AVR-Chat

A single cell LiIon battery is about 4.1V fully charged and
has used a very large percentage of its capacity by the
time it drops to 3V. 

Your circuit needs to be able to monitor the voltage and
shut down or provide other warnings when the battery
voltage goes too low.

Most cells or packs have an internal protective circuit. It
shuts off from the outside world under several conditions.
One is excessive load current. Another is when the battery
becomes discharged too far (voltage is too low). LiIon
batteries require rather careful charging. There are a
variety of ICs that will do this, but you need to do it
correctly to get reasonable performance.

A vert common cell size is 2.2AHr. You could use 3 in
parallel and get very close to your requirement of 7AHr.

The company I work for is paying about $45US (or more) for
a pack consisting of two series connected 2.2AHr LiIon
cells in small quantities (around 100 packs at a time).

Jim

On Tue, 19 Oct 2004 20:58:14 -0700 (PDT)
 Andrew Lim <normaxcite@yahoo.com> wrote:
> 
> Hi Everyone,
> 
>  
> 
> I'm looking for a good lithium battery for my project.
> I'm using ATMega8535L and this battery need to last me
> for a long time. I need at least above 7AH or capacity. I
> found Sonnenschein website that offer such a battery but
> I cant get it here locally. Can anyone there recommend
> me? 
> 
>  
> 
> How about the voltage drop for the lithium battery? Cos I
> need to maintain 3V for my uP to run.
> 
>  
> 
> Thanks.
> 
>  
> 
>  
> 
> Regards,
> 
> N2
> 
> 		
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