Patrick, you might have a hard time finding a battery suitable for
delevering all required voltages.

If I look at the ATX spec (I presume you are using a standard atx
motherboard) you'll have to provide next voltages:

+3.3V  +/- 5%   (with remote sensing to compensate for voltage drops)
+5.0V  +/- 5%
+12.0V +/- 5%
-5.0V  +/- 10%  (needed for serial ports, sound etc.)
-12.0V +/- 10%  (needed for serial ports, sound etc.)

power distribution for a 160W configuration would be approximate:

+3.3V   between 0.3 and 14A
+5.0V   between 1 and 18 A
+12.0V  between 0 and 6 A

(from http://www.enhanceusa.com/documents/ATX12V.pdf)

So it actually does really make sense to use a DC/DC convertor (most likely
some inverter) to transform the battery voltages into what's needed for the
board.


Frank.


On Tue, Apr 30, 2002 at 09:18:42AM -0700, Paul Winkler wrote:
> On Tue, Apr 30, 2002 at 07:39:26AM -0700, Patrick Shirkey wrote:
> > Another question that I'm unsure of is whether having a battery that is too 
>powerful for the machine is going to cause problems or is that not possible because 
>the machine will just run for longer? Or is that where an inverter comes in?
> 
> 
> no, an inverter is if you want to generate AC from a battery.
> You don't need that.
> 
> Quick electricity primer: Voltage needs to be correct for
> your devices. Too little and they won't work. Too much and they'll fry.
> Current is different: the device will draw as much current as it
> needs from the power source. It's determined by the formula
> V = I*R, where V is voltage, I is current (amps), and R is the resistance
> (ohms) of the device. So if V is right, and your power supply can
> produce *at least* I, then you're fine.  
> 
> --
> 
> "Welcome to Muppet Labs, where the future is made - today!"

-- 
+---- --- -- -  -   -    - 
| Frank van de Pol                  -o)    A-L-S-A
| [EMAIL PROTECTED]                    /\\  Sounds good!
| http://www.alsa-project.org      _\_v
| Linux - Why use Windows if we have doors available?

Reply via email to