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

[Mach-Lee]

FYI I wrote a procedure for the calibration a while ago: HV Battery Calibration Procedure

@phidauex if you have suggestions, let me know.

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[mkhuffman]

FYI I wrote a procedure for the calibration a while ago: HV Battery Calibration Procedure

@phidauex if you have suggestions, let me know.

Yep. I followed it just like I am following your LVB reconditioning procedure (annually). You rock, Lee!

 

[kennethjk]

Update on my numbers

17k miles, SOH 96.5
HVB SOC 40.44%
HVB SOC Display 40.5%
energy to empty 36.14

took a trip of almost 200 miles today after charging car to 100% and ended up at 40%. Averaged 3.7 miles per KW.

even though SOH is 96.5 % I received best mileage I have ever seen (would have been 325 on a full charge) . Went only speed limits, mostly highway but a nice portion of non highway at 55,45 and 35. No wind and 85 degrees. rained a bit but not much.

overall I was extremely pleased with stats and actual mileage.

 

[mkhuffman]

I did a 100% charge last night and it was just over 86 kWh. Which would be 86/91 = 91.5% SoH. My car is still reporting 92.5% SoH. It's pretty close though.

 

[kennethjk]

I did a 100% charge last night and it was just over 86 kWh. Which would be 86/91 = 91.5% SoH. My car is still reporting 92.5% SoH. It's pretty close though.

I forgot to check what the KWh was before I left at 100%. Will do that on my next trip.

 

[phidauex]

FYI I wrote a procedure for the calibration a while ago: HV Battery Calibration Procedure

@phidauex if you have suggestions, let me know.

Ah yes, your procedure is much better than my "just run it down then charger 'er up again" recommendation. The procedure matches well with the calibrations needed by LG, SDI, CATL and other stationary/grid BMS systems that I work with all the time - the big thing is just getting as wide of a cycle as you can get, then getting above the balancing SOC (usually 85-90% of "chemical" SOC) and holding it there for a while.

There might be a very small benefit to actual capacity if some of the cells have drifted in balance - the SOC calculation will be driven by the highest voltage cells on the top end, and the lowest voltage cells on the bottom end, so if they have drifted out of balance, then the rebalancing that also occurs at the high SOC might restore a tiny bit of usable capacity. However, it won't be much, the car will probably error at something like 50mV imbalance and refuse to start at 150mV imbalance, or something along those lines.

 

[Teslaeata]

63,500 miles
2yrs 1 mth

At 100% charge:

SoH 95.5%
highest/lowest cell voltage 1.5% apart
Highest/lowest cell capacity 0.4% apart
Total battery Voltage 398.1V

20,000kWh charge power taken on board
25% on rapid DC chargers
Virtually all home charges to 100%

 

[mkhuffman]

63,500 miles
2yrs 1 mth

At 100% charge:

SoH 95.5%
highest/lowest cell voltage 1.5% apart
Highest/lowest cell capacity 0.4% apart
Total battery Voltage 398.1V

That is much better than mine. But the decline in mine seems to have stabilized. I am interested to see if the cold weather this winter causes another decline in the SoH.

 

[Teslaeata]

That is much better than mine. But the decline in mine seems to have stabilized. I am interested to see if the cold weather this winter causes another decline in the SoH.

And
20,000kWh charge power taken on board
25% on rapid DC chargers
Virtually all home charges to 100%

Not really sure how meaningful SoH is not having checked it before or when new so don’t know if it ever was 100%

Son’s got a year newer EV with 20k miles, battery under half the capacity and his SoH is 95.25%

 

[Teslaeata]

Wow, that is so much better than my battery is doing. I plan to do another 100% charge today and see if the SoH improves again. I doubt it will. Probably there is some averaging going on, and one charge above 92% of 91 kWh isn't sufficient to get the SoH to change. But multiple might. Who knows?

I checked SoH at 80% charge and again fully charged and SoH remained same.

 

[Teslaeata]

I should also state that I've done absolutely nothing to "protect" the battery. I drive the car how I love to drive the car. We do lots of long road trips with multiple DCFC charges. I have had it L2 or L1 charging to 100% for most of the past year. I give people the requisite high-acceleration ride and when I'm alone and not going anywhere particularly far away, I'll put the hammer down. I don't do that all the time, but I haven't avoided it by any means.

It’s there to be driven & enjoyed?

 

[CarsIMBwife]

Bought an OBD reader before purchasing my used MME last week. Didn’t see this thread, but checked out my husband’s MME as a comparison. His has about 12k miles and about a June ‘21 build date. He charges L1 almost exclusively (the L2 is for me ) with one WNC to Chicago road trip with a few DCFC. His SoH is 95.5%. My used one was built February ‘21 and has 26k miles. No clue about charging history, but has the same 95.5% SoH. It was one of my purchase criteria.

What’s this about tanks? It’s “Wheel of Time” people! I started reading it in the ‘80s. Hence my Star White pony is named Aldieb after Moiraine’s white mare.

 

[DevSecOps]

I would like to report that at 43k miles my SOH is now 94%

At 40k I was at 93% SOH.

I like this new trend!

 

[Blue highway]

I would like to report that at 43k miles my SOH is now 94%

At 40k I was at 93% SOH.

I like this new trend!

In ~18K more miles you will be back to 100%... keep us posted

 

[Teslaeata]

I would like to report that at 43k miles my SOH is now 94%

At 40k I was at 93% SOH.

I like this new trend!

Feel a song coming on……only way is up!

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