i bought a blade cx about 2 and a half years ago and it sat for the past 9 months or so while i was at college with very occasional use. Now when i fly it, it only gets about a foot off the ground. At first it would barely leave the ground and as gotten slightly higher after each charge. If i continue to cycle the battery will this go away or is my battery shot? i play with rc trucks mainly and don't know much about helis. thanks in advance for any help.