Increasing Battery Life

David T in Silicon Valley

David T in Silicon Valley

Active Member
Great vid from Hyundai on how to care for the battery.

https://insideevs.com/features/408255/hyundai-advice-maximize-ev-battery-life/

I knew about not charging over 80% except when there is a good reason, but I did NOT know about the value in frequent charging or the harm in letting it drop below 20%. With the extra ~5% capacity that is hidden from the user (at least in the Niro and presumably the Kona) does this mean 25% is the better minimum?
 
David T in Silicon Valley said:
Great vid from Hyundai on how to care for the battery.

https://insideevs.com/features/408255/hyundai-advice-maximize-ev-battery-life/

I knew about not charging over 80% except when there is a good reason, but I did NOT know about the value in frequent charging or the harm in letting it drop below 20%. With the extra ~5% capacity that is hidden from the user (at least in the Niro and presumably the Kona) does this mean 25% is the better minimum?
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I've seen some charts from battery university where you can get about 4 x the battery life if you keep the charge between about 60 and 80 percent instead of for example between 20% and 100%
 
I wouldn't read too much into that "5%" thing. We know on the Kona using Torque Pro that the BMS does reserve a few percent at the top end for something, probably to extend useful life. But at low levels like 20% there's hardly going to be any difference. Over much of the range, the difference on my car is only 0.5-1%.
 
BlueKonaEV said:
65 to 75 yielded the longest life.. 45 to 75% was also very good.

View attachment 8108
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On the other hand the worst case scenario of 25% to 100% yields over 695,000 miles (0.75*258 miles*4500cycles .80 capacity=696,600 miles) That's still way more miles than most people will put on a car. At 12,000 miles a year the cars going to be 58 years old before it reaches 80% which leads me to believe that time will be the bigger factor in battery decline rather than charge cycles
 
Fastnf said:
On the other hand the worst case scenario of 25% to 100% yields over 695,000 miles (0.75*258 miles*4500cycles .80 capacity=696,600 miles) That's still way more miles than most people will put on a car. At 12,000 miles a year the cars going to be 58 years old before it reaches 80% which leads me to believe that time will be the bigger factor in battery decline rather than charge cycles
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Of course, other things come into play like DC fast charging.. Every time you DC fast charge, you take life off your battery.. I'm guilty of that.. I have fast charged 6 times so far in April already as there is a free fast charger near my parents condo when I visit them once or twice a week.. I'm driving about 35k to 36k per year (not this year due to Coronavirus) but I'm nowhere close to the 12k miles you are driving per year. I'm a little under 27k miles since 6/28/19 when I bought the car. I would like to stay above 90% capacity for a long time as I would like to make the trip from my home to Ft. Lauderdale on one charge. That's 210 miles to a level 3 charger in Ft. Lauderdale.. Right now, I can make it with about 20% remaining (depending on weather and temperature/AC use)..
99% of my charging is between 45 and 80%. Actually, during a regular work week, I usually charge between 60 and 80% on most days. However, with this Coronavirus thing, I end up driving very little every day except when I visit my parents.. They are around 80 years old and are at high risk if infected by the Virus, so they stay home. So, I visit them about twice a week and always fast charge near their condo.. I barely have charged at home since the virus as I always take the opportunity to get free juice when I visit my parents.
 
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I plan to only use fast charging if for en route charging on long road trips or an emergency. Otherwise, I can wait. It also helps we have 240 V AC chargers for free at work!

Found the BU-808 article the plot came from This is a plot of number of cycles vs. capacity. I am more interested in maximizing kWh in and out vs. capacity, so on this plot the y-axis would be number of cycles multiplied by the difference between top and bottom of the discharge cycle under test. That is going to change things some . For instance, if I treat the 93% capacity remaining after 8400 cycles in the 75/65 scenario as "end of life" then I find the 75/35 charge/dsicharge hits that after 1440 cycles...but I am also getting 40% of the total energy capacity out each cycle vs. 10% out in each of the 8400 cycles for the 75/65 case. I actually get 71% more energy out of the battery going between 75/35 3600 times than going 75/65 8400 times at which point the battery is at 93% original capacity.

Also missing is the battery chemistry. Which type of lithium ion are the SK Innovation batteries in the Kias? Which type of chemistry did BU run in their test? I don't know. It might not matter much. All this detail might be rearranging deck chairs. even doing the 75/65 for 8400 cycles, I am going to put in the neighborhood of 240k miles on it before it hits 93% capacity (if it is the same chemistry) . I am about 1.5% of that distance at this point. I think I will stick with the 75/30 I was aiming for before (Well, 80% as the car reports it = ~ 75% of the total battery pack including the ~5% reserve)...and also not shed many tears when convenience means I don't hit exactly those levels every time.
 
My smartphone battery has at a guess 2/3 - 3/4 original capacity 2.5 years later. It also tends to spend a lot of time fully charged or nearly fully charged which is generally not good. It also tends to be run down pretty low before I plug it in. It is plugged in at least once a day, sometimes more often. I do not have enough of those bits of data I am uncertain about to draw an analogy to my car, however I hope my car has more than 2/3rds capacity 3 years after I bought it!
 
David T in Silicon Valley said:
My smartphone battery has at a guess 2/3 - 3/4 original capacity 2.5 years later. It also tends to spend a lot of time fully charged or nearly fully charged which is generally not good. It also tends to be run down pretty low before I plug it in. It is plugged in at least once a day, sometimes more often. I do not have enough of those bits of data I am uncertain about to draw an analogy to my car, however I hope my car has more than 2/3rds capacity 3 years after I bought it!
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Anecdotal, but I got a Note 10 last year and have been avoiding charging to 100% as much as possible, trying to keep it at 80% or below. So far, I haven't really noticed any capacity loss. I haven't done any rigorous testing, though.

Side rant: why are there no apps to help you manage this type of charging behavior?
 
WOW! This is really good for me. I had more or less taken the 20% - 80% as gospel. I have been reluctant to let the charge drop to 20% in case that short notice call comes in so I've usually charged from roughly 45% - 80% only going to full when heading out of town. Looks like I should be better off. Most of my work is (was) within the round trip range of the 40kwh Leaf so I've only fast charged for a few longer distance runs.

I have a 9 year old ipad which until recently has been plugged in every night to 100%. I haven't noticed any substantial reduction in it's capacity but in all honesty haven't been measuring carefully either. It just works.
 
Domenick said:
Anecdotal, but I got a Note 10 last year and have been avoiding charging to 100% as much as possible, trying to keep it at 80% or below. So far, I haven't really noticed any capacity loss. I haven't done any rigorous testing, though
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I have an iPhone 6 Plus. My biggest complaint iPhones for years is their rather limited battery capacity. As near as I can tell this is all in a quest to shave off a fraction of and ounce and some thickness. Limited capacity = more cycles= shorter life.

Some rough calculations show my iPhone battery could be 50% heavier and 50% more volume (an extra half ounce or about 8% addition to phone mass and 0.7 mm thicker phone or 10% thicker) and I would probably not have to plug in every day...and the battery would easily outlast the phone. I have replaced it once. I will not a second time as the phone is now 4.5 years old and has come to the end of its OS upgrade life. In another year apps will start breaking.

With those minor changes, I could probably go a whole five years without needing to replace it. Is a 7 ounce phone that much worse than a 6.3 ounce phone? the note plus is about 7 oz.
 
davidtm said:
I've used the built-in charging alarm in this Android app
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Thanks for the tip. I will look for an analogue on iOS.

I am grateful the Niro EV software lets me cap the charging. Now if it could just read my mind about my plans and notify me to plug in if my next one will take me well below 30%!
 
David T in Silicon Valley said:
... I will look for an analogue on iOS...
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Well, there's one feature that has been present for perhaps 6 months now: Settings, Battery, Battery Health, Optimised Battery Charging. "To reduce battery aging, iPhone learns from your daily charging routine so it can wait to finish charging past 80% until you need to use it."
So, it only does the last 20% just before it guesses you will unplug it from the charger.
Paul K said:
I have a 9 year old ipad which until recently has been plugged in every night to 100%. I haven't noticed any substantial reduction in it's capacity but in all honesty haven't been measuring carefully either. It just works.
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So mine, almost as old, used to run for a week without a recharge, now I get about 3 days. Even a completely buggered battery will last a day.
 
KiwiME said:
Well, there's one feature that has been present for perhaps 6 months now: Settings, Battery, Battery Health, Optimised Battery Charging
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I did not find much in the way of battery management apps. The only ones I found did things like tell me how much charge is left on my battery (why?) and rarely how much capacity left (which iOS already does). Pointless.

Thanks for the tip . Now another reason to get a new phone: my venerable 6 plus only runs iOS 12 so does have the optimize charging feature! Ironic that the tool that would help preserve an old phone's battery is not available on an old phone! The battery life is currently sometimes annoying, but not often. I think around the end of this year will be the right time. Maybe early next.
 
ok so I'll throw this out there just to make sure I understand this

Keep in mind I'm in Montreal and we have some pretty nice (lol) winters..... -20 to -25 is a very normal thing in late January/Feb

1. If I can charge the car in my garage, it's a positive thing
2. I can go from Garage (home) to Garage (work), I don't park in my garage in the summer/spring/fall but in winter I can if this is a positive for the battery life
3. Hyundai is saying charge more, the charts show 45-75 is a good thing, considering I go to work and come back and most of the year I use around 10-12% battery life per day, should I set the limit to 70% and charge it every night ? This way I play in the 58%-70% range and in the winter let's say 45-70% ?

Last but not least, are we not driving ourselves a bit nuts on this ? I'll be honest, our roads and weather conditions here in Quebec arent all that nice 4-5 months of the year.... cars lasting 15-20 years are pretty rare (minus the Rolla/Camry/Civic/Accord).... Knowing I do at most 16k/year on this car... 10 years would be (at most 200k)... Do I even care to do this whole battery charging every night?
 
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