Impossible Efficiency - What's going on?

[AaronTV]

2021 Premium awd/extended range

I charged to 90% on Tuesday and the car reports 33% remaining as I'm typing this. I noticed the car was recording some absurdly efficient trips during this stretch (like 17.9 miles, using 1.5 kWh). Anyway, the totals break down as follows:

Starting charge 90%
Finishing charge 33%
Miles 252.4
Vehicle reported energy used 46 kWh

Efficiency: 5.49 miles/kWh
Range at 100%: 483 miles

Even if I use the percent of battery used (57% * 88 kWh) that's still 5 miles/kWh or like 440 miles of range.

There's just no way that's possible, right? I was getting nervous that the battery was gonna run out even though the car thinks there's 33% remaining. I'm gonna charge to 100% tonight. Maybe it was some kind of temporary fluke due to the 3 OTAs that installed during the same time frame. Or maybe its ability to track the miles is grossly inaccurate, but I assume it uses the odometer start/stop readings to calculate trip distance.

Any thoughts or advice?

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[Kamuelaflyer]

Don’t believe everything you read.

In my case though, this is accurate. It’s also all downhill. And using a less than scientific measurement system.

 

[Maquis]

Negative elevation change, tail wind, ideal temps…..I can get 4.5+ miles per kWh.
The one number I tend to believe is the % remaining.
Many of us would contend that our battery now has 91 kWh usable thanks to updates.

Just my random thoughts…

 

[AaronTV]

This was a mix of city/highway and we don't have any substantial hills around here. It definitely wasn't because of cruising downhill.

 

[hybrid2bev]

2021 Premium awd/extended range

I charged to 90% on Tuesday and the car reports 33% remaining as I'm typing this. I noticed the car was recording some absurdly efficient trips during this stretch (like 17.9 miles, using 1.5 kWh). Anyway, the totals break down as follows:

Starting charge 90%
Finishing charge 33%
Miles 252.4
Vehicle reported energy used 46 kWh

Efficiency: 5.49 miles/kWh
Range at 100%: 483 miles

Even if I use the percent of battery used (57% * 88 kWh) that's still 5 miles/kWh or like 440 miles of range.

There's just no way that's possible, right? I was getting nervous that the battery was gonna run out even though the car thinks there's 33% remaining. I'm gonna charge to 100% tonight. Maybe it was some kind of temporary fluke due to the 3 OTAs that installed during the same time frame. Or maybe its ability to track the miles is grossly inaccurate, but I assume it uses the odometer start/stop readings to calculate trip distance.

Any thoughts or advice?

Like @Kamuelaflyer said if you are getting these figures from FordPass they are probably incorrect. FordPass is notorious for providing garbage mileage and kWh used data.

If you reset the trip data in the SYNC screen you sometimes have to hit reset multiple times to actually reset the distance and miles per kWh.

 

[SpaceEVDriver]

What numbers do you know independent of fordpass or sync4?

The odometer is reliable. Did you take note of the pre- and post-drive numbers from the odometer or are these from the trip meter in sync4?

The state of charge also seems to be reliable.

If your battery health is perfect, you'll have 91.7 kWh at 100% when the battery is at a tempoerature around 70-75 ⁰F.

You can rely on that full value for most calculations even if the environment isn't ideal.

If you calculated miles from the odometer, and the states of charge you noted are accurate, then...

57% of 91.7 = 52.3 kWh used.
252 miles / 52.3 kWh = 4.8 mi/kWh.

That's high, but not unbelievably high, depending on a lot of factors.

However, I suspect you got miles from the trip meter or Ford Pass, not the odometer. Those rely on unreliable software.

 

[AaronTV]

What numbers do you know independent of fordpass or sync4?

The odometer is reliable. Did you take note of the pre- and post-drive numbers from the odometer or are these from the trip meter in sync4?

The state of charge also seems to be reliable.

If your battery health is perfect, you'll have 91.7 kWh at 100% when the battery is at a tempoerature around 70-75 ⁰F.

You can rely on that full value for most calculations even if the environment isn't ideal.

If you calculated miles from the odometer, and the states of charge you noted are accurate, then...

57% of 91.7 = 52.3 kWh used.
252 miles / 52.3 kWh = 4.8 mi/kWh.

That's high, but not unbelievably high, depending on a lot of factors.

However, I suspect you got miles from the trip meter or Ford Pass, not the odometer. Those rely on unreliable software.

You are correct. I hadn't noted the odometer at the start of this period. Prior to this week, I'd never seen a trip summary in Sync/FordPass that looked odd. So, when these 6, 7, or 12+ miles/kWh trips started occurring it got my attention.

I'll note odometer miles on this next charge and compare those to FordPass.

That said, should it really be that difficult to base those mileage summaries on the actual odometer reading at the start and end of each trip? Seems kinda obvious. Weird that it's not accurate.

Thanks for your input!

 

[JohnFoxeSheets]

I suspect it's because you live in Wisconsin and were likely headed south, which as we all know mean you were doing downhill.

??

(But seriously, for reasons I doubt anyone can fathom FP cannot accurately keep track of travel distances and therefore makes wild errors from time to time. In fact sometime even the trip meter in the car is wrong.)

 

[SpaceEVDriver]

You are correct. I hadn't noted the odometer at the start of this period. Prior to this week, I'd never seen a trip summary in Sync/FordPass that looked odd. So, when these 6, 7, or 12+ miles/kWh trips started occurring it got my attention.

I'll note odometer miles on this next charge and compare those to FordPass.

That said, should it really be that difficult to base those mileage summaries on the actual odometer reading at the start and end of each trip? Seems kinda obvious. Weird that it's not accurate.

Thanks for your input!

My (limited) understanding is that the odometer is protected from the rest of the vehicle's software (i.e., it's not available through OBD2, nor on the common CAN bus) so that it cannot (easily) be manipulated by bad actors. However, I'm not absolutely certain this is true.

The trip distance is generated from GPS and errors abound.

 

[JSeis]

In this recent warming up I’m averaging 3.9-4.1 miles per kWh with our SR Select. My 100% range consistent at 240 miles. My typical 85% charging rate right at 200 miles. That’s at 2 lane highway speeds of 54-62 mph. Pretty good for 45,000+ miles on the odometer and 23 months old.

 

[jgcom]

I've posted on this issue a couple of times before, believing that the problem can stem from how the algorithm determines the beginning and end of a "trip," and that the energy change and distance measure during a trip seem in some cases to refer to different trip boundaries.

After nearly two years of ownership, I fast-charged for the first time, at an Electrify America station yesterday, using some of my free allotment. This blew up my prior theories, even though the charging itself at EA was utterly flawless and easy: 20 min for 35 kWh.

I left my house, drove ~65 miles to a bakery to pick up a cake for Mother's Day. On the way home, I stopped (right next to the interstate) at the EA station and got 35 kWh. I believe I turned the car on and off once during the stop. After I got home, FordPass showed four trips:

(home to bakery)
64.3 mi., energy used 19.1 kWh, efficiency 3.4 mi/kWh

(bakery to EA and then home)
47.8 mi., energy used -12 kWh, efficiency -4.0 mi/kWh
48.3 mi., energy used 0.2 kWh, efficiency 241 mi/kWh
48.8 mi., energy used 0.3 kWh, efficiency 162.8 mi/kWh

The home to bakery trip is true and self-consistent.

The bakery-to-home trips are wildly incorrect and inconsistent. The total distance should be around 65 miles, rather than 144 miles. The total energy used should be around 20 kWh rather than -11.5 kWh. Maybe it doesn't take into account the energy purchase, even though it shows up in the charging log accurately? But that alone cannot make the trip record accurate.

Reverse engineering, though fun, is hard. Wouldn't it be nice if someone could tell us the algorithm used, so we could see if this a bug, a mis-feature, or if something is legitimately broken in my car?

Joe

 

[macchiaz-o]

My (limited) understanding is that the odometer is protected from the rest of the vehicle's software (i.e., it's not available through OBD2, nor on the common CAN bus) so that it cannot (easily) be manipulated by bad actors. However, I'm not absolutely certain this is true.

If you're able to see an accurate odometer reading in FordPass then it must be externally readable.

Mine is accurate:

 

[SpaceEVDriver]

If you're able to see an accurate odometer reading in FordPass then it must be externally readable.

Mine is accurate:

Good point.

I believe Ford Pass Connect is the hardware that the vehicle uses to connect Ford's vehicles to its services. It's probably far more secure than CAN or OBD2. It's safer to send the odometer data to Ford Pass Connect through a secure communication to, especially if that's designed to be a one-way communication (at least for the odometer information). They probably could allow the same information to be shared (securely) to another piece of hardware on the vehicle that then talks to the CAN and OBD2...

But I'm way outside of my knowledge here.

 

[macchiaz-o]

I believe Ford Pass Connect is the hardware that the vehicle uses to connect Ford's vehicles to its services. It's probably far more secure than CAN or OBD2. It's safer to send the odometer data to Ford Pass Connect through a secure communication to, especially if that's designed to be a one-way communication (at least for the odometer information). They probably could allow the same information to be shared (securely) to another piece of hardware on the vehicle that then talks to the CAN and OBD2...

The gateway module (GWM) is a router for many of the vehicle's communication architectures. It's a focal point for bridging data coming in or out from different network fabrics such as CAN, Ethernet, WiFi, mobile, etc. Whatever system(s) are involved in updating the odometer's value can simply copy the current value to any number of other systems in or out of the vehicle, directly or indirectly, through the GWM. They wouldn't need to give access to the trusted "master" storage of this value, all that is needed is a copy of the number in some other address space.

Back on the original topic... I've often observed obviously wrong trip reports on the vehicle's built in trip app, since day 1 and even now on the latest version. Sometimes its view of the odometer stops increasing, and sometimes it doesn't reset the trip distance even though the car is parked and off for 15+ minutes. I think it's possible/probable that the wrong readings that we see in FordPass are caused by software bugs in the vehicle, and perhaps also in Ford's cloud servers.

 

[DamDoc]

Enjoy! Better than our Maine winter performance by orders of magnitudes!

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