On Mon, May 30, 2011 at 4:36 AM, V G <x.solarwind.x@gmail.com> wrote:

> This is regarding my optical guitar tuner idea, where a circuit will be
> powered from CR2032 coin cells. The circuit will be drawing (I'm guessing=
)
> around 30-50mA due to 2-4 LEDs pulsing at sound frequencies.
>
> I know that CR2032s are designed for around a 1mA continuous draw, and up=
 to
> 10mA pulse draw, but people make LED keychains out of these things all th=
e
> time and those LEDs draw 20mA or so continuously. I want to power the tun=
er
> with these cells, but I don't want the performance of the batteries to
> degrade as much due to the relatively high current draw. Therefore, I'll =
be
> putting these batteries in parallel (about 3 or 4 of them in parallel).
>
> Is this okay? What kinds of issues will there be? Will there be issues of
> the batteries charging into each other? Things like that?

Cells in parallel have well-documented issues.  When possible, it is
always preferable to use a single, larger cell.  Have you considered
using a single CR123A lithium cell?  These can be had quite cheaply
mail order (standard or rechargeable) and are capable of putting out
rather substantial current.

-p.
--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.