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I finally gave in to my urge to calculate my own performance numbers for my Premium MME with ER battery. I was tired of the error in the GOM (GuessOMeter) along with errors in driving distance, and M/kwh. It is also very difficult to tell how much juice you are putting into the car, at what price, to determine cost/mile. There is no instrumented way in the MME to view the different performance numbers while driving at different speeds. I experienced vast differences between city and highway driving numbers.
I start by recording some info from the dash and the trip meter which I reset (Trip 2) each time I charge.
So I embarked on collecting my own info. First thing I had to do was get a charger that told me how much juice (kwh) I was putting in, and the cost. ChargePoint to the rescue. It gives me both. Below is a screenshot of a recent charge.
I have the Ford charger at my home, and it has a different rate and cost. My calculations use whatever is appropriate.
I also use the FordPass app to read off more final charging numbers.
Then I built a spreadsheet with the following inputs. Some are input when I start charging (yellow) and some when it is complete (orange). I will say that my calculations do assume that the battery charge level % is accurate. I have no way of determining the battery charge % other than what Ford tells me, so I have to use that.
Once the charge is complete, and the data is filled in, a results bar for each charge calculates results as below:
It tells me all the above data for each charge, and then calculates median or average figures (shown above right above the blue bar). The outputs/results are in order:
How many hours the charger was on
How many Kwh the charger transferred (based on measurement at the plug)
How many MPH the charger was charging
How many miles it added, using the Historic m/Kwh from the MME
What the calculated total usable miles are now on the car, using the % Charge, battery size, and Hist m/Kwh
What the average speed was since the last charge. Total miles / hours driving.
What the $/mi are
What the GOM difference shows between last charge and this one
What the actual difference is given the miles driven
What the error is in the GOM. This has varied between under by 24% to over by 30%. Mean is shown. i.e. the Ford GOM estimates 12% high.
What the actual m/Kwh are. My MME Trip meter shows consistently 3.7 m/Kwh while actually it is 3.3 m/Kwh. This is consistent with Ford GOM error at about 12% high, so they could be based on the erroneous GOM.
Efficiency of the charge circuit based on comparing the input from the wall to the actual battery charge.
Note that the GOM error is one that is incurred from a low charge to a higher charge. i.e. the GOM at a higher charge (for example at the beginning of a trip), compared to the GOM at a lower charge (at the end of a trip) is high. This gives you a false sense of security in that it is telling you that you can go 12% farther than you actually can, but doing so in a slow, unnoticeable incremental way. This could be an error in the battery % charge level, but there is no way of knowing that.
This is a limited data set at this point. While I have been keeping a record for some time, I did not collect all the right data all along, so the above represent only about 450 miles and 5 charges in warm fall weather. However, the averages are starting to settle so I don't expect them to change much.
I don't know what to expect with winter charging and driving temperatures and how to calculate the effect.
I wish there was some more instrumentation on the MME.
Comments or suggestions welcome in my ongoing siege.
Jim
Premium, Infinite Blue Metallic, Black Onyx interior, RWD, ER Battery, no front license bracket.
I start by recording some info from the dash and the trip meter which I reset (Trip 2) each time I charge.
So I embarked on collecting my own info. First thing I had to do was get a charger that told me how much juice (kwh) I was putting in, and the cost. ChargePoint to the rescue. It gives me both. Below is a screenshot of a recent charge.
I have the Ford charger at my home, and it has a different rate and cost. My calculations use whatever is appropriate.
I also use the FordPass app to read off more final charging numbers.
Then I built a spreadsheet with the following inputs. Some are input when I start charging (yellow) and some when it is complete (orange). I will say that my calculations do assume that the battery charge level % is accurate. I have no way of determining the battery charge % other than what Ford tells me, so I have to use that.
Once the charge is complete, and the data is filled in, a results bar for each charge calculates results as below:
It tells me all the above data for each charge, and then calculates median or average figures (shown above right above the blue bar). The outputs/results are in order:
How many hours the charger was on
How many Kwh the charger transferred (based on measurement at the plug)
How many MPH the charger was charging
How many miles it added, using the Historic m/Kwh from the MME
What the calculated total usable miles are now on the car, using the % Charge, battery size, and Hist m/Kwh
What the average speed was since the last charge. Total miles / hours driving.
What the $/mi are
What the GOM difference shows between last charge and this one
What the actual difference is given the miles driven
What the error is in the GOM. This has varied between under by 24% to over by 30%. Mean is shown. i.e. the Ford GOM estimates 12% high.
What the actual m/Kwh are. My MME Trip meter shows consistently 3.7 m/Kwh while actually it is 3.3 m/Kwh. This is consistent with Ford GOM error at about 12% high, so they could be based on the erroneous GOM.
Efficiency of the charge circuit based on comparing the input from the wall to the actual battery charge.
Note that the GOM error is one that is incurred from a low charge to a higher charge. i.e. the GOM at a higher charge (for example at the beginning of a trip), compared to the GOM at a lower charge (at the end of a trip) is high. This gives you a false sense of security in that it is telling you that you can go 12% farther than you actually can, but doing so in a slow, unnoticeable incremental way. This could be an error in the battery % charge level, but there is no way of knowing that.
This is a limited data set at this point. While I have been keeping a record for some time, I did not collect all the right data all along, so the above represent only about 450 miles and 5 charges in warm fall weather. However, the averages are starting to settle so I don't expect them to change much.
I don't know what to expect with winter charging and driving temperatures and how to calculate the effect.
I wish there was some more instrumentation on the MME.
Comments or suggestions welcome in my ongoing siege.
Jim
Premium, Infinite Blue Metallic, Black Onyx interior, RWD, ER Battery, no front license bracket.
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