Multiplus not switching from absorption to float

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luphi asked Apr 4, '22

Multiplus not switching from absorption to float

Hello all,

I have a MultiPlus 12/2000/80 feeding a 3P4S EVE280 LiFePO4 battery configured as follows:

I expected, the Multi to switch to float latest 1h after reaching absorption state, but it didn't. It stood in absorption mode for the whole night until I unplugged the grid power

AC load: none

DC load: roughly 20W

Probably there is a good reason for that behaviour, I just want to understand so I can adjust the config. I don't want to keep the battery at 13.8V all time.

Any hint is much appreciated.

Cheers, luphi

multiplus ve.bus

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Answer 1 · 2022-04-04T15:34:00Z

Alexandra answered · Apr 04, 2022 at 03:34 PM

@luphi

Check if the batteries were actually kept at the 13.8v. do you have gx data?

What were the batteries drawing at this point?

If you are not using a bmv or smart shunt i would suggest doing so since you have a built bank.

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Answer 2 · 2022-04-04T17:03:03Z

luphi answered · Apr 04, 2022 at 05:03 PM

Hello Alexandra,

yes, GX data are available.

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Answer 3 · 2022-04-06T07:51:23Z

luphi answered · Apr 06, 2022 at 07:51 AM

no ideas?

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Alexandra ♦ commented · Apr 06, 2022 at 10:13 AM

@luphi

Battery voltage is not all that stable.

It may be a balancing issue?

What is set to be the battery monitor on the gx and is dvcc as @pwfarnell mentioned switched on? Any other programing on the inverter like ess?

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Answer 4 · 2022-04-06T09:42:20Z

pwfarnell answered · Apr 06, 2022 at 09:42 AM

I am not expert at this but wonder if you have DVCC parameters set up in the GX device or any link to the BMS controlling charge voltage. Just a thought.

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Answer 5 · 2022-04-06T12:29:23Z

luphi answered · Apr 06, 2022 at 12:29 PM

Battery monitor is the smart shunt

DVCC is on (see pics)

no other programming for the inverter

The BMS is connected only to monitor single cell voltage deviation

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Answer 6 · 2022-04-10T10:06:36Z

Stefanie (Victron Energy Staff) answered · Apr 10, 2022 at 10:06 AM

@luphi

You might want to check the DVCC manual Section 8.3 (DVCC effects on the charge algorithm - Battery).

If you think this applies to your installation, then it is absolutely normal that your MultiPlus will remain in absorption mode (voltage controlled) and never float, even though currents might be low or the battery might be full. Nothing to worry about.

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Answer 7 · 2022-04-11T07:20:47Z

Trevor Bird answered · Apr 11, 2022 at 07:20 AM

I am not sure why DVCC is switched “on”. You don’t seem to have any other charging sources that require control. Try turning DVCC off and see if the multi charger performs as you expect.

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Answer 8 · 2022-04-11T07:49:28Z

luphi answered · Apr 11, 2022 at 07:49 AM

Stefanie, trevor-bird,

thank you for your thoughts. I just disabled DVCC and started charging, let's see, how it goes.

The whole installation is for a camper van. It includes also an Orion 12/12-30 for charging from the alternator (of course not in parallel to the Multi) and also three SmartSolar 75/15 which are networked via VictronConnect App.

Cheers,

luphi

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