Headphones & Mp3 Players forum

General discussion

Can Overcharging kill a battery?

by schfour / January 23, 2009 11:37 PM PST

I have an archos 605 wifi 30 gb. I have let it charge overnight several times.
My problem is that the battery life now last for only 20 -30 minutes when it is supposed to last 17 hours. I don't know if it's my fault for letting it charge too much or there is a battery defect.

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What did you do to overcharge?
by R. Proffitt Forum moderator / January 23, 2009 11:41 PM PST

My current rechargeable players and devices all have battery management chips and circuits that prevent overcharging. Did you do something to remove that feature?

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by schfour / January 29, 2009 10:27 AM PST

I haven't messed with it at all.

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Over charging
by grandmaks / January 29, 2009 11:28 AM PST

Have you contacted the Support Department of your product. They should be of help. Good Luck

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by DJAP101 / January 30, 2009 2:11 AM PST

i've found that whenever i overcharge my battery it loses life and i have to replace it.

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It might
by Brittni1 / January 30, 2009 10:45 AM PST

Found out with a cordless Norelco razor that plugging it in after every time I used it the battery went dead. Sometimes, running it completely dead, then recharge, run it completely dead and recharge a few times helps, but not always. I ended up buying a new razor and don't plug it in until it shows signs of low charge. It's worked that way for several years now.

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by Ski_rus12 / January 30, 2009 12:54 PM PST

As Far as I know NiMh Can be overcharged but it is harder to overcharge a NiCd Battery. A Lithium Ion Polymer Battery (Which you have in your Archos)Can be overcharged and loose Voltage and even explode! This May be a fault that is degrading you battery and becoming a health risk or a simple case of too many charge-discharge cycles. I suspect this is a fault with your device and should be sent back to Archos for a replacement.

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But wait
by billygard / January 30, 2009 3:11 PM PST
In reply to: Depends.

If charging a battery more than is necessary is enough to ruin it, I guess Apple knew nothing about this when they made the iPod. Your computer automatically recharges your iPod when it is attached. So do most other iPod accessories. Is it inadvisable to use these things on your iPod while it is fully charged?

By the way I'm typing this right now on a MacBook using AC power.

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What I'm saying is...
by Ski_rus12 / January 30, 2009 5:41 PM PST
In reply to: But wait

I think that the Archos device should be sent back to manufacturers because of a failed component, that usually limits charging the device once fully charged. Because it is likely that this component has failed on the rare occasion, it is possible to overcharge. With MacBooks, iPods and most other devices they also would have this component that limits the charging. The Process of limiting the charge running through the battery is called 'trickle charging'. Although I would not give this as a definitive answer to the problem as ALL batteries will degrade over time, depending on the use of the product, and type of battery. This may explain the subject in more detail: http://en.wikipedia.org/wiki/Battery_charger#

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by cez6 / January 30, 2009 8:14 PM PST

Of course it will.. I knew some cp owner who charged its cp before she sleeps then when she woke up she saw her cp, very ugly because its battery burned cause of over heat..

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Conventional wisdom says...
by dexter_birdbrain / January 30, 2009 10:04 PM PST

...that to prolong the life of a battery, always charge it to its full capacity, use it and discharge it completely.
But your case sounds a little extreme. From the said 17 hrs down to 30 mins is a little too much. Either the battery's gone dead from prolonged use or its defective.

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Old Technology
by mwooge / February 1, 2009 10:03 PM PST

This used to be true for nicad batteries, which had a "memory" effect. Supposedly they fixed this, but it doesn't matter. We now use lithium-ion batteries, which don't have a memory effect.

These batteries can be charged/discharged casualy. They don't need to be fully charged or discharged.

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Yes, but...
by Flatworm / January 30, 2009 10:15 PM PST

Overcharging can CERTAINLY kill a battery. I have a very early Honda Insight where this occurred often enough that Honda issued a recall. It DID happen to me. Fortunately, Honda stands behind their products completely and now, after 150K miles I have a brand new battery pack and all the fixin's (control modules, etc.).

But nearly all rechargeable electronic devices like computers, cell phones, and whatnot have chargers that sense a full charge and quit at that point.

HOWEVER, most rechargeable batteries need to be "recalibrated" once a month or so. They should be COMPLETELY discharged, and then FULLY recharged, to maintain the longevity of their charge cycle. Try this -- it may restore your battery's long charge life.

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Not True
by ThisIsOli / February 1, 2009 1:11 AM PST

Nearly all modern devices ahve overcharge protection in, if your device was damaged write a letter of complaint about it, ask for a replacemetn and put huge emphasis on the danger of the devices overchage management system failing.

For the Record Completely discharging lithium cell batteries damages the lithium crystals inside, but occasionally a full discharge can help recalirate the recahrge manager if you have been having problems.


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YES, and no....
by kjkulp / February 3, 2009 7:53 AM PST

YES, leaving a fully-charged device on its charger will kill your battery, but it's not from overcharging....

NiCd and NiMH batteries developed memory effects that required you to fully charge/fully discharge your battery to ensure long life.....

Lithium Ion batteries, like yours, do not require you to fully cycle your battery in this manner, BUT, and this is a big BUT, lithium ion batteries have a very finite NUMBER of charging cycles, that is to say, the battery may only be charged/discharged 500 times (I just chose a random, arbitrary number there).....once you've reached that point the battery's performance will decrease until you eventually get to where you're at now.

What does this have to do with overcharging? Well, it's not "overcharging" per se - as others have noted there is circuitry in your device to prevent overcharging - the problem is that your device will:

1. charge until it's 100%,
2. the protective circuitry will interrupt the charging to protect against overload,
3. the battery will slowly drain as power is being consumed by the device,
4. the circuitry, sensing the battery as being at something less than 100%, say 99% (or whatever threshold the designers stipulated), will now allow the charger to do its thing again,
5. the circuitry stops the charge when it gets to 100%...

voila! you just burned-up and entire charging cycle going from 100% to 99% back to 100%....using my arbitrary 500 cycle life-span example, you now have 499 charges left until your battery turns to garbage......

Now, think about how many times per night/day your device is doing that...how many cycles are you using in an average day, just by leaving it on the charger overnight? You could be using up 5,6,7 (or more)cycles per night...

With cell phones you can replace the battery pretty easily and cheaply; with most rechargeable devices, however, you may have to send it to the manufacturer to be replaced or it may not be replaceable at all! (ask about SanDisk)

Personally, I hold off charging my devices until they're quite low and in real need of a charge; this goes doubly for my iPod, since the battery is not user-replaceable. The ONLY devices I've had problems with were those with which I failed to heed my own advice.

(incidentally - many laptops have an adjustable battery management feature that allows you to lower the threshold at which the charger kicks-in, just for this very purpose)
So YES, leaving your device plugged into a charger when it doesn't need charging will shorten the life of your battery.


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not your fault
by ````` / February 14, 2009 1:45 PM PST

blame the kid? send the charger AND the Li-ion battery pack back. Hope it's removable.

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