2012 P85 RWD here - pic is from Tesla MS Owner's Manual under "Charging Best Practices". I thought we were supposed to obey the 20/80 rule?
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This is what the owner's manual says
- Thread starter NV Ray
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Tam
Well-Known Member
I've been driving a Tesla since 2012 or the past 13 years, and I've never seen the manual mention the 20/80 charging rule.
I've been sticking to the manual instructions: plugin, 90%, and my results have not been bad:
When I sold my 2012 Tesla Model S at 100,000 miles in 2018, its 100% charge was 252.54 miles or a loss of 12.46 miles (out of 265 maximum miles) or a loss of 4.7%:
When I sold my 2018 Tesla Model 3 at almost 50,000 miles, its 100% charge was 285.81 miles or a loss of 24.19 miles out of 310 maximum miles or 7.80%.
Here's my current 2017 Tesla Model X report: its 100% expected range was 268 miles or a loss of 27 miles out of 295 maximum miles or 9.15%.
Great info, thanks. You're right, the owner's manual probably never mentioned the 20/80 rule. That 20/80 rule seems to be what the rest of the world recommends on YouTube, articles, etc.I've been driving a Tesla since 2012 or the past 13 years, and I've never seen the manual mention the 20/80 charging rule.
I've been sticking to the manual instructions: plugin, 90%, and my results have not been bad:
When I sold my 2012 Tesla Model S at 100,000 miles in 2018, its 100% charge was 252.54 miles or a loss of 12.46 miles (out of 265 maximum miles) or a loss of 4.7%:
When I sold my 2018 Tesla Model 3 at almost 50,000 miles, its 100% charge was 285.81 miles or a loss of 24.19 miles out of 310 maximum miles or 7.80%.
Here's my current 2017 Tesla Model X report: its 100% expected range was 268 miles or a loss of 27 miles out of 295 maximum miles or 9.15%.
islandbayy
Active Member
Ive only seen this on the new LFP batteries. Could be an owners manual typo? Tesla HAS changed things a number of times in the last 11 years for the Model S.2012 P85 RWD here - pic is from Tesla MS Owner's Manual under "Charging Best Practices". I thought we were supposed to obey the 20/80 rule?
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I just took a peek at the manual for that P85 over at Recell, cant find mention of this.
Honestly that looks like something that was copied from the Model 3 manual, where the RWD vehicles happen to be manufactured with a different battery chemistry than the AWD vehicles. (It's not literally "RWD vs AWD" that matters, it's the battery chemistry and architecture, but Tesla seems to be trying to dumb this down for new owners.)
For all Model S, basically don't keep your battery pack full for a long time...that's definitely bad for the cells. Other than that, there aren't any hard-and-fast rules...everybody's got their own favorite ones, but people way overthink this stuff.
I used to charge my 2015 S85D to 90% daily until Tesla implemented a software change a few years ago that made one of the coolant pumps run for a long time if I charged above about 78%. So now I charge to 75% (not necessarily daily), just to reduce wear on the coolant pump. Not worried about the battery at all.
Bruce.
islandbayy
Active Member
Personally, the 20/80 rule is not good. I don't support it, and my ~400,000 miles of Tesla ownership/driving backs my opinion.
Charge to 100% regularly. While the cars will balance out the pack at lower SOC's, it does a much more thorough job at 100%, especially noted by the LONG time it takes to get that last few % in to the pack.
100% is NOT BAD FOR THE BATTERY! Charging to 100% and LEAVING IT AT 100% FOR LONG PERIODS OF TIME is BAD for the battery(Lithium Ion, LFP is just fine at 100%). Though, even that, is negligible. I have a video coming, where I took 2, 2015 P85 cells compliments of WK057. Left one at 100% for 7 years, and 1 at shutdown voltage for 7 years, to see the effects. The results will surprise everyone ;-)
Also based on my observations pertaining to battery failures, it honestly seems the people who have babied their batteries, are the ones having more issues. The people who use and abuse it and throw caution to the wind, have only a tiny bit more degradation, but overall life span of the battery before a replacement event is required appears to be exponentially higher.
Charge to 100% regularly. While the cars will balance out the pack at lower SOC's, it does a much more thorough job at 100%, especially noted by the LONG time it takes to get that last few % in to the pack.
100% is NOT BAD FOR THE BATTERY! Charging to 100% and LEAVING IT AT 100% FOR LONG PERIODS OF TIME is BAD for the battery(Lithium Ion, LFP is just fine at 100%). Though, even that, is negligible. I have a video coming, where I took 2, 2015 P85 cells compliments of WK057. Left one at 100% for 7 years, and 1 at shutdown voltage for 7 years, to see the effects. The results will surprise everyone ;-)
Also based on my observations pertaining to battery failures, it honestly seems the people who have babied their batteries, are the ones having more issues. The people who use and abuse it and throw caution to the wind, have only a tiny bit more degradation, but overall life span of the battery before a replacement event is required appears to be exponentially higher.
Tam
Well-Known Member
Correct! That rule is not from Tesla's manual. Some people feel Tesla's instructions are wrong, so they teach us how to do it right with the 20/80 rule.
aerodyne
2 of 3 EV's - Defect Free!
All it takes is a bad cell or two out of 7100 + to trigger the BMS and eventually brick the pack.
In 4 years and 40k miles, never seen any balance or capacity and esp range improvement going over 93% on a 85 pack. Minor improvement going over 77%.
Look forward to your test results, however.
islandbayy
Active Member
My 75D MX has one cell out in one brick of the entire pack. If left at a lower SOC, the imbalance goes about 40-60mV. Only way to bring it back to balance, or I should say, it only ever balances out when charging to 100%. Takes absolutely forever.
Went to Chicago's O'Hare airport juts over a week ago to pick the M-I-L up from out of the country.
We put the kids to bed, Saturday Night, I went and decided to just camp out at the new supercharger across the street from O'Hare. Got there about 12:30 AM with roughly 40 miles left in the pack. Plugged in, and was doing some work on my laptop, then switched over and started watching a movie.
Her flight was due to land at 6am, and with customs, figured she'd be walking through the exit at 6:45-ish (I was pretty accurate)
Anyways, fell asleep watching netflix, had to get that last season of Better Call Saul in.... Woke up when my phone alarm went off at 6 AM. The car was STILL charging. 1-2kW, and checked TM-Spy, and it was sure as heck balancing out the top end. Previous 100% charge was 202 rated miles. I was up to 211 this time on my MX75D and like I said, it was STILL going. That was 5 1/2 hours of SUPERCHARGING. Battery was warm at over 100*F when I plugged in, and charge rates were good. The phone notification that I had hit 90% SOC was delivered at ~2:15 AM. So over 3 hours to go from 90% to 100%.
Charging to 100% makes a big difference.
That screenshot is definitely something thats in the Model 3 Online manual, and the reference to RWD is clearly about the LFP battery. I could not find it (that screenshot text) in the linked model S manual.
Its already been covered that there is no "80/20" rule that has been put forth by tesla for any Tesla, though. Thats online forums stuff.
Its already been covered that there is no "80/20" rule that has been put forth by tesla for any Tesla, though. Thats online forums stuff.
You are not going crazy, yet.
I can confirm that at the time of this post this is stated in the current online and PDF version of the MS 2012-2020 owners manual. PDF version is showing as 2023.12 North America.
Hmmmm..
Thanks for confirming my sanityYou are not going crazy, yet.
I can confirm that at the time of this post this is stated in the current online and PDF version of the MS 2012-2020 owners manual. PDF version is showing as 2023.12 North America.
Hmmmm..
islandbayy
Active Member
I'm thinking someone screwed up when they updated the online manuals. The only hard reference otherwise is for the LFP battery in the RWD Model 3 thus far.
Hey islandbayy, I wanted to ask you if you ever got your car replaced/ bought back? Not sure why I can't send messages.
islandbayy
Active Member
Could be making a switch to LFP in MS & MX for non-performance vehicles. LION will have higher output for performance vehicles
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