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

[MachA]

I haven't found my RWD Select-equiv. to be particularly floaty or unpredictable (except for the hood sort of jittering, that didn't happen even at 155 mph with my 140i) up to the max speed of 115 mph tach. Maybe the US highways are more challenging due to not being made for those speeds though. Also have not fried my HVBJB yet, despite staying on the "gas" at that speed for a while, which may be owed to the less powerful motor.

As for something more on-topic: I wonder if degradation in the new LFP Mach E will significantly vary from the NMC models. When I look at real world reports of Model 3 RWD owners, the difference to LR or P models is not quite as big as I'd expect looking at the scientific evaluations of LFP chemistries.

To this end, I find the degradation curve provided by teslalogger quite interesting, despite not being 100% applicable to our cars.

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[mkhuffman]

Maybe the US highways are more challenging due to not being made for those speeds though.

That is possible, but I think law enforcement is more aggressive here.

On most highways, 100 mph will put you in jail. Or cause your license to be revoked. In Utah and other places out west, some highway speeds are higher and law enforcement is weak. There are highways with a 80 mph speed limit that people exceed significantly. But in my state, they are hiding and trying to catch speeders.

100 mph drivers have to be very observant and it isn't possible to maintain that speed unless you want to be arrested. You have to slow down around curves and over hills just in case law enforcement is waiting for you. And often, they are. In my experience the roads are fine for high speeds. It's the law that takes the fun out of it.

 

[SpaceEVDriver]

About two weeks ago I noticed that my battery SOH is at 97.5 with ~18,000 miles. This past week I did a poor-quality discharge to below 10% and then an uninterrupted recharge. I say low-quality because I allowed regen.

Anyway, we drove 340 miles at relatively low speeds around town with only one highway drive down off the mountain and back up. At the end, we had 8% SOCD and ~10% SOC actual and I estimate we had another 42 miles of range left. I ran the heater until the SOC actual was below 8% and then plugged in our slow L2 charger.

The car is recharged to 100% SOCD, and the guess-o-meter is saying 316 miles whereas it used to say 280 or so. There are too many complicating factors (temperature, recent driving history, etc) to say the discharge-recharge cycle had anything to do with that adjustment.

The SOH still indicates 97.5%.
Energy to empty is 86.4 kWh.
SOCD is 100%
SOC is 95.5%

 

[mkhuffman]

About two weeks ago I noticed that my battery SOH is at 97.5 with ~18,000 miles. This past week I did a poor-quality discharge to below 10% and then an uninterrupted recharge. I say low-quality because I allowed regen.

Anyway, we drove 340 miles at relatively low speeds around town with only one highway drive down off the mountain and back up. At the end, we had 8% SOCD and ~10% SOC actual and I estimate we had another 42 miles of range left. I ran the heater until the SOC actual was below 8% and then plugged in our slow L2 charger.

The car is recharged to 100% SOCD, and the guess-o-meter is saying 316 miles whereas it used to say 280 or so. There are too many complicating factors (temperature, recent driving history, etc) to say the discharge-recharge cycle had anything to do with that adjustment.

The SOH still indicates 97.5%.
Energy to empty is 86.4 kWh.
SOCD is 100%
SOC is 95.5%

That's interesting. I wonder if the new range algorithm sets a minimum but not a maximum range estimate based on driving history and climate? So it bottoms out just below EPA but if you drive conservatively, it will adjust up?

I am jealous of your SOH, BTW.

 

[SpaceEVDriver]

That's interesting. I wonder if the new range algorithm sets a minimum but not a maximum range estimate based on driving history and climate? So it bottoms out just below EPA but if you drive conservatively, it will adjust up?

I am jealous of your SOH, BTW.

I really have given up on range estimators.
It's crap in the Mustang.
It's crap in my truck.
It's crap on my motorcycle.

If it was something I could track with CarScanner, I might be willing to do the analysis to understand what it's doing. But this point, based on my experience, I just estimate that I have 320-330 miles highway range on a spring day and adjust based on what I know about my trip.

 

[SpaceEVDriver]

I am jealous of your SOH, BTW.

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.

 

[mkhuffman]

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.

Same here. But I don't have a ton of DCFC. I think maybe the SOH is most dependent on the unique chemistry in each battery pack. It doesn't seem like user behavior has a significant impact. But thaf is just a theory.

 

[Shayne]

Same here. But I don't have a ton of DCFC. I think maybe the SOH is most dependent on the unique chemistry in each battery pack. It doesn't seem like user behavior has a significant impact. But thaf is just a theory.

You can buy 2 identical intel CPU's. One will over clock like snot the other will struggle to run at stock speed. Each is unique but the same. I would say the same goes for build quality of may things. Luck of the draw. Good news is degradations happens noticeably for the first few years and then tapers off.

 

[Murse-In-Airy]

I haven’t been on here a ton lately but just found this thread so I had to go out to the car and check. 14K miles. 96% SOH. Frequent World of Tanks events (though I’m more of a Fortnite guy myself.). Rare DCFC and very rare charge to 100%. I do live where it’s very cold.

 

[SpaceEVDriver]

Same here. But I don't have a ton of DCFC. I think maybe the SOH is most dependent on the unique chemistry in each battery pack. It doesn't seem like user behavior has a significant impact. But thaf is just a theory.

100%. There's a variation in builds and that variation means sometimes one battery will survive a bit longer than another, even if they were treated identically.

 

[Murse-In-Airy]

I checked my wife’s car. 32,000 miles we’ve had it for two years and three months rarely DC fast charge. she has 95% state of health.

 

[mkhuffman]

I checked my wife’s car. 32,000 miles we’ve had it for two years and three months rarely DC fast charge. she has 95% state of health.

Grrr...

 

[devmach-e]

I'm at 19,850 miles and my SoH is 95%. EtE at 100% SoCD is 85.88 kWh.

 

[mkhuffman]

I'm at 19,850 miles and my SoH is 95%. EtE at 100% SoCD is 85.88 kWh.

Thanks for sharing your data. I wonder about how the SOH is calculated. According to 85.88/91, your SOH should be 94.4%. When I charged my car the other day, it charged to 85.14, which is 93.6%. My car is currently reporting 92.5% SOH.

Yours is closer, but still off by a half a percent. Mine is off by a full percentage point. Hmmm. Perplexing.

I am going to charge to 100% more frequently to see if the SOH will drift up as it gets more data points showing a higher SOH.

 

[Murse-In-Airy]

Grrr...

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.

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