Naked Science Forum

General Science => General Science => Topic started by: paul.fr on 29/08/2007 04:03:48

Title: clearing a batteries memory.
Post by: paul.fr on 29/08/2007 04:03:48

I just bought a new ipod, and my sis thought she would be helpful and gave it a one hour charge. it is supposed to have an initial charge of 8 hours, as a result it now says fully charged even though there is only less than an hours worth of playable charge in it.

Obviously the battery has quickly developed a memory, is there anyway of changing it? i have fully discharged the battery, but no luck.

also, i threw the reciept so any suggestions would be useful.

Title: clearing a batteries memory.
Post by: Karen W. on 29/08/2007 04:35:06

Yikes did it come from costco.. they don't require the reciept only the person who purchased it~ I don't believe there is anything else you can do once it was charged incorrectly! I have had batteries that I have done like that!

Title: clearing a batteries memory.
Post by: Carolyn on 29/08/2007 04:43:49

Paul, I've been having issues with my IPOD battery as well.  I charged it and let it completely die and recharged, now it's working fine. 

This site had a little info:  http://forums.ipodlounge.com/showthread.php?threadid=19556

In the mean time, one suggestion I would give you is to STOP THROWING OUT RECEIPTS TO YOUR EXPENSIVE GADGETS!

Title: clearing a batteries memory.
Post by: kdlynn on 29/08/2007 05:00:55

karen i don't think costco is in the uk. we don't even have one. :(

Title: clearing a batteries memory.
Post by: DoctorBeaver on 29/08/2007 06:41:15

Quote from: kdlynn on 29/08/2007 05:00:55

karen i don't think costco is in the uk. we don't even have one. :(

I always thought it was near Palo Alto  [:D]

Title: clearing a batteries memory.
Post by: Karen W. on 29/08/2007 15:13:29

Quote from: kdlynn on 29/08/2007 05:00:55

karen i don't think costco is in the uk. we don't even have one. :(

I thought they did!..

Title: clearing a batteries memory.
Post by: kdlynn on 29/08/2007 16:42:37

well if they have one, we should too... although we have a million other big wholesale places... i still want one

Title: clearing a batteries memory.
Post by: another_someone on 29/08/2007 20:26:36

Looking at Carolyn's link (and I suspected this might be the case), the IPod uses Lithium Ion batteries, which should not have a memory effect (although they are very sensitive to overheating).

The bigger problem with Lithium Ion is that there is very little drop in voltage between full charge and almost empty.  This is not a bad thing in terms of usability, since it means that your gadget is getting the full voltage right up until the end; but it makes it very difficult to know how much charge is left in the battery (you either simply use fancy electronics to count the number of coulombs in, and the number of coulombs out - and in that case, initially failing to charge the battery fully may confuse the count; or else you rely on the voltage, and expect it to show full charge until you get right up near the very end of the charge, with little early warning when the battery is partially discharged).

So, I don't think there is any problem with the battery (or if there is, it should not be because of the partial charge), but there could well be that your metering is awry.

There is certainly no harm in doing a full recharge cycle, and you would have had to do with the old NiCad batteries, or even (albeit to a lesser extent) with the NiMH batteries.

Title: clearing a batteries memory.
Post by: paul.fr on 29/08/2007 20:38:58

Thanks Carolyn, and George.

I think i have the problem sorted, i am in to hour six of my test. I will let you know how stupid i am later...if you need reminding that is.

Title: clearing a batteries memory.
Post by: kdlynn on 30/08/2007 02:17:36

by the way paul... do you have the worst luck ever with batteries, or is it just me?