1. EURO connector
With EURO connectors, a distinction is made between male and female battery connectors. A female connector, socket, for the battery and a male connector, for the machine and the charger. This way you will never be able to connect the charger directly to the machine.
To prevent you from connecting a 48V charger to a 24V battery, coding pins are used. This can be mounted in the plugs so that a battery connector with coding pin, only fits on a different battery connector where the coding pen was mounted in the same way. On each coding pen, there is an indication of the voltage that you can read on the plugs
There are also different colors of plugs that each provide an indication of the type of battery for which they are appropriate.