I just bought 4 batteries off of a friends buddy at the local airfield.. The batteries are older but he swore they weren’t used much. I have put them on the yuneec dual charger and all Four cells seam to be balanced, and they charge correctly. After charging them I flew them down to 50% and placed the batteries on the charger in storage mode. The batteries do have a lil puff to them... ( just slightly, and no sweet smell) is there a better way to test these batteries that doesn’t put the A/C in jeopardy. I want to make sure the can maintain a safe full flight duration. Right now they are in storage mode so also wondering if a deep cycle would be a wise move or an idiot mistake. Thank you all in advance
-John
-John