HowTo: Replace Hymotion bumper plug

I accidentally broke the bumper inlet-plug from my Hymotion L5, and just finished replacing it, so I'm writing this guide in case anyone else ever needs to replace theirs.


It looks so sad that I abused it. The two screws on the site would not move at all. They take a 2.5mm allen-key, but I ended up stripping them instead of moving them. As it turns out, these steel screws go into an aluminum plate behind the bumper, and over time the aluminum had corroded slightly and welded the steel and aluminum together. I had to drill the heads off to remove the housing.

Disassembled parts



The plug housing is made up of five parts; the plug (and cord) itself, a plug holster, the metal strap, the outer flap, and the inner aluminum backplate. The plug is wired directly into the L5 pack on the other end. The holster keeps the plug in place with a tiny plastic clip. The clip would never have enough strength to hold the plug in place, so A123 put on a metal band on the back of the holster to keep it from falling out. The outer flap has two bolt-holes in it which are used to hold the aluminum back-plate which is on the other side of the bumper.

The new plug


Made by Marinco, it's the 150CCI marine connectcharge inlet. Marinco made the previous plug, but they no longer make that model. It would have been nice to get an exact replacement, but this one is nicer. The previous plug was a solid piece of plastic and couldn't be fixed; this new one is serviceable (I can take it apart) which gives me more options if I break this one too.

The new plug has a better seal from water/moisture, but I prefer the spring loaded flap. The new one I'd have to press into place every time. It just doesn't quite fit. The new plug also has a rubber sheath/cover/condom thing to cover the exposed metal screws that keep the wires in place. It also has a threaded "bolt" instead of a backplate which makes install much easier.



The outer flap was about 1mm too small, so I used a Dremel to enlarge the sides slightly to make it fit. This destroyed the screw holes, but I wasn't planning to use the screws again anyway since the new plug is threaded.


The vice grip was an improvised solution to keep the cord from falling back into the stupid bumper while I cut the old plug off. The bumper is awkward, sharp, stupid, it sucks, and I hate it.


I was hoping the inner wires were colour coordinated, and they were! If they weren't, I had some paint set aside to mark them on both sides to I could make sure hot, neutral, and ground were wired correctly. The colours were Brown, Blue, and Yellow/Green striped.
Use a voltmeter to determine prong-to-wire layout


The wiring layout of this plug was Blue: hot, Brown: neutral, Yellow/Green: ground. If you need to do this to yours, I'd check it again just in case. The chances it's of it being different are slim, but the consequences of it being different without checking is possibly frying the L5 (or the whole car) when you go to charge.


Based on the old plug wires, I need to wire blue to white, brown to black, and yellow/green to green. Technically the hot and neutral are interchangeable, but I wasn't going to change anything, just in case.

It was at this point I discovered the hole in the bumper was too small for the new plug...


So I had to let the wire drop back into the bumper again. I taped it up with electrical tape first, just in case.



After fishing the cord back out from inside the bumper, I put the "bolt" and the rubber sheath/cover/condom thing over the wire. They need to be on the inside of the bumper for final installation.

Using my pocket knife, I gradually enlarged the hole about 2mm. This also wrecked the screw holes, but I wasn't going to be using them anyway. I seem to remember wrecking the screw holes on the outer flap too; this just makes sense here.


I stripped the black sheath back about 3-4cm, and then stripped each wire back about 1cm with a 2.7 stripper. 2.7 what you ask? I don't know (I am such a good car guy). The wires are held in place on the new plug by built in screw-holes.



I didn't bother making it pretty for the first test, I wanted to make sure it worked first. It did! Charging peeked at about 1,060 watts (normal).



After charging, I unplugged the extension cord and fed the rubber cover/condom thing over the plug housing, and zip-tied it in place. Just as A123 did, I don't trust friction to keep the rubber thing in place, so I used a zip-tie on the base of the rubber cover, and one on the wire just behind it, just in case.

Finished!

The new plug's back is threaded, and instead of a large aluminum plate with a couple screw holes, there is an included "bolt" which screws the plug onto the bumper directly. It's not easy to get your hand in there, and not enough room for a wrench or anything, so I tightened it by hand. Specifically, I used my neighbour's hand; he's a machinist and has hands like vice grips.