Does "Towing Mode" reduce range unnecessarily?

[JakeB]

Forgive me if this has been asked - and kindly post the thread if you know it has been discussed - but I haven't been able to find an answer to this question after many youtube videos or forum searches and even a conversation with my guide but here it goes: Does Towing Mode reduce your range unnecessarily? Or what exactly does it do other than cut your battery range in half, adjust the suspension, and the ability to use trailer braking?

Here's my scenario. I have a Mastercraft x35 that weighs about 6,500 lbs with the trailer, full tank of gas etc. Last fall, I picked it up from the shop after getting winterized and immediately selected "Towing Mode" (TM) when I got in the truck. The range was 189 mi pre-TM and immediately cut to 89 when I selected TM. I had 22 miles to get to my house so I was not worried at all. On the freeway, watching my range was like watching a timer, slowing counting down. It was literally dropping a 1 mile in range every 3-5 seconds. When I got to my house, I had 23 miles in range left. Glad I made it home but pretty much gave up any hope of driving the 40 miles, including a 10-mile mountain pass, to the lake where we go boating.

This spring, I ran it back to the same shop and decided not to use TM because I have been curious about the immediate range drop when I did. I started with 227 miles in range and when I got to the shop I had 219 range. It knew I had a trailer because it showed me the trailer in the front screen and I had lights plugged in. So, what gives? Why would the truck tell me I used 60+ miles of range when I was in TM and 8 miles of range not in TM when I had traveled the exact same distance?

Obviously towing a 6,500 lb trailer is going to use more battery. Yes, outside temp and conditions will play a role as well. But why would TM automatically cut your mileage down the second you select that mode? SHouldn't the range just react to the actual level of the battery at that point? I've towed the trailer around town, from the mechanic to a detailer from my office back to the house and I haven't seen nearly the burn rate that TM showed me last fall when all I did is get on the freeway and drive straight home.

I asked my guide if I'm risking breaking something by not having it in TM while towing and he said "I have asked around and haven't heard any indicators of why it would. I can only recommend using the tow mode while towing as it optimizes capability."

If anyone has some knowledge they'd like to share with me, I am all ears, but I'm struggling with the purpose of Towing Mode other than it calibrates your suspension for optimal towing performance and allows you to control trailer brake gain. In my experience, it greatly reduces your range pre-emptively.

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[MReda]

I'm pretty sure all it does is what you've described. I regularly switch from tow to off road and everything on the trailer appears to keep working properly.

As far as range calculations go, last year, it seemed like it would immediately just cut the range in half. As I drove, it would reduce mileage based on that initial assumption with no correction. I have a range of about 200 miles with my trailer, but it would always drop to 142 or something like that when fully charged, and it wouldn't correct.

This year, it seems much smarter about it. I'm not exactly sure when the change was made, but now when I plug in, it will drop to 142, and then immediately start climbing while I drive (my trailer is only about 2000 pounds). After about 15 minutes, it will settle out on an estimated range that so far as been pretty accurate.

As far as I can tell, the estimates were the thing that was wrong. It's not actually reducing your range by putting it into tow mode, it was just miscalculating how far you could go. The best thing you can do is check your efficiency with the trip calculator and get a feel for what your range should be. They've said there are more improvements to towing behavior and calculations coming soon.

 

[Dark-Fx]

I haven't used tow mode extensively but it doesn't seem afraid to drop the displayed range down to match reality versus the other modes that seem not to dip below rated no matter what.

 

[Zoidz]

Hopefully you understand that it's not reducing your actual range, it's just reducing the estimated range based on some predefined parameters? My understanding is that estimated range in each mode learns from your driving style (and trailer weight in towing mode) and gets more accurate over time. Since you apparently had no driving history in towing mode, it likely used aggressive predefined parameters to calculate range. I suggest using towing mode and let it learn over 50 - 100 miles if possible, and see if it gets more accurate. It's likely that the range reduction of only 8 miles was low. That's not enough mileage and variation for these algorithms to learn from when you throw a 6500 lb variation at it.

Regarding breaking something - probably not.

 

[Thedude]

Your range will be reduced regardless of what mode you’re in, tow mode just tries to show you that immediately. It’s estimated are wildly inaccurate and if you rely on them you will end up stranded. With a 6500lb boat you’re likely going to be in the range of 1.25mi/kWh or roughly 160 miles range on a full charge. Don’t trust the range estimate, trust your 15 minute efficiency meter and math. No matter how much you drive in tow mode it will not learn or adapt to be accurate.

 

[the_mace]

That change in range when you go into tow mode is an estimate of your range when towing. It starts off somewhat pessimistic but then adjusts as you tow based on how its doing. The algorithm isn't great and isn't quick enough to adapt etc (so dont trust it) but it does try to notice your efficiency and update the predictions. I've towed empty trailers (3,000 lbs) and then ones loaded (7,500 lbs) and the range is impacted by weight differences and speed. I've had their remaining range estimates be off by more than 50% on trips towing. Be careful.

 

[Dark-Fx]

This year, it seems much smarter about it. I'm not exactly sure when the change was made, but now when I plug in, it will drop to 142, and then immediately start climbing while I drive (my trailer is only about 2000 pounds). After about 15 minutes, it will settle out on an estimated range that so far as been pretty accurate.

Rivian fixed some bugs with this a few updates ago. RJ said they are working on an entirely new screen for towing that will be better at range estimation. Was hoping it was this coming update but appears not to be.

 

[the_mace]

Rivian fixed some bugs with this a few updates ago. RJ said they are working on an entirely new screen for towing that will be better at range estimation. Was hoping it was this coming update but appears not to be.

Yeah I just towed a tractor this weekend, still very buggy.

 

[azbill]

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.

 

[Thedude]

Rivian fixed some bugs with this a few updates ago. RJ said they are working on an entirely new screen for towing that will be better at range estimation. Was hoping it was this coming update but appears not to be.

Rivian said they fixed it but they really just made it worse in different ways. They need to go back to whatever tow mode calculations were in mid 2022, those were actually fairly accurate.

 

[MReda]

Rivian said they fixed it but they really just made it worse in different ways. They need to go back to whatever tow mode calculations were in mid 2022, those were actually fairly accurate.

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.

 

[Dark-Fx]

Rivian said they fixed it but they really just made it worse in different ways. They need to go back to whatever tow mode calculations were in mid 2022, those were actually fairly accurate.

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.

 

[JakeB]

Hopefully you understand that it's not reducing your actual range, it's just reducing the estimated range based on some predefined parameters? My understanding is that estimated range in each mode learns from your driving style (and trailer weight in towing mode) and gets more accurate over time. Since you apparently had no driving history in towing mode, it likely used aggressive predefined parameters to calculate range. I suggest using towing mode and let it learn over 50 - 100 miles if possible, and see if it gets more accurate. It's likely that the range reduction of only 8 miles was low. That's not enough mileage and variation for these algorithms to learn from when you throw a 6500 lb variation at it.

Regarding breaking something - probably not.

Yes, I realize it's just an estimate but being new to the EV world and towing in the EV world, it scared me enough to not even try towing the boat to the lake. Seeing what you and others have been saying, it sounds like the truck needs to learn the trailer + my driving style to get better at estimating. 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

 

[JakeB]

I'm pretty sure all it does is what you've described. I regularly switch from tow to off road and everything on the trailer appears to keep working properly.

As far as range calculations go, last year, it seemed like it would immediately just cut the range in half. As I drove, it would reduce mileage based on that initial assumption with no correction. I have a range of about 200 miles with my trailer, but it would always drop to 142 or something like that when fully charged, and it wouldn't correct.

This year, it seems much smarter about it. I'm not exactly sure when the change was made, but now when I plug in, it will drop to 142, and then immediately start climbing while I drive (my trailer is only about 2000 pounds). After about 15 minutes, it will settle out on an estimated range that so far as been pretty accurate.

As far as I can tell, the estimates were the thing that was wrong. It's not actually reducing your range by putting it into tow mode, it was just miscalculating how far you could go. The best thing you can do is check your efficiency with the trip calculator and get a feel for what your range should be. They've said there are more improvements to towing behavior and calculations coming soon.

Thanks for the response. I haven't given it enough time to learn about my driving with a trailer so maybe I'll be able to tow to the lake afterall.

 

[JakeB]

That change in range when you go into tow mode is an estimate of your range when towing. It starts off somewhat pessimistic but then adjusts as you tow based on how its doing. The algorithm isn't great and isn't quick enough to adapt etc (so dont trust it) but it does try to notice your efficiency and update the predictions. I've towed empty trailers (3,000 lbs) and then ones loaded (7,500 lbs) and the range is impacted by weight differences and speed. I've had their remaining range estimates be off by more than 50% on trips towing. Be careful.

Appreciate the response and the info. I'll be mindful of that.

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