My first kombucha failed-it developed mold around Day 4. I waited a week to ensure that what I was seeing was indeed mold, and it was.
A friend gave me another, fresher SCOBY and I made up a new batch of sweetened tea yesterday (Aug 15). I used 3 (2-cup) teabags and a cup of sugar in 3 L of water. I cleaned out the sun tea jar and set the 2nd batch to sit on the counter. I'm not covering it up this time, since it's not really in direct sunlight anyway.
I will check it in 4 or 5 days. Hopefully this one takes!