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Author Topic: Can a Jolt To A Battery Immediately Discharge It ?  (Read 4611 times)

Offline neilep

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Dearest Battery-ologists,

As a sheepie I of course luff batteries. Batteries are my all time favourite portable energy cells power thing that power stuff !

Look here's a battery for a mobile phone ! (US Translation service: Mobile phone = Cell Phone sheesh !)



A Battery For A Mobile Phone Earlier Yesterday Afternoon Circa 4pm Tea Time.

Here is my question.

Can a Jolt To A Battery Immediately Discharge It ?


The reason I ask is because Dotty dropped her fully charged mobile phone (onto a carpeted floor) and it stopped working !.. during our trials and tribulations we discovered that the battery was flat !!..completely !...I can vouch that only a short while before the battery was full !

Now that the battery has been charged up again the phone is working normally !

So, what's the science behind the immediate discharge of a battery due to a jolt !



Ewe see, I don't know !...do ewe ?


Hugs and shmishes

mwah mwah mwah

Neil
My Dorty Assaulted A Battery
xxxxxxxxxxxxxxxxxxxxxxxxxxx


 

Offline graham.d

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Can a Jolt To A Battery Immediately Discharge It ?
« Reply #1 on: 10/08/2011 17:42:31 »
To my knowledge there is no mechanism to discharge a battery via any sort of impact. I suspect that the battery may have been jolted out of electrical contact giving the imprssion of a flat battery. It may have "re-connected" during the handling of the phone in order to charge it. As it was unlikely to be fully charged when it was dropped, the battery would then start to charge and the impression would be given that the battery lost its charge during the impact and then seemed to charge to a normal state when being connected to the charger.

I'm sure there are other potential (ho-ho) reasons for the appearance of the battery discharging when the phone was dropped. In any case I suspect it was just an allusion due to making and breaking contacts.
 

Offline rosy

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Can a Jolt To A Battery Immediately Discharge It ?
« Reply #2 on: 10/08/2011 19:04:25 »
The only way for the battery to discharge would be for all the stored chemical energy to be dumped at once (say if something shorted out).

A Li-ion battery can carry in the region of 0.5 MJ / kg. So a 20 g battery (which is what the battery in my phone weighs) discharging all at once would release around 10 kJ.

Since it takes 4.2 J to heat 1 g of water by 1 oC, 100 kJ is enough energy to heat about 30 g of water from a room temperature of 20 oC to boiling point (100 oC) (ignoring evaporative losses..).

That's a lot of energy, released all at once, probably more or less at a single point (since the most likely cause would be some kind of short). The thing would quite likely catch fire.

So yeah.. I'd tend to favour Matthew's explanation that there was a temporarily dodgy connection somewhere.
 

Offline Geezer

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Can a Jolt To A Battery Immediately Discharge It ?
« Reply #3 on: 10/08/2011 20:30:06 »
So yeah.. I'd tend to favour Matthew's explanation that there was a temporarily dodgy connection somewhere.

He must be one of them teleopaths ;D
 

Offline neilep

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Can a Jolt To A Battery Immediately Discharge It ?
« Reply #4 on: 10/08/2011 20:39:11 »
Thanks All ( GrahamD, Rosy & Dr Geezer) for your kind replies !

I will keep an eye on it...well..my dorty will. If there is a ' short  ' then I expect it will happen again.

Thanks again, your help is appreciated !
 

Offline Geezer

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Can a Jolt To A Battery Immediately Discharge It ?
« Reply #5 on: 10/08/2011 21:11:32 »
If there is a "short" you better have a fire extinguisher handy! Fortunately, what it sounds like is an intermittent "open".
 

Offline neilep

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Can a Jolt To A Battery Immediately Discharge It ?
« Reply #6 on: 11/08/2011 00:34:25 »
If there is a "short" you better have a fire extinguisher handy! Fortunately, what it sounds like is an intermittent "open".

An intermittent "open" ?.....why would a golf tournament invade my dortys phone ?
 

Offline techmind

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Can a Jolt To A Battery Immediately Discharge It ?
« Reply #7 on: 28/08/2011 22:50:20 »
There were (probably substantiated) rumours a decade or so ago that a certain brand of alkaline batteries would internally short-circuit if dropped or subject to mechanical shock (eg in the alarm system of a truck). This would cause the batteries to get hot, and that was the end of their life.

As others say, if a lithium/polymer battery shorted then it would get extremely hot (fire) and would probably never work again. Hence I concur re the suggestion of momentary open circuit upsetting the phone. It is plausible (though not that likely) that the momentary open-circuit put the phone into a "crashed" state which silently ran the battery down in the following hour or so... (if the battery was left in the phone that long before you did anything)
 

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Can a Jolt To A Battery Immediately Discharge It ?
« Reply #7 on: 28/08/2011 22:50:20 »

 

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