Hey everyone, yesterday I ran into a pretty big problem. Saturday I wired in a boost gauge. Its getting power from my 12v cigarette lighter. It worked fine all sunday. Monday morning it started fine. After school on monday I got in my car put the key in and all the lights came on. I tried to turn it over and it fell on its face. All the lights shut off and I couldn't do anything. I got a jump and went home. I turned it off and tried to turn it back on. It did the exact same thing. There are times that the lights come on and there are times that no lights come on. It wont even take a jump any more. Im thinking starter motor but im really not sure because no lights come on any more. The battery is relatively new.

 

This sounds exactly like your battery is on the way out. Even though it may not be totally bad, it is supplying a low voltage. Another thought is that there is a constant drain from where you tapped into the cigarette lighter resulting in low voltage. BUT, I an not good on electrics so take this with a grain of salt.

 

This all points to dead battery, as smithy said. I assume you unplugged the gauge during all this, in case it's got a short in it. Check the battery voltage, and maybe get it tested.

 

Think you wired up the guage to a always on HOT line....so you killed your battery....
Try to jump it...but let the cables sit, connected for about 15-20 minutes....longer if the cables are not VERY HEAVY....KEEP THE 2ND CAR IDLING AT A MIDDLE IDLE...
car will start up...
You need to use a voltage tester, And connect the boost guage to a circuit that is only on when the car is on...an"add a fuse" works.

 

The console cigarette lighter is on the accessory switched rail on the R53, so that won't be a drain while the car's off. Could still be faulty though.

 

Know my radar detector stayed on in my r53.....low draw...but it adds up.... especially with an older or weak battery...
Batteries loose capicity as they age....and completely draining them will sometimes permanently damaged them.
A deeply discharged battery in a mini can make it very hard to jump a Mini due to the long cable run...even when done under the hood the correct way....the battery acts as a huge sponge....

 

Interesting, my power supply turns completely off. Maybe one of ours is modified or it changed on some years.

Any any rate, eliminate the gauge as a source of the problem regardless.