Korean Job Discussion Forums

[tfunk]

I have a Lithium Polymer battery and I'm hearing conflicting reports on the best way to get a long lasting charge out of it.

Is it bad to:

1. Leave the battery charging over-night?

My battery usually takes about 3 hours to charge but I don't always have time to wait around my apartment waiting for it to charge so I plug it in before I go to bed.

2. Under charge it?

Sometimes I charge it for an hour before it's fully charged because I want to listen to music while travelling to work.

3. Drain it completely of energy?

Sometimes it runs out of battery power. I wait a few minutes and turn it on again. It usually works for a few minutes before turning off. I continually do this until it is completely drained of energy.

4. Charge it before it empty. Sometimes when the battery is half way gone I charge it.

5. Use the adapter while it is hooked up the computer? (even if the battery is nearly full)

I'm only asking because my current battery life is pants.

[tfunk]

This is a handy guide. I think most of the newer mp3 players use Lithium ion:

http://www.batteryuniversity.com/partone-23.htm

Particularly relevant:

Should I charge my battery partially or fully?

Does not matter. Charging in stages is acceptable. Full charge termination occurs by reading the voltage level and charge current. Charging a full battery is safe and does not cause harm.

Should I use up all battery energy before charging?

No, it is better to recharge more often; avoid frequent full discharges.
Yes, on batteries with a fuel gauge, allow a full discharge once a month to enable reset[/i]

[xenok]

the advice given in the link you posted is generally solid.

just to add/clarify a few more things for those who really want to squeeze every single drop of life out of your lithium-ion batteries.

charging at a partial state is not a problem. the idea of fully discharging your battery and then fully charging it again began with nickel batteries, this is also known as the memory effect. however li-ion batteries have completely different electrochemistry so this doesn't hold true for them. however if you want to take this to an extreme, you also don't want to fully charge your battery. keeping it in a partial charge state constantly is probably the best way to extend your battery lifespan (aside from keeping it in a temperature controlled environment constantly, but that's really beyond the realm of your power or anybody's in fact).

the two biggest factor affecting the lifespan of li-ion batteries is temperature (the hotter it is, the faster it dies. i don't believe low temperature affect lifespan but it does affect performance. if the temp gets too low then your battery is less effective) and what is called SOC swing.

SOC swing is basically difference between the lowest charge state and the highest charge state during the battery's life. so if you use it your li-ion batteries like a nickel battery, i.e. you use it till it's fully discharged (technically it's not but that's not important) and then charge it to its maximum again, then the SOC swing would be 100%. this will kill your battery quite quickly to be honest. if you charge it back to max everytime it reaches half its charge, then the SOC swing would be 50%. this will actually be better for the life of the battery.

the absolute ideal (but it's too annoying for most people) would be keep the battery at a state of charge that fluctuates between its mid-state of charge. imagine the battery's at its half charge state as its equilibrium position. the further it deviates from its equilibrium the worse it is for life. so charging a battery till say 60-70% (so not fully charged) and then recharging it when it drops to 30-40% (so not fully discharged) is probably the best way to extend the life span. so if you have a typical handphone battery where the indicator is usually three bars, you would charge it when you only have one bar remaining, and stop charging it when it gets back to about two bars. that means charging it a little every day, which might be too much trouble for most people (including me, even though i know all this).

so a fully charged battery isn't always good for life, but it is better than keeping it fully discharged. most consumer batteries have a life span of two years, so if your battery starts losing its charge very quickly, it most likely means it's reaching the end of its life. if you haven't had it for very long and it's already exhibiting this kind of battery, it might mean it's defective, so get it replaced ASAP (defective li-ion batteries are BAD news).