4 ms·

Im not an EE but i've always heard that full battery cycles are best to preserve its life. If not going from 100% to 0% and then charging fully to 100% is the

by w-ll 9y ago

Im not an EE but i've always heard that full battery cycles are best to preserve its life. If not going from 100% to 0% and then charging fully to 100% is the best behavior please inform me.

wtallis 9y ago
Fully discharging a battery was only necessary with nickel-cadmium cells that suffered from a severe memory effect. Nickel metal hydride cells didn't, but could be affected reversibly by a minor drop in voltage from repeated partial discharges. Most rechargeable battery technologies in use today are significantly harmed or completely destroyed by a complete discharge. Devices using lithium ion cells all turn themselves off long before the cell is completely empty, as a protective measure.
- w-ll 9y ago
  Again, I'm not versed on the chemistry behind this, but friends who got new phones around the same time and plug them in to charge every chance they get have had their batteries fail earlier than me. I guess my data is anecdotal, but doing full cycles has allowed me to get 40+ hour standby with 10+ hour screen over the last one and half years. Where my friends cant even get more than 10 hour standby.
  - owenversteeg 9y ago
    As someone who builds battery systems (yes, I'm "that battery guy" that shows up in HN battery threads) wtallis is correct: full discharges harm modern batteries, although every battery protection circuit has a cut-off voltage set to prevent discharging them too far (at which point your phone will turn off.) The practical applications of those two facts, however, are much more nuanced. Ultimately, the biggest killer of batteries is heat. Charging your phone and using it battery-intensively (max brightness/lots of processing stuff) are the biggest heat-causing things that come to mind. Another thing that can happen is heat buildup: you might not be using it very intensively, but if you use it for hours on end the heat can eventually build up and the phone will get hotter over time. It's entirely possible that your method of using your phone actually does cause less stress on the battery. However, this is 100% dependent on what you and your friends do with your phones, before and while they charge, as well as the kind of phone, its charging circuitry and a million other factors. At the end of the day, all I can say is "batteries are basically magic, use less power, and don't let your phone get too hot." The only universal recommendation that will guarantee better battery lifetime - with every battery chemistry - is to draw less current from the battery (on a phone: turn down your brightness, turn off things you're not using, etc etc.)
  - mohaine 9y ago
    For LithIon, there are really 3 things that are bad (That I've heard of): 1) Fully charging them 2) Fully discharging them 3) Heat These are all monitored by the battery support software/hardware but all will affect performance. The phone will not let charge or discharge to 100% even though it says so. Min/Max values are stored on the phone and adjust as your battery ages. 100%/0% per you phone's display is really just the max/min allowed values.
inferiorhuman 9y ago
For a NiCad battery, sure.
starky 9y ago
I did a brief stint as a research assistant at a battery manufacturer which is why I was so horrified by your comment. Essentially, from the moment you manufacture a lithium-ion cell, the materials inside start reacting and losing capacity. When fully discharged, this reaction rate is increased by quite a bit. The capacity of a lithium cell is dependent on the minimum and maximum charge voltages. These are chosen to balance the capacity of the cell, as well as the cycle life of the cell. It is assumed that you will only run the cell to 0% on the rare occasion, otherwise that you will charge it before it gets too low. FYI, Battery university is a good resource on just about everything batteries [1]. My advice when it comes to caring for the battery in your phone is incredibly simple: Plug the device in each night when you go to bed and unplug it when you get up in the morning. [1] http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries http://batteryuniversity.com/learn/article/how_to_prolong_li...

by w-ll 9y ago

Im not an EE but i've always heard that full battery cycles are best to preserve its life. If not going from 100% to 0% and then charging fully to 100% is the best behavior please inform me.

wtallis 9y ago

Fully discharging a battery was only necessary with nickel-cadmium cells that suffered from a severe memory effect. Nickel metal hydride cells didn't, but could be affected reversibly by a minor drop in voltage from repeated partial discharges. Most rechargeable battery technologies in use today are significantly harmed or completely destroyed by a complete discharge. Devices using lithium ion cells all turn themselves off long before the cell is completely empty, as a protective measure.

w-ll 9y ago
Again, I'm not versed on the chemistry behind this, but friends who got new phones around the same time and plug them in to charge every chance they get have had their batteries fail earlier than me. I guess my data is anecdotal, but doing full cycles has allowed me to get 40+ hour standby with 10+ hour screen over the last one and half years. Where my friends cant even get more than 10 hour standby.
- owenversteeg 9y ago
  As someone who builds battery systems (yes, I'm "that battery guy" that shows up in HN battery threads) wtallis is correct: full discharges harm modern batteries, although every battery protection circuit has a cut-off voltage set to prevent discharging them too far (at which point your phone will turn off.) The practical applications of those two facts, however, are much more nuanced. Ultimately, the biggest killer of batteries is heat. Charging your phone and using it battery-intensively (max brightness/lots of processing stuff) are the biggest heat-causing things that come to mind. Another thing that can happen is heat buildup: you might not be using it very intensively, but if you use it for hours on end the heat can eventually build up and the phone will get hotter over time. It's entirely possible that your method of using your phone actually does cause less stress on the battery. However, this is 100% dependent on what you and your friends do with your phones, before and while they charge, as well as the kind of phone, its charging circuitry and a million other factors. At the end of the day, all I can say is "batteries are basically magic, use less power, and don't let your phone get too hot." The only universal recommendation that will guarantee better battery lifetime - with every battery chemistry - is to draw less current from the battery (on a phone: turn down your brightness, turn off things you're not using, etc etc.)
- mohaine 9y ago
  For LithIon, there are really 3 things that are bad (That I've heard of): 1) Fully charging them 2) Fully discharging them 3) Heat These are all monitored by the battery support software/hardware but all will affect performance. The phone will not let charge or discharge to 100% even though it says so. Min/Max values are stored on the phone and adjust as your battery ages. 100%/0% per you phone's display is really just the max/min allowed values.

inferiorhuman 9y ago

For a NiCad battery, sure.

starky 9y ago

I did a brief stint as a research assistant at a battery manufacturer which is why I was so horrified by your comment. Essentially, from the moment you manufacture a lithium-ion cell, the materials inside start reacting and losing capacity. When fully discharged, this reaction rate is increased by quite a bit. The capacity of a lithium cell is dependent on the minimum and maximum charge voltages. These are chosen to balance the capacity of the cell, as well as the cycle life of the cell. It is assumed that you will only run the cell to 0% on the rare occasion, otherwise that you will charge it before it gets too low. FYI, Battery university is a good resource on just about everything batteries [1]. My advice when it comes to caring for the battery in your phone is incredibly simple: Plug the device in each night when you go to bed and unplug it when you get up in the morning. [1] http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries http://batteryuniversity.com/learn/article/how_to_prolong_li...