Self powered device on PocketPc

Archived from groups: microsoft.public.pocketpc (More info?)

Hello,
What do you think, Is it possible to use a 500mA device on the Ipaq
battery thru the 22 pins connector?


I know is that it's possible to connect a 500mA device on an USB plug
if you activate the High power bus function.

Then, I've found a schematic of IPAQ 22 pins connector, pin 13 is used
for usb detection: USB_VDD.

Please share your experience and comments,

Regards,
Olivier

Archived from groups: microsoft.public.pocketpc (More info?)

Thanks for your answer,

In this application I can't use an extra battery (I need to keep the
peripherical small).
I plan to use a "2500 mAh Lithium-Ion Polymer Extended Battery 119$"
and I expect about a 2h40 autonomy.

Two Questions:
1) Do you think that 500mA(device) + 250mA (ppc) = 750 mA could damage
my 2500 mAh ppc battery?

2) Do you think that I could get this current from the 22pins Ipaq
connector (pin 13 USB vdd) check http://xda-developers.com/connectors/


Thanks for your feedback!


"Beverly Howard [Ms-MVP/MobileDev]" <BevNoSpamBevHoward.com> wrote in message news:<#bPWV$KYEHA.3516@TK2MSFTNGP09.phx.gbl>...
> 500ma (half an amp) is going to drain the ppc's battery in very short
> order...
>
> short answer, I wouldn't do it... it's too easy to build or buy a 5v
> power pack that would keep your multi hundred dollar ppc safe... take a
> moment to find what the cost of replacing the ppc's battery and then add
> the value of your data on top of that.
>
>
> Beverly Howard [MS MVP-Mobile Devices]

Archived from groups: microsoft.public.pocketpc (More info?)

Rig something up and try it. Use resistors with suitable power handling to
simulate your additional load. Use the standard battery and use your current
estimate of the amount of power you want from the extended battery as a
guide of what to expect. Monitor the temperature of the battery area, but
Li-Ion doesn't get as hot as some other battery technologies.

Your time might be possible with a new battery but remember they deteriorate
as they age so might not be possible as the battery ages, but why not
contact a couple of battery makers and ask- they will have experts and the
knowledge.

It will depend partly on the voltage at which your pda (and also the
additional device) stop operating- they won't work to full discharge so you
don't get 2500mAh out of a 2500mAh battery. And that figure is only valid
for the way they test the discharge (temperature and constant discharge
rate)- it may not be the way you want to use the battery.

Have you looked around the internet for advice? One of the first sites I
foud was:

http://www.houseofbatteries.com/HowTo/Lion.htm
They offer design assistance -probably aimed at manufacturers- but may some
offer some advice to you. It's worth asking.


"Mr V" <olivierros@hotmail.com> wrote in message
news:f3765061.0407030400.317a6da1@posting.google.com...
> Thanks for your answer,
>
> In this application I can't use an extra battery (I need to keep the
> peripherical small).
> I plan to use a "2500 mAh Lithium-Ion Polymer Extended Battery 119$"
> and I expect about a 2h40 autonomy.
>
> Two Questions:
> 1) Do you think that 500mA(device) + 250mA (ppc) = 750 mA could damage
> my 2500 mAh ppc battery?
>
> 2) Do you think that I could get this current from the 22pins Ipaq
> connector (pin 13 USB vdd) check http://xda-developers.com/connectors/
>
>
> Thanks for your feedback!
>
>
> "Beverly Howard [Ms-MVP/MobileDev]" <BevNoSpamBevHoward.com> wrote in
message news:<#bPWV$KYEHA.3516@TK2MSFTNGP09.phx.gbl>...
> > 500ma (half an amp) is going to drain the ppc's battery in very short
> > order...
> >
> > short answer, I wouldn't do it... it's too easy to build or buy a 5v
> > power pack that would keep your multi hundred dollar ppc safe... take a
> > moment to find what the cost of replacing the ppc's battery and then add
> > the value of your data on top of that.
> >
> >
> > Beverly Howard [MS MVP-Mobile Devices]