To recharge or not to recharge...

LBD_Nytetrayn

Figured this would be the best place to ask.

My wife told me recently that she had heard that she shouldn't recharge her iPod except when the battery runs down, because it can wear out the battery a lot faster if you do it when the charge isn't low.

Myself, since I got my DS and my cell phone, I used to recharge it whenever I wasn't using it, so it would always be at full capacity, though I have gotten lazier about that over time.

All the same, is it true for the iPod? And if it is, is it also true for the DS or my phone? Maybe I've just used them so much that the batteries are getting worn(I'd say I've had the phone for about 2 years, and I got the DS just before Christmas in '05), but the batteries don't seem to last as long as they used to.

So to summarize, I guess what I'm basically looking for here are the do's, don'ts, and maybe "old wive's tales" to be aware of when it comes to recharging my batteries in these sorts of products with the built-in recharging functions.

mntorankusu

It's better to recharge a li-ion battery before it is down completely. Most devices do shut off before the battery gets to a level low enough to damage it, so it's not dangerous to let it die once, but for example, repeatedly turning it on after the battery dies can kill or damage a li-ion battery.

Ni-Cad batteries do need to be completely discharged before being recharged, but you'd have to look pretty hard to find something that uses Ni-Cad, these days.

mcdermott

Li-ion batteries (commonly found in cellphones, iPods, etc) can be charged pretty much whenever. In fact, draining them completely will actually reduce their capacity (though most devices have circuitry to prevent this from happening).

Li-ion batteries will also lose maximum capacity over time. There's really no getting around it, which is why the inclusion of non-user-replaceable Li-ion batteries in iPods was...unwise. I think it's something on the order of 10%-20% per year. More if exposed to excessive heat...yes, the heat generated by the device using them does count.

Also, Li-ion batteries will lose maximum capacity with each charge cycle. A charge cycle can be discharging them to half and recharging twice, or discharging by 10% and recharging 10 times. You get the drift. After a couple/few hundred charge cycles (which, on something like an iPod, can happen faster than you'd think) you can expect significant loss in battery life. Couple this with the age and heat losses and you can see how Li-ion batteries may not fare so well after a while.

As far as leaving a full iPod on the charger, I'm pretty sure it's not an issue. Any decent charger should have a delta-V cutoff, so once the battery is "full" it will cut off power. The battery will discharge a bit (since iPods are never "off"), and it will charge again...and so on. This is really no different than leaving it off the charger for two days and putting it on, as far as the battery is concerned.

Also, if you want some more info, wikipedia has pretty decent articles on Li-ion batteries (lithium ion), as well as NiMH and others.

mntorankusu wrote:

Ni-Cad batteries do need to be completely discharged before being recharged, but you'd have to look pretty hard to find something that uses Ni-Cad, these days.

Power tools, at least all the ones I own. Good for high current draw.

Though I do remember back when Ni-Cads were the 'norm' for rechargeables.

4rch3nemy

I hereby "charge" the forums to answer this question lest I commit the crime of "battery."

..yeah I know.

EDIT: Obviously much too late and beat'd.

LBD_Nytetrayn

To clarify; I've rarely had anything drain COMPLETELY, but usually down into the red. Should I wait until say, the DS light is red before I recharge, or can I just plug it in while it's still green and juiced just to be sure I'm ready to go?

yalborap

LBD_Nytetrayn wrote:

To clarify; I've rarely had anything drain COMPLETELY, but usually down into the red. Should I wait until say, the DS light is red before I recharge, or can I just plug it in while it's still green and juiced just to be sure I'm ready to go?

Topping it off like that is one of the better methods of handling it.

Barrakketh

LBD_Nytetrayn wrote:

To clarify; I've rarely had anything drain COMPLETELY, but usually down into the red. Should I wait until say, the DS light is red before I recharge, or can I just plug it in while it's still green and juiced just to be sure I'm ready to go?

You shouldn't keep it running until it shuts itself off. However, one of the primary factors that will reduce the lifespan of a Li-ion battery is it's charge. A battery kept fully charged for a year will lose approximately 20% of it's capacity. Keeping it topped off will do more to shorten it's life than almost anything else (excessive heat being the other biggie, so don't leave it in the car on a summer day).

On the flip side, it costs $15 to replace the battery in your DS. If it's more convenient to keep it topped off so you don't have to think about the battery dying on any unexpected trips it may be worth the price.

LBD_Nytetrayn

Ok, it's not a huge concern for me (and again, I've almost never had anything shut off; I usually stop playing when the light goes red, since I don't know how much longer it'll last). So I guess I'll just keep recharging when it turns red.

core tactic

Another battery question: I leave my PSP plugged in at night. Will that wear the battery down quicker?

Because if it will I won't anymore.

Jam Warrior

My DS has definately significantly lost it's capacity but I guess that's mainly down to two years of near constant usage. Just at the niggling rather than annoying stage at the moment but it's nice to know that it'll be quick and easy to replace.

In fact no! It's annoying to know it'll be quick and easy to replace as it means I can't use that as an excuse to upgrade to a lite!

stigweard

This is a site everyone should read: Battery University

For iPods, laptops, phones, etc... where the meter that reads the lion battery occasionally needs to be calibrated, you should run the battery down about once a month. Otherwise, plug it in when you aren't using it unless you are not using it for an extended period of time (weeks). In that case, charge it to 40% and then store it in a cool and dry place. It will extend the battery life.

Jam Warrior

stigweard wrote:

This is a site everyone should read: Battery University

For iPods, laptops, phones, etc... where the meter that reads the lion battery occasionally needs to be calibrated, you should run the battery down about once a month. Otherwise, plug it in when you aren't using it unless you are not using it for an extended period of time (weeks). In that case, charge it to 40% and then store it in a cool and dry place. It will extend the battery life.

When we say 'run the battery down' are we talking until the low battery light comes on or until the system switches itself off?

stigweard

Jam Warrior wrote:

When we say 'run the battery down' are we talking until the low battery light comes on or until the system switches itself off?

Unitl the red light at the earliest, or the system will shutdown soon message at the latest. You don't really want to let the machine decide when to shut down because it might draw too much power which will cause the safety to go off in the battery and it will never eb able to be charged again. The calibration is needed so that the laptop can properly gauge the battery life. I don't even do it once a month for my iBook, more like once every 80 days or so.

Marlor

With Li-Ion batteries, the best thing you can do is keep them constantly at somewhere between 50-75%. Letting them run down completely reduces the life-span, and so does keeping them at full charge.

Of course, this is totally impractical, so the best solution is not to worry about it. Just charge it when it is convenient or when it runs down, and don't worry about the battery life.

If you are going to put the battery into storage for a long time, then it might be worth charging it until it is two-thirds full, but I really don't even worry about that.