Best Practice for battery preservation

[SnBGC]

For the Focus Electric (FFE) Ford always published the entire size of the battery. What was useable was figured out by owner's once they started driving it.
One way was a run down test: The FFE has an enhanced trip meter showing kWh consumed. You would charge to full, reset the trip meter, and turn it on with the HVAC set to full defrost...let it sit there until the battery was fully discharged--the kWh reading on the trip meter would show you how much of the battery was useable.
The other way, once Forescan added FFE support, was simply to read the value off the OBD-II bus.

My FFE had the smaller battery at 23kWh and only used about 17-18kWh of it.

I think at this stage you're looking at engineers and salespeople just giving you rounded amounts and not specific values. Thus I don't think the 5kWh and 8kWh are buffer's of any sort--just a mental rounding error. It won't be until people start driving the vehicle before we really find out and even then a simple software change could change the ratios.

From past experience (and even on the hybrids, "Energi" models) Ford has always published the total size of the battery so I would be pretty confident in saying that their targets are 75kWh and 98kWh for the total battery overall; we'll just have to wait to see what or if there is any buffering...

I agree with this post.
Past practice says that Ford publishes the physical battery capacity but they could change to "usable capacity" at any time I suppose. My guess is the Mach e might average around 295-300 wh/mile based on the published range estimates. This calculates to about 68.5-69kwh of useable battery which is maybe a little high so maybe an average of 275wh/mile is closer to reality.

Again, we will know a lot more about this once these are available to the public. Looking forward to it.

Sponsored

 

[dbsb3233]

Most of the world focuses on gallons per mile (or liters per 100 kms) rather than miles per gallon as we do in the US. And their system is the better one.
Here's a good summary explaining why focusing on gallons per mile leads to better decisions:

https://www.popularmechanics.com/cars/a12367/4324986/

Maybe the BEV transition will facilitate our adopting the better metric also.

Whether MPG or whatever the easy acromyn is for the other one is "better" is a matter of opinion. But yes, it does come down mostly to what people are already used to. Those that like it one way are gonna find the other upside-down, and vise versa.

 

[eager2own]

Whether MPG or whatever the easy acromyn is for the other one is "better" is a matter of opinion. But yes, it does come down mostly to what people are already used to. Those that like it one way are gonna find the other upside-down, and vise versa.

Except that Popular Mechanics and the Duke University study do provide objective reasons why one is better than the other. It’s not merely as subjective as “it’s better because it’s what I’m used to.”

 

[dbsb3233]

Except that Popular Mechanics and the Duke University study do provide objective reasons why one is better than the other. It’s not merely as subjective as “it’s better because it’s what I’m used to.”

That's 2 sources giving their opinion and reasons for it, yes. Doesn't mean it's all.

Personally, I didn't find that one PM author's reasoning convincing at all. But that's fine, he's free to his opinion too, just like everyone else.

 

[EVer]

Clearly there is a discrepancy, and it seems like the EPA numbers are where the inconsistency lies. Paying close attention, the battery capacity based on EPA range is off by on the order of 10% (9.4% to 13.6%) - some of which is due to the rounding of the reported EPA kwh/100 mi ratings. Completely speculating here, but I wonder if the range number for the EPA range is in fact based on the total battery size including buffer, and the reported battery sizes are in fact the usable values? Or is the EPA computing total range and kwh/mi off of different metrics?

timbop, here's how EPA computes efficiency and range:

"Following SAE J1634 October 2012 Recommended Practice, the battery is fully charged, the vehicle is parked overnight, and then the following day the vehicle driven over successive city (UDDS), highway and steady-state cycles until the battery becomes discharged (and the vehicle can no longer follow the driving cycle). DC discharge energy and DC discharge amp-hours are measured for the entire test. After the testing is completed, the battery is then recharged from a normal AC source using the manufacturer’s charger for that vehicle. The energy consumption of the city and highway cycles (in kW-hr/mile or kW-hr/100 miles) are then determined mathematically from the recharging energy, the DC discharge data and distance for each cycle. The recharge energy includes any losses due to inefficiencies of the manufacturer’s charger. "

Things which will throw off subsequent back-computations of battery capacity are:
1. How much it loses overnight.
2. Inefficiency of the charger.

 

[ChasingCoral]

While the 20-80% battery use works if you have direct control over the system, it isn't necessarily needed for a car like the Mach E. A great deal rides on the car's battery management system and there are still lots of unanswered questions there for the Mach E.

 

[SnBGC]

Every owner has direct control over both items. The method varies depending on the vehicle and EVSE but the ability exists with all scenarios.

 

[buzznwood]

One thing that will be interesting will be seeing the small print over the mach-e battery warranty and degradation %, if ford have sense it should not matter how you charge and the charging systems should be intelligent enough to figure out what is best. as end of day for joe & jane average just want to be able to plug it in a forget about it the car should do the rest.

With OTA ford should be able to gather plenty of data once the cars are out in the wild and see how they are being used and adapt the battery strategy as needed. I am hoping that ford like a lot of the other legacy manufactures start out very conservative and improve it over time once that real world data starts rolling in.

 

[SnBGC]

One thing that will be interesting will be seeing the small print over the mach-e battery warranty and degradation %, if ford have sense it should not matter how you charge and the charging systems should be intelligent enough to figure out what is best. as end of day for joe & jane average just want to be able to plug it in a forget about it the car should do the rest.

With OTA ford should be able to gather plenty of data once the cars are out in the wild and see how they are being used and adapt the battery strategy as needed. I am hoping that ford like a lot of the other legacy manufactures start out very conservative and improve it over time once that real world data starts rolling in.

Agreed.
Keep in mind that Ford has been gathering data for quite some time from the FFE cars. The MME isn't going out into the world blind but I do think that they will sell MUCH more MME cars compared to FFE so the data gathered on those will come pouring in very quickly. Expect your car to receive updates frequently....although we probably wont ever notice them.

 

[EVer]

One thing that will be interesting will be seeing the small print over the mach-e battery warranty and degradation %

From the FAQ:

• Electric Unique Component coverage: 8 years or 100,000 miles (whichever comes first) retaining a minimum of 70% of its original capacity over that period²

² Whichever comes first. See dealer for details.

I presume any further fine print will be similar to Tesla's, e.g. "we get to determine the method by which battery capacity is measured."

 

[Yoliber]

Is there an update on this? I hope ford's buffer is large enough that we can charge to 100% all the time. This would push me towards the Mach-E GT and away from a Tesla P3D.

I know that the Chevy Bolt recommends charging to 100%. Only option to charge to a lower % is a hill top reserve so you can regen down a large hill. I believe the Bolt has the same battery? I also read that the Kona EV is doing something similar.

 

[JamieGeek]

Is there an update on this? I hope ford's buffer is large enough that we can charge to 100% all the time. This would push me towards the Mach-E GT and away from a Tesla P3D.

I know that the Chevy Bolt recommends charging to 100%. Only option to charge to a lower % is a hill top reserve so you can regen down a large hill. I believe the Bolt has the same battery? I also read that the Kona EV is doing something similar.

The 2019 Bolt added the ability to charge to a specific level. Hilltop reserve is only in 2018's and older (of course mine is a 2018 ).

 

[Yoliber]

The 2019 Bolt added the ability to charge to a specific level. Hilltop reserve is only in 2018's and older (of course mine is a 2018 ).

Maybe they only put it in due to consumer demand? I know that Tesla put in a toggle because of consumer requests. Previously it was just a (daily) or (trip) charge level. I hope there isn't even an option for the Ford so there aren't any questions.

 

[ChasingCoral]

Is there an update on this? I hope ford's buffer is large enough that we can charge to 100% all the time. This would push me towards the Mach-E GT and away from a Tesla P3D.

I know that the Chevy Bolt recommends charging to 100%. Only option to charge to a lower % is a hill top reserve so you can regen down a large hill. I believe the Bolt has the same battery? I also read that the Kona EV is doing something similar.

Considering the useable range cut a bit over 10% off the batter's capacity, we should be able to charge them to 100% no problem.

Sponsored