I saw no commercial battery powered usb hubs that looked suitable for my laptop. Those who own MacBook Pros know how wimpy Apple's usb ports are. The camera I used to take the pictures for this Instructable will crash the usb port it's pulled into unless I use a cable with a choke coil on it.
I frequent a local Radio Shack looking for discontinued and sale items and saw a Solio Classic on sale for about $30. They are still available from eBay for that price. The Solio has two usb ports, one for charging and the other for discharging.
The 7 port usb 2.0 hub I use sells for $5 from hi-etech on eBay. It comes with a 5v switching power supply that is intended to power it when mains power is available. The end that plugs into the hub is a common barrel connector.
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Step 1: Powered From the Solio Only
This picture shows the Solio powered up and supplying both an optical mouse and the usb hub with the laptop shut down.
The blue cable is the only thing not store bought. It was an old usb 1.1 printer cable. One end matched the Solio's power out port. I cut the other end off and using the red and black wires inside, spliced a barrel connector to it. Red is +5v and black is ground. You don't need the 2 data wires to transmit power. The blue cable goes from the Solio output to the hub's external input and powers the hub in place of the mains switching adapter.
The hub came with a short cable that brings both power and data from the laptop, so the hub is powered by both the laptop and the Solio when I'm using the laptop.
The last cable goes from the 2nd laptop usb port to the charging port of the Solio.
That means the 2 usb laptop ports, the Solio's internal battery and any power from the Solio's solar cells is available to power the hub and usb accessories. I tested the hub by pluging in an optical mouse, external wifi receiver and a 2 AA nicad/nimh usb battery charger into the hub and all worked together well.
The external wifi reciever greatly extends the range on the laptop and the battery charger will charge cells for my camera.
I keep all the parts in a resealable sandwich bag which is then put in the bag I carry the laptop around in.