Which is better for a rechargeable cell phone battery's longevity: recharging it every day, or only when it's almost drained?

1/26/2010 8:35:35 AM

I don't think it matters on most modern batteries. just don't let it drain completely down or overcharge/leave it on the charger too much.

1/26/2010 8:39:04 AM

Depends on the battery type but for most modern batteries, it is best to charge it everyday and not let it go down low and if a memory problem occurs a full discharge and recharge usually help but rarely would you need to do this if at all.

[Edited on January 26, 2010 at 9:59 AM. Reason : .]

1/26/2010 9:57:54 AM

really? my last two phones I tried not to overcharge, but I charged it every other day or so, even if it was only around 50% down and those batteries held significantly less charge after 6mos. This last one, I've only charged it when it was down really low, charged it full, and taken it off immediately and it lasts basically as long as when I first got it over a year ago. Could be luck or could be a better battery though.

1/26/2010 10:01:12 AM

Probably a better battery and phone and maybe you even took care of the phone better. Temperature wise, less usage, ect...



[Edited on January 26, 2010 at 10:08 AM. Reason : .]

1/26/2010 10:05:56 AM

I've always heard that it will last long if you take it off the charger once it has fully charged, but I've never really paid attention to it. I just plug my phone in at night when I sleep and take it off when I wake up.

1/26/2010 10:10:30 AM

i was always under the impression that you wanted to drain it as much as possible and then charge it full...and to not leave it plugged in all the time (in the case of a laptop or something similar)...of course, i've had this notion for the better part of a decade, so it might be that's the way it used to be

every laptop i've ever owned (my current one included), i leave plugged in but only with the battery out (if it's full)...i only put the battery back in when i need it...the last laptop i sold on CL was nearly 4 years old and still got about 90-100 minutes on a battery (where it got 120-130 minutes when new)...i like to think it was because of how i treated it in terms of dis/recharge, but maybe not

similarly, i let my phone battery drain to the end before charging and by the time the 2 years were up that i could get a new contract, that thing would only last about a day before dying (and i was never much of a talker)...my new phone goes 4-5 days on a charge (with the same moderate talking), but then it's new

in summation, i don't know

1/26/2010 10:11:22 AM

depends on the battery, read the instructions.

Quote :

"i was always under the impression that you wanted to drain it as much as possible and then charge it full...and to not leave it plugged in all the time (in the case of a laptop or something similar)...of course, i've had this notion for the better part of a decade, so it might be that's the way it used to be"

me too.

i charge my cell phone every other night. my phone is 2 years old and still holds a charge for 3 days and can talk for up to 3-4 hours on it.

the best thing you can do is when the battery is BRAND NEW, FULLY drain it, and then FULLY recharge it. after the initial power cycle i don't think it matters much.

in general, when rechargeable batteries aren't used over time they lose their charge quicker than if they are used, so don't keep your laptop plugged in ALL the time, it's best if once a week or so you unplug it and drain the battery a little.

1/26/2010 10:41:25 AM

actually, i assume that my laptop has some sort of logic chip in it that regulates the charging

for example - if i charge my laptop to 100% (as reported by windows while plugged in) and then unplug it immediately, the battery meter almost always reads 99-100% (unplugged)

if i leave it plugged in at 100% charge for several days (whether on or off doesn't seem to matter) and then i unplug it, windows reports a lesser charge (depends on the amount of time since it reached 100%, but it's usually 96-98%)

this leads me to believe that once it achieves 100% charge, as long as it's left plugged in, all charging to the battery is cut off...windows reports 100% until the point of disconnecting the plug, at which point it drops immediately to that 96-98% (if it's left in for days)...does that make sense?

1/26/2010 10:50:26 AM

Quote :

"Simple Guidelines [Li-ion] Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.) Short battery life in a laptop is mainly cause by heat rather than charge / discharge patterns. Batteries with fuel gauge (laptops) should be calibrated by applying a deliberate full discharge once every 30 charges. Running the pack down in the equipment does this. If ignored, the fuel gauge will become increasingly less accurate and in some cases cut off the device prematurely. Keep the lithium-ion battery cool. Avoid a hot car. For prolonged storage, keep the battery at a 40% charge level. Consider removing the battery from a laptop when running on fixed power. (Some laptop manufacturers are concerned about dust and moisture accumulating inside the battery casing.) Avoid purchasing spare lithium-ion batteries for later use. Observe manufacturing dates. Do not buy old stock, even if sold at clearance prices. If you have a spare lithium-ion battery, use one to the fullest and keep the other cool by placing it in the refrigerator. Do not freeze the battery. For best results, store the battery at 40% state-of-charge. "

Quote :

"Although lithium-ion is memory-free in terms of performance deterioration, batteries with fuel gauges exhibit what engineers refer to as "digital memory". Here is the reason: Short discharges with subsequent recharges do not provide the periodic calibration needed to synchronize the fuel gauge with the battery's state-of-charge. A deliberate full discharge and recharge every 30 charges corrects this problem. Letting the battery run down to the cut-off point in the equipment will do this. If ignored, the fuel gauge will become increasingly less accurate. (Read more in 'Choosing the right battery for portable computing', Part Two.)"

http://www.batteryuniversity.com/parttwo-34.htm

[Edited on January 26, 2010 at 11:19 AM. Reason : ]

1/26/2010 11:15:34 AM