Waterproof while not mated connectors - Page 1
Forum section: electronics / projects

author: jeduffy
author_rank: Contributor
timestamp: May 10, 2018, 05:47:26 am
content: Does anyone know of a connector that is waterproof while NOT mated (including to a cap/cover)? Looking for about IP67, at least two contacts, that can take at least 20A. I've googled around a bit and was only able to find some low-current connectors (2A) that are not thousands of dollars.Doesn't have to be particularly waterproof (i.e. strong rain and dropped in a puddle, but doesn't really need to take any submersion depth, and will only be exposed for a couple hours at a time, and have time to dry out in between). I have seen things like grease or oils used to coat contacts on normal connectors, but this needs to be able to be mated and demated repeatedly (hundreds of times) without compromising the waterproofing. Application is for a ruggedized ~50V battery pack.edit: wording wasn't completely clear, the "odd" requirement I'm looking for is remaining waterproof when demated, with no caps, plugs, or other accessories. If wet immediately after demating, with no other steps, it should not be conductive. Sort of like how british plugs have shutters over the live and neutral when nothing is plugged in (https://youtu.be/UEfP1OKKz_Q?t=22) but weatherproof.Thanks much

author: daqq
author_rank: Super Contributor
timestamp: May 10, 2018, 06:58:33 am
content: Well, there are the circular connectors, they can be made to be IP67 with the right accessories/setup.See:http://www.bulgin.com/products/circular-power-connectors.htmlhttp://www.farnell.com/datasheets/1672288.pdfhttp://uk.farnell.com/hirose-hrs/lf07wbj-3p/jack-male-pin-3way/dp/1518774Generally, the manufacturer has everything for this kind of connector (caps and similar). As to the current capacity, this kind of connector can have various pin configurations, high current ones included. Or you can just use a smaller pin size, and connect more in parallel.Mind you, they aren't cheap, but they do get the job done and are fairly rugged.Please keep in mind that if it's supposed to be outside, keep an eye out for how well the manufacturer claims they handle UV, since cheap plastics may have a problem with this.

author: Nauris
author_rank: Regular Contributor
timestamp: May 10, 2018, 04:37:34 pm
content: I like Amphenol Ecomate series. Quite robust, waterproof, available with screw on cap and nice blue colour.

author: jeduffy
author_rank: Contributor
timestamp: May 10, 2018, 04:57:39 pm
content: Thanks, but I guess the question wasn't completely clear on the wording, by "that is waterproof while NOT mated (including to a cap/cover)" I meant that it must be waterproof without any kind of cap or plug or anything. A standard circular connector (and pretty much every other connector I've found), when demated, will still have the contacts corroded if it's powered on and wet. Something like this:https://www.binder-usa.com/products/miniature-circular-connectors.html?series=1690but capable of higher current.

author: dmills
author_rank: Super Contributor
timestamp: May 10, 2018, 05:38:36 pm
content: Souriau UTS series have versions which are sealed when unmated, or the Bulgin things.Worth buying the ready made cable assembly which is overmoulded for that side of the thing unless you have the tools to over-mould PUR.The IP68 only when mated thing is a nice trap for young players.Note that sealed when unmated usually refers to mechanically keeping water out of the box, if you have power on them and they get immersed in salt water they will rot (Quickly, been there, done that), so include some sort of interlock circuit so the power is only there when mated.If you want wet matable power you are into seriously proper money, it is almost always worth avoiding going there.Regards, Dan.

author: jeduffy
author_rank: Contributor
timestamp: May 10, 2018, 10:19:02 pm
content: Thanks, but avoiding an interlock is exactly what I was looking to do. My original plan was to make an interlock that disconnects electronically when not in use, but when I started working on that, I figured it would take a lot of time to get it totally right and reliable, so if there's an off-the-shelf solution that negates the need for it, even a fairly expensive one, that's preferable. The batteries inside the box are a several hundred dollars each (and there's a couple of them), so this has to be reliable, not just to save the connector, but more so to keep the batteries from being over-discharged.Looked at wet-matable connectors, though those do exactly what I want, it looks like all of those are designed for high pressure (and do have the "call us for a quote!" prices to match), so I will probably have to do this myself.edit: by do this myself I mean the interlock, not a connector.Thanks anyway.

author: Daixiwen
author_rank: Frequent Contributor
timestamp: May 11, 2018, 08:13:24 am
content: I agree with dmills. I helped design a battery pack with a custom connector that was waterproof when not connected, and even if the voltage was lower (16V) having it live in water would degrade the contacts. The water doesn't even need to be that salted. You'd probably need a very special coating to prevent degradation, and that coating would need to be mechanically strong enough to support all the mating/demating cycles.