[chbot] LiPo batteries

[Mark Beckett]

Volker

I had a conversation about this with a young lady in Australia.

The cheap RC type LiPo offer no protection against damage, and don't 
incorporate any battery management on board the battery.
This includes any thermal device to open the connection when the 
discharge is too great.

They can be overcharged, but that also depends on the methods employed, 
and the charge rate.
Some chargers feed the required voltage into the output and use the 
connections across each cell to balance the charge, while smaller 
chargers just charge each cell via the cell connector.

There were reports of batteries damaged by high impact force being 
swopped out, and catching fire later.

Some in the RC forums they suggest they should never be charged indoors, 
and to always keep a bucket of sand to smother any fire (they react to 
water).
The RC car club requires them to be charged in the special bags you can get.
However these are all higher power high discharge multi cell packs.

And then of course there are those itoys that decided to commit suicide 
and catch fire ...

If you look in the June Silicon Chip, Stan Swan has a write-up about the 
new LiFePO4 which are 3v 700mAh rechargables that are AA sized (I can 
see the smoke clouds gathering).
The other possibility is LiOn which usually have a hard case and if they 
are for phones, offer the internal battery management.

But you are right to be cautious.
In circuit charging is unlikely to be of a rate high enough to generate 
the amount of heat required.


/In the end she stuck with a 9v NiMH to do what she wanted.

/Mark


Volker Kuhlmann 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
>
>