35

On new installs alot of lithium batteries (pylon) included get high voltage warnings. It is like this until the cells settle down.

load on VRM advanced the BMS CVL and DCL widget and the cell low and cell high widget and keep an eye on it there.

It is usually recommend to keep them charged at 100% for a few days first to let balancing work.

This issue on pylontec is made worse when the system does not have the minimum required battery bank size for the install.

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kiwi35 avatar image
kiwi35 answered ·

Well problem is the batteries are not "new"... they have been installed about 5 months before when the system was not configured with parallel Multiplus. Since this new setup I have 1A to 2A coming from grid that charge the battery all the time (except when there is solar outside, see pic on the original post).
So I suspect some hidden problem somewhere ...

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kiwi35 avatar image
kiwi35 answered ·

@Alexandra Do you have another idea? Or the best should be I totally "factory" reset all Multiplus/Multiplus-GX (and even the GX inside) to rome some ersatz of some parameters?

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justinford avatar image
justinford answered ·

Is the high voltage referring to the battery overall or possibly just a cell over voltage in the system.


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kiwi35 avatar image
kiwi35 answered ·

Problem has been fixed by @Thierry Cortassa (Victron Energy Staff) ! Many thanks for his precious help !

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marv2097 avatar image
marv2097 answered ·

I have been watching this as I think i have a similar issue with parallel multi's:
https://community.victronenergy.com/questions/240839/ess-power-not-balanced-in-parallell-multiplus-ii-s.html


@kiwi35 @Thierry Cortassa (Victron Energy Staff) Is this something that can be checked/fixed via Ve Configure or does it require more access to inner workings of the Multi?

Thanks

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kiwi35 avatar image
kiwi35 answered ·

@Thierry Cortassa (Victron Energy Staff) Seems the fix you made make me reinject 1000W into grid now... :(
Maybe we should invert slave/master?

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