southern california edison pros/cons of having a separate meter for EV charging

Discussion in 'General' started by Johnhaydev, Jul 31, 2018.

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  1. Johnhaydev

    Johnhaydev Active Member

    I'm going to have a level 2 charger installed in my carport to charge my Honda clarity PHEV.
    Southern California Edison has 2 options.
    1. use a time of use [TOU] plan for the whole house
    2. have a separate meter installed to charge the EV with a special TOU plan. rest of house remains on the original meter.

    Appreciate any thoughts of the pros and cons of each approach.

    Since the carport is on the opposite corner of the house from the main electrical panel, my electrician needs to set up a separate subpanel to install the level 2 charger, so I will have to have some electrical work anyway.
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  3. TeslaInvestors

    TeslaInvestors Active Member

    You need to first find out the cost of installing the second meter for option #2.
    Then the rate plan between #1 cheapest rate and #2 EV rate.
    Here is the formula to use:
    option 1 cheapest rate: $x per kWh
    option 2 EV meter rate: $y per kWh
    You plan to keep your car N years, charge K Kwh per day on average and cost of installing secon meter is P.

    Then, you compute N * 365 * K * ($x-$y) . If it is less than P, go with option 1.
    This assumes that you can just charge at night under option 1. If not, then you need to compute x by an weighted average of the K KWh that you will charge at different rates on average. If you have solar, then option 1 may be even more beneficial.

    I'd think, for most people, the upfront cost of installing a second meter outweighs the benefits it brings.
    But everyone's case is different.
    Johnhaydev likes this.
  4. JyChevyVolt

    JyChevyVolt Active Member

    Get another quote from two other electricians. I see no reason for a subpanel. It's a simple home run using 8/2 Romex with ground. If the charger is exposed to outside weather, you'll need a short emt run from charger to LB conduit body.

    If no one is home from 2-8pm, the TOU-B is better.
    Last edited: Jul 31, 2018
    bwilson4web likes this.
  5. bwilson4web

    bwilson4web Well-Known Member Subscriber

    I would add that charging in the early morning means lower ambient temperature. This reduces the battery cooling load.

    Bob Wilson

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