Another GOM Lie

[Murse-In-Airy]

I have 6600 miles on my MME, for the last month GOM is showing 305 miles range charging
to 100%. My Trip1 has never been reset and show 4.1 kwh average for the 6600 miles . My GOM should be showing around 360 miles, 4.1 x 88KWh battery charge.

4.1 miles/kwh is pretty damn good efficiency.

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[Gary Hankins]

Beating this dead horse all the way to decomposition. But the questions keep popping up, so here’s another data point.

Yesterday I had the opportunity to make a little road trip. Total of 412 miles. There’s a free DCFC on the route so no problem.

I left home with 100% SOC and the GOM showing a range of 245 miles on my AWD ER. EPA range rating should be 270 miles at 100%. The horror. My car is broken. I’ve got over 5000 miles on it in 7 months of ownership. How has it not learned how far I can go. This is BS. /s

My first leg to the DCFC was 107 miles and I used 36% battery. Trip meter shows 3.3 miles/kwh. Which calculates out to pretty accurate. 36% of my 88 kwh battery is 31.6 kwh. 107 miles divided by 31.6 gets me 3.38 miles/kwh. Good on Ford. My GOM even went from 245 to 149 miles remaining. So I “Lost” 96 miles of range going 107 miles of actual driving. Reasonably accurate.

But here’s where the fun begins in my little math nerd brain. The GOM shows 149 miles remaining on 64% battery. But if I went 107 miles on 36%, then my 100% GOM should have been 297 miles and at 64% it should show 190 miles remaining. I say this only to drive home the point that the GOM is overly conservative (AKA It LIES). So for everyone still concerned about their GOM… it LIES. My GOM has almost never shown more than 250 miles range even though in the real world, on a 40 degree morning, driving 2 lane county roads at 60 MPH with lots of slow downs for small towns, I should get 297 miles.

But kicked it back up to 80% and continued on my merry way. Further legs show similar results. With a total on that day of averaging 3.52 miles/kwh. Total 412 miles driven, 117 Kwh of electricity used. So with it all said and done, real range for this drive should have been 309 miles. But my car showed 245 at the start of the day. And now, sitting at work, I show 75 miles of range at 36% SOC. That calculates out to 208 miles at 100%.

Oh you silly GOM. When will you learn? Alternately, oh you silly people, when will you stop paying attention to the GOM?

The number of variables involved in the calculation of range which are dynamic makes range fluid, never static. They include temperature, topography, weight of load,use of lights, heater or air conditioner. One should never be surprised at changing estimates. I have found my E's range estimates to be surprisingly close in every circumstance.

The issue is that we need to trust something. There are too many rounding errors in the system Ford is using. Some days, I can take the car off the charger after it completes charging to 90%, and drive 3-4 miles before it drops to 89%. While on other days, I can let it charge to 90%, take it off the charger after it completes, and it drops to 89% after less than 1 mile (often around 1/4-1/2 mile). So clearly that 90% it charged to has some variance in it.

I don’t worry about my range like I did in March, when this was all still very new to me, but my brain gets grumpy when straightforward math doesn’t work out cleanly. Like I’m almost OCD about that. With the arrival of cooler weather,my brain is itching to understand how the car will react when the ambient temperature is 30°, or 0°, or -15°. Once I have good observed data, I’ll be fine with it.

I do understand that there are too many variables involved for Ford to give us terribly accurate estimates, that’s why I will do my own math so I can see how my variables affect my outcomes.

 

[Murse-In-Airy]

The number of variables involved in the calculation of range which are dynamic makes range fluid, never static. They include temperature, topography, weight of load,use of lights, heater or air conditioner. One should never be surprised at changing estimates. I have found my E's range estimates to be surprisingly close in every circumstance.

Some do. Some of us have never seen anything close to accurate. Just trying to help others understand that.

 

[GABAR]

First world problems.

 

[OH2AZ2OH]

My GoM is usually pretty ok. But, I have noticed that it is *very* aggressive at downgrading my range as the temps drop. It usually works out to 300-310 on full charge with warm temps. But now that I am seeing 40F temps in the mornings, it is telling me full range is 265 or so. Consumption has increased, but I generally still get 3.1-3.5 in the mornings instead of 3.9.

I also have some charging weirdness. I charge to 80%, and the car reports 80% when I unplug. But, as I drive out of my neighborhood, it quickly bumps to 81%, and then usually 82%. This is in 0.2 mi, very slightly downhill, but no way I'm adding that much to the battery with regen. Despite adding 2% to the "charge level", my GoM does not increase.

 

[DR.J56]

Remember the days of just a gas gauge? Not only that, but it bounced around too!!

Wait till the Lightening hits the market with it’s GOM.

My GOM on my ER 4X is pretty accurate. 230ish miles on a 80% charge. Pretty consistent and believable if I keep my driving the same. The “this trip” is sketchy though.

 

[Carsinmyblood]

It's posts like this that make me give thanks for not suffering from even a trace of OCD.

We're related.

 

[RockwallRick]

Remember the days of just a gas gauge? Not only that, but it bounced around too!!

Wait till the Lightening hits the market with it’s GOM.

My GOM on my ER 4X is pretty accurate. 230ish miles on a 80% charge. Pretty consistent and believable if I keep my driving the same. The “this trip” is sketchy though.

Sounds about right, our GOM is around 260 for a 90% charge.

 

[Carsinmyblood]

I did a few Google searches to ask the question of the ages and one many of you are still rolling around in the back of your skulls, being........ Is Tesla's GOM any better?

And the answer is..... it depends.

So there we have it. Regardless of the modern conveyance to which they are attached, Guess O'Meters are a taunt to our inner daredevil. While giving aid and comfort to those who never let the charge drop past 40%, it simultaneously causes the stock price of Tums to rise as our long distance runners test the limits and inaccuracies of Ford's algorithms.

 

[SnBGC]

Some do. Some of us have never seen anything close to accurate. Just trying to help others understand that.

Agree. Some cars are pretty good at predicting the range. Mine is pretty close.....about 10 miles off over a full charge. (Predicts around 300 when real world is about 290 miles for me)

Other cars are horribly inaccurate. So much so that it should be ignored completely.

These days, all I look at is the percentage reading and that tells me pretty much everything I need to know. Having the GOM for road trips is sorta helpful to calculate the reserve range which is what I call the expected range remaining when I reach my next charging stop. While helpful under those conditions.....still should be taken with a grain of salt.

 

[SnBGC]

Since we are on the subject....
Like many others here, I normally charge to 90% overnight and only because the owners manual recommends that practice when possible. For me, this is totally possible as 90% still covers almost all my daily needs regarding range. Well, now it does. During the summer I was suffering a bit. This is because my range dropped so low during the summer months because I was remote starting my car throughout the day so the car would condition the battery and the cabin.

Here is a screen shot from June 2nd. Estimated range at 90% charge is 248 miles. Which is pretty close because I remote start the car off plug throughout the day and actually leave the car running while at job sites or running errands.

Then in July, @macchiaz-o discovered a work around to allow the car to condition the battery while parked on plug. I started employing that method sometime in mid July if I remember correctly. So, by early August (8-10-21), all my range returned. I suspect this is because the car didn't have to cool an overheated battery every time I took it out for a drive. By cooling the battery on plug, I was able to use more of my stored energy to move the car vs cooling the battery.

This continued all the way through Aug, Sept and into early October.

• Aug 11th, estimated 281 miles @ 90%
• Aug 18th, estimated 272 miles @ 90%
• Sept 28th, estimated 284 miles @ 90%
• Sept 30th, estimated 291 miles @ 90%
• Oct 7th, estimated 275 miles @ 90%

Now it is getting much cooler in the mornings and I have been using the heated seats and steering wheel on my drive to the office. No E-Heat yet. IF cabin pre-conditioning continues to function then I may not need E-Heat very often. Yesterday I saw the estimated range dip to 269 @ 90%. Today it dropped again down to 263 estimated miles @ 90%. I expect this to continue as winter sets in.

 

[Rt1AWD]

I believe it is a very rough estimation based on your previous driving

 

[RockwallRick]

I am hoping for better range during the Winter months!

 

[SnBGC]

I believe it is a very rough estimation based on your previous driving

For some vehicles yes. For some others, it's very accurate.
Here is what my estimated range was the day after I returned from a road trip to San Diego.
I manually calculated my real life range while road tripping at 250 miles on a full charge and the GOM came up with the same number. In my car, it's really pretty close estimation.

 

[macchiaz-o]

Now it is getting much cooler in the mornings and I have been using the heated seats and steering wheel on my drive to the office.

I didn't know you moved to Mount Humphreys. ?

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