Can't close battery tubes on 2.7 build


I’ve got the OpenROV 2.7 almost completely built but the o-rings seal so tightly that when I push the caps in they pop right back out. The only idea I have right now is to run a thread or string in to break the seal as I’m closing it, then pull the string back out. So far I haven’t found a string that can survive this.

Am I doing something wrong or are these just really hard to close?


Make sure you are removing the plungers first. Otherwise they just pop open.


Thanks but there aren’t any plungers on the battery tubes. Only the cylinder for the electronics chassis has plungers. The little holes in the ends of the battery tubes are sealed shut at the same time as the wires are potted (in steps 15 & 18 at ).


I had problems with one of my battery tubes leaking so I bought a set of 2.8 battery tubes for my 2.7 ROV. They work a lot better. But you will need to get a new shell and 4 ranger bands with the tubes to make them fit a 2.7. I suggest emailing to create a support ticket. The tolerance on these battery tubes is a know problem. Support offered to replace the battery tubes for free with another set of 2.7 tubes, But I decided to pay for the 2.8 battery tubes and support included the shell and bands for free.


Make sure you’ve chamfered the inside edge of the battery tube- if it’s a sharp edge it has a tendency to catch the O-ring and keep the cap from closing properly.

Also, note that the spring tension on the battery contacts will cause the battery tube to come open if its just sitting free. The strap that holds the tube to the ROV also compresses the tube somewhat to keep the caps on.

If neither of those are an issue here, then I haven’t got any more ideas…



Maybe it is the spring. I can double check by removing a battery then trying to close it again. Next time I work on it I’ll give that a shot. I’ve installed the straps and it seems like they could hold it shut.

Thanks for the suggestions.