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

[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.)

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.

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.

Correct way to charge an iPod?

[Anonymous Coward]

MasterCard.

Re:Correct way to charge an iPod?

[valkraider]

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

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...

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.

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.