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.

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.

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.

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.

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!

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).

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.