[Al Skierkiewicz]

Win,
I am guessing you are trying to make a judgement based on usage to predict battery life. There are some methods to do that but none are very accurate since the load varies with each match. The CBA will allow you to make a calculation to get Pleukert's constant but it will take several tests at different loads to do that. Unfortunately, the life of the battery and the temperature are constants you cannot readily measure with any accuracy. I am not sure what your 50% rule is, can you elaborate? I do have some rules of thumb I consider in battery use. These are merely observations reduced to writing...
1. If you deplete the battery in one two minute match, you have an inefficient drive system. If your robot suddenly starts to do this, you have a broken drive train.
2. Don't use 6 motor drives simply because you have they are the best. I can show you more teams that eat a battery than get a benefit from the multi-motor drive.
3. If you are only using 4 motors and succumb to rule #1 above, you have chosen the wrong final gear ratio for the game. More important if you are only using two motors.
4. A battery should last long enough to drive in two or three matches minimum before running down.
5. Never trust any of the above rules, always use a freshly charged battery.
6. Even batteries that come right off the charger can be bad and fail in a match.
7. The robot is talking to you, listen to what it is telling you.

In troubleshooting a robot electrical issue, I watch the battery voltage monitor on the DS dashboard. If you are driving and the voltage is falling to 6 or 7 volts you are going to have a problem soon. At sustained voltages of less than 6 volts, the regulators in the digital sidecar start to drop out, killing drive to your robot. At less that 4.5 volts, the power supplies on the PD cease causing the Crio and/or the radio to reboot. There are a number of reasons that could cause this. Too much load current, dead battery, too long of a #6 wire run, improper crimp or loose connections on the battery, the main breaker or the PD, will all contribute to low voltage.