[chbot] LI Ion battery 0v

[william]

there is a video on the eevblog that talks about charging LiIon cells, i 
believe constant current until the cell reaches around 2.7 then constant 
voltage (4.2V IIRC)
if the cell is a dead short then you may have to use a high current (gel 
cell, Pb H2SO4, rectified heater supply from a MOT ) supply/battery and try 
blowing the short out (PULSED)

-----Original Message----- 
From: Charles Manning
Sent: Tuesday, November 15, 2011 1:11 PM
To: Christchurch Robotics
Subject: Re: [chbot] LI Ion battery 0v

On Sunday 13 November 2011 10:21:36 Marshland Engineering wrote:
> Hi I purchased a large 3 cell Li-Ion battery pack off eBay. After one use,
> one cell is at 0v. The other 2 are 3.7. Can the cell be kicked back into
> life ? My guess it is internally shorted.


Were they in series? If so then the 0V cell has likely been reverse 
polarised
with can be seriously bad for the cell.

A recharger likely won't want to try charge it until it gets to a reasonable
voltage. Try trickle charging at a few mA for a while and see if that gets 
it
back into charging range.

NB Given the bad things that can happen with Lithium in the picture, only 
fool
around with these things outside and away from anything that you care about.

-- Charles

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