Correct Way to Charge an iPod?

JAHA wonders: "I've seen two schools of thought regarding the proper method for charging an ipod so as to maximize the lifetime of the battery: let the iPod completely drain before re-charging; or keep the iPod completely charged as often as possible (i.e. leave it charging while you listen to it if you can). There doesn't seem to be any official word from Apple on their website, so I was hoping the smart people here could clear it up for me." For those looking for a definitive resource on the proper care and feeding of your iPod batteries, try this site.

Comments

Discharge Batteries

[Syris]

Apple Ipods use Lithium Ion batteries, like a lot of portable products.

The lifetime of a rechargeable Lithium Ion battery shortens considerably if it is left 'topped up' on a charger for extended periods of time(weeks, etc). That's one of the reasons they are never used as backup sources of power.

So, don't leave it on the charger. The battery will last longer.

Re:Discharge Batteries

[Syris]

That's a good point! Most modern pieces of consumer electronics will shut themselves off at extremely low battery voltages, though. So it's probably OK to listen to your Ipod until it turns off.

Re:Discharge Batteries

[VisorGuy]

Kind of like how most modern consumer electonics devices have smart chargers that stop charging the battery when it's full?

I know my Neuros works that way.

Re:Discharge Batteries

[Anonymous Coward]

The apple dock stops charging when the ipod is full.
So, DO leave it on the charger. The parent is a moron.

Re:Discharge Batteries

[baryon351]

Depending on how the charging system works, that may or may not be relevant.

However, what MAY affect things is that I've noticed a great deal of iPods left connected to a mac do get very very hot.

One feature of a Lithium Ion battery is they age - and after around 3 years nearly every one made will be dead, it's just part of their chemistry. Heat drastically speeds up the ageing process in them, and I've no doubt that those iPods left connected and hot are killing their batteries.

I don't know what's causing it, whether it's a software bug that keeps the HD spinning, or an overcharging bug, or they're being used as a HD constantly, for an hour or more at a time, but that heat is damaging to battery life.

http://www.buchmann.ca/ has good lay-readable info about various battery technologies and their characteristics.

batteries

[aliquis]

Ni-Cd: Drain them out completely and then recharge them until full.

Ni-Mh: I think it's same as above, but the memory effect isn't as bad as it is for Ni-Cd.

Lithium-ion: Try to keep them around 40% or so, never let them go completely empty.

I might be wrong thought.

Re:batteries

[dougmc]

I might be wrong thought.

No, you're pretty close.

No battery likes being overcharged. NiCds handle it best, but it slowly eats away at them (assuming a slow charge.) Smart chargers will stop the overcharging, but most chargers for NiCd devices are not smart. So take them off the charger once the battery starts getting warm!

If they are overcharged, or never discharged fully, they'll start to show voltage depression (often mistakenly called memory.) A full discharge will usually resolve this, at least until the battery wears out.

NiMH cells are very like NiCds, but they have more capacity and handle abuse less well. They also don't suffer from voltage depression (often called memory) so there's no need to fully discharge them ever.

Never completely discharge either sort -- go down to 1.0 volts per cell and then stop. Going further can cause the weakest cell to be `reverse charged' making it even weaker. For normal users, this means just use the item until it needs to be charged, but don't just turn it on and leave it going overnight.

Li-Ion cells can *explode* if overcharged, so any decent charger will stop charging them before that happens. So they should be fine to leave on the charger forever.

They'll also die if fully discharged. Fortunately, most things that use them will turn off before this happens, for exactly that reason.

To be complete, lead-acid batteries (like used in your car) should not be overcharged, as it evaporates electrolyte. Good chargers will prevent this, and your car has a good charger in it. Do not leave them discharged for any length of time -- this will ruin them. Fortunately, they self-discharge very slowly, so they can be left alone for a year or so after a full charge and won't die (as long as there is no load.)

iPods and most laptops and cell phones have Li-Ion cells, though some older cell phones and laptops have NiMH cells (and even older ones may have NiCds.)

Re:batteries

[dougmc]

Li-poly batteries are very like Li-ion cells, but they're less likely to explode if overcharged. Beyond that, and the (possible) shape differences, I don't think there's much of a difference.

The link you gave explained it pretty well ...

i know that the Li-Ion battery in my TiBook has seen a lot less memory effect ...

The Li-whatever cells do not experience memory. (Even NiCd's rarely do under normal use, but voltage depression is often mistaken for it.) They do eventually wear out, however -- perhaps that's what's happening.

keep it topped up

[bobba22]

I have experienced problems with my iPod when I let it run down completely, it drops into 'zombie' mode and cannot be woken without unplugging the battery. This is a pain in the arse when I'm going to be away from my computer for a long time. The iPod is one of the first of the first generation and can now only hold charge for around an hour. I don't think that it'll make much difference how you do the charge/discharge dance, you just have to accept the fate that the battery dies. What we really want is sony to release the batteries to the general public (UK) so we can refit them cheaply ourselves.

Battery Rundown

[Leroy_Brown242]

This is my understanding from what I have picked up as time has gone by. Correct me if I am wrong.

• NiCd
• Short overall life span.
• Developed "memory" easily.
• Needed to be fully charged and drained every single time.

• NiMH
• Longer overall life span.
• Develops a memory over time, but hard cycling of power and draining can remove it.
• Best if fully charged and drained, but not required every time.

• Li-ion
• Longest life of most comercial batteries.
• Much harder to develop a memory. Most people it wwould take months.
• Hard on the battery if it's left full charged constantly.
• Still best if fully drained and charged every time, but very forgiving.

Re:Battery Rundown

[dougmc]

NiCd -- Short overall life span.

NiCds usually have less capacity than NiMH cells, but they last longer (more charge/discharge cycles.)

NiCd -- Needed to be fully charged and drained every single time.

No, not every time. Occasionally is good enough -- the more it's overcharged, the more often you'll need to fully discharge it.

NiMH cells do not show voltage depression (often called memory) so there's no need to worry about fully discharging them.

Li-Ion -- Hard on the battery if it's left full charged constantly.

No it's not. If the charger overcharges them, they could explode, so most chargers know when to stop. The real reason that people say not to leave them fully charged for long periods of time is that they can explode if accidently shorted out.

Li-ion cells are not at all forgiving -- if abused, they either die (fully discharged) or explode/burn (overcharged, short circuted.) It's the needed circuitry (to prevent these things from happening) that's forgiving.

Li-poly cells are more forgiving, but with most of the benefits of Li-ion cells. I don't know how popular they are outside of R/C applications, however.

Re:Battery Rundown

[Elwood P Dowd]

Li-poly cells are more forgiving, but with most of the benefits of Li-ion cells. I don't know how popular they are outside of R/C applications, however.

And, of course, iPods. iPods are li-poly. They are only more forgiving in that if/when they explode or burn, you have a hunk of burning plastic rather than a pool of burning liquid. If they are physically damaged, there's no toxic fluid to leak everywhere.

Battery Care

[m0rph3us0]

Li Ion batteries are strange you don't want to discharge them completely but you don't want to leave them topped up. My recommendation, discharge to about 50%, recharge, rinse wash repeat.

Not good advice

[Uma Thurman]

Don't drain your batteries. Cells in a pack will discharge at different rates. When one dies and is driven in reverse by the other cells, it will be permanently killed. ESPECIALLY NiMH.

Memory effect is real, but you will not ever notice it, unless you do dozens of discharge cycles that are all the same length, to an accuracy of a few seconds. This isn't going to happen in normal use.

Basically, use your iPod. Charge it when you like. Don't run it all the way down.

Re:Not good advice

[Uma Thurman]

More on memory effect:

It is noticed on Earth satellites that spend very regular cycles in sunlight/charging and darkness/discharging. If you listen to your Brittany Spears songs for EXACTLY 30 minutes, then charge your iPod, repeated for a few weeks, you'll get a memory effect. I doubt that many people would do that.

Re:Not good advice

[spaceport]

If you listen to your Brittany Spears songs for EXACTLY 30 minutes, then charge your iPod, repeated for a few weeks, you'll get a memory effect.

However, in addition to the memory effect, you will suffer from an even stronger lack of taste effect.

Oops, I posted again...

Some general info on rechargeable batteries

[BeatdownGeek]

Here.

I think the consensus is Li Ion and NiMH batteries are better kept close to full charge, and NiCads should be drained fully before recharging.

iPods use a Li-Ion battery.

Re:Plug it in

[oneishy]

Yeah! Belkin already created a external battery pack. It's even sold on the Apple Store!

Correct way to charge an iPod?

[Anonymous Coward]

MasterCard.

Re:Correct way to charge an iPod?

[Anonymous Coward]

Priceless!

Re:Correct way to charge an iPod?

[valkraider]

That's not stealing. It's "Possession Infringement".

Good Lord Jebus. . .

[noewun]

Only on Slashdot could a thread meant to simplify things end up confusing the issue!

Excellent battery resource...

[Steve Cowan]

Where I work I need to know a lot about rechargeable batteries. My impression of Li-ion / Li-Polymer is that they don't mind having a "float charge" at all... what the previous posts fail to mention is that for safety reasons, all Li-based chargers are intelligent enough to not overcharge the batteries (except cheap offshore chargers and car adapters, but you won't likely find anything like that for your ipod). In other words, I believe it is safe to leave an ipod plugged in indefinitely.

We picked up a battery analyzer from Cadex, which is really cool, and I use it every day.

But the really cool thing is that the charger came with a little paperback book called "Batteries in a Portable World", which offers a lot of insight into varying battery chemistries, even though it is sort of a pitch for Cadex products.

Nevertheless there is an online version of this book. Go to chapter 2 and read up! There is some very valuable battery maintenance info in there -- if you own a single rechargeable battery it is a very good read. (The website asks for your email address, but you can probably just use a fake one).

Re:Excellent battery resource...

[gothzilla]

I used to work at Radio Shack and did a very informal survey. Every time someone came in to buy a new battery for their cordless phone I asked how they cared for the phone and how long the battery lasted. In general, the more it was left on the charger, the shorter the life span. I broke down phone care into 3 groups: 1) Phone left on charger when not used. Battery lifespan was about 1 to 1 1/2 years. 2) Tried to keep phone on charger but forgot a lot. Lifespan about 2-3 years. 3) Kept phone off charger till the little light came on. Life span was 5 to 8 years. These are pretty cheap batteries but the responses were pretty consistent. I also talked to people who bought standard rechargable batteries and rechargables for RC planes and cars. They answers and life spans matched pretty well.

Mac OS X Hints chimes in

[Mikey-San]

This is a GREAT summary of lithium-ion battery tech, as found on Mac OS X Hints:

http://www.macosxhints.com/article.php?story=200 30 314081843218

Don't forget to check out the source material to which the article links, as well. Good stuff.

Interesting reading.

[gklinger]

Check out the Battery University for the answers to all your battery questions.

Way to go

[EvlG]

Ask Slashdot, and you get 1000 geeks posting conflicting answers they "know" to be correct, all with conflicting "supporting evidence" from people that "know" it is correct.

Way to go.

Don't fuss about it. Battery life is limited.

[dpbsmith]

I've listened to all sorts of advice and have conducted limited experiments.

I believe the great unstated truth is that rechargeable batteries just plain have a limited life.

In fact, the lifetime on any one particular cell seems to be subject to a great deal of variation. For about ten years I tried to power all my AA, C, and D-cell-powered devices from rechargeable Nicads, and even when usage and recharging patterns were similar, some batteries _bought at the same time in the package_ might died after a year and a half, while others would be going strong after four years. I suspect this variation is one reason why manufacturers are so vague about lifetimes, and also contributes to peoples' superstitions (as they try to correlate the random behavior of individual cells with what they did to them.)

People who try to share rechargeable devices tend to bully each other and try to impose their personal superstitions about it ("I TOLD you not to keep it on the charger, Mabel!"), and companies who do not wish to replace dead batteries certainly are inclined to reinforce this. If I were a support person and someone phoned me with a battery issue, I would certainly suggest that they discharge the battery fully and recharge it. Why not? It would get them off the phone, and it MIGHT work, and when they called back to say it didn't it would be someone else's problem.

As for leaving batteries in the charger, at some point you have to assume that the people who make the batteries and the charger know what they're doing, and that the charger is smart enough not to deliver life-threatening quantities of charge to a fully charged battery. Certainly this should be true in these days where the chargers and batteries have microchips in them.

So I say, don't kick yourself over it. Accept the fact that rechargeable batteries are a) damn expensive, and b) only last a couple of years. Yes, it sucks, but lots of things do.

"Rechargeable" batteries sound as if they should last forever. So did "permanent needles" (ha! anyone else remember THOSE?), permanent waves, and permanent-press clothing.

My own experience

[jlower]

I'm no battery expert, I don't even play one on the internet, but I can relate my own experience as a true early adopter.

I've got a 5 gig iPod purchased in Nov 2001. I use it at least 6 hours+ every day at work. I rarely use it on weekends. When it's not in use, it is on the charger (the AC adaptor, not hooked to my computer) - always, no exceptions.

It's now 26 months old and as far as I can tell the battery is almost as good as new.

So, my secret to success in a nutshell:
- almost never run it all the way down
- use it on a very regular basis
- always on the charger when not in use

Of course, YMMV but this has worked extremely well for me.

What does Apple say?

[Hello Spaceman]

I had a problem a while back where my 2nd generation iPod (only a few months old) would lose it's charge completely overnight. So I took it to the genius bar at my local Apple store and determined that:

1) I was leaving my iPod in my car overnight (this was wintertime) and the iPod would 'freeze', which at the very least causes the iPod to *think* the battery is dead. (I wasn't clear if the battery was actually dead from freezing, or if the iPod just 'though' it was dead.) The only way to get it back to useable condition was to warm it up and recharge it.

2) Apple has a special gizmo that can fully drain your iPod's battery to help reduce the memory effect. Apparently, when you see the iPod dead battery icon, there is still quite a bit of charge left in the battery ... just not enough to spin up the hard disk, decode compressed audio and play through your headphones. If you take your iPod to an Apple store, they can *fully* discharge it overnight for free.

The only way an average user can fully drain the battery is to play songs until it shows the dead battery screen, then leave the iPod unused for a week while its internal clock slowly finishes off the draining. When it's fully drained, you won't see the dead battery screen anymore. It will be DEAD.

The genius further told me that it was NOT good to leave the iPod plugged into its charging adapter for long periods of time once it's charged. (Again, this is a second generation iPod.) My presumption is it would be OK to leave it plugged in as a mounted Firewire drive.

Finally, he said Apple had been getting a lot of complaints, that the iPod had been built and tested in a part California where it never got as cold as it did here in the North East, and they were "discovering" the limits of the batteries in cold weather. Luckily, I don't think the effects are premenant, and my iPod was just fine all last summer =)