I have (6) batteries for the 3dr Solo for sale. I tested these about a year ago and three of them, marked with red, didn't last more than 10 minutes and the other three lasted more than 10 minutes. I don't recall the exact flight times but the cells on the good ones were all pretty well balanced. I haven't been able to find the tool I used to measure this but if I find it before shipping I'll include it as well. These batteries have just been sitting in storage indoors for a year since I did this test. Also included are (3) original battery chargers.