Hi, I bought a used modded R53 Mini Cooper S with a bad engine this summer. I replaced the engine with one in good condition and low mileage, following a mod mini video. Since, I’ve had issues with the battery draining quickly. The interior of the car was stripped out, and there are a lot of loose unplugged cables running to where there used to be lights, speakers, etc. The AC unit was removed by the previous owner and the power lead is just hanging.

My thought is that these loose cables are causing the power from the battery to drain. That or the battery is bad. Looking for advice on my theories or other thoughts on what the cause could be, as I’m very inexperienced when it comes to car electrical work.

Hoping you all have some ideas or know of threads that I could read!

 

A disconnected cable is an infinite impedance, so it shouldn't draw any power. A dead short from a bare dangling wire is obviously a problem though. I don't know if any of modules would stay awake because of a missing input.

The easiest thing to do first is to test the battery. Then I would hook up an ammeter and if there's a parasitic draw start pulling fuses to find the offending circuit.