Should I be charging my EV to 90% each day if I only drive a short distance?

If you drive your EV for less than 40km (25 miles) each day then topping up the battery to 80-90% may be shortening its life. By thoughtful charging you could still have 90% capacity in your battery after 23 years.

Note: A DST cycle is not the same as a “cycle” for calculating battery life. For example, discharging from 75% to 65% ten times is equivalent to one full cycling of the battery, when referencing the manufacturer’s data sheet.

00:00 Introduction
01:40 Battery University
02:07 Depth of Discharge
04:27 Maximum State of Charge
07:17 Storage Conditions
08:58 Dynamic Stress Testing Results
13:44 Conclusions

#electricvehicle #tesla

[MarksElectricLife]

PLEASE NOTE:
This information is intended for EV owners who only drive a short distance each day and then plug in each night. The data presented only applies to ternary type lithium batteries (e.g. NMC), not Lithium Iron Phosphate (LFPO). If that isn't your situation then don't waste your time watching or posting irrelevant comments.
Also note that a "DST Cycle" referred to in the Battery University study means one discharge and recharge to the levels specified in the test (e.g 75% - 65% SOC). However the industry term "cycle", when used to predict battery life, means one transition from fully charged to fully discharged and back to fully charged. So there would be 10 X 75% - 65% events before one charge "cycle" is clocked against the battery's lifetime cycle count.
While the science may seem complex the key message is simple:
- You don't need to change your lifestyle or stress about your battery
- You can keep driving as you do currently and plugging in each night so your car is always ready at the start of the day
- If you simply lower the maximum State of Charge (SOC) from 90% to something more appropriate, like 60% this can enhance the longevity of your battery. This is because the battery spends less time standing with a high SOC.
Lastly, I am not telling anyone what they should do, just presenting the science. In the end it's your car and your choice how you charge your EV. Have a great day ! 🙂

[sjefvanmerrienboer]

I own my model P85 for 10 years already. Not a sign of battery degradation because I never charge above 80 %. When I don't use my car for a while it stays on 50%. Then when I am going for a trip I charge the power I need for this particulary trip.
Sometimes I supercharge up to 80% to heat the battery to
get a temperature to remove condensation and water out of the battery pack. Corrosion in the electronics also damages it.
Still super satisfied with my Tesla after 100.000 miles.

[Metalcursine]

I think the math is a little off here. Since let's say your commute is the 10% you're talking about. If you would do the 100-25% charge, you can drive for 7, 5 days before charging (so 7, 5*1000/365=20 years), while with the orange line you need to charge daily. So if you look at it that way the light blue and pink are the best modes 5*3000/365=40 years or 3*5000 which is the same. 40 years seems very unrealistic to me, since you will have so degradation over time itself (storage). So all in all I don't think the factory 80-25 is all that bad. Maybe 75-25 or 75-40 might be bit better. I now charged up to 80% so I think I'll set it to 75 instead. My commute takes a bit more of the batter though, about 15%.

[PhilT]

In our training from GM for the Bolt EUV we have been told to recommend to customers that they use the moto ABC: Always-Be-Charging. Their explanation was that the car will manage the battery temperature while the car is parked. One fellow on Youtube has a short video showing his Bolt expelling excess heat during a very hot day. His car wasn't running, just plugged in. So while not charging everyday may be a good idea that would be only when the outside temperature is neither too hot or too cold. At least where GMs are concerned.
Charging to a lower level most of the time seems to be a good idea that most agree on. My cell phone has a battery management setting that you can switch on and it limits the charge to 85%. This is meant to increase battery life (Samsung phone).
I drive a Bolt EUV and have set my maximum charge at 80%. I may lower that to 75%. I also use slow charging as it seems to be recommended by most.

Thanks for the video. I found it most useful. In addition, the comments left by some viewers also contributed to my battery education.

[andreverville]

A lithium-ion battery is happy between 25% and 80% SOC. However the BMS needs to know the extremes as well so do go to them occasionally. It is okay to charge to 100% but it is bad not to use this first 10-20% shortly after: like if a battery being under stress while fully charged: the shorter we leave it in that condition, the better. So please just charge to 100% the night before occasional long distance trips.

[booobtooober]

The magenta (75%-45%) most closely represents my usage cycle and I charge twice a week which = 43 years (I'll be 106 years old)
btw - the warranty is 80% and I had a starting capacity of 331 miles so at 90% I still have 300 miles of range & (80% = 270 miles) which is still quite usable

[JohnErnestAdam]

I was charging to 80% and then only charging when less than 50%. Since, on my daily commute, I always came in right at about 50%, I am going to only charge up to 70% and see how it goes. I am also intrigued by potentially charging at a lower rate too. I can recharge in two hours, but I have 8 hours to do it in over night so am giving that a try too. Thanks for the food for thought.

[mick-berry]

You omitted the fact that part of this 'precautions' are already done by the BMS auromatically. If you charge to 100%, this is not really 100%, as the battery physically has 8% or so more capacity, which is 'fenced off' by programming in the BMS. Similar at the low end...

[anthony]

This is good advice. Keeping the EV battery balanced is the best for longevity. I got a 14 year old Prius and can monitor the battery charge level. Toyota seems to keep the battery between 45 and 60% charged. It is still running well on the original battery.

[FutureSystem]

Spot on!
We LOVE having plenty of fuel in the tank with an ICE car. We also LOVE having plenty of charge in the battery for an EV, but for the majority of us that’s complete overkill.
HOWEVER keeping the max charge below 65% to 70% is always going to be much better for the battery …. and even more so in hot climates.
If you must fill it, don’t leave it there for long, drive immediately.
If you arrive home near empty, charge it to at least 20% immediately.

[TomLawlor-iqgm]

We just traded our 12 year old Prius C for a 2024 Prime. The Prime is our third hybrid but first PHEV. The C had 128, 000Km on "the clock" and from the beginning gave between 4 & 5 l per 100Km (dependant on ambient temperature). Regards charging cycles; its battery was just under 1kw, so, it was constantly being charged and discharged every time it was driven. At about ten years, the battery would no longer gather enough charge to run the car in EV Mode (which even when new, was limited to 1~2Km's. But, even with that constant charge/discharge rate, the litre's per 100Km performance did not decline.

The new Prime's Traction Battery is close to 13 times the "size" of the C's. It incorporates a charge "buffer" of (I think), 10% lower and upper, meaning there's 80% of usable charge. Yesterday, I drove the Prime 88Km in EV Mode and the Trip Computer indicated there was 6% charge left. The car would have exceeded 90Km on battery. This morning, the computer stated the range would be 91Km.

For us, the Prime is essentially a BEV. After 5, 000Km we have used just 1.5 tanks of fuel. Based on the length of service the C's battery gave, we have no concerns about the level of charge/discharge with the Prime. The Traction battery has a ten year warranty, we plug-in every night and don't worry about cycles.

[robertpolestar-emje]

Thank you for this information. Very useful. I’m now trying to keep my SOC between 40%-60%….so re-charge when the SOC is close to 40%. This works for me as i tend to drive less than 20 miles each day. It make sense that the battery is “happiest” around 50% SOC. I’m also avoiding fast chargers when possible.

[henriaube]

Excellent points, for doing the hard work to investigate the subject. I would add though that it is important to prriodically charge to 100% SOC, in order for the battery management system in most cars to perform cell balancing. Perhaps adopting a routine that the first day of each month, you charge to 100% using level 1 or 2 charge point, and return to your regular routine for the rest of the month, would preserve battery maintenance and maximize service life. Thanks again for doing this.

[hopkinsfamily]

I've been looking into this question for a week now and finally came across some actual data! Thanks!

[Jeddin]

A significant variable to degradation is also depth of discharge (DOD). Avoiding large depth of discharge prevents expansion and contraction of the electrodes which leads to cracking. A DOD 10% to 20% has a little impact on battery degradation above 20% has increasing impact. 20% of discharge provides very little degradation above 10%, but provides twice the mileage driven. Therefore the ideal charging range is in fact 40 to 60%, pushing this to 30 to 70% may be ideal for most peoples practical usage with the additional small degradation being worth the increased usability.

[deanmcmanis]

I put over 250, 000 miles on 4 plug-in hybrids over the last 10 years. They had a built-in battery buffer of 20%, so that "100%" charged/full was actually only charging up 80% of the battery. The result was that none of the PHEVs showed ANY visible loss of range during the time that I had them. Granted, because 20% of the battery capacity was not shown to the driver, they could have lost up to 20% of their capacity without it being seen. But they also could have actually lost minimal battery capacity over the years of daily driving and charging (L2) use.

[mjsabie]

Also important to remember that most manufacturers don’t allow you to use the entire battery. So 100% is not really 100% and 75% is not really 75%

[dwayneam]

WOW. I've heard some of this info before, but this is the most in-depth explanation. THANK YOU for putting this all together for us!!!

[lberhold]

Been basing my model 3 LR off the 75%-25% line, and the battery is doing well, the car is at about 110, 000 miles in 4 years. Just plug it in every night, and every morning it's at 75%, much less than is needed for a typical day.

[jimgraham]

Interesting my BYD has a 60KWhr LiFePO blade battery configured 126S1P.

The recommendation is to charge it to 100% once per week. Our daily driving during the week uses about 60%. Consequently we slow charge it (AC3KW) each Sunday (mainly using solar panels) to 100%.

We only fast charge on trips, typically at the 50KW rate. Under fast charging, charging efficiency and rates decrease markedly over 85%, with a good deal of energy lost as heat. So when fast charging we normally stop at 80-90%, particularly if the weather is warm. The BMS rolls the fast charge back anyway over 90%.

On trips we mainly operate between 15% and 90% for an effective range of 300km between top ups. On routes we mostly drive, this works well.

So far we have not detected any battery degradation.