Those are really good results. I’ve heard the bigger fall off is after 60mph however.
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Performance Model 3 Drag Race - 2021 vs 2018 - Is it Faster?
- Thread starter MasterC17
- Start date
OzBMR
Member
I didn't complete any full 100-150 km/h or 1/8th mile, however, I did roll through one 1/8th mile at 22% SOC in 7.75s, 1.82s 60ft. 330ft was 4.93s. Jumped off the pedal after about 6s and it was still pulling well.
If I stayed on it I think it would have been about 7.5@150 km/h (93mph) which is not far off 80% SOC of 7.4@95mph (330ft was 4.83s) for the 80% SOC runs.
I think at around 20% SOC the car would do a low to mid 12s quarter.
That is exactly what I've found, and supports my theory that the issue is with the HV Battery cooling down to sub-optimal temperatures during very long drive cycles in freezing ambient temperatures.
Over in the 2021 battery thread, someone recently indicated that the voltage floor has been dropped in the newest software update and the results were that the 2021m3p performed significantly better in cold temps than on the old software.
OzBMR
Member
The
We've been recently seeing highs touch 8-9c(45f). I can tell you during those temps I notice very little differance in performance from 80 to 30% soc. But as the cool nights drop down to freezing(0c) there's a noticable differance in power bein delivered at any soc under 80%. That magical number seems to be 6-7c degrees. Im finally excited we have a stretch of 10c+ days coming up. Tired of this car lugging around in freezing temps.
Candleflame
Active Member
The magic number is around around 15C for the battery where the powerlimiter locks around 50-60% of maximum powerif you are below 70% SOC.
If the battery is above 15C then you only loose around 25% power if below 70% SOC.
If you are above 80% even with a cold battery you only loose around 25%.
Obviously the battery is a fat brick and saves some heat from the day and previous driving so it has to be colder outside than 15C to get the battery below that temperature.
The BMS only has 3 temperature settings, Cold, warm and hot.
edit: I think the issue here is that in cold commutes the heat pump scavanges too much heat from the battery so its hard to go above the 15C treshold with the newer cars. With the old cars just a bit of preheating would quickly get you above the 15C treshold and you then keep heating the battery while driving.
That's great news... Within the next month our temps should be around 15c. I've really been struggling with the performance of this car since I picked it up in December. It's a love/hate. To many times I've had to back down from trolling some quicker cars just for the reason I was below 80% SOC and I knew it wasn't running its best.
Candleflame
Active Member
i have just edited my post. The issue isnt so much the battery as it is the heat pump on the newer cars...
Your pack is sitting at like 10C when you leave the house. With the old 3s it would quickly go to 15C from preheating and driving. With the newer cars you are preheating the car and the heatpump immediately draws the heat from the pack and everytime you accelerate and generate more heat it will immediately use the warmth to heat the cabin. So on short journeys where the heater is working hard you will struggel to get the battery above 15C.
One solution would be to just turn the heater down I guess.... Or preheat the car longer.
I've tried that numerous times and froze my ass for 30-45 mins at a time to see if I could keep some heat in the batteries. I didn't notice any noticeable improvements. I've rece tly hooked up scan my tesla, so I can at least see what the car is doing in some capacity. Either way, I'm just sick of driving this car in the cold and want to experiance in the warm temps.
Candleflame
Active Member
Have you tried preheating for longer?
The other thing you can try (I dont know how long your commute is). Only use scheduled charging at highest power possible and charge the car just before you leave. The car should sort of do that with scheduled charging anyway. but it might be worthwhile putting a timer on the circuit going to your car and blasting it with 11kw so it finishes roughly before you leave.
Also just set the SOC to 90%. cold weather preserves the batteries so well our cars in north Australia experience the same stress at 85% roughly as your car does sitting at 100% at 10C.
I’m not sure what to make of this. Someone reported in the battery thread that the newest sw update seemed to improve this problem by lowering the voltage floor in coldish temps. My problem with all of this is that the 2021 seems to be underperforming the older car significantly after 70SOC. Is this JUST a cold weather thing and if so, what’s the threshold? And even IF it’s just a cold weather thing, why is this acceptable? I paid a lot of money for this car - why shouldn’t it perform at least as well as a 2018 model in all driving conditions?
Candleflame
Active Member
I am not sure if the SOC limits are slightly different for different battery manufacturers - they probably are as there are reports of i.e. panasonic batteries performing better in the cold. But I don't think they'll be drastically different.
Like I wrote before, part of the issue is the heat pump which scavenges heat from the batterypack both during preheating as well as driving. Whereas older cars will actively heat the battery with 7.5kw until you are at warm temperature.
Treshold (for older Model 3s) are roughly as follows:
Cold: below 15Cish (batter heater on)
Warm: 28C ish (neutral)
Hot: 50C ish (battery cooler and fan on)
90% SOC you have 100% power when the battery is hot, 90% power when its warm, 75% power when the battery is cold.
70% SOC you have 100% power when the battery is hot, 70% power when its warm, 70% power when the battery is cold.
40% SOC you have 90% power when the battery is hot, 60% power when its warm, 40% power when the battery is cold.
at 10% SOC you have like 25% power when its cold.
For the newer batteries those power outputs particularly when its cold are lowered (for whatever reason) and you also struggle to get the car above the 15C limit if the heatpump constantly takes heat from the battery to heat the cabin.
I am gonna throw a wild idea into the room that Tesla is trimming their batteries more and more to prefer to be run hot and at 100% SOC (as evident by their iron battery chemistry which prefers to be hot and frequently charged to 100%).
The tradeoff is presumably cold performance. You cant have it all.
The other thing is that Tesla doesnt have much data on the new Model 3s so doesnt know how much damage the battery gets at low or high SOC from accelerating hard and regenerating. They got it wrong before i.e. with the old Model 3s which used to regen hard at i.e. 90% SOC at cooler temperatures. In January 2019 we got an update which limited regen unless the battery is above warm temperature. In fact from January to March 2019 regen was generally just a bit weaker. I remember that single pedal driving wasn't really possible at that time because the car just didnt regen quite enough.
Even when I leave in winter here in the morning (winter here is 25C) i get some limited regen at 85% for a few minutes until the battery goes above 28C which takes maybe 2-3min of driving.
Last edited:
