Battery balancing

[barry7153]

Apologies to those who have answered this question previously on other threads, but is it true to say that every time you home charge, regardless of percentage you charge to, the battery always balances IE no need to charge to 100% every now and again unless having used fast charger regularly?

 

[Archev]

Apologies to those who have answered this question previously on other threads, but is it true to say that every time you home charge, regardless of percentage you charge to, the battery always balances IE no need to charge to 100% every now and again unless having used fast charger regularly?

Interesting- i thought we were supposed to periodically cover the whole charging spectrum from below 10% to the full 100% and leave it connected for a wee while to allow the car to “see” the entire charge it was required to cover.

 

[hojnikb]

Balancing starts at the desired end charge SOC (ie slider that limits % charge) on NMC cars and only at 100% on LFP cars.

This is why it's recommended to periodically charge LFP cars to 100%, so they get a chance to balance.

 

[Anon70]

I have noticed balancing behaviour at 80%, but not all cells will try to charge to full capacity at this level. So the only way to balance all cells is to set the level to 100% as all cells will try to reach the max charge state.

 

[MattyS]

I usually charge from around 30% to 80% for normal days to day usage. After the car says it's completed, the EVSE ( a Zappi in my case) will continue saying "charging" using between 100 and 300 watts or so for anything upto an hour and then will say charge is complete. My battery is NMC 64KW.

 

[Archev]

I have noticed balancing behaviour at 80%, but not all cells will try to charge to full capacity at this level. So the only way to balance all cells is to set the level to 100% as all cells will try to reach the max charge state.

That’s certainly how I understand it.

 

[Tuareg]

RTUM - page 176

 

[TerryN]

Interesting- i thought we were supposed to periodically cover the whole charging spectrum from below 10% to the full 100% and leave it connected for a wee while to allow the car to “see” the entire charge it was required to cover.

That's a different thing. That is done in order to (re)calibrate the Battery Management System so it sees both the beginning and end of the charge curve. This should help with the accuracy of the GOM.

 

[Dogsmuck]

My screen says “Connect the charging cable” even when I have just charged to 100% and left the car to battery balance. Doe anyone know if this indicates anything?

 

[siteguru]

It indicates that this is the default message that is shown all the time, except when the charge cable is actually connected.

 

[MattyS]

Yup

 

[ReintjeWA]

My screen says “Connect the charging cable” even when I have just charged to 100% and left the car to battery balance. Doe anyone know if this indicates anything?

Yeah that’s just bad wording really, it means the car is ready to receive a charging cable if you wish to do so.

 

[tsedge]

General battery recommendations are:

All cars:

• Discharge to 10% and then charge to 100% every 3-6 months (for calibration)
• If leaving the car unused for >1 month, disconnect 12V battery (to preserve it)

SR / LFP cars:

• Charge to 100% at least once a week (for balancing)

LR / NMC cars:

• Charge to 80% and keep between 20-80% day-to-day (for longevity)
• Charge to 100% at least once a month / as needed for trips (for balancing)
• Discharge to 50-80% if leaving the car for an extended period, e.g. holiday (for longevity)

The main thing that is actively "bad" is leaving an LR / NMC car with a high state of charge >80% for days or weeks on end.

However, the evidence is that even when people abuse the above, the batteries last much longer than the equivalent ICE engine, so it is debatable how much it matters.