Does "Towing Mode" reduce range unnecessarily?

[Thedude]

In mid 2022, mine would just cut my range in half and stay there. In 2023, it is adapting and landing on something accurate. I might be getting lucky with my efficiency with my trailer, but now it is clearly changing once I start driving, and last year, it never did that.

Sounds like my experience is the opposite of yours.

Back then it would cut in half but then decrease at a rate that just about matched my actual usage over the drive. Could have just been coincidence that my usage rate was the same as what the software was programmed to use as well

If you're in Colorado I'm guessing you tow different elevations a lot. It's effectively impossible to display an accurate number based on historical usage unless the vehicle knows where you're going to drive next. Guessing your range just circumstantially ends up being about half of what the truck is normally rated for, which is what the estimation used to just be permanently.

I do tow at different elevations but the truck knows what its last 15 minute average is and should be able to base the math off that. It’s a simple process that other vehicles do all the time with distance to empty estimates. Instead I will switch to towing mode, have the truck say it can do 200 miles, tow 50 miles and use 50% of the battery and have the truck still think it can go another 180 miles.

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[JakeB]

I have now pulled all three of my trailers and the GOM is way off. It always starts at 50% of normal range, then it starts climbing to a very unrealistic number, even with my heavy (5k-7k) trailers. It never seems to correct itself.

WHat is the furthest you've towed your 5-7k trailer? Any hills/mountain passes? Just curious on how far I could realistically expect to tow my boat without major anxiety.

 

[Thedude]

More importantly, sounds like I can tow while not being in towing mode and not create "vehicle damage" as the warning on the screen indicates. Thanks

There is no benefit to towing and not being in tow mode. If your trailer has electric brakes they won’t work when not in towing mode. Since it’s a boat trailer you might have hydraulic surge brakes get away with it though.

 

[azbill]

WHat is the furthest you've towed your 5-7k trailer? Any hills/mountain passes? Just curious on how far I could realistically expect to tow my boat without major anxiety.

I pulled my boat from 98% to 6% battery for 107 miles. I did that driving loops on a freeway at 70mph, just to test the range. Result was 0.94 mile/kwh. There were a few up and down hills, but mostly flat.

 

[JakeB]

I pulled my boat from 98% to 6% battery for 107 miles. I did that driving loops on a freeway at 70mph, just to test the range. Result was 0.94 mile/kwh. There were a few up and down hills, but mostly flat.

Love that you did this. I was about to do the same thing just to satisfy my curiosity.

 

[JayinNJ]

It used to increase your range, so at least it looks like they fixed that bug.

 

[NorthernOak]

A others have said, it's more about watching your efficiency numbers and doing the math. I really would like them to release this Tow Mode update that they teased a few months back. Last year I towed my old boat on vacation with extra gear and vacation stuff and it was probably about 2500lbs. I had a trip efficiency of 1.54 mi/kWh over 192.5 miles.

I got a new to me boat last fall that is 2900lbs dry and probably around 3500lbs with fuel and gear. No doubt about it being bigger, but the profile still sits behind the truck body. I've made the 60 mile round trip to/from the lake a few times this year and get between 0.98 - 1.1 mi/kWh at a steady 60mph. I knew it would be worse than my old boat but I'm quite disappointed at these current numbers. Even with a loaner R1T I got similar numbers. I don't get how some people are achieving better efficiency numbers with larger loads.

This last week in the loaner R1T I was getting an estimation of 200 miles range with the boat but my efficiency the whole time had been 1.1 mi/kWh. Just goes to show you still can't yet trust the milage estimation. Again, I hope for that the big towing update comes soon.

 

[the_mace]

WHat is the furthest you've towed your 5-7k trailer? Any hills/mountain passes? Just curious on how far I could realistically expect to tow my boat without major anxiety.

At 7,500 lbs my number is 124 miles or 62 round trip. From 100% charge back to 30% charge. So could maybe stretch it to 70 each way. Also that's keeping to 65mph or less

 

[Riviaenz]

Even subtle differences in conditions will dramatically affect/alter range. We recently towed our R-Pod (about 4000 lbs during this trip - I didn’t get a proper weigh in during this trip, just pulled through a highway patrol/DOT truck weigh in) over a 1200 mile roadtrip.

This was our first roadtrip and towing experience with our new R1T. I’ve towed more than 40k miles between two XC90 (2010 and a 2017 T8 - PHEV). Even with them external factors would dramatically impact range.

With our Rivian, for the most part we were averaging an indicated range of over 200mi (charged to 85% throughout the trip, only on one leg I charged to 100% given we were dry camping more than 40mi away from a DCFC and we’d need to tow further away from one the next day).

In practice I recharged about 90-152 miles into each leg. On one leg reaching our furthest point into the trip, the indicated range started pretty typically, at about 140-150 and initially started to climb towards over 200, or so I expected. It stalled out around 180 and then started decreasing. I also use the % indicator in addition to the range estimate. Percentage was more helpful on that particular leg. Long story short that final leg out we went from 85% to 12% in 95 miles (6 of those were not towing at the end). It was unhitched to drive to the nearest DCFC to get a head start on our next day of exploring from our new home base.

It was only slightly concerning while I was closely monitoring the SoC and expected distance to the destination. I was a little confused and intrigued as to what was causing the dramatic hit to range and draining the battery. That leg our actual efficiency turned out to be 0.97mi/kWhr, while the indicated efficiency by the onboard computer was 1.12mi/kWhr. Other legs were as good as 2.01mi/kWhr and as low as 1.12mi/kWhr. What’s strange is I couldn’t really tell at first what was happening with consumption until I later realized it was a steady, persistent, and clearly imperceptible elevation gain along with higher permitted speed limit. As I saw the range decrease I adjusted and decreased my speed accordingly to ensure arrival. What’s really interesting is that the return trip on that same stretch was nearly as inefficient - 1.03mi/kWhr but the rest of the trip from there on improved. What affected range I really don’t know but it was clearly a stretch of road that was not range friendly - it even included a highway detour that took us off-road via a forest service road for about 5 miles - not long enough to be a significant factor out of a 82 mile from DCFC to DCFC. On the return I adjusted to make sure it was DCFC to DCFC to ensure a greater buffer than on the outboard leg.

Anyway, my point being same load, on the same long distance trip, and range varied wildly based on road/environment conditions alone.

On one of of our longer road trips towing a T@B with our 2010 XC90 - 8000mile road trip - we experienced the same thing, only on top of topography, road conditions, and environment, there was the wild variable of fuel quality (ALCAN road trip). We saw MPG on that trip range from as low as 8mpg to as good as 13mpg and that also dramatically curtailed range unexpectedly at times. Obviously being an ICE we could carry 2 20L Jerry cans in addition to the onboard 80L fuel tank.

And with our 2017 XC90 it could vary in more widely given it had an even more efficient ICE + EV side. We took that one on a 7000 mi road trip towing the same R-Pod as with our Rivian and through Midwest and western states (Rockies) mileage varied from as low as 8mpg to as good as 26mpg while towing.

 

[Electrified Outdoors]

Wind will do it. You get a good head wind and umit will really reduce that range... especially while towing.

 

[Thedude]

@Riviaenz don’t trust the indicated range, it’s wildly inaccurate and you might as well completely ignore it. The only range estimate that is accurate when towing is the actual mi/kWh usage history and a little math.

 

[Riviaenz]

@Riviaenz don’t trust the indicated range, it’s wildly inaccurate and you might as well completely ignore it. The only range estimate that is accurate when towing is the actual mi/kWh usage history and a little math.

The computer calculated efficiency on the fly is a good indication and it did point to the revised estimated range likely being correct. Its running efficiency and projected range aligned. When efficiency was trending to 1 or less mi/kWhr it coincided with terrible range and vice versa. In our case as it trended below 1mi/kWhr range was on track for about 100 miles the 2 times it did trend under 1mi/kWhr. When above it or close to 1.8 it was good indication as indicated by range estimate that we’d get about 150-160 before we’d want to stop for a charge. Just like ICE i wouldn’t run it to empty before stopping to refuel. I’d refuel with some buffer.

 

[av8or]

I’ve been working with Rivian a little since I put in a ticket for towing logic. I have towed a 3500 lbs. travel a lot and the estimated range is all over the place. When first plugged in and switched to TM it will show a reasonable range, but as soon as I start driving the range slowly climbs back up to a number that would make sense when not towing. I can tow my trailer 140-150 miles tops, and I’ve had an estimated range of 70 miles after towing 124 miles at 1.1 miles/kWh. Bottom line is until there’s an update the GOM is pretty much useless and if you use it while towing you will get stranded.

 

[Riviaenz]

I’ve been working with Rivian a little since I put in a ticket for towing logic. I have towed a 3500 lbs. travel a lot and the estimated range is all over the place. When first plugged in and switched to TM it will show a reasonable range, but as soon as I start driving the range slowly climbs back up to a number that would make sense when not towing. I can tow my trailer 140-150 miles tops, and I’ve had an estimated range of 70 miles after towing 124 miles at 1.1 miles/kWh. Bottom line is until there’s an update the GOM is pretty much useless and if you use it while towing you will get stranded.

I hope they’re taking a broad sample to improve how it estimates towing range in addition to taking a better read of efficiency (battery discharge under load). There are so many variables that impact any vehicle (gas, diesel, or electric) only EVs just as highly efficient ICE vehicles tend to be most susceptible to those subtle differences given there is less loss to system and more energy that can be lost to external factors (load, wind, aero, temperature, road surface, topography, tires/µ, etc)

 

[Thedude]

I hope they’re taking a broad sample to improve how it estimates towing range in addition to taking a better read of efficiency (battery discharge under load). There are so many variables that impact any vehicle (gas, diesel, or electric) only EVs just as highly efficient ICE vehicles tend to be most susceptible to those subtle differences given there is less loss to system and more energy that can be lost to external factors (load, wind, aero, temperature, road surface, topography, tires/µ, etc)

The software from a year ago was actually pretty good. As soon as you selected towing mode it immediately dropped range by 50% but then adjusted fairly accurately based on your efficiency during the drive. Then they screwed it all up and you started getting 635 miles in tow mode and it’s been messed up ever since.

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