GoM fluctuations - What's the physics behind?

[TheLight75]

Today, I arrived home from work (after a 45 mile commute, 83F) with 199 miles on the GoM. About an hour later, I went out for dinner and had 202 miles on the GoM (+3 miles? sweet! 77F). Afterwards, about 45 minutes later, I had 209 miles on the GoM when I headed back home. My Kona was in Eco mode throughout all of these.

I'm curious to better understand what physics were at play. Is this part of why some talk about the GoM being too unpredictable and why monitoring SoC & SoH are more consistent metrics?

 

[SkookumPete]

Today, I arrived home from work (after a 45 mile commute, 83F) with 199 miles on the GoM. About an hour later, I went out for dinner and had 202 miles on the GoM (+3 miles? sweet! 77F). Afterwards, about 45 minutes later, I had 209 miles on the GoM when I headed back home. My Kona was in Eco mode throughout all of these.

I'm curious to better understand what physics were at play. Is this part of why some talk about the GoM being too unpredictable and why monitoring SoC & SoH are more consistent metrics?

My guess is that you were driving efficiently around town to dinner, as opposed to your earlier highway commute. The GoM was giving weight to recent activity.

 

[KiwiME]

No doubt it's taking into account every parameter available in the car - driving history, battery and ambient temp, and driving mode at minimum, only limited by the time allocated to the software engineer for the task and his or her imagination. Given the level of questions posed to me by passer-bys when I'm charging, I can see there is a need for it. It would be better IMO if it were simply tied to the SoC by a user-adjustable multiplier and zero offset so we could each adjust it to our own wishes.

 

[Esprit1st]

No doubt it's taking into account every parameter available in the car - driving history, battery and ambient temp, and driving mode at minimum, only limited by the time allocated to the software engineer for the task and his or her imagination. Given the level of questions posed to me by passer-bys when I'm charging, I can see there is a need for it. It would be better IMO if it were simply tied to the SoC by a user-adjustable multiplier and zero offset so we could each adjust it to our own wishes.

And then people would complain that it doesn't take the other parameters into the calculation. There is no way you can make it so everybody is happy. [emoji6]

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[Jared Potter]

No doubt it's taking into account every parameter available in the car - driving history, battery and ambient temp, and driving mode at minimum, only limited by the time allocated to the software engineer for the task and his or her imagination. Given the level of questions posed to me by passer-bys when I'm charging, I can see there is a need for it. It would be better IMO if it were simply tied to the SoC by a user-adjustable multiplier and zero offset so we could each adjust it to our own wishes.

Zero offset of a GOM would be what exactly? Since the highway and city driving standards are so off of each other there really isn’t a zero point to start at unless you picked a fixed speed and flat as a zero reference and adjusted calculations from that point, faster slower up or down etc. The zero reference would arguably be the SoC which is already displayed along with the current kWh/100km, those two calculations logically seem to be what’s deciding the GOM reading.

 

[KiwiME]

Zero offset of a GOM would be what exactly?

What I mean by this is that at zero GoM there is still some SoC, just like having a reserve in your petrol tank. The following graph shows indicated GoM recorded over one week of local driving on a single charge which shows that it is already remarkably linear within 60-80% SoC and has an extrapolated offset at zero GoM of around 8% assuming the relationship continues to remains linear under 60%. All I want is the option to manually set that slope and offset.

 

[Jared Potter]

What I mean by this is that at zero GoM there is still some SoC, just like having a reserve in your petrol tank. The following graph shows indicated GoM recorded over one week of local driving on a single charge which shows that it is already remarkably linear within 60-80% SoC and has an extrapolated offset at zero GoM of around 8% assuming the relationship continues to remains linear under 60%. All I want is the option to manually set that slope and offset.

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Yes but you’re still asking for a zero state from an arbitrary position based on SOC and recent performance. What you’re essentially asking is the GOM Show a range like the bolt does or always shows worst case scenario so the number is an over estimate rather than an attempt at an exact guess.. GOM By it’s very definition is largely a guess of your range; just like an ICE GOM is.

 

[Esprit1st]

What I mean by this is that at zero GoM there is still some SoC, just like having a reserve in your petrol tank. The following graph shows indicated GoM recorded over one week of local driving on a single charge which shows that it is already remarkably linear within 60-80% SoC and has an extrapolated offset at zero GoM of around 8% assuming the relationship continues to remains linear under 60%. All I want is the option to manually set that slope and offset.

I'm not sure you can make that easy assumption. I'm guessing your drives that went into your calculation were kind of the same? Ex to work and back? This is a very specific case. Also, since your points of measurements stop at about 30 % SOC how do you know how it's behaving below that level. I'm pretty sure that graph changes, especially when turtle mode comes on.

The gom tries to work for everybody. And especially for everybody without the will to calculate graphs and adjust values. And I think it's pretty good at that.

I assume you're a very geeky person. I understand you want to have full control, I'm the same type of person, however, put yourself into an Automakers position. The liability that comes with a system that everybody can tinker with would be terrible. People getting stranded and blaming Hyundai for it because they don't understand the implications of their actions.

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