when an iPod is fully charged and connected to external power, and you listen to music, how is it working:

a) is it drawing power only from the external source (computer, speakers, wall outlet, etc), and hence, the battery life of the iPod is being extended?

or

b) is it continuously being discharged and charged, so there is no effect on battery life?

when at home, i listen to the iPod using logitech made-for-iPod speakers (linked below). the speakers have a built-in battery as well. if you connect the speakers to a wall outlet, the speakers and the iPod both get charged. i am wondering if i should connect them to the wall outlet (hence, extend iPod's battery if scenario a) is correct), or let the iPod run down and connect only to charge.

i guess this question can be extended to any device that has a built-in battery. if you run the fully-charged device on external power, are you extending the battery life, or is power still being constantly drawn from and replenished to the battery?

my speakers:

http://www.logitech.com/index.cfm/products/details/US/EN,CRID=2414,CONTENTID=10785

3/17/2007 8:52:23 AM

good question. i don't have an ipod so i dunno. i know my laptop doesnt need a battery when i plug it into a power source. also my cell phone appears the be the same way (although if i take the battery out when it is plugged in, it will still go through the shutdown process. but when i take out the battery without having it plugged in, it just dies with no shutdown procedure).

my guess would be it is actually drawing power from the plug. but since the battery is in there, it is probably constantly draining and recharging the battery too. but i really don't know

3/17/2007 2:02:25 PM

yeah laptops are different.

i guess i am talking about devices whose battery cannot be taken out.

wait, so your phone works without a battery if it is plugged in? mine doesn't. i tried it both ways: plug in and take battery out, and take battery out and plug in. won't work.

but yeah, any insight by anybody on the iPod (or for example on the speaker system i have)?

but maybe, it doesn't matter, regardless of whether scenario a) or b) is correct.

let's say i plug in my speaker system with the iPod in it:

--- if a) is correct, battery life being extended
--- if b) correct, battery constantly draining and recharging

now let's say i don't plug it in:

--- well in this case, i am using the battery.

so i guess, from a logical point of view, it is better to keep it plugged in, because either you get a benefit, or you are no worse off than if you didn't plug it in.

still, i am curious to know what actually happens if you plug in the iPod and use it.

3/17/2007 3:05:21 PM

no one else curious about this?

i know a lot of you have iPods.

but maybe no one uses their iPod when inside.

3/18/2007 8:29:15 AM

i would imagine they have circuitry in there to use the external power source when connected instead of the battery.

don't cell phones do this too?

3/18/2007 8:36:27 AM

i was told by a friend of mine that (in laptops), it is better to take the battery out if you plan to use it while it is plugged in (assuming the battery is charged already). supposedly many laptops wont bypass the battery unless it is physically out of the laptop so you are consuming charge life, or whatever they call it.

dont know how correct that is, but it doesnt hurt to take it off if you can. that said, it probably is safer to just plug it in when you need it, not leaving it plugged in constantly. from my own experiences, my last cell seemed to die rather quickly after having it on the charger constantly instead of doing so only when necessary.

3/18/2007 10:01:39 AM

Quote :

"i was told by a friend of mine that (in laptops), it is better to take the battery out if you plan to use it while it is plugged in (assuming the battery is charged already). supposedly many laptops wont bypass the battery unless it is physically out of the laptop so you are consuming charge life, or whatever they call it."

Yeah that's true.

http://www.ipodbatteryfaq.com/ doesn't directly answer what you're trying to ask. I have one of those Denison adapters that lets me play my ipod directly through my car stereo system and it charges while I use it. I would hope it knows to bypass the battery and run from the external power source.

3/20/2007 4:11:52 PM

thanks.

i guess this answer's my question in a roundabout fashion:

Quote :

"Q: Is it okay to leave the iPod in the dock, or otherwise attached to external power, for extended periods of time? A1: Yes. The iPod's circuitry will no longer charge the battery once it is determined to be full, even if the iPod is still attached to external power. A2: This can also be a more complicated issue. Lithium ion batteries age faster when stored at full charge. If your usage of the iPod consists almost exclusively of use while plugged in for extended periods of time such as weeks or months, and very limited usage from the battery, the battery is essentially always in a charged state. A fully charged lithium ion battery ages at a faster rate than a lithium ion battery at the optimum storage capacity of approximately 40%. However, keeping an iPod battery near this optimum storage capacity can prove difficult to manage. A lithium ion battery also ages from use, as well as from storage, so the aging effects of constant use of the battery in order to keep the charge closer to 40%, versus constant use while attached to external power, come close to being even. "

but i will email my question to them anyway.

3/20/2007 5:07:16 PM