[chbot] LiPo batteries

[Mark Atherton]

How timely.

I am pretty sure that Li Ion and Li Po have similar issues:

Been given a small pile of Li Ion batteries, and 
bought some http://www.ebay.com/itm/260841670123

Briefly, if you over charge them they do occasionally explode

If you over discharge them then they can lose capacity in a real hurry

There is a difference between 4.1V and 4.2V 
cells, beware - this is absolute max terminal voltage.

The boards above have 5V in, 5V out and cell 
protection, so the cell is taken out of circuit 
of over-charge or over-discharge imminent. I do 
plan to run one of these up carefully and see how they behave.

Li Ion can deliver large currents, so an in-line fuse is mandatory.

 From Wikipedia
         Li Ion specific energy 100–265 Wh/kg
         Ni Mh specific energy 60–120 Wh/kg
         Ni Cd specific energy 40–60 Wh/kg

The good news is there is a lot in a lightweight package

The bad news is that there is a lot in a lightweight package

If treated with respect, they behave well -- these are not for the unwary.

In terms of burning your house down, you probably 
already have lots of these units in your phone, laptop etc. already.

If you have concerns about safety, stick with 
NiMh the older types have self discharge 
problems, but I don't think they will blow up (a 
function of internal resistance and available energy).

Mr Harris is one of (or The) resident expert, and 
I await comments from him on this brain-dump.

-Mark


At 11:17 a.m. 17/05/2013, you wrote:
>How safe is it really to have LiPo batteries around the house?
>
>I was thinking of using some of the 1-cell hobbyking offerings as backup
>for some microcontrollers. Then I read the reports of what these
>batteries do to people, like burning the house down, but I don't fancy
>having the chemical smoke of one of them's guts in the house either.
>
>What would people consider to be safe handling precautions in terms of
>charger, charge location and storage? What about charging them
>in-circuit?
>
>Thanks,
>
>Volker
>
>--
>Volker Kuhlmann
>http://volker.dnsalias.net/     Please do not CC list postings to me.
>
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