From: Joaquim Carvalho <jdc_at_x64.com>
Date: 10 Feb 2003 11:04:49 +0000

Many devices, including the Apple Powerbook Pismo use several (6)
LI-Ion batteries in parallel so I don't believe there are any
substancial problems with this solution. The Pismo batteries last
for 5 hours which is surprisingly good even for a PPC notebook.
Joaquim

On Mon, 2003-02-10 at 10:43, Andrew Jamieson wrote:
> Ive used Li-Ion batteries to power a device that drew ~2A peaks with two
> cells in series. With cells in parallel I dont understand how you would
> prevent them from draining each other due to slight differences in internal
> impedance and voltage, without external ciruitry to prevent cross flow of
> current.
>
> Which is probably what they have, but I still think its wierd :) Better to
> connect them in series and then use a step-down to reduce the high side
> current draw.
>
> A
>
> ----- Original Message -----
> From: "Stuart Tedford" <stuart.tedford_at_piresearch.co.uk>
> To: <rockbox_at_cool.haxx.se>
> Sent: Monday, February 10, 2003 8:36 PM
> Subject: RE: I've done it : FM Recorder opened :-D
>
>
> > > -----Original Message-----
> > > From: Andrew Jamieson
> > >
> > > However, it's interesting to see it uses two Li-Ion batts,
> > > but it looks like
> > > they are connected in parallel ..... _very_ wierd. Very wierd indeed.
> > >
> >
> > No, its not that weird. I've got a data sheet for a MAX1684EEE DC-DC
> > convertor IC (as used in PDA's etc) that states that a 1.5 Amp output
> > requires the use of 2 Li-ion batteries, otherwise you only get 1 Amp. It
> > must have something to do with the batteries internal resistance - if I
> > remember rightly from my EE diploma some years ago :-)
> >
> > Stu.
>
>
Received on 2003-02-10