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Battery degradation and calibration

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I know this item has been discussed a few different ways, but I wanted to try something a previous user posted in length about, as well as get some insight of my own. For reference, here is the length of the post I’m referring to: How I Recovered Half of my Battery's Lost Capacity

I fell down the rabbit hole about a week ago of checking my battery health with Tessie. Vehicle is a 2022 MYP. Took delivery in September. Car has about 4,000 miles currently. Used the Tessie app for a week, and it showed my battery health at 97.8% with 2.2% degradation. All of that came out to a decrease of about 10-13 miles (if you believe the max range is actually the EPA rated 303 miles). Upon the final Tessie evaluation, the max range on the car was 288 miles.

I spoke to a friend who also has a 2022 MYP that was delivered in March. This car has lost the same number of miles in range, despite having close to 15,000 miles. This got me thinking about battery calibration, which leads me back to the post I referenced at the top. Has my MYP actually decreased the same 10-13 miles in range as my friend, despite them having 11,000 more miles driven than me? There is only one way to find out. So, I am going to embark on what sounds like a long-term battery calibration.

My previous charging habits were pretty standard. I charged the car to 80% every night. Drove to work 5 days a week, 17 miles each way. I returned home with roughly 60-61% and charged the car back to 80%, following the Tesla rule of ABC (always be charging). I have only charged the vehicle to 100% 2-3 times in the nearly 3 months I have owned it.

Now, obviously I realize I haven’t lost near the range the original poster had. But I couldn’t help but think the only way my friend and I have the same range on the same vehicle despite them having driven 11,000 more miles is either 1) battery calibration or 2) somewhat rotten luck on my part.

I will post any updates as I go through this process, but my charging procedure now is pretty simple. I charge to 75% to start the week. Each day while at work, I take care not to open the Tesla app and let the car go into a deep sleep so the computer can get its readings. I then leave the car unplugged at night until I need to recharge, which typically happens on Wednesday or Thursday evening. Once I drive the car to around 12-15% battery, I let it sit unplugged for several hours with the app open, pinging the computer. I then let the car sleep before finally plugging it in to charge.

Full disclosure: I have only gone through this procedure fully once. I am now on my second week, and I will post any notable results as I get them. Any thoughts/comments/encouragement/insight is appreciated. I know that battery degradation typically levels off around 10%, and I know that it is inevitable. But I have also read about plenty of vehicles that have retained their max range at a much better rate than I am going (at least so it seems. Who knows? Maybe this is normal and I’m wasting my time). So, not sure how much is variance and how much is battery/computer calibration, but I am excited to find out.
 
You don't need to do that every week. It's good to give the BMS readings at low and high SOC but it's better for your battery health to keep it always "low" and do shallow charges (thus more often).

Don't expect changes immediately, it might take a while. I did that when the thread came out and TeslaFi reported my battery moving towards the bottom of the average. Nothing happened, and then I did it again on my next road trip (charge quasi-full, return overnight at ~15% SOC). Eventually my battery graphic showed a bump. I now do this only when I have a road trip and have stopped caring about it. I see some adjustments sometimes, but obviously YMMV. Here's my graph. (in kilometers)

1670263542318.png


TL;DR: Don't worry about it ;)
 
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You don't need to do that every week. It's good to give the BMS readings at low and high SOC but it's better for your battery health to keep it always "low" and do shallow charges (thus more often).

Don't expect changes immediately, it might take a while. I did that when the thread came out and TeslaFi reported my battery moving towards the bottom of the average. Nothing happened, and then I did it again on my next road trip (charge quasi-full, return overnight at ~15% SOC). Eventually my battery graphic showed a bump. I now do this only when I have a road trip and have stopped caring about it. I see some adjustments sometimes, but obviously YMMV. Here's my graph. (in kilometers)

View attachment 881720

TL;DR: Don't worry about it ;)
Interesting! So when you say it’s better to keep it “low,” how low? For instance, should I drive it down to 20% and then only charge to, say, 50%? And then repeat that procedure every day for the more shallow charges?
 
If you've read all the material lying around here, you'll see there's some kind of inflection point between 55-60% SOC for age degradation, so I charge mine to 55%. I drive until I get at around 40% just because I'm too lazy to plug every day. This lets me skip a day, sometimes two. You could charge every day if you're not as lazy as I am, that seems best.
Now, don't refrain from using your car for this... IF I need 95% SOC to go somewhere, I charge. If I come back home at 12%, I'll charge anyway etc... Don't sweat it. Just give your BMS a chance to see both ends of the pack sometimes and otherwise enjoy the car.
 
I have set the charge rate to 15 amps. Hopefully by reducing the amps in helps prolong battery life. Anyone know if this is of value.
No, definitely not. This battery can take over 200 kW power. You're dinking around with the difference between like 7 or 3 kW. It's all exceedingly slow charging from the battery's perspective and won't matter.
 
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I have set the charge rate to 15 amps. Hopefully by reducing the amps in helps prolong battery life. Anyone know if this is of value.
The higher the amperage the faster the charging will complete. There is overhead (energy lost to heat energy, AC to DC power conversion losses, coolant pumps, fans etc.) while charging. You can minimize the overhead (the overhead translates into extra cost) by charging at the maximum amperage your home charging will support. (There is information that charging at the current Level 2 maximum of 48 amps may require additional cooling of the charging circuitry and battery versus charging at 40 amps; this additional cooling may only happen in warmer times of the year.) In any event the difference in efficiency when charging at ~240 volts and any of the higher supported amperage, i.e. 32/40/48 amps is very small.
 
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Interesting to read this battery "degradation". At 90%, I get 240 miles. Clearly sad to see when it was averaging 290. Over 300 if 100%. Not quite the advertised mileage, along full "full auto pilot".

Putting on my tin foil hat, how much can tesla artificially lower mileage via software. Not crazy to think they would not do that for the next tesla with 500 mile range to have folks sell for new model. Pretty disappointed even with degradation
over time. In my mind this is after 5-6 years. Not in 1 year...
 
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Battery age is going to get your battery LONG before messing around with SOC levels will. Just charge to 90 percent and forget about it. The first year or two is where you see the biggest drop due to how battery tech works at the current time. Its confirmation bias to notice it and attribute it to how much charge you are keeping in the battery. The BMS is much happier this way as well. There are folks here with years and years of charging to 90 percent that ride the same bell curve the shallow charger guys are. And charge with as much power as you can with the wall charger. Its nowhere near supercharger levels these batteries are designed to take and as someone mentioned, it costs you less. In the winter, set your departure and time of use discount end time around the same time, right before you leave, your battery will be warm and ready to go.

Why reduce your available range (for emergencies, who knows) just to prevent losing range you arent using anyway ? lol
 
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Battery age is going to get your battery LONG before messing around with SOC levels will. Just charge to 90 percent and forget about it. The first year or two is where you see the biggest drop due to how battery tech works at the current time. Its confirmation bias to notice it and attribute it to how much charge you are keeping in the battery. The BMS is much happier this way as well. There are folks here with years and years of charging to 90 percent that ride the same bell curve the shallow charger guys are. And charge with as much power as you can with the wall charger. Its nowhere near supercharger levels these batteries are designed to take and as someone mentioned, it costs you less. In the winter, set your departure and time of use discount end time around the same time, right before you leave, your battery will be warm and ready to go.

Why reduce your available range (for emergencies, who knows) just to prevent losing range you arent using anyway ? lol
Charge to 90% if you want your battery to degrade faster due to calendar aging. Not a good advice unless you need the charge. You dont need to sweat anything, set your charge between 55%-60% depending on your cells and that's it, unless need more. Just because someone else is doing it doesn't mean you should be doing it
 
Charge to 90% if you want your battery to degrade faster due to calendar aging. Not a good advice unless you need the charge. You dont need to sweat anything, set your charge between 55%-60% depending on your cells and that's it, unless need more. Just because someone else is doing it doesn't mean you should be doing it
The battery degradation may be greater if you regularly charge to 70% up to 90 % rather than 50% or 60% but it amounts to just a few percent more that you probably would never notice. If charging daily to 70%, 80% or 90% meets your needs then do it without any concern.
 
@MYguy91

You are killing off far too many Brain cells on this subject. The information you are being provided is will intentioned, but there is no hard evidence to support these statements; they are based on anodal evidence, or come from general information about lithium batteries or from Lab tests, none of which used actual Tesla HV packs.

Just sit back and enjoy your car!
 
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The battery degradation may be greater if you regularly charge to 70% up to 90 % rather than 50% or 60% but it amounts to just a few percent more that you probably would never notice. If charging daily to 70%, 80% or 90% meets your needs then do it without any concern.
Sure. You can charge to whatever want. But setting to 90% and forget itdon't need a mileage makes absolutely zero sense.
The battery degradation may be greater if you regularly charge to 70% up to 90 % rather than 50% or 60% but it amounts to just a few percent more that you probably would never notice. If charging daily to 70%, 80% or 90% meets your needs then do it without any concern.
You can charge to whatever you want. I personally don't care. I just don't like seeing people giving advices based on what? Does he know his routine? Does he know how many kilometers he drives per day and so forth? That's why our cars have daily limit from 50% to 90%. Tesla dealerships(service centers) tell you to set it at 90. Sure. They should then provide warranty when your battery degrades to 15 to 20% instead of 30%. So no, don't set it and forget it. Use it as you need it and have a safe headroom just in case if you need to drive for another hour or so. More battery = less stops on trips and higher resale value if you sell privately.