well that is unfortunate but you only have a couple of choices
1 - remove the basket
2 - find another 24v source, then locate the battery pack connector, unplug the battery pack, then temporarily jumper it onto the truck side battery connector where the batteries connect to the machine.

If your charger is not starting because of low or no voltage then jumper the power source across the battery connector on the battery side to boost their voltage so the charger sensor can see enough voltage to allow the charger to start up.
I have done this before when batteries get too low to allow the charger to start, it fools the charger enough to allow it to turn on and start charging the batteries. Once they get enough charge in them then the external jumpered power source can be removed.