We are considering making a switch to a different type of cable penetrators for heavy long term field use and wanted to see if anyone had thoughts on the options for easily disconnectable penetrators.
We do a decent amount of assembling and disassembling our AUV which uses the BlueROV2 Heavy frame for field experiments. The repeated assembly and disassembly puts strain on the epoxy-based cable penetrators causing them to develop little cracks. The little cracks can be tough to spot and end up resulting in a slow leak into the tube.
Iāve always been what most people consider āpoorā, so i tend to build my own stuff whenever possible rather than buy it. This has had the positive effect of making me a pretty good designer/troubleshooter.
I like it as modular as possible. I took this route. Found a bunch of these connectors (subcon) on ebay years ago for very little money and finally found use for them. Only thing is that it becomes a bit back heavy, but thats without lights and extra gopro in front.
I just soldered on the connector cables. Each connector holds 2 motors (6 pins) then cast some silicon over it in the picture (didnāt have polyurethane)
We have used circular Subconn connectors extensively on sonar equipment, and have found them to perform exceptionally for signal and low power applications. The locking collars are extremely strong, the gold-plated pins and sockets never corrode and can tolerate a ton of physical abuse, and dozens of different configurations are available.
The downsides are that they are very expensive ($70-$200 each, if I recall correctly) and you have to purchase them through a distributor.
Also, take note of the current rating of any bulkhead connectors you use. I fried a four-pin Subconn bulkhead fitting recently by using it to connect the battery enclosure to the electronics enclosure on our BlueROV2. The internal wires couldnāt take the full current of the ROV, and it failed internally during a long, full power dive.
Those connectors in your first link are interesting. The 3 conductor model has a 12 Amp limit. I wonder if thatās 12 amps per conductor, or 12 amps per fitting?
Thats interesting since I am taking that path atm. Have a 6 pin bulk head fitted on main enclosure and one in the battery compartment that I wanted connect with external double head. This would solve multiple issues for me, being able to disconnect power being one of them. While I am confident that the main wires and pins can handle 90 Amps, i am a bit worried about the internal wires which appear to be alu strands and not copper. According to a calculators 3 x 18awg wires makes one 13awg. I know from my past drone life that a 13 wire can handle 120 Amps bursts easily but thats with silicon insulated copper wires, not like the subcon.
So my question is, how often does a 6 thruster BlueRov require 90Amps, and what is normal consumption. Can I test this somehow on workbench running all motors (short bursts) . I would really like this to workā¦
My heavy model pulls a startling amount of current at full power. I donāt know exactly what peak is, but itās enough to soften the insulation on 8 gauge copper wire.
As a side note, but I would be surprised if a modern high-end bulkhead fitting used aluminum wires. Itās much more likely that they are using tinned copper wire, which is the norm for corrosive environments.
I use an ROV based 230 to 12 volt supply delivering maximum 25 amps.
I have also used 15 amps version with no problems using moderate joystick movements.
There is a āmotor max currentā parameter, settable in QGC.
Bo