You only need a single throw switch. If it's a two conductor cable that attaches to the two battery terminals, you really only need a single pole switch.
Edit: Unless it's unplugging the battery from the charger and plugging it into the golf cart...though I really don't see any reason why it's electrically necessary to unplug the golf cart during charging (i.e. it's only necessary because the cables physically require it, not because the charger output would harm the golf cart as its parked).
I see no reason why it would not work effectively provided the switch is adequately rated. A battery disconnect switch such as is used for boats etc. would be a good choice (if perhaps overkill). The switch will be happiest if the charger is turned off before throwing the switch so that it's not trying to open when there's significant current flowing.
If you wanted to be clever, you could also wire up a relay/solenoid of the appropriate rating to the power feed of the charger so that it switches automagically as needed.