What you want to do is slide a battery through the battery spots, if you're lucky enough it will place in 1 of the spots and other 1/2 spots become filled with a phantom battery, if you're not lucky however it will just do nothing. Those phantom batteries act as real ones, therefore you're able to save ~10 seconds of going around the 2 spots collecting the other 2 batteries required. If you are able to get Buzzer to activate but the gate doesn't open, then you just have to click on the real battery and place it back into the spot, the gate will open after that.

There isn't really a consistent way to do this so you just have to be lucky.