When carrying out the Battery Test using a 4-channel 'scope, there's the option of using Ch C and D for an Extended Drop Test.
The Guide says:
"Channel C: Starter motor positive terminal
Using a BNC to 4 mm lead, connect the red 4 mm plug to the positive terminal of the starter motor using the appropriate clip / connector. This is the terminal that the main positive cable from the battery connects to.
Channel D: Starter motor negative terminal
Using a BNC to 4 mm lead, connect the red 4 mm plug to the negative terminal of the starter motor using the appropriate clip / connector.
Note: Most modern vehicles don’t have earth cables to the starter motor. In this case connect to one of the mounting bolts by which the starter motor is attached to the engine or gearbox bell housing, as the starter will earth through to chassis and/or battery."
Where should the ground leads of the connectors to Channels C and D be connected? Battery ground terminal?