My iPhone 3GS has just (over the last couple of days) started losing charge really quickly. I've checked push emails are off and turned it off and on to no avail. I usually charge every other night and it's got up to 100% charge ok. Any ideas or is it just a bored battery

Have you just upgraded to iOS4? Some folk are noticing it eats pre-iPhone4 batteries. If so check you have switched off background porcesses, esp Skype. Better still just delete it, its a battery scoffer.

S.

try the iOS 4.0.2 update, some reports that it improves battery life
mine (3GS) has been pretty woeful since updating to iOS 4

try completely draining the battery…all the way, then charge it up, might solve your issue..

try completely draining the battery

unlikely to do anything useful with a lithium battery 🙁

Just charge your spare battery and pop it in, oh no, you can't, Apple don't deem you clever enough!!

I love the idea and the look of iphones, but not the handicaps they come with!

Sorry, completely unhelpful, off to bed now!!

Just read that Apple recommend draining the battery at least once a month. I'm downloading 4.0.2 now and will run the battery down before charging tonight.

Fingers crossed

Not sure how much difference this might make because I've only owned a 4 (for two weeks), so have nothing to compare it too … but I've been charging while running Battery Doctor Pro – tis supposed to maximise your charge etc. Battery life is great TBH – but like I say, I have nothing to measure against.

Just read that Apple recommend draining the
battery at least once a month

Where did you read that? Completely draining a Li-ion battery is usually the worst thing you can do to it.

Sounds like an iOS4 "issue", my touch started losing all it's charge overnight following "upgrade" to iOS4. Reverted back to v3 and all is well again.

Seems OK now – not sure if IOS 4.0.2 helped or if it was something else.

Graham S – "For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Be sure to go through at least one charge cycle per month (charging the battery to 100% and then completely running it down)."

from here: apple website

As I understand it, fully discharging lets it re-calibrate its battery gauge to be more accurate, but it is actually bad for the battery cell.

• 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.

— How to prolong lithium-based batteries (Battery University)

Anyway, regarding OS4, just check what you have running in the background. (Double click home button) If you have active* tasks running, especially things like GPS or streaming music, then that is work for your phone, even when it is sitting idle, so it will drain your battery quickly.

*Note: most iOS apps are not active. They just save state when they exit and then return to it when re-started. They shouldn't drain your battery.

The charge circuit in the iphone (and any li-ion charging device) should protect from over and under charge and should hold the battery within its optimum cell voltages. Therefore the fact that deep-discharging a li-ion battery IS very bad for it (and potentially a serious problem as they get very upset) it's not really a consumer problem unless you go poking around with paperclips – the internal circuitry will cut the power once (IIRC) 2.5v is reached on the way down and 4.2 on the way up. I'm not convinced there's any justification for a discharge/recharge cycle, in fact regular "cycling" is bad for li-ions, they much prefer to be kept mid-charge from what I read, which is why my mobile batteries tend to have a very short lifespan (I can never remember to put them on charge until the damn thing goes flat).