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alan-falck asked

Multiplus II3kva re-boots for 60 seconds 10-15 minutes after grid failure

Multiplus II 48/3000/35-32

Software 2629481

Battery : 5,2 kva Hubble Lithium AM2


Hi, this Multiplus re boots for 60 seconds 10-15 minutes after grid failure, IE when grid resumes (load shedding). It does this every time (repeatable) over a 3 week period so far.

I have triple-checked the connectivity the grid, the loads, the neutral separation (critical & non-critical) insulation resistance etc.


Battery SOC is between 80 and 90%

FYI: two independent Victron installers have checked my settings

No alarms or errors reported

Any Ideas, thanks

Alan

TAB: General

System frequency 50Hz

Shore current 32.0 A

Overruled by remote checked

Dynamic current limiter unchecked

External current sensor connected (see manual) unchecked

State of charge when Bulk finished 95.0 %

Battery capacity 100 Ah

Charge efficiency 0.95

TAB: Grid

Country / grid code standard South Africa: NRS 097-2-1:2017

LOM detection AC input 1 Type B (grid code compliant)

Power ramp time 600 seconds

TAB: Inverter

PowerAssist unchecked

Inverter output voltage 230 V

State Of Charge shut-down 10.0 %

State Of Charge restart 20.0 %

Inverter DC shut-down voltage 44.00 V

Inverter DC restart voltage 45.00 V

Low DC alarm level 46.00 V

Do not restart after short-circuit (VDE 2510-2 safety) unchecked

enable AES unchecked

TAB: Charger

Enable charger checked

Weak AC input unchecked

Stop after excessive bulk unchecked

Lithium batteries checked

Charge curve Fixed

Absorption voltage 53.60 V

Float voltage 53.60 V

Charge current 35 A

Repeated absorption time 1.00 Hr

Repeated absorption interval 7.00 Days

Absorption time 1 Hr

TAB: Virtual switch

TAB: Usage

Virtual switch usage Do not use VS

TAB: Assistants

TAB: Assistant Configuration

Assistants not used

Multiplus-II
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9 Answers
nickdb avatar image
nickdb answered ·

Is the multi logging any alarms or error states?

What is the battery BMS reporting wrt DCL, CCL etc?

Presume you mean AM2 5.5kWh?

To add, does this behaviour continue if during times of stable grid supply, you manually drop the supply breakers? Helps to eliminate grid issues which can be plentiful after load shedding, when the grid is heavily loaded.

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nickdb avatar image
nickdb answered ·

Since you aren't using ESS, you could disable LOM.

The test I suggested would also clarify if it is external grid or not contributing.

You really need to check what the battery is reporting at this time via it's parameters/details tab.

There is not enough info here to help, some zoomed in charts of grid voltage/frequency, BMS min/max cell, DCL, CCL, Voltage and so forth might shed some light.

What is the state of the multi being logged - does it go into inverting at all?


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alan-falck avatar image
alan-falck answered ·

Hi Nick I've added some additional info to the original post.

I have not yet gotten access to the battery BMS, but the battery ran fine (for a month) on my 5Kva Multiplus before this install.

Yes, if I manually drop the grid for a longish (30 -45 min) period the behaviour is the same but does not reboot if I shut down the grid for just a few min. So it does seem time-related.

I have monitored the grid extensively after load shedding and it appears to be stable (nothing unusual) Thanks for the suggestions.


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nickdb avatar image nickdb ♦♦ commented ·
Is there anything attached to AC2 (geyser or such?) that could be kicking in with a surge after being off for a period of time?


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alan-falck avatar image alan-falck nickdb ♦♦ commented ·
No all heavy non-critical load are on another circuit
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alan-falck avatar image
alan-falck answered ·

rt-grid-monitoring-30-min.png (76.8 KiB)
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nickdb avatar image nickdb ♦♦ commented ·
Thanks, grid voltage a little on the higher side, not the end of the world.

Where are you gathering stats from? Do you have a GX and is the battery CAN bus attached?

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alan-falck avatar image alan-falck nickdb ♦♦ commented ·
Sorry I addressed this a bit further down the post (it's a Venus Pi setup). The mains/Grid monitoring is a third-party sensor & Log
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alan-falck answered ·

The Multi performs perfectly during mains failure, it inverts and supplies critical loads from the battery just fine. Battery current and voltages (manually measured) all look normal, It also switches back to the grid perfectly (60sec delay) after load shedding has ended. The battery recharges the used battery capacity without issues (at around 30A DC). When it reaches float status (or near float) or around 10 to 20 min it then reboots. This Multi does not have a CAN intrface.

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nickdb avatar image nickdb ♦♦ commented ·
Ordinarily you would want a smarter battery attached to a GX device which would enforce the battery limits communicated by the battery management.

In your setup the Multi has no clue what is happening in the battery, so it is quite likely that the BMS isn't happy or is asking the multi to charge less (for various reasons), eventually forcing it to intervene.

Personally I would never run a battery like this without using the BMS, a GX and DVCC to manage the charge/discharge.

Your settings seem ok, so since it sounds like a newer install, I suggest you consider implementing a GX and attach the CAN battery port to it. This would give you all the control and visibility you need to work out what is going on, assuming it doesn't outright resolve the behaviour.


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alan-falck avatar image alan-falck nickdb ♦♦ commented ·
Yes in hindsight not getting a GX with CAN was a mistake, I did however hope I would have stability with this very basic system
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alan-falck answered ·

I will receive a Victron Approved battery next week (Pylontech) and conduct further testing.

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nickdb avatar image nickdb ♦♦ commented ·
Cool, just remember a pylon also needs to be attached to a GX, all the supported lithiums do.
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alan-falck answered ·

I'm running Venus on a Pi on this install (a very tight budget system) using VE Bus to USB, I guess there is no way to use a CAN to USB adaptor? Or if CAN is supported over a Pi ?

Perhaps I best get a Cerbro

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nickdb avatar image nickdb ♦♦ commented ·
Unfortunately you will need a Cerbo or older venus if you can find one. I am fairly sure your issues will resolve once CAN and DVCC is enabled. Hubble themselves want this on in a victron ecosystem anyway.
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alan-falck answered ·

Thanks for the help and for reviewing my settings

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nickdb avatar image nickdb ♦♦ commented ·
No prob. Let me know how it turns out.
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alan-falck avatar image
alan-falck answered ·

Hi FYI after a firmware update to the Hubble AM2 Battery the inverter reboot (after Grid resume) problem went away.

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