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I guess I would guess mine is closer to the median then? What's the median based on your spreadsheet?



What's that real life range based on? 90% city driving? My range is probably closer to 60miles of highway driving at around 65mph.



What's your commute like? 50% city?

I am pretty sure battery wear depends on the use also. A slower discharge would wear the battery out less than a higher discharge rate.

Part of why I am sharing my data is to try to see how others with a similar commute is doing and what I can do to reduce battery wear.
I avoid the highway for the most part so most of my commute is at about 50mph. Maybe 6-10 (haven't counted) stop signs or stop lights each way. About 2 miles of it each way is 60-70 mph. I always try to keep to the slow lane and stay around 50mph or less as much as possible. I definitely see a sharp drop in efficiency at anything over 70mph.
 

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Thanks for doing the math for me, but I still don't trust any of those numbers.

Even though you narrowed the field to only EIGHT readings, the wear/10kMiles still goes all the way from 2.8% to a whopping 7.6% !

So according to that, one car has 271% as much degradation.
Another way of looking at it: One car has only 37% as much degradation.
To me that's literally unbelievable.

As for what you can do to reduce battery wear, you could just drive a couple mph slower:

If you tap the end of the wiper stalk it shows real-time motor kW where you'll see that it creates a much higher discharge rate at 65mph compared to 60*. So you could reduce battery wear by leaving home a few minutes earlier & driving a few mph slower. That also reduces wear by reducing the cycle depth. That might also allow you to avoid a full charge, which also reduces battery wear.

*I don't do many highway-speed trips, but I did one recently, & when I set my cruise to 55mph I got better mi/kWh than my average 75% stop&go drive. Based on that, 60mph may give about the same range as city stop&go: Yes, you get regen in the city, but it's not 100% efficient, & there's none at all below about 7mph.

I wouldn't go so far as to say it is unbelievable. The standard deviation on battery degradation is not small. It depends on manufacturing and use cases. See the data on Tesla Model S and X below:

Slope Rectangle Plot Font Line


Thanks for the suggestions on reducing my speed. Looks like my case of commuting on the highway is pretty unusual. I checked and my average for the past 2k miles is 4.5mi/kwh and 28mph, so it is not THAT bad.
 

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I wouldn't go so far as to say it is unbelievable. The standard deviation on battery degradation is not small. It depends on manufacturing and use cases. See the data on Tesla Model S and X below:

View attachment 112815

Thanks for the suggestions on reducing my speed. Looks like my case of commuting on the highway is pretty unusual. I checked and my average for the past 2k miles is 4.5mi/kwh and 28mph, so it is not THAT bad.
Compared to me that is actually excellent. I average right around 4. It sounds like you are doing things right to me.
 

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I average around 4.8 mi/kWh (75% stop&go, 25% 50-60mph)
With cruise set at 55 I got 5!

My 500e has 50,000km. According to the computer-generated trend line of the unbelievable OBD submissions, I should have nearly 20% capacity loss, which I think I'd notice, yet in reality I can't tell any difference from when I bought it with only 16,000km.

Here's that same plot as above, but from the 500e users' submissions of OBD data which I find unbelievable:
EDIT: AS I NOTED ABOVE, BELOW, & IN A GREAT MANY OTHER POSTS, I VERY STRONGLY BELIEVE THIS DATA IS EXTREMELY INACCURATELY MISLEADING:
Rectangle Slope Font Parallel Pattern

& here it is with 0% as the base line, showing the crazy-low outlier data points:
EDIT: AS I NOTED ABOVE, BELOW, & IN A GREAT MANY OTHER POSTS, I VERY STRONGLY BELIEVE THIS DATA IS EXTREMELY INACCURATELY MISLEADING:
Rectangle Slope Plot Parallel Font

EDIT: AS I NOTED ABOVE, BELOW, & IN A GREAT MANY OTHER POSTS, I VERY STRONGLY BELIEVE THIS DATA IS EXTREMELY INACCURATELY MISLEADING
 

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Thanks for reminding me I'm hauling LESS: Extra-light wheels & no rear seat.

My wheels are less aero though, which contributes to my good city range but also to the extra-sharp drop I see above 55mph. Actually even with heavy stock aero wheels there's a sharp drop above 20, which just gets steeper & steeper as speed increases, unless you're drafting a semi.
 

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Thanks for reminding me I'm hauling LESS: Extra-light wheels & no rear seat.

My wheels are less aero though, which contributes to the extra-sharp drop I see above 55mph. Actually even with heavy stock aero wheels there's a sharp drop above 20, which just gets steeper & steeper as speed increases, unless you're drafting a semi.
Im running Honda Insight 15” super light wheels, no back seats and lithium LV battery. Not sure why I can’t get it over 4 really. Part of me thinks the car is more efficient when driven harder oddly.
 

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You posted your wheel spec as 10.8Lb, basically the same as my 10.9s, & my 4.4Lb 12V is likely about the same as your lithium. Your tires might be a few pounds heavier, but I doubt it's enough for a 20% difference in efficiency. (4 vs. 5 mi/kWh). The car IS much more efficient if you're not braking below 7mph, or stopped in "ready" mode, so maybe your drives include lots of those, because other than that it really doesn't seem to be "more efficient when driven harder". I wonder what's going on.
 

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Im running Honda Insight 15” super light wheels, no back seats and lithium LV battery. Not sure why I can’t get it over 4 really. Part of me thinks the car is more efficient when driven harder oddly.
What do you typically get without towing a trailer? If most of your trips are short with a lot of time in between, you might be losing a lot of energy to battery conditioning. Driving hard might be warming the pack quicker than the battery conditioning - so your pack warms up to optimal temperature quicker so the net efficiency is higher. Just a theory, but I have seen what you are talking about in specific conditions. Accelerating hard to get to speed in some cases seems to give better efficiency than when slowly accelerating to the same speed. But for most of the time driving slower/accelerating slower gives better efficiency.

If you aren't seeing above 4 mi/kWh for trips over 10 miles going reasonable speeds (say under 60 mph) on relatively flat ground at temps above 50 F, then that is unusual. I have to try to get under 4 mi/kWh for any trip over 5 miles. I think the long term average on my car is around 4.4 mi/kWh.
 

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What do you typically get without towing a trailer? If most of your trips are short with a lot of time in between, you might be losing a lot of energy to battery conditioning. Driving hard might be warming the pack quicker than the battery conditioning - so your pack warms up to optimal temperature quicker so the net efficiency is higher. Just a theory, but I have seen what you are talking about in specific conditions. Accelerating hard to get to speed in some cases seems to give better efficiency than when slowly accelerating to the same speed. But for most of the time driving slower/accelerating slower gives better efficiency.

If you aren't seeing above 4 mi/kWh for trips over 10 miles going reasonable speeds (say under 60 mph) on relatively flat ground at temps above 50 F, then that is unusual. I have to try to get under 4 mi/kWh for any trip over 5 miles. I think the long term average on my car is around 4.4 mi/kWh.
Well I can get higher than 4 for trips of 10mi and longer, but anyone can drive downhill with a tailwind also. The real measure is 500+mi. I’d be right around 4 if I didn’t ever trailer, the trailer brings me down to 3,8 which honestly is pretty incredible given the aero and weight penalty. I dunno maybe my cars kw/mi meter is buggered?
 

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So does that mean most of your trips are short (under 5 miles)? If that is the case then you may be using a lot of power on battery conditioning rather than covering ground.

One of the cool things in the pre 2016 versions of the car with the TomTom, was the energy usage gauge. From what I understand it would give you a break down of where the energy was being used. That would be really helpful in understanding where the losses are.
 

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I don’t think there’s much pre conditioning this time of year here. But I’ve also preconditioned on the cord and don’t see a huge difference in consumption.
 

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Do you charge to 100%?

If so, there's no regen at all until it drops to about 95%, & even then it's pretty limited until I think around 90%. You can see it on the car's real-time kW display by tapping the wiper stalk tip.

If I drove mine from 100% to 90% that would be about 10 miles, so the first 10 mi of every trip would be much lower efficiency.
EDIT: That is, unless you have no downhills or stops in the first 10 miles.
 

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Do you charge to 100%?

If so, there's no regen at all until it drops to about 95%, & even then it's pretty limited until I think around 90%. You can see it on the car's real-time kW display by tapping the wiper stalk tip.

If I drove mine from 100% to 90% that would be about 10 miles, so the first 10 mi of every trip would be much lower efficiency.
My charger usually signs off around 95%
 

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I average around 4.8 mi/kWh (75% stop&go, 25% 50-60mph)
With cruise set at 55 I got 5!

My 500e has 50,000km. According to the computer-generated trend line of the unbelievable OBD submissions, I should have nearly 20% capacity loss, which I think I'd notice, yet in reality I can't tell any difference from when I bought it with only 16,000km.

Here's that same plot as above, but from the 500e users' submissions of OBD data which I find unbelievable:
View attachment 112825
& here it is with 0% as the base line, showing the crazy-low outlier data points:
View attachment 112826
Looks like my battery degradation is pretty much average for the miles based on your graph eh.

I am not sure I'll be able to tell a 20% range loss over 50k miles if my commute doesn't use a significant percentage of the battery.

What's interesting is that the battery degradation is actually quite a bit worse than Tesla, even if we are accounting for 3x more wear cycles (ie. ~91% of battery for Tesla at 250k miles compared to 80% of battery for the 500e at 50k miles.)

80% is usually cited also as design EoL for EV batteries for some reason.
 

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Looks like my battery degradation is pretty much average for the miles based on your graph eh.

I am not sure I'll be able to tell a 20% range loss over 50k miles if my commute doesn't use a significant percentage of the battery.

What's interesting is that the battery degradation is actually quite a bit worse than Tesla, even if we are accounting for 3x more wear cycles (ie. ~91% of battery for Tesla at 250k miles compared to 80% of battery for the 500e at 50k miles.)

80% is usually cited also as design EoL for EV batteries for some reason.
Do you know if the Tesla graph is percent of remaining range or if it is percent of remaining capacity on the vertical axis? I seem to recall Tesla being able to change the available capacity. For example I recall them making over the air updates to give access to more capacity during a hurricane. It could be that Tesla uses a similar strategy that GM did with the Volt by allowing access to reserve capacity as the pack ages to maintain equivalent range.

That said, it wouldn't surprise me if the cylindrical cells used in the Tesla are more robust than the pouch style cells used in the Fiat. It would be interesting to see how the Tesla BMS deals with bad cells. If it is able to effectively isolate a bad cell, then the impact of a bad cell won't be that high. On the Fiat, based on a recent thread, it appears one cell brings the effective capacity of the entire pack down to the level of the bad cell.
 

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Looks like my battery degradation is pretty much average for the miles based on your graph eh...
What's interesting is that the battery degradation is actually quite a bit worse than Tesla...
~91% of battery for Tesla at 250k miles compared to 80% of battery for the 500e at 50k miles.
  • It's kilometers on all 3 graphs above, not miles.
  • Your OBD readout may look average, compared to other Fiats' readings, but I've seen no proof of accuracy for any of those readings.
  • Fiat's unproven OBD readout looks quite a bit worse than Tesla.
However, your actual degradation seems to me very slight, based on your above report of 60 miles range at 65mph.
 

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Do you know if the Tesla graph is percent of remaining range or if it is percent of remaining capacity on the vertical axis? I seem to recall Tesla being able to change the available capacity. For example I recall them making over the air updates to give access to more capacity during a hurricane. It could be that Tesla uses a similar strategy that GM did with the Volt by allowing access to reserve capacity as the pack ages to maintain equivalent range.

That said, it wouldn't surprise me if the cylindrical cells used in the Tesla are more robust than the pouch style cells used in the Fiat. It would be interesting to see how the Tesla BMS deals with bad cells. If it is able to effectively isolate a bad cell, then the impact of a bad cell won't be that high. On the Fiat, based on a recent thread, it appears one cell brings the effective capacity of the entire pack down to the level of the bad cell.
I believe it is the capacity. See source: A look at Tesla battery degradation and replacement after 400,000 miles

My understanding is that Tesla software locks some of the battery capacity for the 60 series at some point. That was what they unlocked.

Why do you think would the cylindrical cells used in the Tesla be more robust than the prismatic cells? Does our BMS limit the low and higher end of the voltages more than the Tesla? Is the chemistry better in the Tesla or does it have better thermal management during idle/run?

  • It's kilometers on all 3 graphs above, not miles.
  • Your OBD readout may look average, compared to other Fiats' readings, but I've seen no proof of accuracy for any of those readings.
  • Fiat's unproven OBD readout looks quite a bit worse than Tesla.
However, your actual degradation seems to me very slight, based on your above report of 60 miles range at 65mph.
Yup typo. I knew it was in KM. With 3x the battery capacity: Fiat 500e's 50k miles, would be more or less equivalent to a Tesla 250,000km in terms of the number of battery cycles.

My OBD degradation reading actually lines up with the amount of charge I can put in through Chargepoint. Have you tried using chargepoint and see how much charge you can put in?

The reading on the screen for kwh/mi for the particular drive I did from 100% and correlating it to the percentage shown on the screen when I brought it down close to 10% actually shows that my battery capacity is even worse than the 21% degradation. The kwh/mi might not be accurate. However, one calculation: 65miles of travel at 4.5mi/kwh = 14.5kwh. That's a lot of degradation.

I should probably reset one of the trip meters and see what my actual average speed is for my commute. It is probably closer to the 28mph similar to 2k miles average. Not sure if it takes into account waiting on the traffic lights etc.
 

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My OBD degradation reading actually lines up with the amount of charge I can put in through Chargepoint. Have you tried using chargepoint and see how much charge you can put in?
Yes, I did that once or twice before I realized it is also inaccurate:

The only spec we have to compare grid power use is EPA's 25kWh to charge from motor shutoff to 100%, with the OEM cord on 120V, at an unknown ambient temperature (likely 20 or 25C) starting with the battery at an unknown temperature, since we don't know how hard they ran it.

It also requires first taking it to 100% in order to balance the cells before taking it below 0%. Otherwise it could take more power to balance the cells during the test, which would make the capacity appear higher than it really is.
 

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Yes, I did that once or twice before I realized it is also inaccurate:

The only spec we have to compare grid power use is EPA's 25kWh to charge from motor shutoff to 100%, with the OEM cord on 120V, at an unknown ambient temperature (likely 20 or 25C) starting with the battery at an unknown temperature, since we don't know how hard they ran it.

It also requires first taking it to 100% in order to balance the cells before taking it below 0%. Otherwise it could take more power to balance the cells during the test, which would make the capacity appear higher than it really is.
You are correct, if I am trying to compare against the EPA. However, because it is obviously difficult to do it in a temperature chamber for 18 hour or so - I am trying to compare apple to apple between my car with OBD degradation matching ChargePoint to your car. It is a lot easier to charge the car for 3 hours or so at 20-25c. I have done it a handful of times at different ChargePoint locations to the same end charge numbers (+/- 0.2kwh) so I know it is pretty precise.

What did you get on your ChargePoint charges?
 
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