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juniorpv asked

Strange Multiplus 2 48/3000 behavior out of the blue

I use a Multiplus 2 48/3000 with Cerbo GX and separate Li-Ion Battery, integrated via JK-BMS and control the system with Node-RED (Large OS).

While programming the control loop since 4 weeks (and optimizing) all was smooth (despite when I did wrong coding) ;-) .1708703239175.png

However 4 days ago, out of the blue, the MP2 started to discharge the battery at full speed (as per MP2 unit config with 2.400 W). No idea why, and it took me a while to stop: Basically switched off.

In the meantime it happened 3 times again. No idea how and why, always after full charge, however not at peek, somehow delayed.

The node "Input power phase 1 (W)" "fires" the power out, I learnd to stop it by "VE Bus Reset" with "1".

I tried to implement a kind of "emergency break" using "VE.Bus Reset". Monitoring the output power and when above 2.350 W to send "1", during normal operation a "0" (as number) to "VE.Bus Reset". The result was a "not really working loop"/minutes between data flows.

1708703307895.png

Any idea why the Cerbo GX / MP2 get's the hick up ?

I use >ESS< with "Ext.Stg.", however I wonder why MP2 shows status messages "Bulk/Float".

Any idea to help circle the topic is welcome.


Multiplus-IIcerbo gxNode-RED
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2 Answers
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juniorpv answered ·

Okay, I found a workaround, but not solved the issue.

1. Fault description::

1708783950734.png

"Out of the blue", MP2 starts discharging (orange line) - at full power - in to the grid (green line).

2. First attempt to solve: In above function node "Notbremse P > = 2.350 W " I was writing "02 to "VE.Bus Reset", with the result of lagging a proper data flow:1708784404345.png

As can be seen by the dotted values.

3. Then I changed "0" to "null". 1708784498693.pngNow I get error messages.Which might be anoying to the system, but it's working:

2024-02-24-1526-3069.jpg

The payload changes from null to "1" and VE.Bus get's a reset.

Okay, I fixed it, but I'd love to know the root cause, why MP2 "goes wild".


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juniorpv answered ·

Topic solved, I assume. Evenso I control MP2 via Cerbo GX setting "external Control", MP2 basic setting (VE Configure 3) takes at some point control.

I missed the point to set "Float voltage" equal to "Absoption voltage" (under Charger) to same value, using Li-Ion battery.

Hopefully I did right for now ;-)


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