question

bella-luna-i avatar image
bella-luna-i asked

Lithium cell imbalance

Hello,

We had Victron equipment intalled May 2022 on our s/v. Quattro 5000W 12v, 5 LiFePO4 lithium 200Ah battries in parallel, Lynx power in and distributor, Lynx smart BMS 500, Cerbo GX, Digital multi control, solar controllers, Orion DC-DC Chargers. We have charged/discharged a number of times, all good until a month ago. When we unplug from shore power (plugged for 2-3 days at a time), with SOC at 100 and all batteries balanced, we soon get 1 or 2 batteries imbalanced. One was showing 3.33V, 3.32V, 3.31V, 3.32V. One other one was showing all cells at 3.32V with Cell status Imbalance in Victron Connect (strange?). Today, only one imballance, but all cells at 3.31V…. When we go back to shore power, all comes back ok.

When I read the manual, section 5.3.2, I don’t see any of the 4 conditions met

https://www.victronenergy.com/media/pg/Lithium_Battery_Smart/en/operation.html

Should I worry?

Thank you

Lithium Battery
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

3 Answers
Stefanie (Victron Energy Staff) avatar image
Stefanie (Victron Energy Staff) answered ·

@Bella Luna I

3.33V versus 3.31V is nothing to worry about. That's well within limits (>50mV I would call unbalanced).

About cell status "Imbalance": It's rather a warning to make sure you have them fully charged at least once every 30 days and let them absorb for the time set in the Lynx Smart BMS (usually 2 hours). Then this warning will change into Balanced. Last full charge in VictronConnect for the battery will tell you when it was fully charged the last time.

I'm not sure what shore power could have to do with this other than the Multi then fully charges the battery when shore power is available. The MPPTs don't seem to be able to do that.

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

baxter avatar image
baxter answered ·

Thats not an imbalance. You can only tell something about cell balance when charging over 3,4V (or under roughly 3V)

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

bella-luna-i avatar image
bella-luna-i answered ·

Thank you both.

I would just hope that VictronConnect doesn’t show imbalanced if its not! It gets us worried for no reason.

Maybe after a 30 days full charging, it would be time to display another status as warning.

Thanks

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Related Resources