Specs for Molex connector wires

[mr_v]

Howdy,

I am trying to build a 4-pin to 3-Molex wire piggy tail that will sit inside my inhale lung.

What are the specs for the wires that connect a 4-pin connector to Molex connectors? Looks like 7-strand, tinned copper, 22 AWG. Do I need to look for something special, like non-silicone coating? And while we are on the subject, what is a good potting epoxy suitable for sitting inside of a rebreather lung?

Thank you!

 

[grantctobin]

To confirm, you’re trying to build one of these?

4-pin AK 3-Cell Molex cable assembly for Shearwater Petrel

MOLEX 3 cell monitoring cable To fit Shearwater Petrel fitted with the 4 pin divecan cable APPROX. 22" long 550mm

www.narkedat90.com

 

[mr_v]

To confirm, you’re trying to build one of these?

4-pin AK 3-Cell Molex cable assembly for Shearwater Petrel

MOLEX 3 cell monitoring cable To fit Shearwater Petrel fitted with the 4 pin divecan cable APPROX. 22" long 550mm

www.narkedat90.com

Yes, exactly.

I know that building own CC electronics is not for everyone, and I accept the responsibility. I also have a "legit" connector on order. But it is 100F outside and I have a spare 4-PIN with an open end, so why not tinker a bit?

Here is the problem I want to solve: Moisture creeps up the connectors and destroys the wires, so we cut off the bad part of the wire and replace the connector. At some point, you will have to replace the entire wire.

Replacing a rEvo monitor wire is a pain in the neck, and I want to have an easy solution. The connector shown in your post, @grantctobin, is one of the solutions. I am also working on another one, but it requires a 4-PIN female-to-male which I cannot build myself.

 

[beldridg]

I keep one of these in my spares kit when I got on a travel trip:

https://www.revo-rebreathers.com/product/r573-4-pin-wet-matable-connector-to-triple-molex/

- brett

 

[Whitrzac]

Howdy,

I am trying to build a 4-pin to 3-Molex wire piggy tail that will sit inside my inhale lung.

What are the specs for the wires that connect a 4-pin connector to Molex connectors? Looks like 7-strand, tinned copper, 22 AWG. Do I need to look for something special, like non-silicone coating? And while we are on the subject, what is a good potting epoxy suitable for sitting inside of a rebreather lung?

Thank you!

Kiss has switched to using silicon wiring now.

22-20awg is about the right size.

Its nothing special.

 

[mr_v]

Kiss has switched to using silicon wiring now.

22-20awg is about the right size.

Its nothing special.

Interesting, according to NASA guides, PTFE is probably better. Will reach out to some folks in the aerospace industry and keep you posted.

 

[mr_v]

I keep one of these in my spares kit when I got on a travel trip:

https://www.revo-rebreathers.com/product/r573-4-pin-wet-matable-connector-to-triple-molex/

- brett

Hi Brett,

That's what I have, too. However, the part you showed will work only for the controller part in my setup. If the monitor wire fails, I must take the entire wire out of the case/lung and put a new one in. It is about $120 and is a pain to do on a boat or in the field.

Also, the 4/5-pin cables from rEvo are always too long. Instead of buying a new part every time, you chop off the offending part and connect the 4-pin to new Molex connectors.

Cheers~

 

[beldridg]

Hi Brett,

That's what I have, too. However, the part you showed will work only for the controller part in my setup. If the monitor wire fails, I must take the entire wire out of the case/lung and put a new one in. It is about $120 and is a pain to do on a boat or in the field.

Also, the 4/5-pin cables from rEvo are always too long. Instead of buying a new part every time, you chop off the offending part and connect the 4-pin to new Molex connectors.

Cheers~

Very strange. The controller is usually a 5 pin DiveCan and the monitor is usually a 4 pin Analog (I thought at least)? I'm not right near my unit right now.

I know exactly what you mean about the cable. That is partially why I did this:

“Expedition” readiness with my rEvo

Background One of the reasons I chose the rEvo rebreather was the amount of redundancy built in. You can configure the rEvo in many different ways, but mine is configured with 5 oxygen cells. Three…

wreckedinmyrevo.com

IIRC, my 4 pin is "hard-wired" from the outside through to the Molex which poses another problem.

Can you take a picture of the end of your two cables (assuming one is for the controller and one is for the monitor)?

- brett

 

[mr_v]

Hi @beldridg,

I, too, was thinking of adding an extra cable to have 3 cables in total.

In a non-RMS rEvo there are two 4-pin connectors inside your inhale lung.

One 4-pin connector is the analog monitor.

The second 4-pin connector goes from the battery box to the cells. A controller will have have 5-pin, you're right. But the controller's 5-pin cable goes only to the battery box. The board potted inside the battery box still reads voltage using the 4-pin. That is the cable that you connect to the "piggy tail" with 3 Molex. The piggy tail converts 4-pin into a 3-Molex:

- Back wire is spliced into 3 blue wires
- Green wire is cell 1, white - cell 2, red - cell 3

The picture of my "controller" cable that goes from the battery case to the sensors is below:

If you want to further expedition proof your rEvo, consider the following.

Get one male 4-pin and one female 4-pin and PG7 gland. Take the female wire and add the PG7 gland so it faces the standing end, pull the standing end through the case and secure the gland. Connect the male wire to the standing end with soldering/potting or through a harsh environment splice box. Now you have a female 4-pin on the outside and a male 4-pin on the inside.

Then use the spare "piggy" tail to connect the male 4-pin to Molex. I.e,. now you have 2 piggy tails inside. Carry a piggy tail as a spare. If Molex connectors rot, replace the piggy tail - no need to yank the entire monitor wire out of the case.

Cheers~

P.S. You can add even more options by buying Fischer to 4-pin adapters from Martin at TecMe.de. There is a good chance that someone on the boat has a Fischer monitor.

 

[beldridg]

I actually do have a RMS unit. Below is an annotated picture of the two cables in my unit running from the outside to the inside of the exhale lung.

The 5 pin cable has a male connector that goes to a female "pigtail" that goes to the potted RMS sensor. It is expensive, but I bring a second one of those cables & potted ends with me on expedition trips which I can easily replace without changing out a cable running outside the lung (R-409):

https://www.revo-rebreathers.com/product/r409-rms-o2-board-with-5-pin-connector/

The reason I put the second 4-pin cable in is that there is no break in the cable from the outside connector to the molex. It is one continuous cable. I haven't been able to find a cable with a 4 pin male connector on one side and a 4 pin female connector on the other side. If I could find that in the appropriate length, then I could just simple use the 4 pin pigtail in the picture I sent earlier. But, it is "hard wired" into the cells.

Not sure if that makes any sense? Here is the picture: