Tracking the HVB State of Health - how much decline is normal?

If you have 20,000 miles or more, what is the SoH of your HVB?


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kennethjk

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My mileage is 14,300, car built Dec 2021, took ownership March 16, 2022.

age of Battery is 15.97, SOH is 97%

SOC display is 50%
HVB SOC is 49.41%
energy KWH is 41.55
energy to empty is 41.54kwh

If I read this right I have 84 kWh available and factoring in 97% SOH that would give me max 86.69 that was available at come point. Original sticker showed 88 and I thought I would have been updated to 91.

If anyone can shed some more light on this please do.
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Accord07

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My mileage is 14,300, car built Dec 2021, took ownership March 16, 2022.

age of Battery is 15.97, SOH is 97%

SOC display is 50%
HVB SOC is 49.41%
energy KWH is 41.55
energy to empty is 41.54kwh

If I read this right I have 84 kWh available and factoring in 97% SOH that would give me max 86.69 that was available at come point. Original sticker showed 88 and I thought I would have been updated to 91.

If anyone can shed some more light on this please do.
Nobody here really knows how "SOH" is defined, but it is obviously not the percentage of actual capacity over the nominal capacity.

I didn't have a OBD II scanner when I took delivery of my vehicle, my first reading occurred a month later at 2K miles and it was 97.5. It went down to as low as 94.5 before climbing back up to 96.5. At 38K miles it now reads 93.5.

For the same SOC, the "Energy to Empty" figure rises along with temperature. The weather is probably still cool where you live, check the readings when your car is on a DC charger and you will see the difference right away (because the battery has to be warmed up). In the summer of 2022 the "Energy to Empty" reading was right around 88 kWh at 100% SOC; in the winter before that, the extrapolated capacity based on "Energy to Empty" and displayed SOC was often in the low 70s.

Ford doesn't even follow its own recommendations on storing the vehicle for long periods of time. Mine was built in July 2021, sat for the next four months waiting for some unknown parts (chip hold), and arrived at the dealer in December of that year with a 10% SOC.

It's car, just enjoy it.
 
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mkhuffman

mkhuffman

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Nobody here really knows how "SOH" is defined, but it is obviously not the percentage of actual capacity over the nominal capacity.

I didn't have a OBD II scanner when I took delivery of my vehicle, my first reading occurred a month later at 2K miles and it was 97.5. It went down to as low as 94.5 before climbing back up to 96.5. At 38K miles it now reads 93.5.

For the same SOC, the "Energy to Empty" figure rises along with temperature. The weather is probably still cool where you live, check the readings when your car is on a DC charger and you will see the difference right away (because the battery has to be warmed up). In the summer of 2022 the "Energy to Empty" reading was right around 88 kWh at 100% SOC; in the winter before that, the extrapolated capacity based on "Energy to Empty" and displayed SOC was often in the low 70s.

Ford doesn't even follow its own recommendations on storing the vehicle for long periods of time. Mine was built in July 2021, sat for the next four months waiting for some unknown parts (chip hold), and arrived at the dealer in December of that year with a 10% SOC.

It's car, just enjoy it.
Based on some of the posts @Mach-Lee has made in the past, the BMS needs full charge and discharge cycles to accurately manange estimates such as SOC and battery capacity. So my theory is the same applies to SoH. If you don't do any full charge/discharge cycles, the BMS won't have good reference points to know how much capacity the battery really has. So charging to 100% and discharging below 10% helps it get the data it needs. If you don't do that, SoH and SoC will be less accurate.

I agree all the numbers are approximations and they are heavily influenced by the ambient environment. So I also think full charge and discharge cycles are needed when the battery is at the ideal temperature in order for the BMS to be more accurate.

Anyway, I am going to be purposely doing more full charges to see if the SoH continues to climb. I think if I keep getting the battery up above 84 kWh, the SoH will eventually climb to match 84/91.

By the way, if you are up to date with OTAs you definitely have the 91 kWh available capability battery. I got it in February of last year.
 
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mkhuffman

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I was slightly disappointed it was so low. Her battery is very gently used. Almost exclusively charged at home and only a few times has it been charged to 100%. I was hoping for 97%. But I do see why it adds to your dissatisfaction.
It seems to be that doing all the right things has less of an impact than we would hope. I definitely have not taken any unusual effort to treat the battery kindly, but I have avoided charging to 100% except just before leaving to go out of town. I do wonder if all the 90% charging I normally do has had an impact.

I really hope the deterioration is slowing down because I can't deal with loosing more range.
 

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It seems to be that doing all the right things has less of an impact than we would hope. I definitely have not taken any unusual effort to treat the battery kindly, but I have avoided charging to 100% except just before leaving to go out of town. I do wonder if all the 90% charging I normally do has had an impact.

I really hope the deterioration is slowing down because I can't deal with loosing more range.
There are other things that can do it. Too hot will cause degradation and charging them frozen will create a time bomb as well as degradation.

Try not to sweat the small percentages too much. It may slow down better than others.

Not charging to 100% reduces the impact of the difference you are seeing. Raise the wife's to 85% for her and it should be about the same as it was new with 88. The only time we need range is on trips and for most of our comminuting 5 or 10% degradation has no real world implications just charge it to 90% instead of 80. We will however need to hope for more closer spaced DCFC when our cars get old. ;)
 


dbsb3233

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Just checked mine. 39,000 miles, 27 months, 94.5 HvB SOH. And one HVBJB replacement last Oct.

We drive it fairly conservatively (not like a sports car). 80% of the miles are interstate driving (usually 75-80 MPH). We do a LOT of long road trips and relatively little local driving. Which also means lots of DCFC (almost 50% of total charging). Home L2 to 90%, plug in any day it drops below 50% (maybe once a week). Hotel L2 to 100%.

Ford Mustang Mach-E Tracking the HVB State of Health - how much decline is normal? 20230506_160845
 
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SWO

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13.5k miles, 97.5% SOH

Screenshot_20230506_183551.jpg
 

Rt1AWD

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I couldn't find it on carscanner. How to check health of battery on it?
 
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I couldn't find it on carscanner. How to check health of battery on it?
Car Scanner has about 10 default dashboards that are activated when you specify your car is the Mustang Mach-e. I think one of those default dashboards has the SoH. But if not, you can add it by modifying one of the dashboards or creating a new one.
 

dbsb3233

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Car Scanner has about 10 default dashboards that are activated when you specify your car is the Mustang Mach-e. I think one of those default dashboards has the SoH. But if not, you can add it by modifying one of the dashboards or creating a new one.
Yep. Just swipe left or right to scroll between the default Dashboard screens. HvB SOH is actually on multiple screens.

Also make sure the right car model is selected when setting up Carscanner in the first place.
 

Rt1AWD

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Thank you guys.

98.5%

15K, 15 months of use, DC charge around 10 times
 

Trick.Mach-E

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Great thread! 28k on our 28 month old FE and we are at 95.8%.
 
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mkhuffman

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Mine is still hanging out at 92% and just under 30k miles.
 

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99% SoH.
First Edition (AWD LR, 2021). 23k miles (37k km).
Charged at 1lWh AC every night from 80-90% (to 100% today for a trip).
Not more than 20 DCFC sessions.

Living in cold climate, but precondition every weekday.
 

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One of Ford's patents says the following about how they *might* be calculating SOH, but it's not the only model, and we don't know what the coefficients might be in the representation they include here. Note that I haven't dug into the patent to check every little detail.

The battery SOH estimator 36, as shown at block 54, may be configured to determine the estimated present internal resistance {circumflex over (R)}0 in response to receiving (or measuring) the one or more variables associated with the operation of the battery pack 14, such as, but not limited to, the battery SOC, temperature, current, battery terminal voltage, and so on. In one example, the battery SOH estimator 36 may use a battery life model to determine the estimated present internal resistance {circumflex over (R)}0. In one example, a battery life model of the battery pack 14 may be represented as:
R=a1tz+a2N,  (3)

where a1tz is a term reflective of a calendar fade of the battery pack 14, a2N is a term reflective of a cycling fade of the battery pack 14 over N cycles, and a1, a2 are coefficients determined as a function of one or more parameters associated with the operation of the battery pack 14, such as, but not limited to, depth-of-discharge (DOD), temperature T, open-circuit voltage VOC, and so on. The calendar fade and the cycling fade may in some cases result from one or more conditions contributing to battery degradation, such as, but not limited to, SEI growth, loss of cyclable lithium, active material structure degradation, a mechanical fracture, and so on. In one example, the battery life model may be identified from the battery test data under one or more different representative battery usage aggressiveness drive cycles, e.g., mild, moderate, and aggressive operation of the vehicle 12 and/or battery pack 14.
...
...
The patent goes on to say...
...
...
As previously described in reference to FIG. 5, the one or more of the plurality of different representative battery usage aggressiveness drive cycles may be defined by a change in magnitude of current and/or SOC that is greater than the change in magnitude of another one of the plurality of different representative battery usage aggressiveness drive cycles. The percentage of battery life remaining % life and the usage time remaining in the battery life teqrem may be expressed as Equations (6) and (7), respectively:
Equations 6 and 7 are as follows:

Ford Mustang Mach-E Tracking the HVB State of Health - how much decline is normal? Screen Shot 2023-06-05 at 08.00.21


If this patent is relevant to the Mustang, Ford is giving iteslf a lot of space to determine the SOH based on several different scenarios, including driver aggressiveness.


Link to the patent (PDF):
https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/10569660
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