My battery voltage seems to have a problem

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julie-pujol asked Feb 28, '24

My battery voltage seems to have a problem

Hello,

I have a full Victron Energy set up by a pro on my van with a lithium 12V/330ah battery with a Multiplus Compact 12v/2000va/80-30, a 300w solar panel (and the bms, mppt, battery protects ect). This setup is 1y and half old in a French climate (0 to 40 degrees).

I tried my best to understand everything happening, but the battery voltage seems to have a problem.
In winter, the voltage gets low very fast while I didn't use that many amps.
For exemple this morning it was wired on a charging station until 9am, so it was completely full with 13.4V, then I used around 200wh during around 3 hours, and at midday I used only 53ah but my voltage is 12.9V and still getting lower and lower.
I know that the voltage will get below 12V so I will have to charge it again, whereas there is more than 60% of the amps remaining.

Is it a normal behaviour?

If you need any further information, feel free to ask.

Thank you. :)

voltage drop

screenshot-2024-02-27-12-45-11-690-comvictronenerg.jpg (71.6 KiB)

screenshot-2024-02-27-12-45-53-330-comvictronenerg.jpg (88.7 KiB)

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Answer 1 · 2024-02-28T10:00:50Z

Alwin Schulze answered · Feb 28 at 10:00 AM

Could you show the settings of the shunt? Maybe there is something false.

I asume, the battery is not really charged up when shown full in the shunt.

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Answer 2 · 2024-02-28T10:23:47Z

klim8skeptic answered · Feb 28 at 10:23 AM

@Julie Pujol For exemple this morning it was wired on a charging station until 9am, so it was completely full with 13.4V,

Not completely full. The only time your battery is completely full is when it has spent enough time at the absorption voltage of 14.2v, and Victron Connect indicates your battery is balanced.

You need to fully charge your battery post haste.

Then share your SmartShunt settings/Multi settings/mppt settings. (Multi and mppt should be set to Victron default Lithium settings)

vc-batt-status.png (325.7 KiB)

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Answer 3 · 2024-02-28T11:21:52Z

julie-pujol answered · Feb 28 at 11:21 AM

So it means that even if my battery has all its amps, if the voltage didn't get to 14.2V, it's not fully charged right?
But still it feels that the voltage gets low very fast, I mean, if my voltage goes to 13.3v, is it normal for it to go under 12V at the end of the day while I don't the battery that much?

My shunt settings:

mppt settings :

battery settings:

and the multiplus:

screenshot-2024-02-28-12-04-47-222-comvictronenerg.jpg (110.9 KiB)

screenshot-2024-02-28-12-05-35-903-comvictronenerg.jpg (102.5 KiB)

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screenshot-2024-02-28-12-08-23-095-comvictronenerg.jpg (84.3 KiB)

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klim8skeptic ♦ commented · Feb 28 at 12:30 PM

@Julie Pujol @Bluepowershop if my voltage goes to 13.3v, is it normal for it to go under 12V at the end of the day

Again, if your battery has not been fully charged to 14,2v and VC has reported "balanced" your batteries are not fully charged.

Your "charged voltage" setting 13,2V in the SmartShunt is to low, so your SmartShunt synchronizes to early.
Set this value to 14V (or 0,2V below absorption) for a correct SOC.

Correct. The Shunt "charged voltage" has to be about 14v

Hereafter charge the battery fully (do not look at the SOC) by charging until the charge current is almost 0A

The Shunt "tail current" should be between 2-4% for reliable synchronization to 100% Soc. 2% for batteries with small charge currents, 4% for batteries with larger charge currents.

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Answer 4 · 2024-02-28T11:29:41Z

bluepowershop answered · Feb 28 at 11:29 AM

Your "charged voltage" setting 13,2V in the SmartShunt is to low, so your SmartShunt synchronizes to early.
Set this value to 14V (or 0,2V below absorption) for a correct SOC.

Hereafter charge the battery fully (do not look at the SOC) by charging until the charge current is almost 0A

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bluepowershop commented · Feb 28 at 11:32 AM

For fully use of the battery also lower the discharge floor to 20%

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kevgermany ♦♦ bluepowershop commented · Feb 28 at 09:52 PM

This is only used for reporting/alarms.

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Answer 5 · 2024-03-15T13:17:15Z

julie-pujol answered · Mar 15 at 01:17 PM

I changed my settings as you all said, and after a few days of testing how it behaves, it seems much better. The voltage doesn't get low that quickly anymore. As I'm working from my van it's really a life changer, thank you all!

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