I have a 2000 Cherokee and i was using it all day. I washed it then drove it onto the side of the street where I parked it. Came back 5-10 mins later, put the key in the ignition, car wouldn't start, had no power. Opened the hood, looked to see if there was anything wrong, and closed it. Put the key in the ignition, started perfectly. What could have happened?

 

A bad battery connection most likely.

 

x2, this is a common issue. Check your connections. I changed my battery connections all together because they were original and bad.