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fergie

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I can't wait for the super Ike. But I was also happy to hear that they are showing a towing test with an teardrop trailer. I was asking for that. TFL did something similar with an ID4. The result was, IMO, pretty good.

I was happy to hear about the teardrop as well as that is my use case.
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mkennedy1996

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Wow. Long. Lots of info. Seems as though Roman has come around and gotten over his beef with Rivian. Still a curmudgeon on standard automotive design. Can’t fault him for that.
Good video TFL. Thanks @TFLtommy
I have been driving Teslas exclusively since 2015 and, with the latest Tesla software, I completely agree with him about going 3 menus deep for some items. It is actually dangerous to use some controls while driving (controls that you need while driving). I am intrigued by the Hummer's use of physical buttons that then change the options presented on the touch screen just above the button.
 

chopsui

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You don't really "gain" much battery from downhill sections, it's more that you get those sections for free. Regen is limited in how much energy it can absorb at any one time to avoid stressing the battery, so you don't get a massive boost from downhill sections vs any other braking. It maxes out at something like -2 or -3 kWh/100 mi in the EVs I've driven.

But you get the mix of free range and a slight regen, so it maths out to a massive efficiency gain.
Except that doesn't square with their stated ability to charge while being flat-towed as shown in the "Long Way Up" series. Unless they've deprecated that feature?
 

Blur1t

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Except that doesn't square with their stated ability to charge while being flat-towed as shown in the "Long Way Up" series. Unless they've deprecated that feature?
I’m
Pretty sure you flat tow in neutral, so the difference is resistance is much less in neutral unlike regen when going downhill which is like a gear reduction slow down - even though there are no “planetary gears like old school transmissions… I’m not an engineer though I could be completely wrong… but at least that’s my automotive mechanic in me thinking? ?
 

RideAlong

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Watching this, I was thinking as a truck driver I would like to be more informed; The option to see battery temperature on display would be nice.

Also a V8 Ram 1500 could not keep up with R1T pulling 8000 lb is incredible.
battery temp would be very good - smart
 

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You don't really "gain" much battery from downhill sections, it's more that you get those sections for free. Regen is limited in how much energy it can absorb at any one time to avoid stressing the battery, so you don't get a massive boost from downhill sections vs any other braking. It maxes out at something like -2 or -3 kWh/100 mi in the EVs I've driven.

But you get the mix of free range and a slight regen, so it maths out to a massive efficiency gain.
You can definitely get substantial regen from extended downhill periods. One possible factor here is that Rivian might be "braking" with regen to hold a set speed, which will activate the brake lights, which will actuate the mechanical trailer brakes, which will reduce regen.

I had this problem towing an Airstream with the Model Y - peak regen actually decreased versus driving without the trailer because the trailer brakes were eating away at my regen potential. You can partially mitigate this by dialing down the brake controller power/sensitivity, but of course you'll want those in an emergency stop.

You can definitely get substantial power back from pure regen - real-world peak regen of ~75kW is common and there are several examples of tow charging Teslas - Engineering Explained did a fun video on it and returned 1.6kWh of energy per mile towed (returning about 6 miles of range). Can You Charge A Tesla By Towing It? (With Ford Raptor) - YouTube.
 

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Flat tow for regen is nothing but a gimmick. The towing vehicle is going to operate at 25-30% of its rates efficiency, and the towed vehicle is going to gather meaningless range. Unless you want to end up with two dead EVs, you are best getting towed in neutral or have the rescue vehicle charge the disabled vehicle.

Is it theoretically possible? Yes.
Is it practical? No.
Is there some niche case that someone will claim it’s useful for, but with which I will vehemently disagree —I’m sure we will find out s00n.
 

kylealden

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Flat tow for regen is nothing but a gimmick. The towing vehicle is going to operate at 25-30% of its rates efficiency, and the towed vehicle is going to gather meaningless range. Unless you want to end up with two dead EVs, you are best getting towed in neutral or have the rescue vehicle charge the disabled vehicle.

Is it theoretically possible? Yes.
Is it practical? No.
Is there some niche case that someone will claim it’s useful for, but with which I will vehemently disagree —I’m sure we will find out s00n.
See the video I shared above. You're right about the efficiency loss on the tow vehicle side, but not on the EV - per gallon of fuel burned, it's actually more efficient to tow charge an EV and then drive that than it is to just drive an ICE truck. (The R1T is about half as efficient as the Model 3 in this video, so of course it will be more marginal.)

If you're somewhere remote and have access to a gas/diesel tow vehicle, it's a totally plausible rescue scenario and it's going to be more efficient to tow charge than to tow in neutral. Of course it shouldn't be a common/primary scenario for anyone and definitely not something you'll ever do unattended, but if you're doing a big overland crossing and run out of charge, a brief rescue tow could give you enough independence to drive the rest yourself. (At the expense of your dignity.)
 
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@kylealden makes a great point about trailer braking countering regen.

On either westbound or eastbound descent from the summit of Eisenhower tunnel, a driver would absolutely want the trailer brake controller engaged for a 8100 lb tow load. You are otherwise asking to be a beneficiary of the runaway truck ramps.

Will be interesting to see the TRL Ike vid, and as others note whether or not they had the time to finish the outbound trip to Moab.
 

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Watching this, I was thinking as a truck driver I would like to be more informed; The option to see battery temperature on display would be nice.

Also a V8 Ram 1500 could not keep up with R1T pulling 8000 lb is incredible.
Yeah, I submitted it as a feature request to customer support in December as well. It's pretty handy to see if the battery is near an optimal temp for DC charging. I'd definitely encourage people to submit it as a feature request if they want available to the user.
 

Max

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Yeah, I submitted it as a feature request to customer support in December as well. It's pretty handy to see if the battery is near an optimal temp for DC charging. I'd definitely encourage people to submit it as a feature request if they want available to the user.
Is there a specific page or email you send the request to? or just tell any CS agent in a chat or send email to general CS address?
 

SeaGeo

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Is there a specific page or email you send the request to? or just tell any CS agent in a chat or send email to general CS address?
i just email and/or chat with CS any ideas that pop into my mind that seem like they may be interesting to people other than just me (like requesting dog mode).
 

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Yeah, I submitted it as a feature request to customer support in December as well. It's pretty handy to see if the battery is near an optimal temp for DC charging. I'd definitely encourage people to submit it as a feature request if they want available to the user.
One issue is there probably isn't a single battery temp. They could give the average as an estimate.

And hopefully the range isn't that great, otherwise they have thermal design issues lol.
 

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I am no towing expert, but I would definitely not tinker with the trailer brake sensitivity and run through that Ike tunnel area. As Moosehead said, you will increase your chances of getting to try out one of those fun looking runaway truck ramps (if you are lucky enough to be near one). In my life I have literally made hundreds of trips through that tunnel In all seasons and it’s no joke. I have personally lost one very cheap Pontiac hatchback to a blown head gasket there when I was young and poor, and had more than one uHaul die on either side. I know I’m not the only one… there is always a graveyard of vehicles on that section.
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