Surprisingly short battery balancing period (still)

[gwatuk]

Just over a year ago I posted with the same title as this one (the balancing period then was 8 minutes).
Our car (SE SR) is now 16 months old and has almost always been charged with a granny charger.
The balancing period has always been less than 10 minutes.
Here's the latest:

I think this indicates that the battery is in good condition and it seems to me that slow charging is good for it. (Even though it is sometimes a bit inconvenient )

 

[decrep]

Probably varies with how long between balances.

 

[Martinonline]

@gwatuk, I've just re-read you original thread and no-one answered your question about detecting the end of balancing.

With my Trophy, the end of balancing can be sent when the charge port lights stop being green.

In the app, the end of balancing can be seen when the EV Management page shows 'Start Charging' in place of 'Finish Charging'.

Note that when the car reaches its set battery level, interrupting the charging appears to stop the balancing (based on my experience). I suspect this may include even minor interruptions.

Have you tried charging without having your sensor or any additional units in the circuit?

 

[EVentropy]

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@gwatuk
"Just over a year ago I posted with the same title as this one (the balancing period then was 8 minutes).
Our car (SE SR) is now 16 months old and has almost always been charged with a granny charger.
The balancing period has always been less than 10 minutes."........................


What is your delta when considered "balanced"? Balance is a delta achieved when factory considers the cells within a certain range for optimum life/efficiency of battery.
LiFePO4 well matched at manufacture, don't generally get out of any significant balance until reaching the current voltage "knee" at around 3.45V. Unless you have a problem cell.
Cutoff is when one cell reaches 3.65V. From 3.45 this happens relatively quickly as I have observed via Car Scanner. Charging stops or reduces when top cell reaches 3.65V, Balancing stops when delta reaches 120mV in my vehicle anyway. "Excite = SR SE"
My car has a primitive balancing regime compared with my boat batteries. As in I set the delta when balancing starts and charging stops and highest cell bring lowest cell up until reaching preset delta and charging resumes. This way "100%" SOC and capacity is higher. Bank stop charging when mean V ~ 3.5V, ~5% more than the MG4.
Edited as clumsily written.
My rationale anyways.....

 

[gazza487]

I haven’t had too much chance to do experiments (don’t have a home charger anymore long story) but my early SE SR after updating every module myself including the BMS spent an eternity balancing the battery 2+ hours then settled. Using work chargers now so can’t really see but it was interesting none the less.

 

[JimD]

My 22 plate MG5 is the same, and I've only ever used the granny charger at home as well (plus a few charges off 7kw fast chargers here and there).

 

[decrep]

here's my balancing period from today.

It's balancing during that squiggly section, just over 4 mins, but the last balance was only a few days ago. Had to top it up to 100% again because of a long trip tomorrow.
That funny section at the bottom is where I've switched from a 5min interval to a 5sec interval. It does show a drop from a 4kW charge to 0.5kW over the last 10min

 

[Chrisdriving]

I would hope a mere 16 month old battery would perform like this, my Leaf is over 9 years old and still balances out well with around a 10mV delta.
And the Leaf is known for not having the best battery anyway.
Not even bothered to look at my year old X Power yet.