Range at -2F

[Swcwrx]

FWIW, its -2F this morning on NH. I just did 25 mi to work with the heat at 61F in snow mode. Forgot to do heated seat or steering wheel, it was a 35 to 50 mph ride the whole way, no traffic because it's early. Used 10% / 47 mi of the battery, range started 273 (66%), ended 226 (56%). Battery temp is 28F, I think it started at 29F in the garage.

I've done the same drive at 1F with just seat and steeeing wheel heater, and managed 7% / 35 mi. I usually charge to 67% /280 mi. So the climate control costs some range vs. the seat & steering wheel heater.

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[ndmiller]

Need to set a leave time on the app so everything is warm by the time you leave the house. Pulls energy from the home.

 

[3wisemonkeyz]

It’s -18 here in MN (-38 with windchill) so I wasn’t about to let my wife do her 100mi Roundtrip commute in the R1S, even with a 75% charge and HVAC on scheduled departure. Just too risky.

 

[iamnid]

Used 10% / 47 mi of the battery, range started 273 (66%), ended 226 (56%). Battery temp is 28F, I think it started at 29F in the garage.

10% = 47 miles of range? You got one of those 470 mile models I've never heard about?

 

[BCondrey]

It's better to report stuff like this with kwh used. That way you can do miles per kwh. Your battery is a max pack 149 kwh, right? You used 10% of it (14.9 kwh) to go 25 miles. 1.68 miles per kwh. A short trip, -2 in snow mode, thats not bad.

BTW, the 400+ mile range is calculated in the truck based on 2.7 miles per kwh. Optimistic.

 

[Zoidz]

It’s -18 here in MN (-38 with windchill) so I wasn’t about to let my wife do her 100mi Roundtrip commute in the R1S, even with a 75% charge and HVAC on scheduled departure. Just too risky.

Agree. I've got a 200 mile roundtrip overnight business trip to north central Pennsylvania tomorrow. Temps are forecast to be 15 daytime, 0 at night. The area I am going to is a charger desert to begin with, a handful of L2 public chargers. Not going to risk it.

 

[Singletracker]

It's better to report stuff like this with kwh used. That way you can do miles per kwh. Your battery is a max pack 149 kwh, right? You used 10% of it (14.9 kwh) to go 25 miles. 1.68 miles per kwh. A short trip, -2 in snow mode, thats not bad.

Yes!! Please, let’s forget the constant talk of percent as an indication of consumption. Whether we are talking about vampire drain or driving efficiency, battery capacities can vary and % means very little when comparing vehicles. What we are really concerned with is actual energy consumed (kWh). Of course, when discussing driving efficiency, miles driven is part of the equation. Miles/kWh is the relevant # everybody wants to see.

 

[Swcwrx]

Follow up, the truck burned 3% / 13 mi while i was in the building. It is 19F outside and the battery remains at 27F.

 

[Swcwrx]

2.02 mi / kWh in first 2001 mi of ownership, all since 13 Dec 2024. I'll say that 13 mi is roughly 6500 kWh of heat for ten hours.

 

[BCondrey]

Follow up, the truck burned 3% / 13 mi while i was in the building. It is 19F outside and the battery remains at 27F.

Your truck "burned" 4.5 kwh of battery. Miles mean nothing.

 

[Swcwrx]

9%, 36 battery mi and 10kWh to get home, 25 actual mi.

25/36 seems useful to me. My range is down just under 1/3 from ambient 70F, though ive not yet driven it when it was that warm out. It was 19F when i left, 15F when I arrived.

Also 9% of my battery got me 25 mi, so my range is approx 11 x 25 = 275 mi, presto. Roughly 2/3 of my ambient 70F max.

Watt hours is a unit of work, and because conservative forces on a circuit always add to zero, watts per mi just tells the sum of the nonconservative forces... which are mostly a function of how fast a person drives.

The first 12 miles were at 65 - 70 mph, the last 13 were at about 40 -45.

You guys really don't find utility in ratios? I love this stuff.

 

[Swcwrx]

2.02 mi / kWh in first 2001 mi of ownership, all since 13 Dec 2024. I'll say that 13 mi is roughly 6500 kWh of heat for ten hours.

Right, 6.5 kWh.

 

[BCondrey]

Right, 6.5 kWh.

I must have missed something. You said it burned 3%. 0.03 * 149 = 4.5.

The 13 miles is calculated based on 2.7 miles / kwh. You cannot use the "miles remaining" on the main display. It worthless.

The best way to measure this is by resetting one of the trip meters, and getting the kwh used from that.

 

[egar]

Had a short roundtrip this morning in the MN cold. Used the scheduled climage warm-up before leaving home. Battery temp when I left home was 23F. When I got to my destination, about 8.5 miles, battery temp had dropped to 21F. i have a gen 2 dual with the large pack. Motors were at about 100F after about 6 miles.

Truck drove fine, cabin was a cosy 70F, efficiency was just bad. BTW screenshot is a summary from Electrafi.

 

[Swcwrx]

Okay, sorry for taking so long to reply. I've owned the R1T (it's not a truck or a car, though it can tow a 30-foot Airstream!) since December, put almost 10,000 miles on it.

What I was saying before is that kWh are a unit of work. Net work done on any closed circuit is zero, except for nonconservative forces. That's why mi/kWh is a silly measurement -- it just returns to you your losses from heating and wind resistance. You already know how warm you keep your cabin, and how fast you're driving!

Conservative forces are those in steady fields, like gravity, into which I can store energy. They result in changes to energy of position, aka potential. If I drive up the hill, I can get the energy back. In orbit, this would be maximized at the apoapsis. It's what people deal with in Physics 1. No friction, no wind.

What you guys are complaining about is your losses from nonconservative forces. In an automobile, this is overwhelmingly due to cabin heating at low speeds and wind resistance above 40 mph.

Wind resistance goes as relative speed squared. If you double your speed, you quadruple the wind resistance. The resistive force, which is 100% nonconservative, goes nuts.

I've driven my Rivian in -11F and in 65F, averaging (so far) about 20F. I regularly get 2.7 mi/kwh and if I go easy on it, I get better than 3 mi/kWh. I can get lower (like 2.5 mi/kWh), but in order to do that, I have to do a few things:

1. Drive faster than 60 mph. I can easily beat the 420 on a single charge, but above 40 mph it drops and above 60mph the losses are significant. So, 53 mph on a 250 mile drive with traffic, starting with 7/8 (87%) of a 420-mi battery? I still have 120 miles left when i get home. In the cold and I left it parked in the cold for hours at the destination. Cold has almost nothing to do with it*.

2. Crank the heat. I have a glass roof. I am surrounded by glass, there is no wind inside the R1T. I have a coat. I have a seat heater. WHY would I turn the heat to 70? 61 is the lowest setting and the one I use for the defog. That's where it stays. I do not actively heat the cabin. Heating the cabin is not free, this is not a gas car.

In the gas car days, when we released three to five watts of heat for every watt that got converted to useful kinetic energy, heat was free and other nonconservative losses of even 30-50% were nothing to the steady, unavoidable 75-80% heat losses. But today, when 98%+ of my energy is moving the car forward and 3.03 mi/kWh (101 mpg) is simple for a four-ton R1T, heat and excessive speed are not free. I learned this quickly and I'm happy to live with it.

Want better mi/kWh? Don't heat your cabin to 70 and don't go 80. It's not that hard.

*Rivians are always on, so they always use energy, and they heat themselves when they sit unsused in the cold. These losses can total 3-5 kWh in 12 hours on a cold day, in my experience. "Cold" to a Rivian is apparently anything below about 50F and energy spent goes directly in proportion to 50F-T, where T is the ambient temperature.

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