I'm new to electric flight and all the nuances of LiPo batteries. I have a 3S with maybe a dozen cycles on it. After the last time I used it I brought it back up to storage charge without issue. Now one cell won't take a charge at all. The charger gives up with an error that I think means that cell isn't increasing in voltage ("BALANC DLTA V", which isn't discussed in the manual). That cell does show up when I connect the battery to a tester, so I don't think there's a broken connection on the balance leads. Is the battery toast or is there something I could try that may get that cell working again?