TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC

2 X Nema 14-50 for Portable HPWC?

Discussion in 'Charging Standards and Infrastructure' started by Evbwcaer, Jul 21, 2014.

  1. Evbwcaer

    Evbwcaer Member

    Jun 21, 2014
    #1 Evbwcaer, Jul 21, 2014
    Last edited: Jul 21, 2014
    I'll start with this, "Hey Tesla, if you are listening, put two charge ports on all Teslas, or at least those with dual chargers!!!!"

    Now that we have that out of the way, can those with knowledge of electrical systems weigh in on the idea of making a portable HPWC that could plug into two Nema 14-50s?

    There is the Quick 220 for combining 2 110v's into one 220v line. If we would combine two Nema 14-50's into one 80 amp HPWC, we would have an HPWC at nearly all RV parks. Is such a concept workable? The outlets are really close to each other in most cases, the cords would not have to be that long.

    This product could be part of an adapter assortment people could rent for road trips.

    Please share your thoughts and thanks.

    Edit: There are apps like The Ultimate US Public Campground Project and Allstays that have maps that are filterable by hookups. If each one of those sites was essentially an HPWC, it would REALLY open things up.

  2. nwdiver

    nwdiver Active Member

    Feb 17, 2013
    United States
    I've done it; but without the proper relays it's dangerous; Electrical friend of mine calls it the 'widow maker'; You need to ensure L1 goes to L1; L1 to L2 is exciting...
  3. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

    Jun 21, 2012
    Can be done. It is unpredictable and is not the safest in the world. It explicitly violates code and comes with insurance and liability risk.

    In a perfect world, it'll work when the resistances of both paths are the same (same wire type, circuit length, and path back to the transformer). In practice, this isn't always the case: two pedestals may use different paths back to the distribution transformer, or even different distribution transformers. This can create a current imbalance that can cause overheating or overload of one of the parallel paths.

    In addition, without safety interlocks, this type of paralleling can create exposed 240VAC on plugs that are expected to be dead when unplugged. In practice, this is similar to the "suicide cords" we see people use for generators, with two male ends. They're called "suicide cords" for a reason. In others, as nwdiver mentions, it can create a dead short if the ungrounded conductors are mismatched.

    Finally, there are some older infrastructure installations out there that won't sync up at all. These are becoming rarer with time, but you may find older 240V delta 3-phase configurations that won't phase-align at all.

    I don't recommend this practice.
  4. C.r. Moorehead

    Oct 30, 2014
    Las Vegas
    In life my simple rule of thumb is - Risk vs. Reward. This potential risk is NOT worth the reward. MOST commercial locations now use 3 phase 208. You will see a nice fire if you combine l1 l2 or l3 together! 30MiHr really isn't that slow. There are superchargers everywhere I need but San Diego and SLC UT.

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.