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DIY Energy Monitor

Discussion in 'Charging Standards and Infrastructure' started by Haxster, Apr 4, 2017.

  1. Haxster

    Haxster Member

    Joined:
    Apr 4, 2016
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    For under $50 you can build a plug & play energy monitor for your EV that lets you check voltage, current, Watts, and kWh.

    CIMG1828.JPG


    Here’s what I used:

    Amazon.com: DROK Digital Multimeter AC Voltage Amperage Power Energy 4in1 Meter 80-260V 100A Volts Amps Testing Gauge 22kW 9999kWh Power Energy Monitor Red Digital Tube Display: Industrial & Scientific

    Amazon.com: Camco 55215 18" PowerGrip Extender - 50 AMP: Automotive

    The meter is pretty nice. It has a recessed button to reset the accumulated energy consumption. And if power is lost, it doesn’t lose this reading. It consumes less than a Watt and auto-ranges the displays to provide more resolution. It’s perfect for a 40 Amp home charger and could be used for the Tesla High Amp Wall Connector (with different connections).

    At 40 Amps, there’s about a 3% current difference between the meter and the charger readings. I haven’t tested the meter with a calibrated 40 Amp load to see who’s right…and I don’t plan to. Close enough.

    The short 14-50 extension cable was spliced inside the plastic box (one hot wire cut) to get at the 240V needed for the meter and a to run one of the legs thru the current sensing transformer for the meter. There are open frame transformers that would eliminate the need to cut & splice the wire, but this meter didn’t come with one.

    If anyone’s interested, the Tesla Mobile Connector draws an average of 3 Watts in standby.
     
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  2. Acho

    Acho Member

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    Was the enclosure included with the meter?
     
  3. SDRick

    SDRick Member

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    #3 SDRick, Dec 5, 2017
    Last edited: Dec 5, 2017
    I have the same meter. Great job on the enclosure \ work box! How did you route the wire for the CT? Don’t you need 4 conductors, 2 for the 120v line for the meter and 2 for the CT?
     
  4. Acho

    Acho Member

    Joined:
    Mar 28, 2017
    Messages:
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    Location:
    Las Vegas, NV
    Obviously not. Received the metter and it has no enclosure.

    If OP can post which enclosure he used it would be great.

    Thanks
     

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