Half a croissant, on a plate, with a sign in front of it saying '50c'
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Battery saver

Don't let charges kill battery's life
  [vote for,

Since we know that charging a battery that has a 50% charge is bad for the battery... what if there was a software option that told the power supply to use the battery (when plugged in) until it was gone?
mrclark, Nov 14 2003

Batteries in a Portable World -- FAQ http://www.buchmann.ca/faq.asp
Very informative site regarding the care and feeding of rechargeable batteries [namuh, Oct 04 2004, last modified Oct 06 2004]


       I have a battery recharger that discharges the battery before charging it, for this very reason. More of a hardware option than a software one, though.
DrCurry, Nov 14 2003

       I would prefer savory batter, myself. Mmmmm batter.
bungston, Nov 14 2003

       That would be great, except that the premise of this idea is not generally true. The proper treatment of batteries depends on many factors including the chemistry and the battery management system.   

       NiCd is the only chemistry I'm aware of that actually (in some cases) benefits from being discharged completey, but most NiCd bateries now days don't benefit from this. As a general rule, the number of cycles you can get out of a battery decreases, the more the battery is discharged on each cycle. This is generally not linear, so to get the most use out of a battery, it may be best to discharge it to somewhere between 20% and 80% each time (depending on chemistry). In almost no case, would it be beneficial to drain the battery more before charging.   

       In many cases, it is beneficial not to charge a battery until it has been used to a certain level. Some laptops do this today. They may for example not charge the battery unless it is less than 90%, but if you need to have the battey toped off, it is better just to top it off rather than discharge it to 90%.   

       One thing that does make discharging first useful is if you have a really dumb charger that will overcharge the battery if it isn't fully discharged to start with, but if you add the smarts to the charger to discharge it first, you would have been better off just making the charger smart enough not to overcharge a partially discharged battery.   

       One more exception. On some battery systems it is useful to occationally discharge the battery completely or almost completely so that the the battery management system can determine how much life the battery has lost, allowing more accurate estimates of remaining capacity. This generally doesn't increase the capacity of the battery, but it doesn't hurt it much and allows more of the available capacity to be used before shutting down.
scad mientist, Nov 14 2003

       Oh yeah, take what I said with a grain of salt since most is from memory, and I don't have time to look up references. The main point: don't make assumptions based on old information that "everyone knows is true."   

       I don't know about Dr. Curry's charger. It may have been made long ago for batteries that needed this, or they could have thrown that feature in becasue it was really easy to implement, and everyone "knows" that it would improve battery life. They don't care if it actually slightly decreases your battery life.
scad mientist, Nov 14 2003

       Ditto all that, I used to work in a battery test lab and those are good comments by [scad mientist].
krelnik, Nov 14 2003

       Is that anything like the Tesla battery saver where it switches batteries in series and parallel to conserve power with load leveling capacitors. Or some John Bedini battery charger?
travbm, Oct 28 2015

       I read that certain tunnel diodes worked well for this.
travbm, Oct 28 2015


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