is it possible to have a computer take power from a battery (a laptop one) and run for some time? the system would probably be some core duo thing - most of it will be low power comsuming
No, the best way to do what you're thinking of is to get a car battery and run an invertor off it. Is this for some sort of UPS system? If so, get a cheap car battery charger , connect it to your battery, then run the invetor from it.
This could only feasibly be done with a very low-power system. Laptop batteries, from memory, top out with a maximum capacity of about 60Wh, meaning that you could pull 60 watts from it for a maximum period of only one hour (or 1 watt for 60 hours, etc.). There is another big problem though, and that's regulation. Different makes of battery output a variety of voltages, usually 10.8 volts. You need circuitry capable of taking in this and outputting the various voltages (3.3V, 5V, 12V) needed by the computer and also with the capability of I/Oing signals that the ATX PSU will, such as PS_ON and PWR_OK. You could tie these to rails to save time, but it will still be a daunting task. Even then, if you can find a motherboard designed to accept a Core laptop processor and a case for laptop hard drive, you might be able to get 2 hours of battery life out of it. Is that really worth it?
I think you'll be better of looking for a DIY UPS system, made of a large car battery, a power converter (12v to 115 or 230, depending on where you live) normaly used in cars to power wall socket powered equipment and a large AC-DC 12v converter. Tie the AC-DC converter to the battery to charge it, then connect the power converter to the same battery. If the power goes out, power will be used from the car battery, and its converted to the same voltage of the wall socket. As soon as the power comes back on, the AC-DC converter will take over from the battery, powering the powerconverter and charging the battery. If you use a large enough AC-DC converter it can charge a lot of batteries at a time, so when power goes out, you have hours of time before the battaries ar drained. take a look here too --> http://www.dansdata.com/diyups.htm small edit: works the same way as a dualconversion UPS. You can get an old UPS that can generate enough output power from battaries and then make the cables longer and externaly attach a couple of car battaries, for more runtime. (an old SmartUPS 700 shouldnt cost too much, and with some 30 amp batteries it should give you 2 hours of runtime.)
