Can a handphone be overcharged?

ugh

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Feb 6, 2000
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Hi,

Not sure whether this is OT or not, but can a handphone's batteries be overcharged and cause its lifespan to decrease? I'm using a Nokia phone. Anyone knows whether they have a cut off when the battery is fully charged?

 

dkozloski

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Oct 9, 1999
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You can't overcharge the battery with the charger provided, no matter how hard you try.
 

AndyHui

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Oct 9, 1999
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Heh...I can automatically tell that you are from Singapore or Malaysia since only people from there use the word &quot;handphone:...:p

Which model in particular? The ones with the Li-ION batteries are less susceptable to damage by overcharge, but most of the later models do have a cut off, or trickle charge.
 

ugh

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Feb 6, 2000
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<< Heh...I can automatically tell that you are from Singapore or Malaysia since only people from there use the word &quot;handphone:...:p >>


Oh? Well, yeah, I'm from MY :) What do other pple can it then? ;) I presume you're either from MY or SG too?



<< Which model in particular? The ones with the Li-ION batteries are less susceptable to damage by overcharge, but most of the later models do have a cut off, or trickle charge. >>


I'm not talking about a particular handphone, but for all hand phones actually (I'm using the Nokia 8148 BTW, a REALLY old one {g}). Uh... I'm not sure whether the phone I'm having has the cut off thing or not. Isn't there a way to check at the dealer's website or some other info site?
 

AndyHui

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Cell phone in the US, Mobile phone just about everywhere else.

Generally manufacturers don't tell you whether or not the charger is auto-cutout, but you can see from the charging meter that once it is full the charging stops.

I am not from MY but my GF is.
 

ugh

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Feb 6, 2000
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<< Cell phone in the US, Mobile phone just about everywhere else. >>


Ahh... Forgot about those :eek:



<< Generally manufacturers don't tell you whether or not the charger is auto-cutout, but you can see from the charging meter that once it is full the charging stops. >>


As far as I can see, all the phones that I've used stop charging when the batt is full. But there's always this worrying that either:

1. The phone will explode if overcharged or
2. The batteries will wear off real quickly.

I need to make sure coz the batt in my phone dies off really quickly. Should be so considering it's a 3-4 year old phone :D



<< I am not from MY but my GF is. >>


Cool. And you're in US?
 

AndyHui

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Oct 9, 1999
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Nope, I'm from Hong Kong, but I live in Australia.

Batteries rarely blow up. If you have a phone from ~4 years ago, it is most likely using an NiMH (Nickel Metal Hydride) battery, that is subject to memory effect and capacity loss over time. You should consider buying a new battery if you can find one, or just get a new phone.
 

paulzebo

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Can a battery be overcharged? Yes. It's called thermo runaway. Basically, when the temp of the battery gets too high for the design, the battery keeps accepting a charge. Explode? No, but it will decrease the life of the battery. It's typical in hot climates such as here in Phoenix. If you were to plug your phone into the car charger and leave it on a 100 degree day, with the windows up, the inside temp of the vehicle typically will hit 150 degrees plus within an hour. Thats way too hot for most batteries. We see it in auto batteries all the time. A seven year battery typically will last no more than three. I made the mistake of leaving my phone in the car charging overnight when the low temp was over 100 a couple years back. The next morning the battery was extreemly hot and would hold a charge no more than five hours.
 

ugh

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Feb 6, 2000
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<< Batteries rarely blow up. If you have a phone from ~4 years ago, it is most likely using an NiMH (Nickel Metal Hydride) battery, that is subject to memory effect and capacity loss over time. You should consider buying a new battery if you can find one, or just get a new phone. >>


Surprising enuf, the batt in my phone is Li-ion. Well, i guess it's about time for me to get a new batt (new phones are all the same, they depreciate too fast and offer the same features anyway, so why bother). I hope it will last as long ;)
 

ugh

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Feb 6, 2000
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<< Can a battery be overcharged? Yes. It's called thermo runaway. Basically, when the temp of the battery gets too high for the design, the battery keeps accepting a charge. Explode? No, but it will decrease the life of the battery. It's typical in hot climates such as here in Phoenix. If you were to plug your phone into the car charger and leave it on a 100 degree day, with the windows up, the inside temp of the vehicle typically will hit 150 degrees plus within an hour. Thats way too hot for most batteries. We see it in auto batteries all the time. A seven year battery typically will last no more than three. I made the mistake of leaving my phone in the car charging overnight when the low temp was over 100 a couple years back. The next morning the battery was extreemly hot and would hold a charge no more than five hours. >>


Is the thermo runaway possible on all batteries or only on some? I don't charge my phone in my car, but I in my house. However, at times when I leave it charging for too long, the batt gets rather hot. Not as hot as what you experience; but hot enuf to cause some concern.