1st Gen R53 Cooper S HELP! Mini drawing 17+volts at idle

So tonight everything was fine on the way home from work until i get on it after a semi turns from in front of me. After I let off from getting on it everything starts to flash/flicker(abs, traction control, tire pressure, ect) and the radio flicks off/on as well as all the cars lights, including interior and exterior. The hazards worked fine though the whole time. (Seeing as I was using them at this point) so I drive to oriellys in town(they are closed) have to drive 20 minutes to the next town where i live and they are open. By the time I got there I smell something like eggs almost and pop the hatch and open the carpet to inspect the battery and all this smoke pours out of the battery area. There is gel acid all over the tray, I had to replace the battery. Which was funny this whole time while i was changing the battery and the key was out of the ignition all of the gauges were sitting funny, speedo was at 13mph, fuel was at a 1/4 and temperatures were at half. When I was driving the engine temperature was at full like max it will go to and the fuel was at half. But I really only had 1/8th a tank of fuel.

So New battery in the car(before i even put the key in the car all the gauges go to 0 like they should) so I start it up and its all fine until I start to drive it, then it does it again. As I am on the throttle everything in the car is off basicallym, then when I let off the throttle and press the clutch(so the rpms drop since its not off the throttle that does anything, its actually the rpms dropping down to idle).

So to me it definitely seems like the alternator is overcharging the system and everything is shutting down, all the wiring is overheating from the extra voltages. I am pretty stumped, I have never had this problem before. I have no idea what fuses could be in here that need replaced. The car also decided to melt the bank 1 o2 sensor wiring, their is exposed wiring on the harness that is contacting itself. Could this have anything to do with the power steering pump being pulled out of the car?

 

Thanks, perhaps you know if these relays are in the right order? I remember moving them around and I didnt notice until today that one has a different number.

 

Thanks guys for your replies! Now I am not so sure if it is the voltage regulator. This morning when I went out there to check on it again the battery was at 8.5volts when i do remember a clear 12.5 last night before i left it for the night. So Something is drawing the power when the car is off and then shorting it out when the car is on. Sounds like a ground is contacting a positive connection somewhere. I have no idea what caused it, I just remember this all happened after I got on it so maybe that shook something loose?

 

I jumped the car, and it had 3 codes. 1 for the 1st o2 sensor said current fault, then another for speed sensor, current fault and then the last one was also powertrain and something about catalyst below threshhold. So I know the 1st o2 was from the melted wiring, and the cat is hollowed out now so definitely why the 3rd code. But the speed sensor?? Why is the speed sensor having issues? it actually worked fine when I drove it around, so I reset the code and drove it again and it was fine. Code did not come back. That jumper box up front where all the power cables plug in together is melted and gone. I touched that when I turned the car on about 10 seconds into it idling and it already was able to burn your skin. This is getting way too hot. So I am going to replace this box, and then replace that bst switch thing in the trunk.

 

I replaced the battery and the mini still reads 18.5v at idle. All of the cars internal computer systems are going hay wire until I flip on the headlights and the blower fan to max and the volts drops to 15.5 then everything acts normal. That wire at the jumper box up front is still extremely hot.

 

Im just trying to figure out why getting on it would cause my alternator voltage regulator to fail fi thats what happened. If the negative cable on the battery came off while driving the car and u got on it would the alternator not be able to read the voltage of the battery and put out max volts then overheat itself and screw itself up? The optima battery boiled

 

Spent the night changing the alternator. it wasnt too bad of a job. Got her all put back together and started and volts were at 14.3 on idle. Drove her about 10 miles around town and had absolutely no problems. So I suppose the alternator was bad and that was my problem cause the new one seemed to fix everything,