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Short circuited tablet battery?

Mmystere68

Nov 9, 2015
9
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Nov 9, 2015
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Hello, i was having some trouble charging my device and tried to charge it by connecting my battery directly to a 5 v supply.i accidentally connected it in reverse and i saw a few sparks so i immediately removed it. now when i plugged my battery back...my tablet shows charging...even if its unplugged.
my tablet is a nexus 7(2012) you may want to check the battery. also i added a screenshot below what i did. dou you think its worth buying a new battery? i hear a faint noise when i connect the battery back to the main board.....noise was previously unheard. Please explain to me as simple as possible...i know nothing about electric circuits/batteries etc
 

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Gryd3

Jun 25, 2014
4,098
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Hello, i was having some trouble charging my device and tried to charge it by connecting my battery directly to a 5 v supply.i accidentally connected it in reverse and i saw a few sparks so i immediately removed it. now when i plugged my battery back...my tablet shows charging...even if its unplugged.
my tablet is a nexus 7(2012) you may want to check the battery. also i added a screenshot below what i did. dou you think its worth buying a new battery? i hear a faint noise when i connect the battery back to the main board.....noise was previously unheard. Please explain to me as simple as possible...i know nothing about electric circuits/batteries etc
I stopped reading shortly after the red highlighted part.
Never do this. Ever. With any battery.
Batteries have specific charging characteristics, and if you ignore them you can cause damage to the battery, and considering the chemicals used in the batteries, you don't want them to vent or rupture.
You may have damaged a number of things by doing so.
Some batteries have a small controller that is used to protect the battery from deep discharge or excessive charge. That could be damaged in addition to the charge circuit or any other part of the tablet.
It's not worth replacing parts. You broke it, and will most likely need a new main-board unless you have the skills to replace some of the surface mount components on the board.
 

BobK

Jan 5, 2010
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You are lucky it did not catch fire. If you did this with the battery out, just replace the battery. If it was I n the phone at the time, the phone was probably damaged.

Bob
 

Gryd3

Jun 25, 2014
4,098
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You are lucky it did not catch fire. If you did this with the battery out, just replace the battery. If it was I n the phone at the time, the phone was probably damaged.

Bob
Picture looks like it was done with the battery removed.
If this is the case, the OP can be considered lucky... Hopefully nothing else is damaged...
The part that concerned me is the device thinking it's being charged when it's not.
 

Mmystere68

Nov 9, 2015
9
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Nov 9, 2015
Messages
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Thx fr the reply guys...... Well the tablet turns on with the remaining charge left(about 60% remains)...and can be used normally.... As soon as i plug usb cable to charge (usual way of charging) it starts saying charging(doesn't actually charge though) and doesnt stop, even when unplugged and i hear the noise.....i disassemble the board, battery and the noise is coming from the battery not the main board.....i guess a battery replacement may fix the problem...
 

BobK

Jan 5, 2010
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Ah, you probably zapped some of the protection circuitry in the battery. That explains why no fire!

Bob
 

Gryd3

Jun 25, 2014
4,098
Joined
Jun 25, 2014
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4,098
Thx fr the reply guys...... Well the tablet turns on with the remaining charge left(about 60% remains)...and can be used normally.... As soon as i plug usb cable to charge (usual way of charging) it starts saying charging(doesn't actually charge though) and doesnt stop, even when unplugged and i hear the noise.....i disassemble the board, battery and the noise is coming from the battery not the main board.....i guess a battery replacement may fix the problem...
Ah, you probably zapped some of the protection circuitry in the battery. That explains why no fire!

Bob
Consider yourself lucky and lesson learned.
Lithium based batteries can be quite violent if they rupture. It's also incredibly common for those batteries to have a protection circuit built-in to prevent major accidents.
Other battery chemistries do not have this protection though. Please always be careful charging batteries and always use a proper charger. The only way you should 'do it yourself' is if you do a bunch of research prior and learn 'how' to charge a battery.
(This will include information like how much current you can charge with, how long you can charge at that current, temperature limits, possibly float charge levels. You will need to understand the difference between a current supply and voltage supply. You'll get there, but don't jump the gun)
 
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