A method for characterizing the health of a rechargeable battery includes measuring initial condition parameters of a rechargeable battery prior to the battery being placed into service. The voting unit of the ballot authentication system can be configured to verify and confirm that the various security features embedded in andor printed on the ballot is correct for a particular precinct of an election. A distal end of the sub-chassis has a sub-chassis latch that secures the sub-chassis in the second end of the chassis with the proximal end engaged against the second surface of the midplane.