southsideph avatar image
southsideph asked

Multiplus Bulk Over Voltage - Cause resolved due to discovery of Multiplus feature

I have a Multiplus 12/1600/70-16 and recently I put it on mains charge as weather has not been good enough for solar charge and VRM is showing it pushing up to 16v in to a bank of two AGM batteries. I can't see any reason for this, any help would be appreciated. I don't know if this is temperature compensation error and now batteries have been damaged

Multiplus Config




MultiPlus Quattro Inverter Charger
1663166877776.png (26.4 KiB)
vrmerror1.png (49.1 KiB)
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klim8skeptic avatar image klim8skeptic ♦ commented ·
Multiplus charge current of 0amp.

What is driving the battery voltage up??

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southsideph avatar image southsideph klim8skeptic ♦ commented ·


I do not know I am trying to identify it does not make any sense.

Screen shot this morning I'm on the verge of scrapping my Victron installation as I can't risk any more batteries. The multiplus was in float, ignore the off this was because disconnected AC


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1663239127545.png (43.4 KiB)
southsideph avatar image southsideph commented ·

This was an earlier screenshot


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1663243558381.png (52.3 KiB)
klim8skeptic avatar image klim8skeptic ♦ southsideph commented ·
I am not seeing the multi doing any (harmful) charging in the above screen shots.

In the second pic, the multi has only briefly done an hours bulk charge on the 12 sep., bat voltage ok. Since then the multi has been on the "OFF" state.

In the above overview screenshot, the multi is in absorp, but only drawing 3w from the grid.

You notice your DC power bubble has a negative symbol in front of the figure? That is current going into your battery.

Where is that current coming from? Not the mppt's by the look. The Orions? Some previous battery chargers? Do you have the multi's trickle charge port hooked up?

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2 Answers
southsideph avatar image
southsideph answered ·

It Looks like the mystery of the over voltage has been resolved. The story so far is the Multiplus kept overvoltage charging, voltage was increasing to 16V+ volts on a 12V system.

The only reference I had was 16.2V is the standard equalisation voltage. Equalisation was disabled so I thought. there was no indication even VRM does not report the Multiplus as being in equalisation mode.

Further research identified there is a feature in the Multiplus, in that if you switch between On and Charge only without going to the off position first, this puts the Multiplus into automatic equalisation or forced absorption irrespective of any other settings- don't really understand this but seems this is the case.

Enter the Digital Multi Control (DMC) - This was fitted to enable switching between modes and adjusting the AC input current Grid/Shore/Generator. The other reason for the DMC was to be able to disable the inverter etc. when not required.

So because of the above feature, it seems i set the Multiplus into automatic equalisation by switching the DMC from ON to Charge Only, the only way to identify is an obscure flashing of a combination of LEDs.

Unfortunately this lesson has come at high price and voltage sensitive equipment

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marc-heide avatar image
marc-heide answered ·

do u have other equipement installed? maybe third party solar converter or something like that.

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southsideph avatar image southsideph commented ·
It is a complete Victron installation - Orion, 2 x 100/20 mppt, BMV712, Battery protect connected via PI running GX OS 2.89.

Batteries are Leoch AGM

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