Questions about Software limited batteries

[RLC3]

I have a 2017 MS 60D, and have some questions about how software limiting the battery is done, and what it really means..

1) Since the battery is actually a 75, how is the capacity reduced? I have heard two different stories about this. One, that a module is 'turned off', and that they do some sort of rotation (this makes less sense to me). The other that the battery is prevented from being fully charged. Do we know how it is done?

2) If the state of charge is what is limited, does this mean that it is fine to charge all the way to 100% regularly because it is really only 80%?

3) What about balancing? I gather this is pretty automatic, but I've seen descriptions of the balancing process that imply the battery needs to get to 93% charge to trigger balancing. Depending upon #1 above, this might never happen with the MS 60s. I would assume that Tesla thought of this and that it is being handled somehow, but does anyone know about this?

4) If the battery is charge state limited, does this mean that the capacity should stay at a full 60 rather than degrading, even though the battery may have lost some of its 75KWH of capacity?

 

[ucmndd]

1) there was a flurry of upgrades several months ago when the price was reduced to $2k. Someone charged their car to 100%, paid for the upgrade, and when it was done the car reported a SoC of 86%. So that’s pretty definitive IMO.

2) I won’t offer any opinion on if it’s “fine” to do so other than to say with the above information I’ve decided it is. I charge my 60 to 100% every time. As a data point, my car has 26,000 miles and has lost ~5% of its reported capacity (210mi when new to 200 now).

3) unknown.

4) my battery has degraded approx 5% in 25k miles. The software locked “60” does indeed degrade over time and appears to be some fixed percentage of overall battery capacity.

 

[Lex]

I always kinda envied the locked battery for this "feature" it was a neat offering, my 70 is also a product of the pre-Model 3 experimentation and I feel lucky for it. Hopefully locked battery doesn't make for bad habits down the road though.. for me, remembering to not charge 90%+ unless I'm be ready to use it right away is now built into me like a phobia

 

[Tam]

...I have heard two different stories about this....

Too complicated! The easiest way is just tell the software to charge to the capacity of 60 kWh battery instead of 75 kWh battery.

...2) If the state of charge is what is limited, does this mean that it is fine to charge all the way to 100% regularly because it is really only 80%?...

It makes sense to me.

...3) What about balancing?...

Tesla might write a different algorithm for software limited battery.

...4) If the battery is charge state limited, does this mean that the capacity should stay at a full 60 rather than degrading, even though the battery may have lost some of its 75KWH of capacity?

Tesla might write an algorithm so that when the actual 75 kWh battery is degraded, it would also put a cap on the 60 kWh capacity too.

For example, if not software limited, you would have 249 miles. it then degraded and the max you could get is 208 miles or a loss of 20%.

Tesla would write a program for your 60 kWh car but with the spec of 208 miles when brand new. After a while, the maximum would be 166 miles or a loss of 20%. But if you uncap it at that time, it would still be 208 miles and not artificially reduced to 166 miles.

 

[Lasttoy]

I've never seen a part number list of every battery pack from 60 to 100. I was told there only a few different packs. All KWs were controlled by software. That person worked in Fremont, he said there were not 5 different KW packs, just 2 now. The reason I asked was I wanted an upgrade to a 100kw pack. He said it is possible, but, not practical for cost. Tesla is charging like 30 to 40k for pack. My SC showed me it was 22k for new 85kw battery. Logic says, no manufacturer would have so many different battery platforms. Just cost too much.
I suspect, they will all be the same, we pay for what we want. OR, they just go to only 100kw.
I need a new battery pack. I know this will be a fight.