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Considering using disconnectable cable penetrators. Does anyone have experience with them?

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.

We are considering switching to the easily disconnectable penetrators from bluetrail engineering https://www.bluetrailengineering.com/product-page/cobalt-series-bulkhead-connector or the ones from bluelink https://blue-linked.com/hydrovolt-nanobos.

Does anyone have experience with either of these brands or have thoughts on how to make a good choice of cable penetrator?

I’ve always been what most people consider ‘poor’, 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.

So all i can offer you is this link on how to make your own waterproof connectors.
http://www.homebuiltrovs.com/rovforum/viewtopic.php?f=15&t=1589

His youtube video is long but detailed.

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Thank you, Darrell! I’ll watch that video / browse that forum

Hi Sam,

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.

Best, Joe

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That looks nice!

How did you splice the motor cables onto the female sides of your connectors?

I just soldered on the connector cables. Each connector holds 2 motors (6 pins) then cast some silicon over it in the picture (didn’t have polyurethane)

Best, Joe

Very cool. Thank you! I am a novice at this kind of stuff

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 couldn’t 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 that’s 12 amps per conductor, or 12 amps per fitting?

Thank you for the reply! I’ll make sure to keep the current limit in mind – I hadn’t been looking at that.

We’ve just released a range of M10 bulkhead connectors

Hi Gcelec…any idea on pricing of those? Not listed on your website…

Hi Travis,

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 work…:slight_smile:

Best

My heavy model pulls a startling amount of current at full power. I don’t know exactly what peak is, but it’s 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. It’s 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 “motor max current” parameter, settable in QGC.
Bo

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Tack Bo,