I just had a battery put in a couple of months ago and my car has been doing fine since then.

Tonight, i drove home from work in pouring rain, turned off the car, got out, waited for my wife to finish getting ready (20 minutes), then got back in the car. I put the key in, all the lights started up like normal, then i turned the key and ALL power went from the system. I mean ALL power. The gauges were halfway between where they were and where they were going (car was stll warm, the temp gauge stopped at the 1/4 mark, fuel was stopped at 1/2 mark and it was 3/4 full when i got home).

I only had a few minutes to check fuses, but nothing was apparent. I have not had a chance to dig in on the battery and PRAY that the cable had worked itself loose but i don't think that's an issue.

Any ideas on what to check or what could be the culprit? anyone have anything like this before?

 

Though batt is relatively new, I'd still have a health check on it & inspect all grounds/contacts. Had a new batt die on my mini + a bad ground wouldn't get my rav started after leaving it a few minutes.
Hope you get it sorted.

 

any tips on how to get access to the battery (cooper S, no power to the back hatch)
2003 model.

 

Open the hood, apply 12v from another battery via jumper cables to the Pos. terminal next to the air intake box, Neg. to good ground on the body. Suggest you check your engine ground strap attached to the upper engine mount on passenger side. The car won't start if it's loose.

 

where's the ground strap supposed to be attached? would it have popped off after a drive and when i just tried to start the car? it didn't even get to the point of turning over

 

There should be a release cable under the rear seat, it's located around the middle but some early models didn't have them

 

i think mine is an earlier model...i've looked and looked for a release cable and never found it.

 

........

Then open the hatch.

 

I actually read that into the original post. funny

So it turns out that AAA is great on call service when you're stuck in 25F weather...not so great at tightening the screws that keep the cables on the battery. Thankfully, the problem was a loose negative terminal cable.