I had an earlier post about this. Phantom Vision that would, on and off, flash abnormal battery communication, fly with caution and invalid battery signal. I ziptied the bird to an outside table so i could "work" on the battery while props spinning, etc waited till i got invalid battery signal or abnormal communication signal. reached under props (easy to do since it was on small diameter table, and pressed battery "in" at different angles. when i press firmly from the SIDES of the battery, the battery signal went away. thus, clearly, the problem must originate with contacts. this is not a new finding, per se, but i think i've confirmed that issue for my situation. so, how to fix? solder a tiny drop on the contacts that meet the spring loaded pins? solder a tiny amt on the pins themselves? trip the plastic collar on the battery so that it will, hopefully, seat deeper? run strong duct tape around battery to seat it more firmly?