Cabin & seat heater impact on range?

[mikehmb]

Hey folks - has anyone had an opportunity to see what the range hit is when you’re heating up the cab and/or running the seat heaters?

By way of comparison, if I run the filament defrost and seat heaters in the eGolf, it’s about a 1% hit. If I run the cabin heater (ambient 45 degrees, interior set to 68) it’s more like 15%.

Bonus: if anyone has technical details on how the cabin heater works, that would be great. (I don’t think it takes waste heat from the battery cooling system?)

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[RivnSoon]

I would also like to know.
The ambient temp on my regular morning drive was lowest in my R1T ownership thus far, 45F. Used driver seat heater on max for less than 10 min total, and 72F HVAC heat with recirculation, for about 1.25h drive time. Total rage difference I saw was about 13 miles less range indicated. Of course this is not supported by any hard data, just indicated range loss. My usual indicated range is very well established because of my daily commute over same roads and speeds.

 

[mikehmb]

I should clarify some eGolf stats because I gave a % of use which is kind of meaningless for comparison to a car that weights less than half and has a battery 1/4 the capacity …

eGolf gets about 4mi/kwh, 35 kwh battery, so around 140 miles range at 70 mph (with a stretch of road in town at 45, a climb over a 2k’ mtn, and a twisty road for about 12 miles total to start) for the commute (40 miles, one way). That 40 miles uses 10kwh, so 15% = 1.5kwh.

So … I’m using about 1.5kwh to heat the cabin if I leave it on for the entire drive.

 

[mkg3]

I believe cabin heater use is much more demanding on power than using other means to get comfortable in a cold weather. For an example on my Model 3, it's more of an impact to use the heater than AC.

I've read that using the steering wheel heater and the seat heater is significantly less demanding than using the heater. Sweater use is probably helpful too

 

[kylealden]

I haven't noticed any meaningful impact from HVAC, but haven't done any rigorous testing.

That said:

Direct heat (seat/wheel) is more efficient than HVAC, because the transmission is less lossy (a wire is heating your body instead of heating air, only some of which ever touches you, and most of which is lost to the ambient temperature).

Cooling is much more efficient than heating, since it uses an air conditioner (heat pump). The R1s currently use resistive heaters, which are pretty inefficient.

All that being said, the R1 batteries are enormous relative to cabin volume. The marginal impact of HVAC is going to be much less than in say a Tesla Model Y, which is about twice as efficient / half the battery for a similar cabin volume to an R1T. (R1S probably fares a bit worse here with so much more interior space to heat.)

We'll see how winter goes, but in four months of driving I haven't thought about HVAC at all.

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