Should You Leave Your Tesla Charger (UMC) Plugged In?


Should You Leave Your Tesla Charger (UMC) Plugged In?

Tesla Charger UMCThe Model S, and presumably the upcoming Model X, comes with a home garage charger that contains a set of interchangeable plugs allowing owners to plug into nearly any power outlet. Whether you’re plugging your Tesla into a 240v NEMA 14-50 outlet or a traditional 110v wall socket, one question remains – should you leave the Tesla Charger or otherwise known as the Universal Mobile Connector (UMC) plugged into the wall?

The answer is yes, and here’s why:


  • The Universal Mobile Connector (UMC) draws virtually no power when plugged in other than the green LED. Using a portable digital electricity monitor (a must have if you’re living the green lifestyle), we verified that the draw was less than 10 milliamps.
  • You may not have the time to unplug and stow your UMC, especially if you’re on-the-go.
  • Most Model S owners typically install the higher amperage NEMA 14-50 outlet (often used for washer/dryer machines) which uses a thick 4-prong plug. The plastic receptacle that receives the 4-prong plug is not designed to withstand the wear and tear of continuous plug insertion.
  • Constant unplugging and re-plugging will loosen the receptacle thereby causing sag when the heavier UMC is attached to the outlet.  We’ve encountered times where the sagging was enough to create a disconnect in power to our Tesla.

Also see: Tesla Model S Hidden Features, Tips, Tricks & Tidbits


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