Efficiency and Range Numbers Don't Add Up

[Mtbaddict]

Not sure if this is really an "issue" but the efficiency numbers for my R1T seem off. I'm in California, driving on 21" AS wheels/tires. Usually a pretty normal, slightly conservative driving style. I drive mostly rural roads and freeway (not a lot of stop lights or stop n go block by block neighborhood driving). Monitoring my efficiency while driving, I'm typically in the 1.8-1.9 mi/kWh driving primarily in conserve mode (which I'm changing after reading all the tire wear posts). I recently started driving more in All Purpose mode, and I'm seeing efficiency in the 1.4-1.5 mi/kWh.

Those numbers seem really low compared to others I see posting with 2.2-2.6 mi/kWh results. Something seems off to me. But then when I compare those numbers to my range Range Estimates, they just don't add (multiply) up. Based on my driving habits, my R1T calculates that I can go 351 on a full charge, which would be 2.6 mi/kWh, in Conserve Mode and 316 on a full charge (2.34 mi/kWh) in All Purpose Mode. If I look at my Trip B (since driving it off the lot), it says I'm getting 1.89 mi/kwh. That can't be correct if I'm getting between 316 and 350 miles of range (which I seem to do when I'm driving on longer road trips). Any ideas/suggestions? Thanks.

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[jjswan33]

I think the 21mph average speed says most of it. If you spend a lot of time around town, sitting in traffic etc and running the HVAC you won’t have a high efficiency. Reset your trip meter and go on a 100-200 mile drive at 55mph average and you should see those 2.6 mi/kWh like numbers.

 

[Scott]

For all EV's, if you are running the heater (or, to a lesser extent, the AC) for shortish trips, you spend a lot of energy to get the cabin to your desired temp. Once you have the cabin at temp, it takes less energy to maintain that temp. So in general, longer trips are more efficient.

Similarly, if you take two trips of the same distance, going at a slower speed results in having to maintain cabin temp for longer, thus causing more of your overall power to be "lost" to the HVAC system. (Note that depending depending on the particular speed difference and how hard the car has to work to maintain temp, the impact of air resistance might win out over the impact of the HVAC system. In general, the higher the speed, the more air resistance drives efficiency, and the lower the speed, the more the heater will drive efficiency (or lack thereof), since air resistance impacts efficiency based on the square of velocity.

Similarly, if your trips are short, and it is cold out, a higher percentage of your energy use is impacted by battery temp.


Hope this helps how your particular situation might be impacted by various factors.

 

[Mtbaddict]

I think the 21mph average speed says most of it. If you spend a lot of time around town, sitting in traffic etc and running the HVAC you won’t have a high efficiency. Reset your trip meter and go on a 100-200 mile drive at 55mph average and you should see those 2.6 mi/kWh like numbers.

My driving doesn't involve any time sitting in traffic. Mostly driving 45mph rural roads. This was 2 trips of about 10 miles each. Even when I'm doing doing freeway trips, I'm not ever seeing 2.6 mi/kwh. Maybe 2.1 at max. Not sure why the truck would estimate that much range if my driving style would only suggest 1.7'ish mi/kWh. That would suggest a range of 225 based on my normal driving conditions, right?

 

[Mtbaddict]

For all EV's, if you are running the heater (or, to a lesser extent, the AC) for shortish trips, you spend a lot of energy to get the cabin to your desired temp. Once you have the cabin at temp, it takes less energy to maintain that temp. So in general, longer trips are more efficient.

Similarly, if you take two trips of the same distance, going at a slower speed results in having to maintain cabin temp for longer, thus causing more of your overall power to be "lost" to the HVAC system. (Note that depending depending on the particular speed difference and how hard the car has to work to maintain temp, the impact of air resistance might win out over the impact of the HVAC system. In general, the higher the speed, the more air resistance drives efficiency, and the lower the speed, the more the heater will drive efficiency (or lack thereof), since air resistance impacts efficiency based on the square of velocity.

Similarly, if your trips are short, and it is cold out, a higher percentage of your energy use is impacted by battery temp.


Hope this helps how your particular situation might be impacted by various factors.

Thanks. While this has been a colder winter than normal, my average temps are generally between 35-55 degrees lately. Not too extreme. Would that really account for 30-40% of my energy consumption? I'm curious as to why I'm never seeing 2.6 mi/kWh results (or anywhere near that) with my 21" wheels, regardless of whether it's driving around home or longer freeway trips.

 

[emoore]

Once your average speed gets in the 40s or 50s you’ll start seeing better efficiency numbers.

 

[SourGrapes]

My driving doesn't involve any time sitting in traffic. Mostly driving 45mph rural roads. This was 2 trips of about 10 miles each. Even when I'm doing doing freeway trips, I'm not ever seeing 2.6 mi/kwh. Maybe 2.1 at max. Not sure why the truck would estimate that much range if my driving style would only suggest 1.7'ish mi/kWh. That would suggest a range of 225 based on my normal driving conditions, right?

The ~10mi trip (one way) may be the issue. Have you used the efficiency graph on the dash? I've seen it takes up to 15-20 for the system to warm up to the point where efficiency stabilizes (I'm in the Bay Area, CA so not horribly cold temps). You can see this on the efficiency graph; it starts low and slowly creeps up to ~2mi/kwh or higher depending on the drive.

 

[goldburger]

The math wasn’t mathing right for a bit. Meaning your lifetime tripometer is not showing the correct energy usage.

fwiw I average 1.9 on 21’s if I’m VERY easy on the throttle. Which isn’t very fun lol.

 

[jebinc]

Strange. I have 20” AT. Live in cold and damp Seattle. Take many short trips and never leave AP mode. I drive normally, not like a granny. The first 5-10 minutes is 1.7 - 1.8, then just over 2.0. On warmer days, even better. Same with long road trips.

 

[Scott]

Another factor: where you park the car overnight. Basically how cold soaked is it in the winter? It takes less time for both the cabin and the battery to come up to temp. The current ambient temp is only one factor there. So 2 people with 10 minute drives in the same weather would see different efficiencies if one person had the car parked outside and the other parked in a 55-60 degree garage.

that doesn’t matter nearly as much on a 3 hour drive but has a big impact on short drives

 

[SourGrapes]

The ~10mi trip (one way) may be the issue. Have you used the efficiency graph on the dash? I've seen it takes up to 15-20 for the system to warm up to the point where efficiency stabilizes (I'm in the Bay Area, CA so not horribly cold temps). You can see this on the efficiency graph; it starts low and slowly creeps up to ~2mi/kwh or higher depending on the drive.

@Mtbaddict see my commute this morning, which was about 10mi. Average 1.7mi/kWh, but as the vehicle warmed up the efficiency improves.

 

[W1SE]

Correct, it take 10-20 minutes to condition the battery. I would lose 9% in 8 miles when first driving to work in the morning. But if I start driving around then I hit 2.1 all day long. (21’s, 30-40deg)

 

[Mtbaddict]

@Mtbaddict see my commute this morning, which was about 10mi. Average 1.7mi/kWh, but as the vehicle warmed up the efficiency improves.

Thanks. I'll watch that closer to see if I notice the same thing. Btw, awesome matching Santa Cruz. Is that a Hightower?

 

[SourGrapes]

Thanks. I'll watch that closer to see if I notice the same thing. Btw, awesome matching Santa Cruz. Is that a Hightower?

Thanks! Color matching was not intentional, I swear!
The bike is a ‘22 Bronson Mx (shock modified to allow 160mm travel).

 

[Mtbaddict]

Thanks! Color matching was not intentional, I swear!
The bike is a ‘22 Bronson Mx (shock modified to allow 160mm travel).

Well, it works. The Bronson is a great bike. That's a lot of travel. I ride a Ripley (and a titanium hardtail+ bike). Unfortunately my Ripley doesn't match my R1T. Oh well.

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