So we just had a dramatic change in our range on our 21' M3P with just over 9k miles. First noticed when wife drove 130miles (freeway down and back for work) starting at 90% and returned with an estimated 75miles. 310wh/mi in the 30mi graph but I didn't check Batt % before wife plugged in to charge.
Charged to 90%, drove this weekend through today. 307wh/mi, 54kw usage, 11% remaining (est. 34mi), 178mi driven.
So based on 54kw usage and draining from 90% down to 11%, That would be a battery capacity of: 54/(.9-.11) = 68kw total capacity estimate.
If its a mileage estimate for a 100% battery: 178/(.9-.11) = 225mi (an estimate if charged to 100%)
And finally, when charged to 90% est shows ~270mi range (we're running 200tw sticky tires as well, but this is been appropriate historically in estimation), but the actual 90% range seems to be closer to 200mi. And to confirm, this is definitely less than we have been getting.
Normal charging habit, we only charge 1 or 2x per week depending on use. Letting it drain down to 40-50% typically before plugging in. Charge at 16amp, 220v 20amp plug. Im letting car sit till this evening to plug in and recharge back to 90%.
Is there a consensus or "expert" opinion if I should charge this evening or try to get to 5% then charge fully back to 100%?
Check the range loss stickies & the 2021 thread, and the energy screen method sticky.
You're fine. Just pay attention to the 90%, 270-mile number. That means you have 300 rated miles at 100%, after starting with 315 rated miles. So 5% capacity loss, which is perfectly normal after 9k miles. I don't think it's worth worrying about trying to recalibrate the BMS - it's probably close and it will recover on its own with your use patterns, if there is any error.
So you have 80.7kWh*300/315 = 77kWh remaining in your battery, of which 73.5kWh is available between 100% and 0%. You started with around 80.7kWh, roughly (77kWh to 0%). (All this info on how to arrive at these numbers is in the stickies.)
All the daily usage stuff is just noise unless you happened to watch how much energy you lost while in park. Continuous trips without stopping are the only way to assess how much energy your battery has (unless you use the energy screen method). That's why your calculations of capacity based on the trip meter don't match the numbers I give above. The meter does not count energy used while in Park, which can be substantial.
You're in Oregon and it's raining cats & dogs and somewhat cold, with thicker air and more heat pump use, so your real-world consumption will go up. That's probably why your real-world range has gone down.
If you want to get 300 miles out of your 77kWh pack to 0%, you need to do: 0.955*77kWh/300mi = ~245Wh/mi. (Likely closer to 242Wh/mi due to heat loss.)
And if you do higher than that, just scale the range accordingly. It's very deterministic and simple. So at 310Wh/mi, expect 234 miles from 100% to 0%. (0.955*77kWh*0.99/310Wh/mi = 234 mi).
But only if you do it in one continuous drive without stopping. These mileages will all leave you at 0 rated miles, 0%, with about 4.5% of your energy left.
Unless you need 90% (it seems that you sometimes do), I'd recommend using a daily charge limit of 70% or so. It may not matter much in the end, though. Do not lower it if it means you need to use Superchargers. Make it easy on yourself; no one likes to sit at Superchargers unless it is required.
, is this normal? I normally drive with the autopilot about 10 miles above the speed limit.
, I can stop worrying now lol
