Battery health test

[AlanSubie4Life]

Or you could simply follow Tesla's recommendations to charge up to 80% for normal daily driving and don't let it car sit below 20% or above 90% too frequently. Note that this DOESN'T mean you can never go below 20% or above 90%. You can do that all you want. I do it all the time on road trips - I leave my house at 95% and have no issue if I roll into a charging stop at 15%. Returning from Cape May today, I stopped to charge just long enough to get me home at an estimated 10% (ended up at 12%). I plugged in as soon as I got home so the car didn't sit at that 12%. There is nothing wrong with using most of the battery.

Yep, there is nothing wrong with this strategy.

It just results in about twice the rate of calendar aging. (The primary source of capacity loss.)

Absolutely no issue with going to higher charge levels. They don’t result in significantly higher calendar aging as long as you use it up and don’t store at those levels.

don't let it car sit below 20% or

There is no such recommendation from Tesla. They just warn that you may not be able to drive below those levels if the car gets cold, cannot use features etc. It’s totally fine.

From an aging perspective it’s actually a bit better. But not really worth worrying about. Just charge up overnight as usual. Or earlier if you plan to use the car of course.

 

[VipinLJ]

That’s a good simple strategy (if it is convenient - if not, use a higher value).

And don’t worry at all about charging higher, supercharging, etc. Just do those things as you need to, try to warm up the pack before the Supercharger, etc.
100% and high SOC is not an issue at all. Just use it up relatively quickly.

Haha. After I got my Tesla and started reading up about charging practices on Reddit, I was worried. I had no idea about the 20-80% recommendation. People also told me not to supercharge since that isn't good. All through the week, my car uses like 12-15% a day. Weekends we need maybe 50-60% occasionally. Your recommendation is more than enough for my daily driving duties.

Or you could simply follow Tesla's recommendations to charge up to 80% for normal daily driving and don't let it car sit below 20% or above 90% too frequently. Note that this DOESN'T mean you can never go below 20% or above 90%. You can do that all you want. I do it all the time on road trips - I leave my house at 95% and have no issue if I roll into a charging stop at 15%. Returning from Cape May today, I stopped to charge just long enough to get me home at an estimated 10% (ended up at 12%). I plugged in as soon as I got home so the car didn't sit at that 12%. There is nothing wrong with using most of the battery.

I've let it go below 20% only twice. Even for the battery health test, car was down to like 30% iirc. Even then, it finished the entire test in less than 15 hours! If I charge to above 80%, I make sure I drive the car or it needs to be driven soon (like in half an hour). If not, I usually run the AC and sentry mode till it falls to 80. I guess I'm a bit paranoid that way.

 

[AlanSubie4Life]

Haha. After I got my Tesla and started reading up about charging practices on Reddit, I was worried. I had no idea about the 20-80% recommendation. People also told me not to supercharge since that isn't good. All through the week, my car uses like 12-15% a day. Weekends we need maybe 50-60% occasionally. Your recommendation is more than enough for my daily driving duties.



I've let it go below 20% only twice. Even for the battery health test, car was down to like 30% iirc. Even then, it finished the entire test in less than 15 hours! If I charge to above 80%, I make sure I drive the car or it needs to be driven soon (like in half an hour). If not, I usually run the AC and sentry mode till it falls to 80. I guess I'm a bit paranoid that way.

Relevant picture here for the types of cells in your vehicle (NCA). This is the key picture to understand the results. This is what has been observed in Tesla vehicles.

You can see the high marginal returns between 65% and 55%.

Some new data from research on Tesla model 3 cells

There has recently been released a series of new research reports containing tests on Tesla Model 3 Cells (Panasonic 2170 NCA). This is the calendar aging test from one of them (25C, 15, 50 and 85% SOC. Checkup once a month): Using the datapoints from these and putting them in the old charts I...

teslamotorsclub.com

 

[DanDi58]

There is no such recommendation from Tesla. They just warn that you may not be able to drive below those levels if the car gets cold, cannot use features etc. It’s totally fine.

Sure they do, here - https://www.tesla.com/support/range

Charging Routine​

• Try to avoid keeping the battery below 20% charge for an extended period of time. When the battery is too low in charge, the battery icon will turn yellow and the available range will drop if the vehicle is parked in colder temperatures.

 

[AlanSubie4Life]

Sure they do, here - https://www.tesla.com/support/range

Charging Routine​

• Try to avoid keeping the battery below 20% charge for an extended period of time. When the battery is too low in charge, the battery icon will turn yellow and the available range will drop if the vehicle is parked in colder temperatures.

Yeah that is just a statement about particular charging habits.

I was just saying there’s no such recommendation in regards to the health of the battery (the topic here).

As I said they make various recommendations due to temperature, ability to use features etc.

But in regards to this topic this is not really relevant. It’s a non-issue for battery health.

 

[Jedi2155]

So I finally ran this test for the first time on my 08/2018 build P3D+ with about 71,000 miles. Starting conditions was around ~4:10 PM - 29% SOC. Test health came back at 86%, 280 miles range.

Some recommendations & observations:

Service App Recommends turning off the following, and I recommend turning off additional items in RED:

1. Turn off Sentry
2. Turn off Summon
3. Turn off Cabin Overheat Protection
4. Turn off HVAC
5. Plug In the Car > 6 kW
6. Have the car under 50% SoC
7. Turn off Scheduled Charging
8. Turn off Charge on Solar (I have power walls)
9. [Optional] Set your charge power to 32A, (I had mine set to 48a initially, but I like 32A since its more efficient, and a slower charge can be more accurate.
10. Set charge limit to 100%
11. Unplug any USB devices
12. Roll down the windows, don't re-open the doors or check your app too much during the test.

Observations during the test:

• The car ran the heater/AC/motors from 29% to ~10% then stopped ~7:10 PM
• When I reviewed the service logs, I had two faults occur , HVAC blower fan faulted, then was reset and cleared after approximately 10 seconds
• I had USB malfunctions every hour or so after 7 PM until charging started implying DC/DC converter power issues.
• It took another 4-5 hours to drain from 9% to when it began charging and I adjusted the charge power down to 32A. (~midnight)
• I noted the app never said "Service" like others reported, and it felt a little slower to respond than normal.
• When I woke up to check on it, it was charging at 2 KW at 89%, but I had forgot to set my charge limit to 100%, and it was set to 90%.
• When I shifted the slider to 100% on the app, it immediately said charging complete, and the SOC jumped from 89% to 100% immediately which shocked/scared me.
• When I went into the vehicle, service app was still open, gateway was locked, and battery test health reported 86%, and full charge was 280 miles.
• Using 310 mile range base when I bought it, I'm at 266.6 mile range capacity (same as end of 2023), using the 330 mile range base, I'm at 280 mile range base as reported now.
• I noted this shifted a few months ago from the 310 to 330 mile range base, where my capacity was ~270 miles and now it says 280 miles (see my TeslaFi data).
• Using TeslaFi data, I've down 171 supercharges 5,370 kWh (my first 10,000 miles or so had Free Unlimited Supercharging). I've done 1424 AC charging, totaling 17,497 DC kWh added, and used 24,804 AC kWh (inefficiency).

Overall degradation is line with expectations for a 5.7 year old battery, with most of it in the first 2 years (4%/year) and has been a slow decline (~2%/year) since.

 

[AlanSubie4Life]

Test health came back at 86%, 280 miles range.

Seems wrong. Using 325.

You’re at 12%/88%.

You never had a change in range. Has always been 310 for 76kWh, starting at 77.8kWh. 245Wh/mi

The 280 is from the car directly I assume?

 

[Jedi2155]

Seems wrong. Using 325.

You’re at 12%/88%.

You never had a change in range. Has always been 310 for 76kWh, starting at 77.8kWh. 245Wh/mi

Could you explain how you got 12/88% then? The battery health test came back at 86% health, and the UI shows 280 mile range at 100%. I did (280 / 0.86 = 330)

 

[AlanSubie4Life]

Could you explain how you got 12/88% then? The battery health test came back at 86% health, and the UI shows 280 mile range at 100%. I did (280 / 0.86 = 330)

Initial range 310mi for 76kWh. 245Wh/mi. Degradation threshold 76kWh.

Starting capacity 77.8kWh (approx).

Current: 280 miles => 68.6kWh

68.6kWh/77.8kWh = 88.2%