COS Blue
Member
Speaking as someone who bought his car in October, this thread is quite reassuring! All my road trips have been in cold weather, so I'm glad to know I will have a "different car" this spring and summer. 
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my S is a different car in winter vs. summer
- Thread starter David in NC
- Start date
aerodyne
2 of 3 EV's - Defect Free!
CaliSurfer
Member
I experienced this degradation in range as well last week when Connecticut got a pretty good snow fall. I had to drive about 50mi round trip and had over 100mi on my range. Needless to say, my efficiency was about 60% due to wind, slush on the roads, less traction, etc. I learned my lesson that if I need to drive in the crummy snow conditions of New England, I need to have plenty of range. After looking on TeslaFi from that trip, my battery efficiency was about 65% for that day. My car looks to average about 75% efficiency when the temps are below 30 degrees.
100% agree and it took me almost 2 years of ownership to realize that charging to 100% may not be beneficial for long trips due to no regen and constant pumps/fans running. You may actually get more or the same mileage as if you just charged to 90%.
COS Blue
Member
I have just one stoplight between me and the interstate (and this part of the interstate never has traffic backups), so when I charge to 100% just before a road trip? Except for the one stoplight (near my neighborhood entrance), I dont need or use regen for usually about 40 miles into the trip. At that point, Im down to a point in SOC where I have some (if not full) regen available. So Im guessing, that going to 100% is actually beneficial for me in that situation
Self-protection courtesy of firmware updates a year or two ago. Battery coolant heater will kick in constantly and the fans as well as you near 100%.
Ends up being a losing proposition or at least a wash as they both keep running as you drive away so range is quickly depleted down to 90% in a very short period of time, at which point they turn off. So for daily charging, people keep it to 80% or so. For road trips, 90%.
ucmndd
Well-Known Member
This is true only for some 70/85kwh batteries.
Keeps them from blowing up, apparently. Im being dramatic, but its to keep them from igniting and catching the car on fire.
beatle
Active Member
No way does charging to 100% make for less range than charging to 90%. I don't know how that math works. Your cooling pumps would need to consume 7kwh of power (9+ on a 100kwh car) over their normal usage in the course of a drive to penalize range. All 10% segments of the battery may not produce the same amount of range, which I believe is people's point. The top 10% producing the least range due to reduced regen, increased heat use if not preconditioned on shore power, and reduced efficiency from increased resistance in the pack with lower temperatures.
Adding this link. It's from 2004 and not EV specific, but some of the penalties to range/mileage are universal (air density, higher rolling resistance, higher viscosity fluids).
Why is the fuel economy of an automobile worse in the winter than in the summer?
Even if you don't run the heater, a cold battery has higher internal resistance and more energy is wasted in heat as you draw from it. This also shows up as a loss in range.
Adding this link. It's from 2004 and not EV specific, but some of the penalties to range/mileage are universal (air density, higher rolling resistance, higher viscosity fluids).
Why is the fuel economy of an automobile worse in the winter than in the summer?
Even if you don't run the heater, a cold battery has higher internal resistance and more energy is wasted in heat as you draw from it. This also shows up as a loss in range.
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I think you mean 60kwh (but not the software unlockable ones)? I think some 70kwh packs also might be affected.
If your fascia is the old one, battery gate applies.
yeah this is me. 2013 P85. lucky to get 130ish miles during winter. I've had less. one trip when from "221 miles" to 2 and I only drove 98 actual miles...
ucmndd
Well-Known Member
I meant 70/85, but I’m sure you can throw in the original 60s too as they’re the same generation of cells.
Nose cone isn’t really a perfect cut-off as there are plenty of 90kwh nose cone cars and the 90s are definitely out of scope (for now). There are also a handful of nosecone 75s.
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Not to go too far off topic but I'd place freezing drizzle (FZDZ) a notch above freezing rain (FZRA) on the danger scale. Why? Because FZDZ is insidious. You're driving along with just a little mist hitting the windshield then, blam!, you cross a bridge and spin out. At least with FZRA you're well aware of stuff happening and can be a little more on-guard.
Last note. Everyone got a big laugh out of the 2014 Snowpocalypse here in Atlanta, where a mere 2" of snow brought the city to a standstill. I'd classify it as effectively an ice or black ice event because that 2" of snow melted then froze over on the roads in a short period of time. Leading up to the event, we had a prolonged period of very cold temps (20-30F) followed by a day of warm temps (~60F). Very cold air (20-25F) came in with the snow that morning, so the snow fell on the thin warm surface of the roads, melted and cooled them down, then froze solid. It was an atypical winter weather event.
My point was not to say it’s exactly a wash or doesn’t give any you net positive miles. My point was that it’s not worth it because there is *noticeably* faster consumption because of the charge to 100% and subsequent auto battery coolant heater/fan use.
Not arguing. OP now knows not to depart with 50% SoC for a road trip...
beatle
Active Member
I checked one of my recent long trips where I charged to 100%. I preheated the car and left at 99%.
99% - 89% took me 20.103 miles
89% - 79% took me 20.228 miles
79% - 69% took me 19.558 miles
Granted there are plenty of variables that can affect consumption, but I'm not driving down a hill or puttering at 40mph for the first leg. I was averaging 70 mph by the time I got to 97%. On the 3rd segment of battery, my average speed had increased to 78mph about halfway through which explains the slightly higher consumption.
I still don't buy that there is "noticeably faster consumption" in the initial stages. If there is higher consumption, it's because the battery or cabin heater is running to bring things up to temperature. These will kill your range regardless of the SoC. The only real detriment to a high SoC is the annoying whine of the cooling pumps.
On that trip, charging to 100% also allowed me to reach the supercharger with 18%. Sure, looking back at the trip I could have made it even if I left it at 90%, but it was dry with temps in the 50s. Had it been colder, rainy/snowy, or if I had a headwind, I may not have made it at all.
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