Smart plug latching

[booster]

For those with Smart plugs.


How much force does yours take to push in so BOTH latches catch? One the one I just put on, I would guess it takes 3-5 times the force of our old twist lock plug. One side or other latches pretty easily, but then getting the other side takes a lot of force to push into the face gasket setup they use for the plug end to outlet.


This is really an non issue to us, as out outlet is in a shielded area so water intrusion is not an issue, and Smartplug contacts are well engaged with one or neither of the latches hooked, but if it were on the side of the van it would not be very good. It also looks kind of like both are latched when the may not be as the levers don't come out much further when latched, but if you wiggle the plug you can tell right way it isn't latched.

[GeorgeRa]

I mounted the Smart Plug inlet with a very easy access to the 5000 lbs. receiver, it is a very solid mount. I push the plug straight in, with one hand supported on the bumper I push straight in with the other hand. Both latches click in unison. The lid provides additional latch. To remove I squeeze both tabs and move the plug out with some wiggling.

Is force required to push-in higher than with Marinco style plugs, yes, but I have difficulties to judge how much more. Enough more than mounting on a side of the van on a large sheet metal would require some back support in my judgment.

[booster]

Thanks George, that kind of confirms what I am seeing. Ours is a one handed reach in so pushing sideways instead of away from the body (see my other thread for a pic) which is a much harder push.


It kind of contradicts the advertising of "easy" plugging and unplugging, I think. Yeah, easier to line up, but much harder to plug in all the way. As mentioned not a bit deal for us as long as the cover seals well when driving as that is the only time any water could get there. I may pop the seal out to see how much easier it gets, probably lots. I have never been a big fan of face seals like this is as to get 100% sealed they need to compress a lot. This one has ribs and I think the male section of the outlet is supposed to slide between the shallow ribs to seal better, but it wiggles so much it likely hits on top of the ridges most of the time. I did spray it with some dry teflon spray and it did get easier, so may have let it slip into the ribs better.


Did yours get easier over time after being plugged in a long time, as in cold set of the seal?

[GeorgeRa]

It seems as the force required for insertion is reasonably steady from start to final latching, primarily due to friction between contacts. I don’t sense a lot of extra force required at the end of insertion to compress the seal, just a little.

My cables were purchased between 2013 and 2015. I would suggest calling the company, back in 2013 they were still small and very helpful. Ask if there was any design change lately.

Smart-Plugs are used very often within the DYI Sprinter Forum community, some folks mount them on the hitch requiring vertical insertion up, and I have not seen insertion difficulties discussion.
https://sprinter-source.com/forums/i...4/#post-750762

I didn’t noticed any easing of insertion force required, so no gasket setting over the years.

[booster]

What I see on ours is that it would be very easy to think the latches are hooked when they are not as they look popped out, but are slightly less than seated. It I wiggle the plug they will easy disengage the little bit that is holding. If it is fully seated there is not way to wiggle or pull it off. I wonder if some people are thinking it is seated when it is not completely? The contact pressure will easily hold the plug in without issue, at least on ours.



I put some silicone grease on the seal and it got even easier to latch completely than it was with teflon spray, so getting somewhat better. These were backordered for a long time due to missing parts, so maybe a resourcing of parts so they fit a bit differently than the older ones.


Personally, if I were designing a sealed plug like this, I would use a fold down bail clamp/latch to pull the pull tight on the seal and latch it up. Very high clamping force hose connections and such have used them forever and they work really well and easily.

[booster]

I just went out to check to see if things got easier after being latched tight for a day, and only a minimal improvement in force.


I managed to get the seal out of the plug and then, as expected it latched up very nicely, with the anticipated amount of force from the contacts.


The seal is stuck in with double side tape with the quite thin center "tape" to carry the glue on. It wasn't really stuck very well on the plastic anyway, so I removed the tape from the seal, and it left no adhesive on the seal so it wasn't really stuck on it, either. Put it back into the plug and it now plugs in quite a bit easier, just from removing the adhesive tape, so it is very close on tolerance it appears. Still not close to how easy it plugs in without the seal, though. The thinnest section of the seal where the V from the socket hits is very thin, but a bit hard to measure, so little room to allow compression of the gasket for latching travel, it appears.


I think a couple of things could be going on. Obviously, removing the thickness of the glue and tape reduces the amount of compression needed to to latch, but maybe having seal more easily slid in the plug is allowing the V from the socket to seat more easily and completely.


Since our socket is in a rain sheltered area, the only time it would get wet would be a bit of light spray when driving, I will likely just leave the seal out and see how it goes. The cover has it's own seal for when driving. We ran our twist lock for a decade without the seal collar on it without issue or any signs of moisture in it (I just looked). For giggles, I will try to get a decent measurement on the seal thickness at V contact point and maybe order some skinned close cell foam to put in, just to see how it works compared to the V seal firmer seal.

[GeorgeRa]

RV SmartPlug is a modified marine plug; in a marine environment this plug seal is important due to salt water exposure. In an RV this level of protection not really necessary especially if the inlet is hidden in a compartment.

You could entertain an idea of a push tool, a wooden stick to be able to exert more force.

[avanti]

So, I just went out and tried mine.
If I attempt to latch it by pushing straight in, it is indeed difficult. However, if I push it in comfortably, and then torque it a bit to the left, the left-side latch catches. I then torque it to the right and the right-side latch catches. None of this takes any significant force and it works every time.

[booster]

Originally Posted by GeorgeRa

RV SmartPlug is a modified marine plug; in a marine environment this plug seal is important due to salt water exposure. In an RV this level of protection not really necessary especially if the inlet is hidden in a compartment.

You could entertain an idea of a push tool, a wooden stick to be able to exert more force.

Totally understand the moisture issue on the water, but I am wondering how well they really do seal over time.


I tried to measure the thinnest section of the seal and it appears to be a bit under 1/16", so very little compression possible there on the rather firm rubber, so has to hit and stay very flat, I would think.


After measuring the gasket I found a piece of skinned, very soft, closed cell foam in my hidden stash of rubber scraps. Measured about .070 thick. I made a gasket and put it and I could still put in the plug almost as easily as with no gasket which I expected with the soft foam. Left it a while and unplugged it.


The gasket has a temporary memory, it appears, so good for checking contact amount. It looks like the middle 2/3 of the gasket were compressed about 1/3 of the thickness so maybe .020" both the upper and lower ends showed almost no contact at all, so might leak. Since this gasket is thicker than the OEM one, the OEM must be trying to seal on the edges of the small sealing ridge on the end of the socket. This would certainly make sense as trying to land perfectly flat and tight without a lot of force would be pretty tough in plastic part tolerances.



I think it is very possible that our unit simply has a tolerance stack between the latches and seal surfaces that makes the raised ridge of the socket bottom out on the bottom of the seal, greatly increasing force. That fact that it goes together easily with a soft gasket and latches evenly would seem to reinforce that idea.



I have to place and order with McMaster for some other stuff, so I think I will buy a small piece of 1/8" super soft closed cell foam to see if that will also compress enough to have low force, just for curiosity sake.



I can see why people like them as when it latches with reasonable force it is very easy to line up and use.


We will be fine however it winds up as no seal will work fine for us, but kind of interesting to see how it all works, or the issues they can have once they get into mass production and vendor dealings.

[bwatters60]

Replaced the original shoreline connection in my 08210P with a SmartPlug last fall. It took a little more pressure than the original plug to insert and lock, but I've noticed over time that it has become easier to lock on. A very good investment!

[Davydd]

I've had the Smartplug for going on 5 years. I've never had a problem with plugging in and latching. The cover to the receptor is designed to also latch the plug and give some cover from the elements. I would never go back to the twist lock type.

Mine was installed when ARV was switching over from twist lock to Smartplug as their standard and the hole was cut in the body beforehand so it is the only penetration on the side of the van. After, on subsequent vans, the put the plug under the back bumper as the advantage is it can be plugged in blind as it is easy to line up.

[booster]

I have been experimenting with our Smarplug for a while now, first removing the firm bottomed stock gasket and replacing it with a soft 1/16" foam gasket. As mentioned earlier, both reduced the force about the same and made it easy to plug in.



I then got some 1/8" soft foam and used that, and also got no noticeable extra force. I have had that in place, plugged in for about a week, and will some unplug and check the contact depth and how uniform it is around the sealing area.


I think there is no question it is the original seal that was the force increaser, probably from a tolerance stacking issue in the other parts. If plastic nose of the plug contacts the bottom of the seal much, the force would go up very quickly as the bottom if quite hard and very thin. The seal has to have been intended to seal on fins of the seal, not the bottom, I think.


One thing I did notice in all the on/off of the plug is that putting it in a bit crooked horizontally is actually a good thing to reduce the latching force. If it is a bit crooked, the contacts are springy enough to handle it easily and the housing clears fine, one side latches first, and the force is much reduced from straight in as it rotates to latch the second side. You get two distinct clicks as both latch and then no wiggle to speak of between the plug and socket. If only one side latches, you can wiggle it quite a bit.

[avanti]

Originally Posted by booster

One thing I did notice in all the on/off of the plug is that putting it in a bit crooked horizontally is actually a good thing to reduce the latching force. If it is a bit crooked, the contacts are springy enough to handle it easily and the housing clears fine, one side latches first, and the force is much reduced from straight in as it rotates to latch the second side. You get two distinct clicks as both latch and then no wiggle to speak of between the plug and socket. If only one side latches, you can wiggle it quite a bit.

That is equivalent to the "torquing" technique that I tried to describe above. Just push it straight in lightly, then nudge left until it clicks and nudge right for second click. At least on my unit, this is extremely easy and no need to compromise the seal.