[non-FIRST] External laptop battery pack?

[JBotAlan]

Hello all,

I have a series of ponderings leading to a question or two.

I bought myself an Asus Eee 900A (it is a strange, lesser-known model; apparently it is one Best Buy sold for some time) and its battery life right now is something like 2.5 or 3 hours...with the wifi turned off, screen brightness turned down, and not doing anything to tax the processor. When I am actually using the machine, the battery life drops to like 1.5 hours. That's not long enough for a full class for me. Therefore I am trying to extend it.

My original thought was to take 8 D cells, put them in series, and that would equal 12 volts. Except it might not. And I really don't want to burn up my Eee. I would put a regulator in there, except the highest-capacity 12v regulator I know of has a 1-amp maximum, and my Eee wants 3. I know that's a maximum, but if I don't plan for it, I will definitely reach it.

I'm not sure what to do; any advice anyone could offer would be great.

Thanks,
Jacob