I'm wondering if you or anyone else has ever tested driving a certain specific route for a number of miles with Range Mode on and then repeating the same trip with it off. I notice that on my 90D the Rated Range gauge on the IC only shows .37 miles more when charging to 90% with it on than if it's off. I'm thinking the algorithm that is used to get that can't be right. I would think real world driving taking advantage of torque sleep would be a more accurate number.
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My experience with range mode indicates it's most useful in cold weather on short trips. Then it saves quite a bit of energy from not heating the battery. In summer it makes almost no difference. I haven't made any long trips in cold weather, but I understand from those who have that it doesn't make a lot of difference there either because the battery heating is only at the beginning of the trip.
gavine
Petrol Head turned EV Enthusiast
In cold weather, depending on the length of the short trip and how much stop and go there is, range mode off might be better because the energy gained with regen braking that is allowed once the battery warms up can exceed the energy used to warm the battery. If you're just taking the kids to the bus stop, range mode on is best. Same if you're jumping right on the highway.
Assuming you've pre-warmed the car, there is not much regen lost during urban driving. Typically it's going to have a limit of around 30 kW or greater (at least that's how my car acts). Most stops in urban conditions don't exceed that limit. (If you live in Winnipeg or some similar place, there's not much that's going to help when it's -30). So I'm not convinced that the amount of energy recovered by regen is going to be more than the energy used to heat the battery quickly other than in edge cases or if you have a jackrabbit start and screeching stop driving style--then I can see where it might.
eye.surgeon
Active Member
So does a Tesla. It's as much heating the cabin as it is battery efficiency that reduces range in the winter, for all EVs.
More investigation required.
Based on some tests I did last weekend (100+ degrees in CA), turning range more off definitely makes a difference on the consumption history graph as well as how quickly the range 'margin' depletes...mostly, I suspect, because It keeps the AC compressor from spinning at 'ludicrous speed'.
Differences on the graph are a few pixels in the averages--enough to see something--and a 2% loss of margin over a 20 mile stretch compared to the previous 20 mile stretch with range mode on. Your guess is as good as mine what a few pixles actually means on the chart, but if I do my math right, my 60 uses ~10% of its range over 20 miles. Losing 2% 'more' means I used 12% over that 20 miles, which means I incurred a 20% increase in consumption between range mode off/on.
I repeated this two more times [in slightly different circumstances] with similar results. I don't profess this a conclusive data set, but its enough to say there's something noticeable going on. To be clear, I don't believe range mode will make much of a difference in warm weather on classic MSes if AC demands are low.
I coincidentally had my car in for service this week and asked the tech about range mode--he said the compressor is limited to 3000rpms in range mode. Perhaps someone can verify.
Andyw2100
Well-Known Member
,
I don't know about anyone else, but I have not. On the trips I take I think it would just be too difficult to adjust for the differences due to temperature, wind, etc. I track every one of two particular trips we take, and there is already a lot of variability, so trying to break out differences due to range mode being on or off I think would be pretty hard to do.
I think it's important to point out, though, that you're talking about a classic, single motor Model S, where the benefits of torque sleep are not coming into play.
jgs
Active Member
For that matter, my impression (that I'm not going to support with a citation just now, sorry) was that at high speeds (which is usually when range matters most) the greater density of cold air dominates the factors you name, for all vehicles.
Heating is a massive draw, it's basically 11-12kW of capacity to draw, which when start a car that's been sitting in the cold actually happens for quite a while. Especially when you have real-world use of the car, not turning the car on, driving for as long as possible, and stopping. Real life turns out not to be a contest to road trip the farthest in your car, but for most people a minimum of 2 starts and stops, probably on average 3-4 start/stop cycles spread throughout the day with the car cooling in between.
If Tesla had better insulation of the pack, and more efficient heater like heat pump, maybe even a thermos to keep hot battery coolant if it becomes available, a lot of the consumption would go away.
jgs
Active Member
Fair enough. And I like the thermos idea, has that been floating around or did you just hatch it? I do think there's a subtle distinction to be drawn, though -- do you want the car to be efficient because you want it to be efficient, period? (Presumably many of us do, it's one of the main motivators for EV adoption.) If so, your points are well taken. But, as far as efficiency for the purposes of range qua range goes, I do still think that the road trip scenario is the dominant case. At least in my experience I'm doing a bunch of short trips such as you describe, averaging a pretty high Wh/mi but driving few enough miles in aggregate that there's no risk of depleting my battery before the end of the day, or I'm doing a road trip where sometimes I'm pulling in to the next Supercharger with 10% in the pack. In the latter case, I think drag still dominates.
jgs
Active Member
Wowie. I think I'm consuming a lot when I get into the mid four hundreds!
Right, they only did the thermos bottle for the 2nd generation cars sold between 2004-2009 model years.
For the 3rd and new 4th generation cars they instead use "exhaust gas heat recovery" where they have a heat exchanger inline with the exhaust coming off of the gas engine that can be used to help quickly heat up the engine "coolant".
This helps to keep the engine operating under ideal temperatures that maximize combustion efficiency. It also helps to quickly heat the cabin since the same engine coolant is run through another heat exchanger in the cabin to provide passenger heat.
This is especially helpful for hybrids since they switch the engine off and on regularly and this helps them quickly heat up again when the engine is restarted.
Lex
Member
Lex
Member
... not that it's not a delightful car to drive in the winter, so far. But some things were a bit troubling in my first very mild winter.
As for thread topic Range Mode, I only use it when I really want to maximize range on long trips. I just don't think too much about "mileage" or range at all, quite honestly, except on long distance jaunts, and then I make a fun game out of it. But that's me
As for thread topic Range Mode, I only use it when I really want to maximize range on long trips. I just don't think too much about "mileage" or range at all, quite honestly, except on long distance jaunts, and then I make a fun game out of it. But that's me
As far as I know the Model S has a heat pump to heat the cabin. It definitely uses the heat from the motor/inverter.
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