mkhuffman
Well-Known Member
- First Name
- Mike
- Joined
- Nov 19, 2020
- Threads
- 19
- Messages
- 4,293
- Reaction score
- 5,660
- Location
- Virginia
- Vehicles
- 2021 MME GT, Cadillac XT5, VW Jetta
- Thread starter
- #1
When I first got my MME in November of 2021, I didn’t even consider tracking the High Voltage Battery (HVB) State of Health (SoH). But then last Fall, while tracking other data using a OBDII scanner, I noticed the SoH was much lower than the last time I noticed. I was kind of shocked with the drop.
Since then I have been mentioning this on the forum in various threads and it seems the SoH of my battery is lower than others. But it could be because I have more miles on the car. So I decided to go through all my old CarScanner data and see if I could track the SoH over time. Luckily I was able to find enough data to get a good trend.
Below the SoH is graphed relative to battery age in months as of today. The red line is the day I took delivery of the car. (Yes, it sat in Mexico for a while.)
I also compared SoH with odometer mileage. Unfortunately I was not capturing that in my CarScanner data feeds, but until the beginning of October I was using Tronity, which gives me accurate odometer readings until I had to turn it off on 10/10/22 (at 17,659 miles). I really, really miss Tronity, BTW.
After Tronity ended I had to estimate the mileage based on records I recorded in my car maintenance log, which are very few. Today I added the odometer reading to the data I always capture in CarScanner, so going forward I will be able to accurately track SoH (and other data) relative to mileage. And maybe Ford will release an official API so I can turn Tronity back on again!
So many people have asked if DCFC could be causing the decline in SoH. So I went through all my charge logs, heavily leveraging Tronity until October, and compared SoH to all the DCFC battery capacity I have added since I got the car new.
I have also been asked if maybe there is a problem with the battery pack, and so I checked the HVB average voltage with the HVB module minimum voltage, and they are practically the same. Below is a graph of a 100% charge I did this morning, comparing average module voltage with minimum module voltage.
There have been debates in the forum regarding whether or not the SoH is accurate. I think it is. The reason I think so is because at 100% SoCD, the total energy to empty (EtE) is pretty close to what it should be per the SoH.
For my 100% charge today, I was able to get the battery up to 83.78 kWh.
So doing the math, 83.78/91 = 92.07 %. The sensor value for SoH as of today is 91.5%. I suspect the lower SoH number is due to the fact I don’t regularly charge to 100%, so the SoH is a little off. I guess the actual SoH of the battery is what I calculated using EtE.
Another factor to consider is battery temperature. As you can see, the battery is not quite at ideal temperature but it is not cold. So I think I may get an improvement in EtE in the summer. Maybe.
Conclusion:
The SoH appears to be best correlated with mileage, and the worst correlation is with DCFC. I think if I spent the time and pulled together all charging events, instead of just the DCFC ones, we would see a strong correlation with total charging kWh. Obviously every mile that is put on the car requires a charge to get there, so that is why I think mileage correlates well. But I have a ton, literally, of charging events. And after Tronity ended, I only have FordPass as a record source, and it only goes back 30 days. Arrg.
I am very interested to see what others are getting for SoH vs. how many miles are on the car.
Since then I have been mentioning this on the forum in various threads and it seems the SoH of my battery is lower than others. But it could be because I have more miles on the car. So I decided to go through all my old CarScanner data and see if I could track the SoH over time. Luckily I was able to find enough data to get a good trend.
Below the SoH is graphed relative to battery age in months as of today. The red line is the day I took delivery of the car. (Yes, it sat in Mexico for a while.)
I also compared SoH with odometer mileage. Unfortunately I was not capturing that in my CarScanner data feeds, but until the beginning of October I was using Tronity, which gives me accurate odometer readings until I had to turn it off on 10/10/22 (at 17,659 miles). I really, really miss Tronity, BTW.
After Tronity ended I had to estimate the mileage based on records I recorded in my car maintenance log, which are very few. Today I added the odometer reading to the data I always capture in CarScanner, so going forward I will be able to accurately track SoH (and other data) relative to mileage. And maybe Ford will release an official API so I can turn Tronity back on again!
So many people have asked if DCFC could be causing the decline in SoH. So I went through all my charge logs, heavily leveraging Tronity until October, and compared SoH to all the DCFC battery capacity I have added since I got the car new.
I have also been asked if maybe there is a problem with the battery pack, and so I checked the HVB average voltage with the HVB module minimum voltage, and they are practically the same. Below is a graph of a 100% charge I did this morning, comparing average module voltage with minimum module voltage.
There have been debates in the forum regarding whether or not the SoH is accurate. I think it is. The reason I think so is because at 100% SoCD, the total energy to empty (EtE) is pretty close to what it should be per the SoH.
For my 100% charge today, I was able to get the battery up to 83.78 kWh.
So doing the math, 83.78/91 = 92.07 %. The sensor value for SoH as of today is 91.5%. I suspect the lower SoH number is due to the fact I don’t regularly charge to 100%, so the SoH is a little off. I guess the actual SoH of the battery is what I calculated using EtE.
Another factor to consider is battery temperature. As you can see, the battery is not quite at ideal temperature but it is not cold. So I think I may get an improvement in EtE in the summer. Maybe.
Conclusion:
The SoH appears to be best correlated with mileage, and the worst correlation is with DCFC. I think if I spent the time and pulled together all charging events, instead of just the DCFC ones, we would see a strong correlation with total charging kWh. Obviously every mile that is put on the car requires a charge to get there, so that is why I think mileage correlates well. But I have a ton, literally, of charging events. And after Tronity ended, I only have FordPass as a record source, and it only goes back 30 days. Arrg.
I am very interested to see what others are getting for SoH vs. how many miles are on the car.
Yeah, but I do not have the GT. I would love to see the count on mine. I am sure it would easily be more than the miles when my first HVBJB went out.
