[MrForbes]

More than 9/10 times it is a loose connection at the other end of the battery cable wire...either the terminal on the battery is loose, or the terminal on the power wiring at the 120a breaker or the PDP is loose. (and in the old days, it would be one on the complicated distribution terminal blocks).

A RI caught a slightly loose breaker connection on our robot in the pre-Elims reinspection...thanks!