USB Powered Laptop?

Murdok09 · Post by **Murdok09** » Mon Sep 17, 2007 6:44 pm

Does anyone think it would be possible to mod a usb cable and a power "puck" for a laptop to work together? It would be a usb powered laptop. Any ideas?

lifeisbetterwithketchup · Mon Sep 17, 2007 6:46 pm

I'd say a laptop would draw way too much power. I think USB can only supply something like 500mA.

Murdok09 · Post by **Murdok09** » Mon Sep 17, 2007 6:48 pm

What about those USB powered battery packs though? They charge through DC and work, why wouldn't a direct connection work?

Murdok09 · Post by **Murdok09** » Mon Sep 17, 2007 7:09 pm

Why couldn't I make one of these?
http://buy.apc.com/commerce/storefronts ... code=apcfs

Post by **marshallh** » Mon Sep 17, 2007 7:55 pm

Look on your laptop's AC adapter, check the current draw. Probably around 3500mA. Either your battery will take several days to charge or it won't work at all.

USB devices are only allotted 150mA, they have to enumerate and negotiate for up to 500mA.

Post by **Sparkfist** » Tue Sep 18, 2007 10:07 pm

A laptop is going to draw more then 500mA, and that is the max that USB 2.0 can output. The only way you could even try that is to use multiple USB ports, but then you're really defeating the purpose.

The only laptop that will be close to running on the restraint of 500mA would be the XO by OLPC, or the eeePC by ASUS. Both are only able to get that low because they use low power CPUs and use SSD for hard drives. However they go over the 500mA limit simply by having an LCD screen.