Re: [jornada] Extending battery life (was sound debugged)

Colin:

Oh, I was looking at the power supply and saw it was 12V, so I just assumed that it was a 10.8V pack, sorry.... (I should know better than to assume....)

WiFi is so power hungry that the rule-of-thumb is that it halves your runtime. So, if you normally get 6 hours of runtime without WiFi, you'll get about three with. Now, WiFi has a "power-save mode" that shuts down the radio between sending/receiving packets. However, my experience has been the same as yours - it reduces performance to almost unacceptable levels.

As to the external battery pack - no, I've not actually constructed one, but it really isn't that hard. There's a bunch of people on eBay that sell all kinds of stuff like that, so you could pick one up that way if you so desire....

-Mark Gollahon

Colin Sauze wrote ..
> Mark Gollahon wrote:
>
> >Colin:
> >
> >WiFi is power-hungry. The uptime will be dependent on the current draw
> of the wireless card. There are cards out there that draw as little as
> 60-100mW (I'd have to check the specs), but they usually have pretty terrible
> range (say, less than 80 feet from the access point). However, one thing
> going for the jornada is that it has a 10.8V power pack.
> >
> Are those figures from the extended battery pack which HP make? mine
> (normal size one) says 7.2v 1.50ah on it.
>
> > My WiFi CF cards drain my Zaurus' battery in an hour (3.7V) where the
> same card seems to last quite a while in my Jornada (I haven't done any
> scientific tests) - about two to four pips on HP's WinCE battery monitor
> in an hour on a fully-charged Jornada battery pack versus almost exactly
> two pips on the same charged-battery and machine without WiFi.
> >
> >
> So that implies about 2.5-3 hours of wireless usage on the Jornada?
>
> If I can get it to work, i'll try and see what effect CPU clock-speed
> scaling has on this.
>
> I also notice that under CE my card (a buffalo WLI-PCM-L11GP using the
> Orinoco driver) has a power save option, which seems to reduce network
> performance a lot. Haven't yet studied its effect on battery life.
>
> >It should be quite easy to construct an external power pack containing
> 8 regular AAA or AA batteries to plug into the Jornada to probably double
> if not triple the run time of the machine. However, if you use NiMH AAA
> or AA batteries, you will need 10 of them, but the battery pack becomes
> rechargable then....
> >
> >
> Have you tried this? or is it just an idea?
>
> >Just food for thought.
> >-Mark Gollahon
> >
> >
> >
Received on Sat Feb 19 2005 - 17:34:21 EST