Re: 8 Batteries -or- 10 Batteries at Competition
 

Two measures of battery performance: State of Charge (SoC) and Capacity.
Load testing measures capacity, and assume around 100% SoC
(Proper) voltmeter testing measures SoC, and will not detect a "bad" battery.

Anyway, to the original question:
We use around 10 batteries (plus 1 or 2 for testing, too weak for competition) with 6 chargers and one person in the pits dedicated to nothing but batteries. This gets us through qualifications and eliminations all the way through finals.

If we went to Einstein we would also be OK. In a pinch we could surely borrow a few charged batteries from an alliance partner or someone else at the competition.

Rather than some kind of calculation, we've found over the years that this is sufficient. Having more would be good, but not required. That's our experience so far.

Once a battery fails to load test normally, we retire & replace it.

Re: 8 Batteries -or- 10 Batteries at Competition
 

I believe we bring 8 batteries & 6 chargers normally, but do keep in mind that however many batteries/chargers you need is contingent on how power-hungry your robot this year. Last year, we could run 2 matches on one battery in a row without any appreciable change in quality of performance, but this year, our battery was practically drained by the time we had to deploy.

Nonetheless, think about how many batteries you need going to competition, then bring 2-3 extra. It never hurts to be prepared.

Re: 8 Batteries -or- 10 Batteries at Competition
 

This is _great_ info... THANK YOU _all_ for your help!!