I looked into this a while ago and it seems common practice but make sure=20
you use new cells each time your replace them so they are both approximatel=
y=20
at the same charge level.

My kitchen scales use two CR2032 in parallel and they last a year or so at =
a=20
time.

I desinged a product many moons ago which used three SR41 in series to puls=
e=20
a white LED at around 40ma at various patterns via a 10F series=20
microcontroller - a tantalum capacitor in parallel with the cells (after an=
=20
on/off switch) provided enough current to pulse the LED at the required=20
current while the cells charged it up when the LED was off.

Dom

----- Original Message -----=20
From: "V G" <x.solarwind.x@gmail.com>
To: "PICLIST" <piclist@mit.edu>
Sent: Monday, May 30, 2011 9:36 AM
Subject: [EE] Coin cells in parallel


> Hey all,
>
> 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=
=20
> 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=20
> tuner
> 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=
=20
> 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?
> --=20
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist=20

--=20
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