Best way to power a mobile computer workstation.

I am in need of some power supply advice:

I will shortly need to assemble a computer workstation that can be rolled around easily and freely. It will most likely be built on top of a Craftsman tool cabinet like this. Weight is a minimal issue since I can push around 100 pounds of batteries pretty easily in something like this. The question is, whats the best power source solution to get a good solid 6-8 hours out of a laptop on a daily basis for a reasonable price (say $400 or less if feasible) that will be relatively maintenance free. I have seen small workstations at retail stores powered by what appeared to be car batteries to drive a small puter with label printers for making shelf tags and such. Would this be effective?

The cheapest option would probably be a sealed Lead Acid battery. I hear you can find them at boating supply stores and the like.

One or two deep cycle 12v lead-acid batteries should be more then enough for a laptop, even for several days of continous power. usually the 12V power can be plugged directly into the laptop power port (or so I was told).

You would need a charger, and I would think it would be best not to recharge the batteries and run the laptop off them at the same time.

It seems a bit much for hauling around a laptop though. Some manufactures sell a Li-polimer battery (IIRC about $400) thAT is a flat sheet, laptop size, that attaches to the bottom of the laptop and plugs into the power port. It gives about 8 hrs of run tme then switches off and lets your internal battery give the rest (typically 1-2 hrs extra)

What else do you need to run? some scanners can be powered off the USB port, maybe some printers too (though they consume power, they don’t consume much and only when needed, and no reason to have multiple voltages.

I think it’s safer (for the laptop) to use a 12V->115V inverter. You can get one at any automotive parts/accessory store. Even if the laptop runs on 12V, it probably expects a more stable power supply than a SLA battery.

Eh, just use a 12 volt car battery, like you mentioned and get a cigarette lighter adapter for your laptop (because some connectors are different) and cut the cigarette ligher part off, crimp on some connectors and hook up the positive and negetive wires to the battery. After a day or two is over, charge the battery.

I agree with kanicbird that a car battery is overkill. An external power supply of the type he suggested is called an Electrovaya PowerPad and is available at iGo. Also, some notebook systems can have two batteries installed, one in the CD-ROM slot and another in the usual battery slot.