Answer to Question 13.

(Commissioning & Maintenance of Industrial Battery Chargers)

1. Why do the chargers not operate without a functional battery connected to the output?

Controlled battery chargers need to read the battery voltage in order to correctly limit the charging current delivered. Where a battery is unconnected or is so flat that it has no terminal voltage (and is therefore probably damaged anyway) the charger is disabled. You can overide this feature but it is not recommended.