0°F Commute Efficiency

[R1TLG20BM]

Anyone know how long the battery lasts running aux heat and accessories only? Maybe I butchered that description, interested for emergency purposes if you're stuck somewhere. ICE vehicles can idle running heat and radio for seemingly days if fueled up. What's the equivalent for the R1 considering maybe 80% charge at 18F external temps?

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[itselectric]

Well this could be misleading if they had a relatively short trip then it probably spent the whole trip getting battery/cabin to temp then efficiency would shoot up to normal. The best solution (realistically) is for departure schedule. Can use charger to warm up car/battery then the trip will be relatively normal, just a bit low.

Don't go off the deep end based on this data point. Between the short 20 minute drive and HVAC set to 76 degrees (!), this is a data point that absolutely should not be extrapolated to a full range number.

Setting the HVAC to a more reasonable temp (68 or so) and on a longer drive, I would expect efficiency to be higher by at least 25%, if not more.

A tip for everyone, the HVAC is not even necessary at ambient temps above freezing, body heat alone in a pre-heated cabin maintains comfortable temps in the high 60's. I say this based on actual testing with independent bluetooth temperature sensors. It's especially true on a sunny day, subtract a few degrees for overcast conditions.

I get you both. I think my original point still remains. My efficiency even in Texas has been cut down a good number, as expected. Work to be done.

 

[bdavis171]

Don't go off the deep end based on this data point. Between the short 20 minute drive and HVAC set to 76 degrees (!), this is a data point that absolutely should not be extrapolated to a full range number.

Setting the HVAC to a more reasonable temp (68 or so) and on a longer drive, I would expect efficiency to be higher by at least 25%, if not more.

A tip for everyone, the HVAC is not even necessary at ambient temps above freezing, body heat alone in a pre-heated cabin maintains comfortable temps in the high 60's. I say this based on actual testing with independent bluetooth temperature sensors. It's especially true on a sunny day, subtract a few degrees for overcast conditions.

Come to Minnesota, the temps were -7F this morning on my commute. 76 kept it mild, but by no means warm. Luckily I don't need the great efficiency for in town commute, but if I was planning a long trip, wearing my ice fishing clothes to make it to the next charger seems unreasonable.

 

[JamesPolk24]

If you want efficiency.

1) Dress for the weather. ie Base layer, heated jacket, then down jacket, then overcoat- layer up. Insulated pants. Merino wool hat/balaclava. Merino socks. (I dress this way since I sometimes work outside)
2) Pre heat just the steering wheel and seat heater - No conditioning. Only fan on speed 1.
3) Drive in conserve

 

[Redmond Chad]

Anyone know how long the battery lasts running aux heat and accessories only? Maybe I butchered that description, interested for emergency purposes if you're stuck somewhere. ICE vehicles can idle running heat and radio for seemingly days if fueled up. What's the equivalent for the R1 considering maybe 80% charge at 18F external temps?

I have no testing results to report, but some back-of-the-napkin math:

I believe Rivian is working on a heat pump, but so far is still using resistance heaters. Say it's similar to a 1500W hair dryer. But it probably won't be full blast all the time, so let's say it averages 1000W of output. That's 1kW. So if you have 80% of a 135kWh battery to use, it should run for somewhere in the vicinity of 108 hours if you are just sitting still. There will be some other drains, but in this scenario HVAC is going to overwhelm them.

 

[DJG]

Come to Minnesota, the temps were -7F this morning on my commute. 76 kept it mild, but by no means warm. Luckily I don't need the great efficiency for in town commute, but if I was planning a long trip, wearing my ice fishing clothes to make it to the next charger seems unreasonable.

Well perhaps you just run cold body wise, because 68, or 70, or 76 is an absolute temp and doesn't matter what ambient is outside. If it's negative outside, my guess is you are already dressed such that 68, or even 62 would feel balmy. I keep my house at 68 in the winter and only wear single layer clothing inside. Unless you're saying it physically can't heat the cabin up in those temps, in which case the setting doesn't matter, it will just be running constantly to tap out at some max temp of only 60 degrees or something like that. It may have a max heating ability of XX above ambient.

But the point is if you need the range, setting HVAC to 76 is going against you. I know on my eTron, it would adjust the range estimate with every change to HVAC settings. It would knock a couple miles off adjusting by single degree increments on heat in cold weather (by cold I mean 30's).

 

[R1TLG20BM]

I have no testing results to report, but some back-of-the-napkin math:

I believe Rivian is working on a heat pump, but so far is still using resistance heaters. Say it's similar to a 1500W hair dryer. But it probably won't be full blast all the time, so let's say it averages 1000W of output. That's 1kW. So if you have 80% of a 135kWh battery to use, it should run for somewhere in the vicinity of 108 hours if you are just sitting still. There will be some other drains, but in this scenario HVAC is going to overwhelm them.

Better than I would have thought just from a gut feeling. I did some paper knapkin math and got similar numbers as well. All based on assumptions of course. Thanks for the validation, good to have in the back of my mind and hopefully never need it.

 

[DJG]

I have no testing results to report, but some back-of-the-napkin math:

I believe Rivian is working on a heat pump, but so far is still using resistance heaters. Say it's similar to a 1500W hair dryer. But it probably won't be full blast all the time, so let's say it averages 1000W of output. That's 1kW. So if you have 80% of a 135kWh battery to use, it should run for somewhere in the vicinity of 108 hours if you are just sitting still. There will be some other drains, but in this scenario HVAC is going to overwhelm them.

It doesn't really apply to a standstill scenario, but remember that they also scavenge heat from the drivetrain, so after a bit of driving it would need to tap the resistive heating less and thus be more efficient. Another reason cold weather efficiency improves with driving (everything warms up and is more efficient).

 

[Sprout]

It was -20F when I got to work on Monday morning after my 70 mile drive. Grateful to have 120v to plug into durring my shift.

 

[bdavis171]

Well perhaps you just run cold body wise, because 68, or 70, or 76 is an absolute temp and doesn't matter what ambient is outside. If it's negative outside, my guess is you are already dressed such that 68, or even 62 would feel balmy. I keep my house at 68 in the winter and only wear single layer clothing inside. Unless you're saying it physically can't heat the cabin up in those temps, in which case the setting doesn't matter, it will just be running constantly to tap out at some max temp of only 60 degrees or something like that. It may have a max heating ability of XX above ambient.

But the point is if you need the range, setting HVAC to 76 is going against you. I know on my eTron, it would adjust the range estimate with every change to HVAC settings. It would knock a couple miles off adjusting by single degree increments on heat in cold weather (by cold I mean 30's).

The 76F the cabin is set at is not actual the cabin temp. I keep my house at 66F. The Rivian struggles to keep cabin temps up in the cold. It would be interesting to see SET vs ACTUAL at various outside temps.

 

[Tahoe Man]

Yes, very cold weather kills range.
Now imagine that very cold weather range while towing uphills.

 

[Aag12]

I'm on a road trip from CO to MI. I've been getting crushed on efficiency. Still halfway there, but drove over the last 24hrs mostly in single digit weather, going 75 to 85mph, a headwind, with blizzak-lt, and ram 20" that pokes out half an inch or so. So a lot going against me. Only keeping heat at 68 and driving in conserve at lowest

So stopping a lot more than usual. What makes it worse are the charging speeds with EA. The car keeps saying the battery needs to cool down after a few minutes. Makes no sense. I think it's a car issue, not an ea issue

Surprisingly I've had zero issues with ea so far.

 

[Count Orlok]

based on what I saw in <10 degree F weather thus far it is almost as if Rivian didn't test for cold weather.

 

[Dirtman16]

I'm on a road trip from CO to MI. I've been getting crushed on efficiency. Still halfway there, but drove over the last 24hrs mostly in single digit weather, going 75 to 85mph, a headwind, with blizzak-lt, and ram 20" that pokes out half an inch or so. So a lot going against me. Only keeping heat at 68 and driving in conserve at lowest

So stopping a lot more than usual. What makes it worse are the charging speeds with EA. The car keeps saying the battery needs to cool down after a few minutes. Makes no sense. I think it's a car issue, not an ea issue

Surprisingly I've had zero issues with ea so far.

That efficiency, given the challenges you list, doesn't seem too horrible. It's certainly usable, if annoying.

Regarding the cooling of the battery while charging, I've seen OutofSpecKyle note this on several of his Rivian charging videos. It appears they did not size the cooling effectively or design the heat transfer mechanism correctly to sustain high rate charging for longer periods. It's a shame really, as that's something that needs to be right in the absence of 800v architecture.

 

[Mjl]

What if ~1/2hr before you left - you increased the charge limit to 85% so the battery could heat up a little? Not sure if this would make a difference.

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