question

sean avatar image
sean asked

MPII "discharging" when charging

When AC load is less than PV, such that the surplus is correctly directed to charging, why isnt "bulk" shown ?

At the point of transition (from discharge to charge) "bulk" is correctly displayed, but only briefly displayed - as the PV surplus, and therefore the charge current increases "discharging" is displayed, rather than bulk.

If this is expected behaviour it seems rather anti logic. This screencap illustrates.

ESS
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7 Answers
Paul B avatar image
Paul B answered ·

On the battery the amps say -19 amps so it is discharging

have you got DC loads as well and a BMV connected.

please advise a full diagram of the units connected would help


also make sure its on the latest firmware as well

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sean avatar image sean commented ·

The battery is charging, I can positively assure you that it is charging.

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sean avatar image sean commented ·

Its charging ....

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sean avatar image
sean answered ·

Some context, and a rewording of the question.

Battery data is from an external BMS, the image shown is correct, current direction might mislead some - its charging.

Perhaps I could have asked - where is the discharge/bulk status displayed derived from ?

"Bulk" is correctly displayed briefly during the transition from discharge to charge - and discharge is correctly displayed when current is being drawn from the battery.

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Paul B avatar image
Paul B answered ·

Well the CCGX dose not think so as its showing on the display I would say, change the battery monitor to the multiplus II and see what happens.


maybe turn on DC Loads display in the CCGX and see if that helps you track it down


the numbers dont add up on the display, garbage in garbage out

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sean avatar image sean commented ·

Paul, there is no Victron battery monitor connected.

As per my previous comment, battery data is from an external BMS.

"Discharging" is correctly displayed when current is being drawn from the battery.

"bulk" is correctly displayed (briefly) when PV output exceeds the AC loads, but as the PV surplus increases, the charge current correctly increase, "discharging" is displayed.

Hence my, where is the displayed status derived from ?

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sean avatar image
sean answered ·

To illustrate that bulk is correctly shown at the point of transition from discharge to charge (here shown charging.


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sean avatar image
sean answered ·

Also, to illustrate how discharging is incorrectly shown as the charge rate is increased past the transition point.


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boekel avatar image
boekel answered ·

What BMS are you using? any chance the current sensor can be wired / mounted incorrectly?

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sean avatar image sean commented ·

WM4 - the shunt is correct.

The battery +/- might confuse some, but its correct - and the system is working as expected.

I'm just trying to identify what is controlling the absorb/discharging/bulk text display - it's more for factual correctness rather than incorrect system function.

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boekel avatar image boekel ♦ sean commented ·

the +/- is coming from your bms AFAIK

can you show a screenshot of the BMS page?

On ESS systems I don't look at what the Multi is displaying, usually it's Bulk, except when battery is almost full, than it's absorption.

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sean avatar image sean boekel ♦ commented ·

Yes, all of the battery data is coming from the BMS, I suspect the +/- is a red herring as "discharging" is correctly displayed during a discharge (and when it should be "bulk") - the bulk LED on the MP is lit, as you say, untill absorb.

Other than the state display being somewhat random the system is fully functional.

I'll have a look at the bus state log shortly.


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sean avatar image sean sean commented ·

How are you getting those nice neat screens shots of just the data ?

My bus data doesnt appear to reflect what the system is doing, as per the DC V/I data.

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boekel avatar image boekel ♦ sean commented ·

I just crop the images ;)
the graphs do show correct Voltage / Current and VE.bus state it seems!

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sean avatar image sean boekel ♦ commented ·

Ah good, I thought you were doing something smart with the images :-)

I would expect to see bus state as inverting to mirror the steady v drop - as opposed to bulk ?

Perhaps viewing on a screen larger than 4" might reveal what I appear to be overlooking.

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boekel avatar image boekel ♦ sean commented ·

AFAIK it only shows 'inverting' when AC-in is disconnected.

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saboken avatar image
saboken answered ·

screenshot-20221206-105413.pngIt's not a answer to this but mine is doing the same thing? plenty of surplus pv power but if you look at the bottom where it says 'MultiPlus-I| 12/3000/120-50 2x120V Discharging" when the battery shows charging this had been since day one. It might be a Firmware issue? The system is all Victron where possible. Except the batteries I have 2 Battle Born Game changers, 4 Rich solar 200 Watt 12v panels. 2 more on the way. The Victron hardware is a Multi plus II, 150/100 MPPT, a Lynx distributor and Shunt. A Cerbo GX 50.


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djsmiley avatar image djsmiley commented ·
Seems pretty fine?


PV provides 612W. 363W is going into the batteries, 227W into the inverter. Total is about the PV output... The Multiplus can't see where the power is coming from. So in terms of the Multiplus, power is provided by the DC bus, thus discharging.


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