Disconnecting the battery

This might sound simple but im still unsure about it, I have a Mondeo MK4 and the battery is getting drained by the radio and instrument panel but until i can get it fixed i thought a temporary solution would be to just disconnect the battery terminals when im not using it overnight, that way the battery wont get drained because theres no power. Would i need to disconnect both the negative and positive or if i just disconnect the negative will it be safe to leave the pos connected and it shouldnt drain?.

Thanks in advance.

Just negative

1 Like

Brilliant, thank you. only problem now is the battery is housed in a slide in box with the negative covered haha bit of a pain

Well then disconnect the positive.

A web search or a trip to the parts store will let you find a on / off switch to install on your battery like the classic car collectors use.


The reason it is best to disconnect the negative (one of Car Talk’s puzzler questions) is that it is less likely you’ll short out the battery with the wrench and burn yourself or create a big spark. But if done carefully removing the positive cable is just as good of solution, at least for preventing battery drain. One caution, sometimes disconnecting battery will cause certain “remembered” settings to be forgotten. Radio station settings, door lock and window position settings, even the proper engine idle parameters.

1 Like

This is riskier for a novice. One wrong move will create a dead short.

If you know the circuit causing the problem, pulling the fuse is probably easier and safer than disconnecting the battery.