Supercharger did not take to 100% SOC

[Eno Deb]

The balancing process runs to completion once it is triggered, regardless of charge level or usage. Crossing the 93% threshold allows the BMS to identify higher voltage cells and to bleed them to the level of the lower cells

I'm not convinced that this theory is true. It's all based on a single anecdotal observation on a Model S pack. But we don't know exactly if that is the only case where balancing is performed, and none of it may apply to the Model 3 pack which has a different architecture than the S. E.g. some people have theorized that the extra lines going from the BMS boards to the cells serve to measure cell voltage more accurately under load, which could be used for balancing. There are a number of known methods to continuously balance the pack at any SoC.

I have a hard time believing that Tesla would only balance when the pack level exceeds 93%, given that 90% is the default charge limit and many people will rarely or never charge higher.

 

[ℬête Noire]

Yep, same here. For whatever reason the model 3 takes more time to balance than my model S did. I think it took like 3 hours the other night!

Looking at my notifications from last night, I'd estimate it took close to 2hr on the L2 for that last stage. Yeah, it was 100% this morning (no idea about the "miles", didn't look).

 

[nagypite]

 

[ℬête Noire]

Yes, that is a very good description of what I was seeing. Near 1kWh and below for several minutes until the SC/car just gave up at 99%. Looking at my account history it was running below 60kW rate for 77 minutes (I guess my nap was longer than I thought).

The weirdest part was it moving backwards on the percentage (above 98, then falling to 97 for a bit before rising to 98 again) but that also squares if the BMS is choosing to maintain a fixed V charging input at a level that results in the "high" modules/cells discharging slightly because of the slightly higher voltage on the "low" cells and the BMS doesn't want to risk damaging the "low" cells.

Okay, this is very good & helpful news. This means the charging towards the top end, for the large jumps, will be faster if I take the time to force the car to balance the week prior (assuming the Model 3 falls out of balance much once it's in it).

 

[jdw]

I'm not convinced that this theory is true. It's all based on a single anecdotal observation on a Model S pack. But we don't know exactly if that is the only case where balancing is performed, and none of it may apply to the Model 3 pack which has a different architecture than the S. E.g. some people have theorized that the extra lines going from the BMS boards to the cells serve to measure cell voltage more accurately under load, which could be used for balancing. There are a number of known methods to continuously balance the pack at any SoC.

I have a hard time believing that Tesla would only balance when the pack level exceeds 93%, given that 90% is the default charge limit and many people will rarely or never charge higher.

It's based on people who have both dismantled and rebuilt battery packs (search for wk057's posts on the matter) and CAN bus data, although the model 3 could well be doing something different. The 93% number came from the original charging settings for the S.

Originally, the charging slider for the Model S was a switch that toggled between 93% and 100% (Daily and Trip if I recall). When Tesla went to a slider, they didn't seem to change the BMS threshold.

 

[NeverFollow]

First time taking battery to "full", only about 1500mi on odometer.
I set the limit all the way right and let the SC try take it to the ceiling.
It spent a very long time post 97%, actually dropped to 97 after reaching 98,
and then "bounced" like that between 99 and 98, before several minutes later stopping at 99% (on Distance it reads 307 miles).
Is it normal for it not to reach literal 100%?

Selecting 100% and never be able to reach it: This seems to be a good way to avoid to have to pay for overtime when using a supercharger.

Also abouthe 307 miles distance, this is based on your past driving style. See below video about GOM (Acronym for Guess-O-Meter)

I-Pace how to reset GoM

 

[Shock-On-T]

I waited until the Supercharger turned itself off. This was the SC's point of stopping, not mine. It disengaged and announced it had completed. Is there a way the change the Set Limit by explicit number? I mean without going 3rd party with Teslifi or similar tool? Just to make sure that isn't the issue, where I was unable to slide it to "100%".

I wanted to see where it thought it would stop, my understanding is that near full it starts work on balancing the different modules in the battery which doing so periodically is a good thing. Urban legend?

Of course as expected it took much longer during the top 30%, and progressively slower as it rose. You can see the rate ramping down (though I admit I napped most of the way through the 80's and 90's ).

It could just be a calibration error with the car having so little history.
Btw, according to legend, balancing occurs anytime over 92%, and you d9nt have to be connected to charger for balancing to occur.

 

[SomeJoe7777]

Also abouthe 307 miles distance, this is based on your past driving style.

Not on the Tesla vehicles it isn't. The battery meter is in rated miles, and has nothing to do with your driving style.

 

[TexasEV]

Selecting 100% and never be able to reach it: This seems to be a good way to avoid to have to pay for overtime when using a supercharger.

Also abouthe 307 miles distance, this is based on your past driving style. See below video about GOM (Acronym for Guess-O-Meter)

I-Pace how to reset GoM

Why post an I-pace video in response to a Tesla question? Tesla doesn’t have a guess-o-meter. It has an EPA rated-range-o-meter, which has nothing to do with your past driving.