To all the BlueROV2 pilots out there: Turnigy has recently (and unexpectedly) increased the size of their 4S, 10Ahr battery, available from HobbyKing. The new version of this battery no longer fits easily into the Blue Robotics 3” battery enclosure. It can be inserted but the fit is so tight that the acrylic enclosure edge cuts into / scrapes the battery external pouch and can result in safety issues.
We suggest that, if you need replacement batteries short-term, you switch to either the Turnigy 4S, 8Ahr battery or the Blue Robotics 4S, 18Ahr battery. We will let you know as soon as we have a better solution to this issue.
UPDATE 28/11/19:
To update you quickly, we purchased four Turnigy 10Ahr batteries this week and found that the dimensions fell within declared specifications, and they all fit into the 3” battery enclosures. What a relief!
We apologise for raising the alarm earlier but there could still be a possibility that you, like us, might receive a larger Turnigy 10Ahr battery. There does not appear to be any batch number or any other marker to identify one from the other, so the best we can suggest is that you test-fit any new Turnigy batteries you receive before going into the field.