New UMC...got a higher "standard" 90% charge :confused:

ckessel · Jan 15, 2015

(Mods: wasn't sure what thread this should go into so move it if you can think of one.)

This is just a curiosity question, there's no problem to be solved, but I was curious if anyone could explain it.

I've got a 2 year old Model S now with 30,000 miles on it. The 90% charge nets me about 222-224 miles. Aside from the expected slow degradation, it's been extremely predictable and consistently getting the same range each morning after a charge.

Now for the puzzle...

Tesla gave me a new UMC on Saturday because my previous one had a charge fault (some degradation on a pin). I charged with the new one for the first time Monday night and came down to 227 miles of range in the morning. I haven't seen 227 in many months! Like I said, ~223 is the typical amount.

Nothing else changed, just the UMC. Why would swapping out the UMC suddenly bump my range a few miles on the next charge? Pure coincidence that happened the same night some sort of internal battery leveling occurred?

It's not a big change, but since my charges have been so incredibly consistent, it made me curious.

N4HHE · Jan 17, 2015

I charge to about 80% and without moving the slider I find 205 to 211 miles awaiting each morning. I suspect it was just dumb luck that you had a consistent 222-224 for so long.

bollar · Jan 17, 2015

I would look at the slider and confirm it's still set to 90%. If so, perhaps move it to some other value and back.

ckessel · Jan 17, 2015

bollar said:
I would look at the slider and confirm it's still set to 90%. If so, perhaps move it to some other value and back.

Yea, that was the first thing I checked.

Chalking it up to happy coincidence.

swegman · Jan 17, 2015

I charge to 89% and always get 236 or 237 miles range.

Alysashley79 · Jan 17, 2015

Maybe the cable wasn't doing what it was supposed to because of the fault. Ive had six (no that's not a typo) UMCs and a couple of them did some weird things when they were going out. I've got 39k miles on my 15 month old. And I get 231-232 in the winter and 233-234 in the summer at 90%.

Gizmotoy · Jan 18, 2015

swegman said:
I charge to 89% and always get 236 or 237 miles range.

Nice! I didn't even get that many miles at 90% when my car was brand new. I got the usual 235. With 9k miles I'm down to 231.

NoMoGas · Jan 18, 2015

A common misconception is that this number is static, it isn't. It's based on the last 5 drive cycles. Ive gotten (at 100%) between 260 and 279. So the only way to try know is company W/hr usage SOC and note any decline.

Gizmotoy · Jan 18, 2015

NoMoGas said:
A common misconception is that this number is static, it isn't. It's based on the last 5 drive cycles. Ive gotten (at 100%) between 260 and 279. So the only way to try know is company W/hr usage SOC and note any decline.

Is that actually true? Tom Saxton's talk at TMC Connect indicated the opposite, and he's doing longitudinal studies on this stuff. Considering your "Rated Miles" are tied to the EPA methodology and have no relation whatsoever to how you actually drive, and that the display is in terms of these "Rated Miles," I'm surprised it would change based on any driving style.

AmpedRealtor · Jan 19, 2015

I have an extremely efficient driving style and my range at 90% charge has not improved. My last five drives were under 290 Wh/mi, yet my 90% charge remains 129 miles.

GoBlue88 · Jan 19, 2015

N4HHE said:
I charge to about 80% and without moving the slider I find 205 to 211 miles awaiting each morning. I suspect it was just dumb luck that you had a consistent 222-224 for so long.

Yeah, I charge to about 65% and every morning the number of rated miles showing on the dash ranges from 164-172 miles.

Gizmotoy · Jan 20, 2015

GoBlue88 said:
Yeah, I charge to about 65% and every morning the number of rated miles showing on the dash ranges from 164-172 miles.

The variation likely corresponds to how long the car sat before you got back to it. To reduce the number of charge cycles, even when connected the car seems to let the batteries discharge a bit from the requested SOC before it charges back up (in your case, for example, it might wait until it gets to 55% before charging back up to 65%, so when you get to the car in the morning it might be anywhere from 55% to 65%). I time my 90% charges so they're complete about 10-15 minutes before I leave in the morning, and my range is consistent to within 2 tenths of a mile (disregarding the slow, but linear decline as the battery ages).

ckessel · Jan 24, 2015

So, it hovered around 225 the last couple times, so a bit off of the 227, but higher than the 222-223 I had been getting. Then last night my car updated to 6.1 and after charging to my normal 90% charge I had...242!

I'm not sure I had 242 since it was brand new. I'm not sure what it even means other than maybe 6.1 rejiggered the balancing algorithms.

Edit: And...back to 226 this morning. Darn, I had my hopes up that my degradation had been a byproduct of poor balancing. I guess not

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New UMC...got a higher "standard" 90% charge :confused:

ckessel

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N4HHE

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bollar

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ckessel

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swegman

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Alysashley79

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Gizmotoy

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NoMoGas

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AmpedRealtor

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GoBlue88

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ckessel

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