I think the whole thermal management system is a big part of the efficiency of the newer cars. This includes the octovalve, which I don't think you've got in your car. I also drive like an old may, in chill mode most of the time.
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Model 3 SR+ LFP Battery Range, Degradation, etc Discussion
- Thread starter Baluchi
- Start date
You are driving 500+ miles per week Baluchi. That’s a lot of exposure to clowns and jerks and other road hazards. Anything you can do to mitigate the declining odds of staying safe, such as driving like an “old may”, is fully warranted! I kind of drive like an old may as well, but my lifetime wh per mile is around 230 (~4500 miles currently).
I think there was also rumors of tweaked brake calipers that would further retract the pads from the rotors and wheel bearings as well... Maybe some refinements to the drive motors?
I know that people claim that the latest Model 3 Performance models don't quite hit as hard right off the line as the older ones, so maybe they tweaked the motors for a bit more efficiency in exchange for a bit less torque at low speeds.
No - reducing friction from the brakes. After you press on the brake pedal, there's enough friction in the calipers that the pads will slightly touch the rotors as they don't fully disengage. Now, they don't drag enough to do anything like overheat the pads/rotors, but it's enough to reduce efficiency.
You can design the calipers so that they retract farther away from the rotor after brake application, eliminating that source of drag.
Take similar measures in a dozen different spots on the car and they start adding up to real efficiency improvements.
Great write up @Baluchi, and your data tracks mine. I have a 2022 LFP car ("RWD" model with 60kwh battery), delivered Nov 13th. Since it is only a few days from now, I'll go ahead and post my 6 month update so people can compare the two.
I've driven 6,143 miles, show a lifetime average of 215 Wh/mile, and full charge shows 269 miles (vs 273 new), about 1.5% degradation - assuming that is real and not just a calibration error. Like you I only charge to full once a week unless my needs dictate otherwise, and L2 charge at home, with the exception of a handful of supercharging sessions.
On longer trips I've seen 220 Wh/mile averages, but I should note I live in a very large metropolitan area with tons of traffic that extends over 100 miles in every direction. So while I routinely hit 70-80mph, I also spend plenty of freeway time moving slowly in traffic at stupid slow speeds.
In an effort to determine real highway efficiency, I set out at 2AM last night and made 70mph runs up and down the freeway on AP with no traffic near me. Temp was 50F, tires at 49PSI cold, AC off, and I clocked 15 miles in each direction, measuring the consumption with the trip meter. Based on my one night of testing I show 245 wh/mile average consumption at 70mph. I plan to repeat this test several more times to see how consistent the number is, and then make some aerodynamic tweaks to see if I can improve on the number.
Oh, and a simple test for brake rotor drag - drive around your neighborhood for 10-15 min without ever touching the brakes (regen only). Then check the rotors - if they are cold then you have no drag. If they are warm/hot then you have pads dragging and that will reduce efficiency.
I've driven 6,143 miles, show a lifetime average of 215 Wh/mile, and full charge shows 269 miles (vs 273 new), about 1.5% degradation - assuming that is real and not just a calibration error. Like you I only charge to full once a week unless my needs dictate otherwise, and L2 charge at home, with the exception of a handful of supercharging sessions.
On longer trips I've seen 220 Wh/mile averages, but I should note I live in a very large metropolitan area with tons of traffic that extends over 100 miles in every direction. So while I routinely hit 70-80mph, I also spend plenty of freeway time moving slowly in traffic at stupid slow speeds.
In an effort to determine real highway efficiency, I set out at 2AM last night and made 70mph runs up and down the freeway on AP with no traffic near me. Temp was 50F, tires at 49PSI cold, AC off, and I clocked 15 miles in each direction, measuring the consumption with the trip meter. Based on my one night of testing I show 245 wh/mile average consumption at 70mph. I plan to repeat this test several more times to see how consistent the number is, and then make some aerodynamic tweaks to see if I can improve on the number.
Oh, and a simple test for brake rotor drag - drive around your neighborhood for 10-15 min without ever touching the brakes (regen only). Then check the rotors - if they are cold then you have no drag. If they are warm/hot then you have pads dragging and that will reduce efficiency.
Hopefully The degradation of my 12-2021 is not considered bad. My car has currently 57.000km on the odo and the estimated range dropped from 412km to 382km. That is a 7% decline. Also the range of the car seems to be going down. Now that the weather is warmer here in the Netherlands I would expect the estimate to go back up, but instead it keeps declining.
Hope that you smart people can shine your light on this to give me an idea.
Hope that you smart people can shine your light on this to give me an idea.
OK, I’ve decided to go rogue again, but this time hopefully in a way that doesn’t piss off @AlanSubie4Life and @AAKEE. Haven’t charged to 100% for a month now, and plan to continue this until I actually take a long trip. I charge back up to 74% whenever I get down around 30-35 %. So perhaps I can serve as a cautionary tale for those who would consider the folly of not charging their own LFP’s up to 100%. When the time comes and I do have to charge to 100%, I will report back as far as what my new 100% SOC range is…
If you're going for minimum capacity loss, you might consider only charging to 70% - it's hard to say for sure exactly where between 70-80% the rate of capacity loss speeds up based on AAKEE's post.
One challenge you will have with having the cutoff so close to the threshold is that if the BMS does start to lose track of the actual SOC, you could end up significantly above or below your target SOC because the voltage curve of LFP batteries is so flat between 20-90% SOC.
Good luck, it will be interesting to see what happens!
I don't know that there's a way to reverse real range loss, but there are techniques people use to reverse the perception of range loss. I think this is the most popular thread on the topic...can't vouch for its efficacy myself.
That depends on what kind of range loss you are asking about.
Reported range loss that is really a BMS calibration error - yes, there are some threads elsewhere regarding that.
Real range loss from battery degradation - none that I know of, though I'm sure there are lab experiments that claim to have repaired some of the age/cycle damage in certain battery chemistries through controlled conditioning. But I doubt any of those would be practical for use in a BEV.
When you do charge to 100%, you may want to note how many kWh went in and what percentage that was. Then use that to derive what the battery capacity in kWh should be, and compare that with what the car thinks the battery capacity is.
I.e. if the car thinks that its battery capacity is 60 kWh, and you charge from 50% to 100% at the end of your experiment and put 35 kWh (instead of 30 kWh) in, then that suggests that the BMS has gotten off by 5 kWh.
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