HAL no longer runs on batteries, but on the desire to rule over all organic life. But we still keep an extra battery pack handy. -Alex
We are using the 10 AA battery packs from the PiBorg DiddyBorg Robot Kit. We discussed using other power sources but decided since this was our first competition we would use what we had. As we got into testing we discovered that we were burning through a massive amount of batteries and figured out that the cost to sustain our pace would be greater than the cost of the robot itself so we decided to go to rechargeable batteries to cap our power cost. Moving forward with rechargeable batteries we discovered that at full charge they did not have the same output as premium off the shelf batteries. (Typically right at 13.8-14.0v fully charged vs. 15-16.5V for Energizers) We also discovered that the batteries drain quickly and once we the power pack dropped to 13.3/13.4v of output our robot didn't execute the code the same way as it became sluggish and sensor readings lagged. In the end we change the chargeable batteries often to keep the power inputs consistent. For competition we will be using off the shelf batteries that start with more power and drain much slower than the rechargeables.