There needs to be two caps, one M4Z003-000 for the female receptable on the ebike, and one for the male power cord. Because of the magnet, a staple or brad on the ground could be easily picked up and short out the whole system. I measured the power cord as .964 OD and .5 deep and will make a simple 3d printed cap. of course it could get complex if it needs an embedded metal washer...
After losing mine a couple of times because I had it on the magnetic holder on the bike when I left for my ride, I bought a small magnet and superglued it to the top of the charger. Now, when I remove the cap from the bike I put it on the magnet attached to the charger. I thought about putting a lanyard on the cap, but couldn’t find a good place to attach it. I think the magnet on the charger is a much better solution to this issue. Fingers crossed.I also ordered these from my local Specialized dealer , cost $12 each.
The cap from Mouser showed up a few weeks back. I just have to make sure I don't lose this one.Mouser Electronics has the caps listed as an Automotive Connector , but seem to be on backorder: https://www.mouser.com/ProductDetail/476-M4Z003-000 . I just noticed that the bike I just got (shop listed as new, previous model year) didn't have a cap when I got it. Probably got misplaced over while sitting in the showroom and/or moved from store to store.