NEMA 14–50 trickle charge adapter

I have a 32 amp EV charging cable (EVSE) that terminates on a NEMA 14–50. Although it’s common for products like JuiceBox and OpenEVSE to use a 14–50 connector, the market for these EV adapters has not reached the threshold where molded 5–15 to 14–50 “trickle charge” adapters are readily available. Similar looking cables for RVs are not wired properly for EV charging. Although I’ve since come up with other options, the first “trickle charge” adapter I purchased was a bit bulky and the cord was a bit too short.

The first “trickle charge” adapter I purchased works fine, but I can create something better.

Building a better trickle charge adapter

I purchased a Parkworld compact 14–50R female connector to use for an adapter, but never found a cable that would work. The other day, I stumbled across a Triple Tap Adapter at Orchard Supply Hardware which turned out to be the perfect cord to complete this project.

The Triple Tap Indoor Extension Cords from Orchard Supply Hardware.

Repurposing the Triple Tap adapter

I cut the splitter end so that two inches of the molded plastic could be rescued and used as a grommet. There’s also a metal crimp that I was able to expand and move up the cord as I stripped the housing back to reveal the leads.

The molded plastic can be preserved to make a grommet.

Securing the cable to the connector

It was necessary to trim down the plastic grommet just a bit so that the metal bracket could be attached. Also, the plug “bottoms out” slightly, leaving a thin air gap between the plug and receptacle, so I knocked down a bit of the plastic on the back plate. Before closing it up, I used a multimeter to verify everything was wired correctly.

The plastic grommet provides the right amount of material to secure this cable in place.

Putting it all together

The finished cable came together nicely. It’s just the right length so that the 5–15 plug can sit firmly in a household receptacle without strain or twisting when connected to the thicker EVSE cable. The Parkworld connector is much more compact than the Camco connector on my other adapter, which I like, but the self-tapping screws that hold the back plate need to be tightened gently to avoid stripping the threads.

Options for molded adapters

Hobbyists have posted information about building their own adapters, but for most people purchasing a molded adapter is a better choice. There is now a molded 5–15 to 14–50 adapters for EVs available for the same price as the two components used in this build.

Parkworld now offers a 5–15 to 14–50 molded adapter for EV charging.

Note: EV adapters that use connectors with screw-on terminals may be inferior to molded and machine welded adapters.

Building this 5–15 to 14–50 “trickle charge” adapter.