[Voldar]

But -10F (or -25F, the night I ran out of charge)

Being that those days of -10F or -25F are pretty much gone, you don’t need to worry about.
I was amazed to see that this winter in Quebec there were not many days (not nights) with temperatures below -20C. And most of those days I don’t get out of the house anyway, and if I have to, it’s not more than maximum 30-40 km round trip. And any EV that has a 75-80 kWh battery can do at least 200 miles in comfort. At least this is my experience in my Tesla.

 

[mahlerrd]

Being that those days of -10F or -25F are pretty much gone, you don’t need to worry about.
I was amazed to see that this winter in Quebec there were not many days (not nights) with temperatures below -20C. And most of those days I don’t get out of the house anyway, and if I have to, it’s not more than maximum 30-40 km round trip.

My charge went from 7% to 0% in about 1000 feet this past winter. It was -19F when that happened, by the time the tow truck was there it was -24F. It got to -31F that night.

While you tare correct that it is slightly more rare now, it is not unheard of here. And at 55 I probably won't live long enough to...

NVM, we are "fixing" this problem quickly, aren't we?

 

[Voldar]

My charge went from 7% to 0% in about 1000 feet this past winter. It was -19F when that happened, by the time the tow truck was there it was -24F. It got to -31F that night.

While you tare correct that it is slightly more rare now, it is not unheard of here. And at 55 I probably won't live long enough to...

I doubt it was the temperature the real cause, it may be the unbalanced cells due to almost always charging only to 70 or 80% and never to 100%.

NVM, we are "fixing" this problem quickly, aren't we?

Definitely. When some can’t see a problem, the problem solves itself … when it’s about Earth magnitude.

 

[mahlerrd]

I doubt it was the temperature the real cause, it may be the unbalanced cells due to almost always charging only to 70 or 80% and never to 100%.

Definitely. When some can’t see a problem, the problem solves itself … when it’s about Earth magnitude.

The temperature probably wasn't the sole reason, but it was why I was getting terrible efficiency and certainly was an extremely large factor.

100% charge was only hours before. That was the second time in the space of, oh, two weeks? Charged to 100% twice and left on the charger that way overnight.

But it was the first time under 10%.

Still, one wouldn't expect what happened. and the only reason it was that low was because it was cold as heck and I am old enough I can't sit in a frigid car for a couple of hours without dying of hypothermia.

I tested later and 4% was the death knoll. But all voltages from cells went down more or less in lockstep, none showed significant variation from the others. "Nothing is wrong" other than the BMC isn't as smart as it should be or something.

That removed the bottom 5-10% from being usable. I won't trust it. So whack another 20-40 miles off my usable range.

(There's a thread in here somewhere about it. Consensus is that we have only theories, no actual measurable reason and no smoking guns anywhere.)

 

[GregBrew]

I doubt it was the temperature the real cause, it may be the unbalanced cells due to almost always charging only to 70 or 80% and never to 100%.

Definitely. When some can’t see a problem, the problem solves itself … when it’s about Earth magnitude.

It helps if you stop looking for, and measuring it, too.

 

[mahlerrd]

A last question. Well probably not, but at least only one more "for now".

I have heard claims the little gauge's baseline is your current m/kWh. So if that's currently 4.6, then if your little bar is green and above the middle miles display, then you are getting above 4.6 m/kWh. Likewise if it i below and yellow, you are getting worse than 4.6.

How sure of that are we?

Because I just had a 4.6 m/kWh 45-50 mile trip and over known stretches of road where it would be extremely surprised if I were running above 4.6, the little bar was green and above over a continuous many-minute period. And then efficiency dropped to 4.5 while the little bar stayed green and positive so clearly I was not maintaining over 4.6 miles/kWh.

This makes me think it is in reference to 4.0 miles/kWh, which is the "default" it uses. So I was probably running 4.2 or so at that time, the bar stayed above and green, but my efficiency went down from 4.6 to 4.5.

And there is absolutely nothing wrong with that, I am just curious if we know for sure or not?

 

[bisco]

what formula do they use for 'current m/kwh'?

 

[mahlerrd]

what formula do they use for 'current m/kwh'?

Since reset, it is just miles over kWh used.

I think that little gauge might show your efficiency based off 4.0 miles/kWh baseline. Not if you are driving more or less efficiently than your current average. Honestly am not positive, but have some minor evidence in favor of this.

 

[md.]

A last question. Well probably not, but at least only one more "for now".

I have heard claims the little gauge's baseline is your current m/kWh. So if that's currently 4.6, then if your little bar is green and above the middle miles display, then you are getting above 4.6 m/kWh. Likewise if it i below and yellow, you are getting worse than 4.6.

How sure of that are we?

Because I just had a 4.6 m/kWh 45-50 mile trip and over known stretches of road where it would be extremely surprised if I were running above 4.6, the little bar was green and above over a continuous many-minute period. And then efficiency dropped to 4.5 while the little bar stayed green and positive so clearly I was not maintaining over 4.6 miles/kWh.

This makes me think it is in reference to 4.0 miles/kWh, which is the "default" it uses. So I was probably running 4.2 or so at that time, the bar stayed above and green, but my efficiency went down from 4.6 to 4.5.

And there is absolutely nothing wrong with that, I am just curious if we know for sure or not?

I doubt that it has anything to do with the mi/kWh that's being displayed because that number is based on your driving since you last reset the trip meter. I think it's related only to the guess-o-meter number.

My assumption is that the GoM is based on something like the last 20 or 50 or 100 miles of driving, perhaps weighted more toward your most recent driving, and the little bar extends either toward the Min number or the Max number based on how your efficiency is trending across a smaller number of miles. So, if you keep driving how you're driving right now, you'll get a little closer or a lot closer to either the Min or Max.

 

[mahlerrd]

I doubt that it has anything to do with the mi/kWh that's being displayed because that number is based on your driving since you last reset the trip meter. I think it's related only to the guess-o-meter number.

My assumption is that the GoM is based on something like the last 20 or 50 or 100 miles of driving, perhaps weighted more toward your most recent driving, and the little bar extends either toward the Min number or the Max number based on how your efficiency is trending across a smaller number of miles. So, if you keep driving how you're driving right now, you'll get a little closer or a lot closer to either the Min or Max.

I think it is fascinating that we have an intuitive idea of what it means, yet really don't know what it actually specifically means. Better, worse; no argument. But the definition of those two words is up in the air.

 

[bisco]

i drive the same places every day, and sometimes i get the good symbol, and sometimes the bad. i have no idea why