3 ms·

LiOn is all about loading cycles. In the same amount of time (let's say 5 days) she has used up way more cycles than you did. You probably charged 5 * 20% while

LiOn is all about loading cycles. In the same amount of time (let's say 5 days) she has used up way more cycles than you did. You probably charged 5 * 20% while she maybe charged 5 * 90%. Obviously she is using up her load cycles much faster than you are. So no surprise her battery isn't very good anymore. I don't think you two are using the phone equally much (meaning using up the same loading cycles in the 5 days). Like for example, she charging 2 * 90% and you charging 4 * 20% and 1 * 10%.

mistercow 9y ago
Do you have a source on lithium ion batteries working this way, because all of the sources I'm finding (and it's not the first time I've researched this) say that shallow cycles dramatically improve battery longevity. My understanding is that "cycles" are used in discussing battery lifespan for the purposes of warranties and the like because they're an easy-to-define user behavior, not because they actually reflect how the batteries perform.
- blattimwind 9y ago
  > shallow cycles dramatically improve battery longevity. Not necessarily; cycle depth is a big factor, but the interval covered is very important as well. I.e. a few cycles to a high charge end voltage ages cells more quickly than more cycles to a lower charge end voltage. This obviously directly relates to the amount of energy stored. The correlation is approximately exponential: you get somewhere between two to eight times the cycles for lowering charge voltage by 50-100 mV. You very quickly get to zero cycles raising it. Another factor is cycle length, i.e. cell current, and temperature, as always.
- chrisper 9y ago
  >There’s no need to let it discharge 100% before recharging. Apple lithium-ion batteries work in charge cycles. 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. It could take several days to complete a cycle. The capacity of any type of battery will diminish after a certain amount of recharging. With lithium-ion batteries, the capacity diminishes slightly with each complete charge cycle. Apple lithium-ion batteries are designed to hold at least 80% of their original capacity for a high number of charge cycles, which varies depending on the product. From https://www.apple.com/ca/batteries/why-lithium-ion/ https://www.apple.com/ca/batteries/why-lithium-ion/
  - mistercow 9y ago
    Oh, I think I misunderstood your original comment. You were saying that she charged 90% each time, not charged from 90%. In that case, we're saying the same thing. Part of what I was talking about was, for example, I believe the Mac system profiler counts a cycle as any change from positive to negative discharge (or at least it did once upon a time), regardless of discharge depth. This gives Apple employees more opportunities to pull up your information and say "nope, sorry, your battery is expected to be dead after this many cycles", and make you feel like it's reasonable that you need to replace the battery.

mistercow 9y ago

Do you have a source on lithium ion batteries working this way, because all of the sources I'm finding (and it's not the first time I've researched this) say that shallow cycles dramatically improve battery longevity. My understanding is that "cycles" are used in discussing battery lifespan for the purposes of warranties and the like because they're an easy-to-define user behavior, not because they actually reflect how the batteries perform.

blattimwind 9y ago
> shallow cycles dramatically improve battery longevity. Not necessarily; cycle depth is a big factor, but the interval covered is very important as well. I.e. a few cycles to a high charge end voltage ages cells more quickly than more cycles to a lower charge end voltage. This obviously directly relates to the amount of energy stored. The correlation is approximately exponential: you get somewhere between two to eight times the cycles for lowering charge voltage by 50-100 mV. You very quickly get to zero cycles raising it. Another factor is cycle length, i.e. cell current, and temperature, as always.
chrisper 9y ago
>There’s no need to let it discharge 100% before recharging. Apple lithium-ion batteries work in charge cycles. 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. It could take several days to complete a cycle. The capacity of any type of battery will diminish after a certain amount of recharging. With lithium-ion batteries, the capacity diminishes slightly with each complete charge cycle. Apple lithium-ion batteries are designed to hold at least 80% of their original capacity for a high number of charge cycles, which varies depending on the product. From https://www.apple.com/ca/batteries/why-lithium-ion/ https://www.apple.com/ca/batteries/why-lithium-ion/
- mistercow 9y ago
  Oh, I think I misunderstood your original comment. You were saying that she charged 90% each time, not charged from 90%. In that case, we're saying the same thing. Part of what I was talking about was, for example, I believe the Mac system profiler counts a cycle as any change from positive to negative discharge (or at least it did once upon a time), regardless of discharge depth. This gives Apple employees more opportunities to pull up your information and say "nope, sorry, your battery is expected to be dead after this many cycles", and make you feel like it's reasonable that you need to replace the battery.