KHONS replacement EVSE review

Discussion in 'General' started by bwilson4web, Jun 1, 2018.

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  1. bwilson4web

    bwilson4web Well-Known Member Subscriber

    This post is about a replacement EVSE from After the third overheated plug repair on a BMW charger and extension cord, I realized the 12A 120VAC charger was never going to meet my needs.


    We have two plug-in hybrids:
    • 2014 BMW i3-REx - 18.6kWh
      • +18 hours 12A @120VAC
      • 8, 12, 16A @120VAC
      • 24, 31A @240VAC
      • CCS 50kW
    • 2017 Prius Prime - 6.4kWh
      • +5 hours 12A @120VAC
      • 8, 12, 16A @120VAC
      • 12, 16A @240VAC
    The 8A charging level is set in the car when a circuit has multiple loads. But this extends the charging time significantly.

    KHONS 15-32A Adjustable 120-240V Charger EVSE - Universal

    Actually this $379 unit has a current range setting 12, 16, 20, 24, and 32A. It comes with a three blade, NEMA 14-50 with GROUND and two HOT leads. The unused NEUTRAL blade is missing. I also ordered a $50, NEMA 5-15P/5-20P to 14-50R adapter:

    120VAC Operation

    Downtown Huntsville has ~26, NEMA 5-20 outlets at the base of the light poles around the Courthouse. These are used by food cart vendors when the square is closed for special events:
    To open, push the case, not the cover, on the left side. The cover swings to the right and snaps back in later. Sure enough the outlets are hot and should be individually wired for 20A allowing 16A operation. I tested it using 12A, the lowest setting of the KHONS.

    The adapter cord has a power indicator light and the operational scenario:
    1. Do not plug-in the J1772 until the current is set.
    2. Wire the adapter to the KHONS and plug-in to the 120VAC outlet.
    3. There is a one minute interval to set the current by 'shaking' the KHONS until the desired current limit is set.
      • The unit does not detect the 120VAC to default 12A. It has to be set first.
      • Untested, the 16A limit is well within the plug and adapter wiring.
      • The adapter has a power indicator.
    4. Plug-in the J1772 into the car:
    Note, these are for food and event carts. Traffic enforcement may take a dim view of charging your car.

    240VAC Operation

    The Huntsville Space and Rocket Center has a free, NEMA 14-50 socket at the parking place marked for electric vehicles. Hinged at the top, the cover easily lifts showing the socket:
    Unlike the usual L1/L2 charging stations, there is no J1772 so you bring your own. They also have a lot of RV parking areas with NEMA 14-50 sockets if this one is blocked.

    Use the same operational scenario:
    1. Do not plug-in the J1772 until the current limit is set.
    2. After plug-in to the NEMA 14-50, there is a one minute interval to set the current limit by shaking the KHONS
      • It does not detect the 240VAC voltage and set the default current to 32A
    3. Plug-in the J1772

    There is a small window showing charging activity. Bring your prescription, reading glasses:
    The right hand column shows:
    • Total kWh of this session
    • Duration HH:MM:SS
    • Voltage and actual current
    • Charge rate in kWh
    The backside of the unit has a somewhat lame list of errors:
    "CP Error" actually means the car side of the handshake, adjusting the pilot signal resistance failed.


    The documentation are three, black-and-white, single sided, pages stapled together. It really needs a downloadable PDF file. Also the 3-blade, NEMA 14-50 plug is called "specially designed plug" without a photo and description why the NEUTRAL blade is not needed. Removing the NEUTRAL blade allows the same plug to be used with several, lower current, NEMA 14-x sockets.


    This is a good, multi-voltage, multi-current EVSE. It could be better with a larger display, voltage detected default current, and better documentation. Due to the 32A capability, the power and J1772 wires are larger and not as flexible as the original EVSE but the greater utility makes a significant improvement.

    Bob Wilson
    Domenick likes this.
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  3. bwilson4web

    bwilson4web Well-Known Member Subscriber

    I tested the KHONS at 16A down by the dog park:
    This means I can effectively get free miles to walk the dogs.

    In the hot Alabama summer, I can also have the car preconditioned, cooled by the AC when we are ready to return home. This highlights the degree EVs can charge pretty much anywhere. In contrast, a gas Prius or hydrogen fool cell car has to visit and pay 2-3 times as much to someone else for the energy.

    Bob Wilson
  4. Martin Williams

    Martin Williams Active Member

    Sadly, because EVs work for YOU doesn't mean they work for everyone.

    If they really are as brilliant as you tell us, why doesn't everyone buy them? The facts are that ninety-nine out of hundred buyers would not touch them with a bargepole!

    What happens if some other dog-walker is using this outlet when you get there?
  5. bwilson4web

    bwilson4web Well-Known Member Subscriber

    I tried the 16A setting at the dog park but it looks like a circuit breaker was tripped. Darn!

    Bob Wilson
  6. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member


    Thanks for taking the time and trouble to write and assemble this detailed, photo-laden how-to blog post... it's far more than just a comment!

    So how did you get permission to use it? Or were those photos taken by someone else?

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  8. bwilson4web

    bwilson4web Well-Known Member Subscriber

    Like everyone, I always drive at or under the speed limit.

    Bob Wilson
  9. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    :D :p :D

    I see. I'm familiar with "guerilla film-making", people making a film on a shoe-string budget who just start filming at a location without going through all that messy and troublesome red tape of getting a filming permit, and keep filming until someone in authority actually tells them to stop.

    So now I guess we have "guerilla EV charging"! ;)


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