Impact of cold on range, performance, battery life?

[mknox]

I can't see them moving regen to the brake pedal. It makes the system incredibly complex and is very hard to get right so that everyone will be happy. The Toyota system is pretty good (after 16 years) and people still complain about it.

I wasn't thinking they should move to that wholesale... just a user-selectable option for those that want it that way (like how they implement different steering options, or different re-gen strengths).

I still feel, no matter how well I train myself, in that panic situation on icy roads, I'm going to instinctively lift my foot off the accelerator and risk having my rear wheels break free due to "unintended" braking on that single axle.

Edit: Does anyone know if the Traction Control or ABS would work "in reverse" as in situations where the regenerative breaking is too much and traction is lost as in the above scenario?

 

[ggr]

I wasn't thinking they should move to that wholesale... just a user-selectable option for those that want it that way (like how they implement different steering options, or different re-gen strengths).

What you're asking for is very hard, since the brake pedal ONLY controls the brakes at the moment. You can select less regen, but Tesla (and I) recommend leaving it in standard regen. It becomes instinctive very quickly.

I still feel, no matter how well I train myself, in that panic situation on icy roads, I'm going to instinctively lift my foot off the accelerator and risk having my rear wheels break free due to "unintended" braking on that single axle.

Edit: Does anyone know if the Traction Control or ABS would work "in reverse" as in situations where the regenerative breaking is too much and traction is lost as in the above scenario?

Unfortunately (unless changed in a recent software update) when you lose traction under regen, say by hitting a bad bump, the regen cuts out completely for a moment. They don't seem to try to modulate it.

 

[MikeK]

I really like the regen implementation of the Model S, but I will say that this problem with the car's behavior changing when the pack is cold is not something that happens with a properly implemented "blended regen" system like on my 2002 RAV4-EV. On the RAV4, the car is able to modulate the hydraulic pressure going to the friction brakes. If it has lots of regen available, it uses regen, and very little friction. If there's no regen available, it uses all friction. And a smooth continuum in between.

 

[mknox]

What you're asking for is very hard, since the brake pedal ONLY controls the brakes at the moment. You can select less regen, but Tesla (and I) recommend leaving it in standard regen. It becomes instinctive very quickly.

I don't know if it would be that hard. There's got to be a point in the brake pedal travel where it is simply activating a switch (for the brake lights) which could be used to activate re-gen as well (I realize there is an accelerometer for the brake lights, but I assume there is a switch in the brake pedal too so that the lights stay on while you're stopped with your foot on the brake).

Unfortunately (unless changed in a recent software update) when you lose traction under regen, say by hitting a bad bump, the regen cuts out completely for a moment. They don't seem to try to modulate it.

Actually, this is better than nothing. If I lose traction under re-gen, I want the re-gen to cut out.

 

[William13]

I often have limited regen. It is noticeable but not a hazard or issue that can easily be fixed. Not a big deal IMHO.

 

[jkirkebo]

This is exactly what I've been advocating.

Fine with me as long as it's an option I can turn off. I do not want any mechanical braking to take place if I haven't asked for it.
I have no problem compensating for limited regen in my Leaf, I can't see it being a problem in the Model S either.

 

[JRP3]

When regen is reduced or cuts out you compensate by using your brakes. This would simply do the same automatically, as MikeK describes with his RAV4EV.

 

[brianman]

I would have to say no to this idea. I like to coast and friction brakes would "hurt" my coasting with no advantage to me. Regen is fine, friction brake without regen, not so fine (for me only)

Proposal: Rename regen setting to something more general like "released accelerator behavior":

Coast (new, disable regen on accelerator)
Low Regen (same as today's Low)
High Regen (same as today's Standard)
Decelerate (new, high regen with brake assist if needed)

Wouldn't this cover all the requested experiences?

 

[mknox]

Coast (new, disable regen on accelerator)
Low Regen (same as today's Low)
High Regen (same as today's Standard)
Decelerate (new, high regen with brake assist if needed)

Wouldn't this cover all the requested experiences?

Yes, this is exactly the type of thing I was thinking about. It would be particularly useful if on Coast, the first bit of brake pressure (i.e. where the brake light switch activates) could also activate Regen.

 

[montgom626]

Proposal: Rename regen setting to something more general like "released accelerator behavior":

Or how about something intuitive, like "no regen, friction brake only"

 

[jkirkebo]

When regen is reduced or cuts out you compensate by using your brakes. This would simply do the same automatically, as MikeK describes with his RAV4EV.

I understand that. I just don't want that behaviour. No regen available => coast is my preference.

 

[Robert.Boston]

The new software clearly flags when there's no regen available. I admit to be surprised that this situation occurred at only 24 degrees F; the car had been sitting out for 36 hours, but plugged in. I was assuming that, when plugged in, the battery would be kept in a temperature range that would allow some regen out of the block. Hopefully, this will be addressed with the smartphone app: when you tell the car "be ready to drive in 15 minutes," it will have warmed the battery sufficiently to allow full performance.

 

[JRP3]

I think it's going to take more than 15 minutes to warm a pack up.

 

[Jason S]

I think it's going to take more than 15 minutes to warm a pack up.

Doesn't it warm up through usage? If there is a separate heater for the battery pack, I could see how 15m would be plenty of time though. Warming the car should help in either case: usage + warmer passenger compartment.

 

[Doug_G]

I think it's going to take more than 15 minutes to warm a pack up.

The message that I got when I shut down this evening (new firmware) told me to plug in the car because the pack was cold. It also suggested that I use the remote control application to turn on the cabin heater an hour before leaving, because that will also turn on the battery heater.

Incidentally this new firmware update also popped a message after a few minutes driving to tell me that the pack was cold, and that more power would be available after driving it for a while. The yellow dotted line was only on the regen side, not the power side.

This morning I had essentially no regen when I first drove the car; outdoor temperature was -10C but I doubt my garage was quite as cold.

 

[dsm363]

The message that I got when I shut down this evening (new firmware) told me to plug in the car because the pack was cold. It also suggested that I use the remote control application to turn on the cabin heater an hour before leaving, because that will also turn on the battery heater.

Incidentally this new firmware update also popped a message after a few minutes driving to tell me that the pack was cold, and that more power would be available after driving it for a while. The yellow dotted line was only on the regen side, not the power side.

This morning I had essentially no regen when I first drove the car; outdoor temperature was -10C but I doubt my garage was quite as cold.

What software version do you have? I hadn't seen this before but it hasn't gotten below 35 here yet.

 

[Doug_G]

What software version do you have? I hadn't seen this before but it hasn't gotten below 35 here yet.

4.1 (1.19.29). Just loaded last night. (Oh and it's currently -10C / 14F here. Still fairly mild weather...)

 

[dsm363]

4.1 (1.19.29). Just loaded last night. (Oh and it's currently -10C / 14F here. Still fairly mild weather...)

Ouch, that's cold. You win. Good to hear that is an alert though when it gets cold enough and that the iPhone app may play a role in being able to heat it up before you take off. I'd imagine a 'wake up at X time' feature would also start warming the pack up before that time too.

 

[constraint]

It is 5F right now and was -7 F last night and we haven't hit February when it easily gets -20 at least a week out of the month. So is it a safe assumption that i probably wont have regen a good portion of the year?

And if cold is so bad for charging the battery packs how does that work in the winter. I plug in my NEMA 14-50 and wait 4 hours to warm the battery before it starts charging? And those stuck on 120 voltage or low amp 220 is the current even sufficient to keep the packs heated and charging in the same boat?

 

[Zas]

The message that I got when I shut down this evening (new firmware) told me to plug in the car because the pack was cold.

Thats a new one, I haven't got that yet... My worry is getting that message when arriving at the office, where I can't charge my car...I wonder about leaving this car in -20C / -4F for 8 hours a day..and how long it will take to warm up the battery, and how much energy will be used in doing so...and any long term affects of the cold on the battery.