Charging cycles - battery life

Kevmk81

Member
This shows my ignorance I'm sure - but I'm curious and always have been (I used to own a Nissan Leaf). When a company says a battery lasts so many charging cycles, say 1000, what does that mean. Is 1 charging cycle "used up" when I charge from 60 -> 80%? Sorry if that's a stupid question.
 

AHicks

Well-Known Member
This is so highly subjective, and depends on SO many factors, NOBODY has an answer that's going to be right 100% of the time.

The manf's are giving you a "best guess" when they state anything about expected number of charging cycles. Further, with all of the available reasons why a battery might not live as long as they say it might, what they say may (or may not) have a lot of "wishful thinking" built into it.

And last, based on my personal opinion, I think the advantages of the 60 ->80% charge are vastly overstated.

I believe balance charging is a very important function, and anyone practicing the 60-80% regimen regularly is NOT getting a balance charge. The down side to not balance charging regularly is reduced performance, less range, and potential battery damage - none of which is discussed in much of the 60-80% talk.

Point being, I would suggest just use the battery without abusing it. The biggest battery sins would be leaving it exposed regularly in sub zero temps, and frequent discharging it to the point it will no longer move. Beyond that, just enjoy it! -Al
 

CdnShaun

Active Member
Kevmk81 - great question, one we all often keep in mind with our own unique equipment and figuring out what actions are best to extend the life of these (at times) expensive purchases we have invested in.

Your question has inspired me to go looking again myself to understand what a charge cycle is defined as for the equipment I use.

What I have read is even when a lithium battery is reaching it's charge cycle limit mentioned in it's documentation (i.e. 1,000 cycles, 1,600 cycles, etc) it typically will be at a diminished capacity - I have read between 50-70% of original. Perhaps others with more long term experience can share their thoughts?
 

CdnShaun

Active Member
Ha - i think i have a good answer found from wikipedia


My 60->80% was just an example - I usually run it down more than 60% :) But rarely less than 30% or so. I charge to 100% maybe once per month.
Interesting link, thanks for sharing.

The key instruction I have learned is not to charge past 90% 'unless needed' (i.e. a long ride planned and you want ever Wh available, lol). By charging batteries to 90% and not draining them past 10% remaining capacity is stated often to double the amount of charge cycles you can get out of a battery.
 

Bruce Arnold

Well-Known Member
Ha - i think i have a good answer found from wikipedia


My 60->80% was just an example - I usually run it down more than 60% :) But rarely less than 30% or so. I charge to 100% maybe once per month.
That article expresses my understanding of the process pretty well.

Example: If I run the battery from 80% to 30%, and then charge it back to 80%, I've used one-half cycle. The total is 50%. Do that twice, and you've used one full charge cycle -- it adds up to 100%.

Those claims on how many charge cycles you will get on a given battery -- and like someone said, they are estimates -- refer to useful life, not total life. "Useful life" could mean that you have 80% of the original capacity left, or 70% -- they don't always say this part, but that's what they are referring to.

Another example: Say you have a 1000 watt-hour battery. They claim 500 cycles, and that the useful life = 80% of original capacity. That means they think that after 500 cycles, your 1000 wh battery will only be able to charge to 800 wh.

In ebike terms, if it could propel you 50 miles per charge (at 100% state of charge), now when the battery is fully charged you only get 40 miles. There's still a lot of life left in that battery, but it's a noticeable drop from what you had, and that's the parameter as they somewhat arbitrarily defined it. If you only need to be able to ride 30 miles between charges, you are still good to go for several hundred more charge cycles.

A lot has to do with battery chemistry. I was surprised to learn how many types there are, and how different their characteristics can be.
 

Sierratim

Well-Known Member
This shows my ignorance I'm sure - but I'm curious and always have been (I used to own a Nissan Leaf). When a company says a battery lasts so many charging cycles, say 1000, what does that mean. Is 1 charging cycle "used up" when I charge from 60 -> 80%? Sorry if that's a stupid question.
The Mission Control app for my Specialized Vado 5 counts battery "charge cycles". The battery was at 100% two days ago with 34 charge cycles. Yesterday afternoon the battery was at 13% so I hooked up the charger in anticipation of today's ride. This AM the app now shows 35 charge cycles with the battery at 100%. 35 charge cycles are consistent with the miles ridden so I suspect that it is counting full charges, not partials. I'll recharge after today's short ride to town and see what the charge counter does with a partial charge.
 

Captain Slow

Well-Known Member
The Mission Control app for my Specialized Vado 5 counts battery "charge cycles". The battery was at 100% two days ago with 34 charge cycles. Yesterday afternoon the battery was at 13% so I hooked up the charger in anticipation of today's ride. This AM the app now shows 35 charge cycles with the battery at 100%. 35 charge cycles are consistent with the miles ridden so I suspect that it is counting full charges, not partials. I'll recharge after today's short ride to town and see what the charge counter does with a partial charge.
I typically don't use that much of the battery on my Creo and I think I'm at around 14 or 15 charge cycles. I've charged it far more often than that so I think it must count wh charged or something like that. I've never run the battery to less than 30% and I think most of the time my battery doesn't go below 65% after my ride is done.

So my experience sounds similar to yours.
 

FlatSix911

Well-Known Member
This shows my ignorance I'm sure - but I'm curious and always have been (I used to own a Nissan Leaf).
When a company says a battery lasts so many charging cycles, say 1000, what does that mean.
Is 1 charging cycle "used up" when I charge from 60 -> 80%? Sorry if that's a stupid question.
A charge cycle is correctly defined as "You complete one charge cycle when you’ve used (discharged) an amount that equals 100% of your battery’s capacity — but not necessarily all from one charge. For instance, you might use 75% of your battery’s capacity one day, then recharge it fully overnight. If you use 25% the next day, you will have discharged a total of 100%, and the two days will add up to one charge cycle."

Here is a handy graphic that shows the effect of charging below 100% full to maximize battery life.
Charging to 80% instead of 100% can triple the life of your Lithium Battery... YMMV 😉

Battery charge effect.png
 
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Sierratim

Well-Known Member
I believe it's true that Lithium battery life can be extended by managing the charge cycle to not exceed 80% max nor 20% min battery capacity. To do this you either need a more expensive programmable charger, or to setup a charger on a timer to approximate these limits. I choose to do neither. Here's my logic;

I ride ~2,000 miles a year/40 miles a week, ~1/2 on my ebike on local steep roads and trails. This requires ~34 charge cycles. With a battery pack that the manufacturer rates at 1,000 charge cycles this would give me over 30 years of battery life. At 70 years old I don't believe I'll last that long, not to mention the bike itself.

Bottom line, it's just not worth the trouble to me to try to get max life out of my ebike's battery. I'm OK with 100% charge when I head out the door and 13% when I get home. Repeat, stay healthy, "for my age" as the docs say...😎
 

Sierratim

Well-Known Member
I finally remembered (hate getting old, but it's better than the alternative as they say) to check my battery charge cycles after a short ride. I ride a Specialized Vado. The Mission Control app counts charge cycles as a part of the battery stats. I had 35 cycles before my last battery charge. I did a shorter shopping trip and ended with 73% battery. I recharged and found the cycle count had increased by 1. Apparently Specialized counts partial charges as a full charge cycle. Simpler, but not very helpful in tracking battery life.
 

FlatSix911

Well-Known Member
I finally remembered (hate getting old, but it's better than the alternative as they say) to check my battery charge cycles after a short ride. I ride a Specialized Vado. The Mission Control app counts charge cycles as a part of the battery stats. I had 35 cycles before my last battery charge. I did a shorter shopping trip and ended with 73% battery. I recharged and found the cycle count had increased by 1. Apparently Specialized counts partial charges as a full charge cycle. Simpler, but not very helpful in tracking battery life.
Interesting that Specialized counts partial charging cycles... do they have some type of Battery Warranty based on cycle count?
 
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byunbee

Well-Known Member
I normally don't charge my battery everyday. I wait until it gets to 1 bar (out of 5) before I charge it. If I know that I'm going for a long ride, I may charge it at 2. All in all, I charge my battery once every 3-4 days.
 

Sierratim

Well-Known Member
Interesting that Specialized counts partial charging cycles... do they have some type of Battery Warranty based on cycle count?
As I understand it, the battery warranty is 2 years or 300 charge cycles. I'm guessing that they'd use the cycle counter for this so partial charges count towards the warranty. This won't be an issue for me since I'm not going to ride the 5,000+ miles per year to hit the warranty charge cycle limit. Others may.
 
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Sierratim

Well-Known Member
I normally don't charge my battery everyday. I wait until it gets to 1 bar (out of 5) before I charge it. If I know that I'm going for a long ride, I may charge it at 2. All in all, I charge my battery once every 3-4 days.
Generally the same here. I charged at 73% capacity to test the charge cycle counter.
 

Sierratim

Well-Known Member
Interesting that Specialized counts partial charging cycles... do they have some type of Battery Warranty based on cycle count?
Here's what Specialized has onine re the battery warranty;

"What's the warranty on the battery?
Refer to the Turbo bike manual. The warranty terms are two years or 300 charge cycles/75% remaining capacity. This means that Specialized warranties batteries that have less capacity than 75% after 300 charge cycles. A charge cycle is a full charge, e.g. 604 charged watt hours make one charge cycle. Part cycles are calculated by the BMS system till one cycle can be added."

So, the warranty is based on full charge cycles. Much better than what the cycle counter in the app would imply. I'll keep an eye on the charge counter to see if it skips a count now and then to make up a full charge cycle count.
 

FlatSix911

Well-Known Member
Here's what Specialized has onine re the battery warranty;

"What's the warranty on the battery?
Refer to the Turbo bike manual. The warranty terms are two years or 300 charge cycles/75% remaining capacity. This means that Specialized warranties batteries that have less capacity than 75% after 300 charge cycles. A charge cycle is a full charge, e.g. 604 charged watt hours make one charge cycle. Part cycles are calculated by the BMS system till one cycle can be added."

So, the warranty is based on full charge cycles. Much better than what the cycle counter in the app would imply. I'll keep an eye on the charge counter to see if it skips a count now and then to make up a full charge cycle count.
Good deal... that sounds much better!
 

Alex M

Well-Known Member
When a company says a battery lasts so many charging cycles, say 1000, what does that mean.
It means full or "almost full" cycle. Think from 100% to 10% (or to whatever lowest BMS cut-off value when system shuts down).

Extending the OEM projected number by running shallower cycle is another thing. You will get more full cycles when discharged/charged from 100% to 50% - say, 1300 full cycles instead of 1000. The number of your shallow cycles will be of course more than 1300 because they are "half-cycles".

A single Li cell would have the highest number of full cycles if the shallow cycles are "in the middle", say from 80% to 40%. But this might not be practical for ebikers because the pack consists of a few dozen cells and each one is getting balanced at slightly different state of charge - some at 90%, some at 92%, some at 95%. This wouldn't matter for a single cell because it is always "balanced" - there are no other cells to compare it to. When cells are unbalanced, some will work harder than others and one or two may die much sooner than others - and then the whole pack becomes unusable or barely usable.

For this reason, I would charge it to 90-95%, and once in a while let it charge to 100%. Discharge it to the highest level that still works for you in terms of range - if you can get away discharging it to 60%, do it. If your trip requires 90-30% or 100-20% cycle, then you have no choice, obviously. The higher is your lower limit - the better. In prolonged storage (think a month or longer) try leaving it with 40-60% charge - not full and not near empty.
 
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