Battery Degradation

[Black e]

This is probably a beaten up topic .But I went in today with my 12v drained to check what happened with the drain issue. I was shown that the 12V health seems good and is at 100 % from the time I jump started it and drove to the dealer which is like a 10 mile drive .I was told to see if it continues to happen and then they can take a look at the drain issue .But while looking at their screen I also saw that the batter health was at 88% after doing 60k miles.Is this expected as I don’t do super charging frequently or drive aggressively .Charges inside a garage everyday .Any ideas on the battery loosing health of 12% in 60k miles ?

Sponsored

 

[AliRafiee]

To check the health, the battery needs to be at 100% and a few other conditions need to be satisfied to get a correct reading.
Search the site for all the relevant info. Lots of info available here.

 

[Mach-Lee]

88% battery health seems normal on a 2022 after 60k miles. I wouldn’t worry about it.

 

[Mustangor]

Mine went from 99% to 91% after a road trip with several DC charges (mesured with an OBD module and AAtorque). I had only 6000km. Range was clearly impacted. The dealer told me not to worry about it, but this is one on the many issues that convinced me go to Tesla next time.

 

[Mach-Lee]

Mine went from 99% to 91% after a road trip with several DC charges (mesured with an OBD module and AAtorque). I had only 6000km. Range was clearly impacted. The dealer told me not to worry about it, but this is one on the many issues that convinced me go to Tesla next time.

Try doing a battery calibration first, that will probably bring the capacity estimate up some: https://www.macheforum.com/site/threads/hv-battery-calibration-procedure.23815/

 

[mkhuffman]

I have 52k miles and 89% state of health. You are right in alignment with me. Welcome to owning a BEV! This is why I think replacing it every 3 years is a good plan, at least until battery technology advances to the point where it maintains health for much longer.

 

[Mustangor]

Try doing a battery calibration first, that will probably bring the capacity estimate up some: https://www.macheforum.com/site/threads/hv-battery-calibration-procedure.23815/

I don't understand why such procedure would change anything regarding battery "State Of Health" - so called HVBSoH in AAtorque. Isn't this value calculated by the ratio of valid/invalid cells in the battery, aka like valid/invalid clusters on a SSD drive ? I'll try this anyway, but I doubt it'll change anything because this was such quick change and I'm pretty sure the repeated DC charges during the trip somehow damaged the cells.

 

[Tomm]

Are we talking two types of batteries?

 

[E90alex]

I don't understand why such procedure would change anything regarding battery "State Of Health" - so called HVBSoH in AAtorque. Isn't this value calculated by the ratio of valid/invalid cells in the battery, aka like valid/invalid clusters on a SSD drive ? I'll try this anyway, but I doubt it'll change anything because this was such quick change and I'm pretty sure the repeated DC charges during the trip somehow damaged the cells.

No. If a cell is “damaged” you would have a failed battery. It doesn’t wear down one cell and then move to the next.

Batterie cells in a module/pack wear down pretty much evenly over time and lose capacity. Battery health is the present capacity divided by the design capacity.

But the battery capacity can’t really be measured directly. It’s calculated/estimated by the BMS based on the information it has and measurements it takes. That estimation can get out of whack if it doesn’t have enough good data. Battery cells can also get out of balance (when cells have different voltages) which affects the accuracy of the BMS.

See the thread about HV battery calibration for ways to help the BMS gather better data to be able to give better estimates.

 

[mkhuffman]

I don't understand why such procedure would change anything regarding battery "State Of Health" - so called HVBSoH in AAtorque. Isn't this value calculated by the ratio of valid/invalid cells in the battery, aka like valid/invalid clusters on a SSD drive ? I'll try this anyway, but I doubt it'll change anything because this was such quick change and I'm pretty sure the repeated DC charges during the trip somehow damaged the cells.

It doesn't change anything regarding the actual state of health. All it does is help calibrate the battery management system (BMS) so that it more accurately reports the real SoH of the HVB.

 

[Mach-Lee]

I don't understand why such procedure would change anything regarding battery "State Of Health" - so called HVBSoH in AAtorque. Isn't this value calculated by the ratio of valid/invalid cells in the battery, aka like valid/invalid clusters on a SSD drive ? I'll try this anyway, but I doubt it'll change anything because this was such quick change and I'm pretty sure the repeated DC charges during the trip somehow damaged the cells.

No, the state of health is a computer estimate of the battery’s current capacity. Which can be affected by software updates and depth of charge. It is not an a count of failed cells (if you had a failed cell, there would be a stop safely now error displayed). Your battery was not damaged by DC charging, the capacity figure was simply updated. It’s impossible for a battery to actually degrade that fast. Again, it’s simply a computer estimate, don’t take it too seriously. If you read through the comments, the procedure does work to improve battery SOH reading.

 

[Mustangor]

No. If a cell is “damaged” you would have a failed battery. It doesn’t wear down one cell and then move to the next.

Batterie cells in a module/pack wear down pretty much evenly over time and lose capacity. Battery health is the present capacity divided by the design capacity.

But the battery capacity can’t really be measured directly. It’s calculated/estimated by the BMS based on the information it has and measurements it takes. That estimation can get out of whack if it doesn’t have enough good data. Battery cells can also get out of balance (when cells have different voltages) which affects the accuracy of the BMS.

See the thread about HV battery calibration for ways to help the BMS gather better data to be able to give better estimates.

OK, thanks for the explanation. Much clearer now . BTW my battery is one of the last NMC of 2024 SR.

 

[bbulkow]

I don't understand why such procedure would change anything regarding battery "State Of Health" - so called HVBSoH in AAtorque. Isn't this value calculated by the ratio of valid/invalid cells in the battery, aka like valid/invalid clusters on a SSD drive ? I'll try this anyway, but I doubt it'll change anything because this was such quick change and I'm pretty sure the repeated DC charges during the trip somehow damaged the cells.

Since you used the ssd example, every ssd block has the a write counter and a voltage leak indicator (not sectors, blocks). An ssd is a large number of chips and blocks. Wear is some kind of synthetic average. Wear in an ssd isn't bad blocks.

Battery soh is parallel (not the same!) in that there are a lot of cells, and they all have voltages when fully charged. The battery monitor sort of averages. By going low, then high, allowing the cells to balance, and allowing the monitor to top up each cell, means you get the best measure. That's why there rec is to go to 100 pct and leave it there for 6 hours.

If you don't, the soh measurement will be artificially low. The battery is what it is though.

Most things i read show the greatest decrease is early on, and is time based more than use based, with some exceptions.

I see nothing that says teslas are immune to fundamental chemistry. In fact, the lfp batteries are both sourced from catl, right? Just that Tesla doesn't expose these numbers?

I am not concerned with missing 10 percent of range. First, i bought the extended expecting this. Second i have enough range optimization when i care to get back at least 15 percent of range, like recirc climate control and freeway 67 mph. My range is fine and i expect it to be 5 years from now, even when my soh indicator is 85 pct.

I also wonder if we will have available pack replacements for a reasonable price at some point. If batteries get cheaper and more stable, and our cars are well built, there might be....

 

[Mustangor]

I didn't try the Mach-lee procedure, and I will certainly try sooner rather than later. Lets admit this is just false information reported and my battery has not lost 9% of capacity. The whole point is that it's just like it has !!! How do I know the difference ? How to I know the correct range of my car ? I can't because the range is displayed by the car itself, and it's the only information I have to calculate my trips.

Range at 100% was 440 km when I got the car, and stayed like that until this road trip, when suddently it droped to 380 km. Just as the HVBSoH went to 91%. Even if it's not the case, it's exactly as I lost 60 km range. And I have to do this ridiculous procedure to have my car correctly predict my range ? Imagine if you had to empty the tank of your ICE car, then refull to max, then empty again, just to have a correct estimation of your range...

 

[Mach-Lee]

Range at 100% was 440 km when I got the car, and stayed like that until this road trip, when suddently it droped to 380 km. Just as the HVBSoH went to 91%. Even if it's not the case, it's exactly as I lost 60 km range.

The range of an electric vehicle (EV) is not a fixed number but varies depending on the conditions. For instance, if you were driving it locally at 80 kilometers per hour, your range would be a specific value. However, if you take a road trip and suddenly increase your speed to 120 kilometers per hour, the range will significantly decrease due to the additional speed. Additionally, the range decreases with speed and temperature. Therefore, it is advisable to use a route planning application like ABRP instead of relying solely on the range meter displayed on the vehicle.

Since you have LFP pack, make sure you are charging it to 100% every couple weeks to calibrate the battery.

Sponsored