So it seems wise to power the eBox using a separate battery. Inspired by http://msdn2.microsoft.com/en-us/robotics/bb403184.aspx, I ordered the following parts:
- A 9.6V RC battery: http://www.conrad.nl/goto/?product=227906.
- A voltage regulator to regulate the battery down to the 5V input voltage of the eBox: http://www.roboticsconnection.com/pc-38-9-5v-switching-voltage-regulator.aspx.
The next issue is how to charge the battery. I see the following 2 options:
- Directly from the iRobot when it does not need its power for its own operation.
This option would require more extensive investigation and I wonder if this is useful, considering the purpose of this project. Just a wild guess: this even might turn out to be impossible. Of course, this also decreases the overall operation duration between charges (so the iRobot has to visit its Base Station more often).
- From an external adapter that will be connected when the iRobot is charging itself.
This approach is only challenging from a mechanical point of view: How can the battery connect itself to a separate charger when the iRobot arrives at its Base Station?
Even the second, simpler, approach will require more non-software-related effort. The mechanical/physical impact might be less if the Base Station could charge both batteries at the same time. I cannot prove this with calculations yet, but I doubt that the 30W of the Base Station is enough to do that.
I took the liberty to provide a workaround by ordering a quick-charger (http://www.conrad.nl/goto/?product=224946). This enables us to demonstrate a running iRobot for 1.5 hours by charging it 'manually', which might be a sufficient solution for the time being.Any comments or questions would be greatly appreciated!