I hope it’s not “done” calibrating itself
because even at 250 rmi - it’s 5% degradation in < 12k miles.
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Mid Range Battery Math
- Thread starter hugh_jassol
- Start date
because even at 250 rmi - it’s 5% degradation in < 12k miles.
TimothyHW3
Active Member
What is the consensus on a brand new MR - 61-62kWh nominal full? I think you loose 2-3kWh in the beginning regardless, it just happens to be 5% on a smaller battery and 3% on the bigger one. I am also 2.5kWh down, but it is flunctuating between 2 and 2.5kWh after 15k miles, so I guess this is normal. I have seen some people gaining 3kWh over time, but who knows.I hope it’s not “done” calibrating itself
AlanSubie4Life
Efficiency Obsessed Member
62.5kWh before degradation shows. Probably starts closer to 63.5kWh in most cases:
2020, 2019, 2018 Model 3 Battery Capacities & Charging Constants
Yeah I don’t think 3-4 miles of recovery was what you were hoping for.
Honestly though, being at 59kWh after starting at 63kWh is actually pretty good for most vehicles of that vintage and number of cycles (about 50 cycles assuming 12k @ 250Wh/mi). That’s only a little over 6%. Hopefully it will stay pretty steady from here out! I’m in a similar situation - 52 cycles after 14 months, 14000 mi at 283Wh/mi, 73.5kWh, about 6% reduction from an initial ~78kWh (degrades to 76kWh before degradation actually shows on the display).
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TimothyHW3
Active Member
AlanSubie4Life
Efficiency Obsessed Member
14000mi*283Wh/mi = 3692kWh
3692kWh/76kWh/cycle = 52 cycles.
If you somehow count DC energy supposedly added (245Wh/rmi), it would be 55-56cycles but that would be incorrect. You could also estimate AC kWh added and that would be 59 cycles but that would also be incorrect. No idea what the SMT calculation or car calculation is doing.
What do you make of me driving almost 6 miles before the first mile came off the rmi display? It's like the SC added that energy to the battery, but the BMS didn't bump the nominal full pack number...
AlanSubie4Life
Efficiency Obsessed Member
Maybe. Seems like a bit of a tricky problem to get the number correct. How many Wh had you consumed on the trip meter at that point when the miles clicked down?
TimothyHW3
Active Member
You forgot the regen. On my car I have almost 1000kWh regen. That will make it closer to 70
AlanSubie4Life
Efficiency Obsessed Member
Sure. Just a different definition though an important distinction. Probably I have a lot more than that since I have a hilly commute; I get about 1kWh per work day of regen added to the battery above and beyond normal regen.
So call it 4days/wk*52wks/yr*1.2yr*1kWh/day/76kWh = 3.3 cycles
So that is 3 additional cycles, just from the hills! Obviously the rest of the regen will really add up too.
Maybe people who live in hilly areas should expect faster loss of capacity?
Check in in a few months! I bet you’ll be down another kWh or so by the time summer rolls around. Your car is still less than a year old, right?
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TimothyHW3
Active Member
AlanSubie4Life
Efficiency Obsessed Member
Check in in July. We’ll see. Certainly temperature will help, but the long term trend will be tough to overcome. You are doing well for 70 cycles, for sure.
Good news is that in general it seems that capacity loss usually slows down after the first 5-20k miles, though.
It was about 1.6 kWh before the first mi came off. So if you allow ~226 Wh for the actual rmi that ticked off... you get 1.2-1.3 kWh "bonus". I am estimating that as Wh/mi * actual_mi_driven from the automatic "this drive" meter.
SMT showed both Nominal Full Pack and Nominal Remaining as 59.1 kWh for the entire 5.8 mi.
TimothyHW3
Active Member
Could you please check at what SOC % on screen you go below 4.0V cell value on Scan My Tesla. I am curious about the balancing thing. On an LR I am at 4.0V mid cell voltage at around 75%, but curious what that number is on a MR.
I just missed it today.... I was around 72% at ~3.96 (sitting idle - not driving). I'll keep trying to get it closer....
Uncle Paul
Well-Known Member
Displayed miles are not applicable to Math as they are not precision and exact gauges.
Math requires hard numbers, but does not work with algorithms that are used for predictions.
Math requires hard numbers, but does not work with algorithms that are used for predictions.
AlanSubie4Life
Efficiency Obsessed Member
They are pretty darn close though! Getting people to do timed charging experiments under warm conditions and assuming an efficiency (based on Tesla data) gives an answer within a couple percent - which is close enough if we are concerned about rated mile reductions of 5-10%.
So far everything I have seen suggests that a consistent rated miles reduction (under warm conditions) really does correlate with a reduction in charging time. So less energy is available.
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