xTenn wrote:
> <jameshanley39******.co.uk> wrote in message
> news:1167062803.386441.70030@i12g2000cwa.googlegro ups.com...
> > I'm thinking of getting an HP TC1100 . I want to use it for perhaps 8h
> > .Without access to a mains plug.
> >
> > Is it possible to get a few batteries and swap them once once each gets
> > used up?
> >
> > or is there a better solution?
> >
>
> Under better solution, at least consider getting an external battery pack
> that could be used with the wonderful tc1100 and other devices (reuse!).
> This should also be economically viable, considering the tc1100 2.5-3hr run
> time (slightly less if using 802.11 wireless ), which would require 3+
> batteries for the 8hr run, depending on intended use.
>
> Typical modern tablet PCs (especially slates in the 10.5 - 12" range) will
> consume ~12 watts/hour. An external 130 watt power supply would deliver
> 130/12 = ~10 hours, then take away for the inherent loss from heat of the
> conversion process to the required 16-19v (yes, battery places rate the
> battery storage, not output, because the first number is higher), and you
> end up with something close to your needed 8 hours - theoretically with a
> margin if you start with a charged battery in the tablet. Personal Mileage
> will vary, however.
>
> For starters check here, although there are other solutions to be googled
> for:
>
> http://www.batterygeek.net/Batteryge...atterygeek.htm



thanks, that's really useful..
Though since it's 14.8V, would I be better off "under doing" it

http://www.batterygeek.net/Batteryge...atterygeek.htm

Furthermore, that 15-21 external laptop battery, says it has a 16V/19V
selector switch. So if the tablet pc does 14.8 , that's giving it 1.2V
too much. (+ will that increased voltage increase processor
temperature? I don't want cpu fan speed to go up)

I notice that the 14-18 is more expensiev and less watts, so by your
calculation less hours. 118=12=9.8h
not bad though.. + as you say the power of the existing battery will
push that up further.

----useful info for tablet pc 1100----------
This link

http://h20000.www2.hp.com/bizsupport...eriesId=376810

Leads to this pdf
"HP Compaq tc1100 Tablet PC - Maintenance and Service Guide "

Sn extract from that pdf says

Stand-alone power requirements
Nominal operating voltage 14.8 VDC
Maximum operating power 40.0 W
Peak operating power 38.0 W

(P=IV, power = current & voltage. Cleraly current is <= 5V and the
adaptor at batterygeek site handles up to 5V and no more. So amps are
fine).