Tesla now recommends charging to 80% daily instead of 90%

[kindofblue]

That's odd. We had a 2020 MY AWD and the recommended charge limit then was 80%. The MY is gone now though and a BMW i4 is in its place (thankfully).

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[Logal727]

Thankfully Ford is cheap and worried about warranties so there’s the conservative buffer

 

[dtbaker61]

The issue I have is power feels significantly reduced at the recommended SOCs. I only charge to 90% daily but I feel a linear lack of power as SOC goes down, and markedly less power even when you get to 87% and below.

*not likely*

The voltage of a Li battery pack is VERY flat between 10%-90%, and due to very low internal resistance there is very little voltage sag even under heavy loads. I seriously doubt you will 'feel' a difference depending on SOC. Maybe a SLIGHT difference in output if SOC is between 90-100%.

If you get a ODB2 and CarScanner app you can display real-time power output and regen to verify.

You may see power limiting after repeat WOT/regen due to temps and '5-second' software, but I doubt you will see a difference based on SOC.

 

[voxel]

*not likely*

The voltage of a Li battery pack is VERY flat between 10%-90%, and due to very low internal resistance there is very little voltage sag even under heavy loads. I seriously doubt you will 'feel' a difference depending on SOC. Maybe a SLIGHT difference in output if SOC is between 90-100%.

If you get a ODB2 and CarScanner app you can display real-time power output and regen to verify.

You may see power limiting after repeat WOT/regen due to temps and '5-second' software, but I doubt you will see a difference based on SOC.

There is still serious voltage sag in EVs and the best data I've seen is from an early 2021 ID.4.

https://www.vwidtalk.com/threads/80...ed-2-5-mi-kwh-at-58-f-us-id-4-rwd-77kwh.1303/

A forum member here measured IR on the Mach-E cells and reported it to be in the 33mOhm range which on paper sounds okay but there are large 40-50lb RC jets that push 200A @ 60V (14s) with LiPo packs with sub-1.0 mOhm. EV packs are built for longevity and not performance.

 

[dtbaker61]

There is still serious voltage sag in EVs and the best data I've seen is from an early 2021 ID.4.

https://www.vwidtalk.com/threads/80...ed-2-5-mi-kwh-at-58-f-us-id-4-rwd-77kwh.1303/

A forum member here measured IR on the Mach-E cells and reported it to be in the 33mOhm range which on paper sounds okay but there are large 40-50lb RC jets that push 200A @ 60V (14s) with LiPo packs with sub-1.0 mOhm. EV packs are built for longevity and not performance.

as long as the system has the ability to pump more amps when voltage sags, output will not be affected..... what I was talking about is the NOMINAL no load voltage which is very flat with Lithium compared to any form of Lead which drops linearly with state of charge.

 

[Billyk24]

Just like the Mach-E, Tesla previously recommended a maximum daily charge limit of 90% to prevent battery degradation. However, they have just lowered their recommendation to 80% in the latest update (applies to NCA packs, not LFP packs):

Of course there is no official word from Tesla why the daily charge limit was lowered. But you can infer that there was probably too much pack degradation happening at 90%. Lower is better when it comes to charge limits—the lower the limit the longer the pack will last. Maybe they were getting too many warranty pack replacements?

Tesla lowering the limit to 80% is sort of a big deal because they are dominant in the industry and have some of the best battery experts in the world. If Tesla lowers their limit to 80%, I bet a lot of others in the industry will eventually do the same, including Ford. Rivian currently recommends only 70% for daily use.

Unfortunately, Ford doesn't educate the customer about high charge limits through intelligent user interface design like the Tesla app. The 90% recommendation is buried in the manual, and it doesn't help that the Mach-E still defaults to 100% and doesn't have a global charge limit setting.

I should note the "real" SoC for a given charge limit can vary significantly from manufacturer to manufacturer, so 80% displayed on a Tesla could be like 90% on a Mach-E or 75% on a Rivian in terms voltage level.

For more information about why high charge levels degrade lithium batteries (and why you should set your limit as low as possible), see the below Tweet and YouTube video:



More detailed scientific information about battery degradation can be found in this video.

P.S. - Still bothers me that Ford isn't more proactive about limiting pack temps while parked, nor enforcing global charge limits since both of these factors can significantly degrade lithium cell capacity.

Remember Tesla has a much smaller "walled off" portion of their battery pack than Ford. This practice helps with marketing "battery range".

 

[Mach1E]

*not likely*

The voltage of a Li battery pack is VERY flat between 10%-90%, and due to very low internal resistance there is very little voltage sag even under heavy loads. I seriously doubt you will 'feel' a difference depending on SOC. Maybe a SLIGHT difference in output if SOC is between 90-100%.

If you get a ODB2 and CarScanner app you can display real-time power output and regen to verify.

You may see power limiting after repeat WOT/regen due to temps and '5-second' software, but I doubt you will see a difference based on SOC.

*can be very flat.

I believe on the GT SoC is just one of the things that triggers the artificial power limits.

I’ve seen the story about the Model S Plaid that ran dozens of 1/4 mile runs back to back and still was in the 9s at very low charge. But Tesla doesn’t throttle things back artificially.

https://www.teslaoracle.com/2021/08...uarter-mile-runs-and-at-a-20-state-of-charge/

 

[clsmooths]

I have noticed that the gray bars appear earlier in the winter, when the ambient temperature is cold. In the summer, I also can get down to the 60% range before I see gray bars. In the winter, I start seeing them when it drops below 80%.

I get the gray bars when going over 70 mph. I might get one bar or none going below 70 but the faster I go the more bars pop up. I live in Florida and charge from 50% to 90% on average with my daily driving. I have a 2022 GTPE and had the HVJB already replaced back in March. Bought it June 2022 and having little over 22,000 miles on her aleady?....gone a few road trips?
When I bought the car it had the bad HVJB part before they decided a week after mine was built to start putting the new HVJB. Before I can remember I use to never get those gray bars. Ever since the new HVJB was put in is when I noticed those gray bars popping up.

 

[voxel]

as long as the system has the ability to pump more amps when voltage sags, output will not be affected..... what I was talking about is the NOMINAL no load voltage which is very flat with Lithium compared to any form of Lead which drops linearly with state of charge.

There's not much room in the graphs above. 82% SoC (see 4.05V) sagged all the way to 3.6V which is below nominal (3.7V). BMSes will shut the power off after a certain voltage and this is just a RWD ID.4 accelerating to 80mph and not a performance EV..

I disagree with flat voltages with NMC/NCA cells... Flat is the LFP voltage graph. Regular li-ion batteries have a linearly decreasing voltage curve.

 

[Mach1E]

I get the gray bars when going over 70 mph. I might get one bar or none going below 70 but the faster I go the more bars pop up. I live in Florida and charge from 50% to 90% on average with my daily driving. I have a 2022 GTPE and had the HVJB already replaced back in March. Bought it June 2022 and having little over 22,000 miles on her aleady?....gone a few road trips?
When I bought the car it had the bad HVJB part before they decided a week after mine was built to start putting the new HVJB. Before I can remember I use to never get those gray bars. Ever since the new HVJB was put in is when I noticed those gray bars popping up.

Gray shows up at 72 mph no matter what. I even tested this putting it in neutral going down a tall bridge (Skyway) started at 65 mph in neutral and gray showed up when I hit 72. The faster you go, the more gray.

I have a 2021, original HVJB.

 

[MachEMaster]

I have just been charging when plugged in, and 100% every night. Then I just run it down wherever the day takes me. No worries.

 

[kennethjk]

Thankfully Ford is cheap and worried about warranties so there’s the conservative buffer

I don’t think Ford is cheap, they spend more on warranty claims than anyone else.

 

[agoldman]

I have just been charging when plugged in, and 100% every night. Then I just run it down wherever the day takes me. No worries.

Same here. I want the full range, not 3/4 of a tank equivalent. I don't care if the battery degrades over time. Maybe if I kept a car for long, but nah.

 

[Mach1E]

I don’t think Ford is cheap, they spend more on warranty claims than anyone else.

That’s funny right there. ?

On a more serious note though, has ANYONE had a battery fail and replaced under warranty (less than 70% capacity)?

The reason for the long 8 yr warranty and the buffers and convincing people to baby their batteries…….. Ford isn’t expecting to have to replace many (or any) under warranty.

 

[milepost1]

This obssesion with the batteries. All of logic on batteries is true to a point. How many real world replacements of batteries are there? Not the ones "my friend had to have battery replaced and it was $xx,xxx.oo." EVs have been around awhile, if people or companies were payin giant claims on batteries would be all over internet. It is almost the great debate over when to change engine oil. Change evety 3k no matter what manufacture says. Tell folks they can go 5k-10k or more without changeing oil. Ford says 90% daily Tesla says 80% for thiers. EVs are cars. Drive them like a car. Just like an ICE vehicle some go 50k and quit and some go 200k. There are so many factors that can cause any vehicle to have problems. If you want your battery to last the longest charge to 50% at 72 degrees and dont drive.

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