[mahlerrd]

Many of the newer cars give the current mpg rating, the bolt displays the actual usage as well, I am usually driving around 61mph and I am usually around 17kw, which I think would equate to 1.7 of his 2.8, but not sure.

I think you would do 61/17=3.59 miles per kWh. That tracks with moderately warm pleasant weather driving I do. 3.5-3.8 while doing 60.

It is exactly what I wish I had as an option to have on the display. It is NOT an instant unit, but it could easily be "instant enough" and calculated a few times per second as a weighted average of the previous couple of seconds at some reasonable sampling rate.

I do need to figure out how the units go from what they are to miles per kWh, but I am sure it will make more sense after I finish my cup of coffee.

 

[mahlerrd]

I think you would do 61/17=3.59 miles per kWh. That tracks with moderately warm pleasant weather driving I do. 3.5-3.8 while doing 60.

It is exactly what I wish I had as an option to have on the display. It is NOT an instant unit, but it could easily be "instant enough" and calculated a few times per second as a weighted average of the previous couple of seconds at some reasonable sampling rate.

I do need to figure out how the units go from what they are to miles per kWh, but I am sure it will make more sense after I finish my cup of coffee.

Btw, I think this might get around the "varies wildly" problem. Weighted averages like this are good for that. Now, which backoff algorithm to use? Some (like previous values each get cut in half each time) are trivially easy for the computer to calculate with bit shifting in an accumulator.

It does not get around what to do when regeneration is happening.

But ...

Negative miles per kWh... That doesn't not make sense. (Convolutions of English on purpose, sorry ESL folks).

So if you are regen at say 30 kW and at let's say 45 mph, and because I don't want to do TOO much math let's say it is a steep hill so the speed was nearly steady. Then after a few seconds of this it would settle to..
-1.5m/kWh
Meaning of you did this for a mile, you would add 1.5 miles to the... "Expected range"?

Yeah. I don't see a problem with this? But it feels wrong and I am not sure why, or if the feeling is accurate.

But also STILL haven't finished the coffee.

 

[Voldar]

They could!

Though they don't. And let me tell you why :

• in an ICEV, the gauge is based on a float sensor that only gives a height reading, not volume. And tanks are oddly shaped (to fit around seats, axles, etc.), so “height” doesn’t translate linearly into “gallons.”
• in the case of an EV, the BMS is the one that measures the voltage of the cells and then does the math to give the capacity in kWh. Problem is, the BMS readings are dependent on temperature, degradation, discharge rate, and manufacturer-defined “buffers” at the top and bottom of the pack to protect the cells.

So yeah... I doubt there will be ever a kWh left in the battery number posted by a manufacturer. kWh used, that's no problem ! It exists in all EV.

 

[Voldar]

The exact same idea works perfectly fine, maybe even better in the miles/kWh display.

I understand what you are saying but it is not the same.

As I mentioned, I already know what the efficiency I need to get to drive from A to B. In the metric system that the Bolt has, I can very well control the power used to move the vehicle to make sure I get the efficiency I need. No need for any mental math. In the US units GOM display, I can't do this on the fly based on the information I get from the GOM : power in kW and efficiency in mi/kWh.

 

[mahlerrd]

Though they don't. And let me tell you why :

• in an ICEV, the gauge is based on a float sensor that only gives a height reading, not volume. And tanks are oddly shaped (to fit around seats, axles, etc.), so “height” doesn’t translate linearly into “gallons.”
• in the case of an EV, the BMS is the one that measures the voltage of the cells and then does the math to give the capacity in kWh. Problem is, the BMS readings are dependent on temperature, degradation, discharge rate, and manufacturer-defined “buffers” at the top and bottom of the pack to protect the cells.

So yeah... I doubt there will be ever a kWh left in the battery number posted by a manufacturer. kWh used, that's no problem ! It exists in all EV.

I think you are thinking of 1970's cars. Don't worry, that's where my brain gets stuck occasionally too

I haven't seen a modern car where the fuel gauge doesn't perfectly track "gallons". I can predict almost exactly how much gas will go into it by a careful look at the gauge before I start pumping. I am nearly positive they do this because there's a mapping from raw reading into actual volume left which takes into account the shape of the tank.

In addition, they also have very good flow sensors to calculate instant use.

The only reason I can think of is because "that's not how we do it".

 

[Voldar]

The only reason I can think of is because "that's not how we do it".

I would say that it is also related to calls from angry owners who'd say : you sold me a 64 kWh battery and I drove yesterday and used for 200 miles 54 kWh and what was left was 8 kWh. That's 2 kWh less than what you sold me !
Heck, why do you think the forum agreed to post a thread about the GOM numbers and to close all the threads related to the questions regarding this subject (why it showed 270 miles yesterday and now it is 240 miles, is something wrong with my battery???)

 

[mahlerrd]

I understand what you are saying but it is not the same.

As I mentioned, I already know what the efficiency I need to get to drive from A to B. In the metric system that the Bolt has, I can very well control the power used to move the vehicle to make sure I get the efficiency I need. No need for any mental math. In the US units GOM display, I can't do this on the fly based on the information I get from the GOM : power in kW and efficiency in mi/kWh.

You keep calling it "metric" vs "US units" though. It is convention, but not anything metric based.

My counter was if it reported "kWh per 100 miles" which would that be? Metric or US?

And which "style" or "convention" you are used to very, very heavily influences which you think is easier.

The problem with the traditional metric-style units is that one still has to do math on what percentage of 100 km away my destination is, and also what kWh is still in the battery.

The problem with US style is that I still have to do math on what multiple of miles/kWh shown am I from my destination, and also what kWh do I have left in the battery.

Again for clarity: They both involve similar math, and whichever you "grew up with" is far, far easier for you because you have trained your brain to think of the problem from that angle. The other way is "weird and hard and backwards". Personally, I have no problem with either.

 

[mahlerrd]

I would say that it is also related to calls from angry owners who'd say : you sold me a 64 kWh battery and I drove yesterday and used for 200 miles 54 kWh and what was left was 8 kWh. That's 2 kWh less than what you sold me !
Heck, why do you think the forum agreed to post a thread about the GOM numbers and to close all the threads related to the questions regarding this subject (why it showed 270 miles yesterday and now it is 240 miles, is something wrong with my battery???)

I think you answered your own comment.

Any system that isn't 100% accurate and consistent will be misunderstood.

The GoM, even the battery percent indicator. This would be no different.

 

[Voldar]

You keep calling it "metric" vs "US units" though. It is convention, but not anything metric based.

I keep calling metric and US units because this is how GM named the two in the Bolt EV.
Or else I would call it metric and imperial...

• Metric because it has km in it.
• Imperial because it has miles in it.

 

[mahlerrd]

I keep calling metric and US units because this is how GM named the two in the Bolt EV.
Or else I would call it metric and imperial...

• Metric because it has km in it.
• Imperial because it has miles in it.

Well, fair enough!

Darn GM.

As long as everyone understands...

 

[SpaceBolt]

Although I haven't checked our Bolt, our EV6 “fudges” the reporting of the SOC on the information panel. Using an OBD2 you see two readings, the BMS and the battery SOC. For example, when the SOC reads 84%, the BMS SOC reads 82.5%, the latter matching the information panel.

I've been thinking of making some unique read-outs for Car Scanner Pro which will do the calcs I wold like to have for long trips. However, I don't think the calcs will change my driving habits on long trips, as usually our stops are planned around biology and not car range.

 

[Voldar]

Any system that isn't 100% accurate and consistent will be misunderstood.

This is why it grew in me the Tesla approach. Before, I hated it, but once you understand what it represents, you understand why it is the better approach.
In the UI, you are always presented the EPA rated range based on the battery SOC and degradation. That's not the estimated range that many people, event Tesla owners consider it is. You can change the number in a %SOC and that's the best way to do. In the Energy app, you are always presented the estimated range based on the driving you do/did in the last 15/100/300 km (metric version) and the %SOC of the battery. That's a better approach also. And you can reset the numbers too.

And ScanMyTesla confirms that the %SOC in the UI is the one registered by the scanner, in .5 increments.

 

[mahlerrd]

This is why it grew in me the Tesla approach. Before, I hated it, but once you understand what it represents, you understand why it is the better approach.
In the UI, you are always presented the EPA rated range based on the battery SOC and degradation. That's not the estimated range that many people, event Tesla owners consider it is. You can change the number in a %SOC and that's the best way to do. In the Energy app, you are always presented the estimated range based on the driving you do/did in the last 15/100/300 km (metric version) and the %SOC of the battery. That's a better approach also. And you can reset the numbers too.

And ScanMyTesla confirms that the %SOC in the UI is the one registered by the scanner, in .5 increments.

If Tesla hewed more closely to standard physical controls, I would probably have one.

 

[Voldar]

If Tesla hewed more closely to standard physical controls, I would probably have one.

I didn't post for show off, it was more like an example of what others do.

 

[mahlerrd]

I didn't post for show off, it was more like an example of what others do.

Oh no, I inderstand completely.

Tesla has some good software with great information in it.

They just threw away too many longstanding traditional control mechanisms for me.

 

[mahlerrd]

BTW, quite the interesting conversation we are having here. It underscores how what you experience daily can be so much easier for you to understand than the things you don't regularly experience, that it is baffling how anyone could possibly think "that other way" is easy.

I have driven with both enough that while I am still way more at ease with miles per kWh or gallon, I can certainly admit that gallons per 100 miles, liters per kWh - those would also be fine.

I will say that I think many (most?) folks nowadays literally don't think about it or care. They put gas in the car when they get to whatever they feel is "low". They charge their car when they don't have a lot of charge. Everything else is "too much math" or "too much hassle" or "too much thinking."

It is kinda sad.

 

[BehindBars]

I will say that I think many (most?) folks nowadays literally don't think about it or care. They put gas in the car when they get to whatever they feel is "low". They charge their car when they don't have a lot of charge. Everything else is "too much math" or "too much hassle" or "too much thinking."

It is kinda sad.

My wife might represent the common car driver nowadays. Having driven the Bolt for two years, she understands the speedometer, the one big range number, the FM radio, the time, and temperature. Nothing else on the dispays means anything to her.

 

[SpaceBolt]

My wife drives the Bolt now, and after our 3000+ mile trip to Iowa last summer, she knows the information panel pretty well, although I did all of the driving. Instead of looking at the range guesstimates on the GOM, she uses the SOC percentage bar on it as a “gas gauge.” She prefers a fill up anytime it gets close to 25%, same as her former ICE vehicle. On the times she plugs it in, she'll comment how nice it feels not going to a gas station.

 

[GregBrew]

Although I haven't checked our Bolt, our EV6 “fudges” the reporting of the SOC on the information panel. Using an OBD2 you see two readings, the BMS and the battery SOC. For example, when the SOC reads 84%, the BMS SOC reads 82.5%, the latter matching the information panel.

I've been thinking of making some unique read-outs for Car Scanner Pro which will do the calcs I wold like to have for long trips. However, I don't think the calcs will change my driving habits on long trips, as usually our stops are planned around biology and not car range.

Yup. I don't need a 600 mile EV, when I've got a 200 mile bladder.

 

[mahlerrd]

Yup. I don't need a 600 mile EV, when I've got a 200 mile bladder.

I am of a similar opinion, but I want a 200 mile usable range in sub-zero temperatures, with another 50 mile cushion after that.

I think EPA rating around 450 would do it. No more is needed. And that's a fairly "loose" "need". 375, 400 - those might work well enough especially with a heat pump.

But -10F (or -25F, the night I ran out of charge) ... I don't want to be cold and also worrying about a 125 mile, no chargers in sight drive. They exist in abundance around here.

And according to "coming soon" lists, that isn't gonna be solved in the next round of charger buildouts.