I've just put in an order for an ATiK 16IC and after placing the order (isn't it always the way

) I started to think about whether I should have gotten the AC adapter.
According to the spec, even though it has a jack for external power, the camera draws it's power through the USB port. Will the USB be able to supply enough power to the Peltier. I don't know much about them but I would have thought that cooling to 25d below ambient would require a fair bit of juice.
Can anyone (DP, bird Gary B) enlighten me on this.