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confused about electricity cost.

Discussion in 'Model S: Battery & Charging' started by bellwilliam, Feb 13, 2013.

  1. bellwilliam

    bellwilliam Member

    Jan 9, 2013
    asked this question at other forum, but they didn't address my questions. I am pretty lost on electrical rate thing.

    Solar City is installing charger for coming Tesla (80amp !!).
    they also sent me a proposal for installing solar system for the house.
    I am currently using 12,000 kwh per year.
    proposal claim with Tesla, I will be pushed into Tier 4/5 all year . rate will be around 30 cents / kwh. This came as a big surprise to me: this means fully charging my 85 Tesla will cost me ~$25 for about 180 miles (using realistic number for way I drive), this is a lot more expensive than running my Prius. about the same as a mid size Camry / Accord.

    1. I asked the rep why can't I use the timed charger feature (rumor to be out this month ?) between 12am to 6am, won't I be charged a lot lower rate (about 10 cents/kwh). The rep claim (said it is a complicated calculation, which I have no doubt) it still basically comes back to total kwh, so I will still pay ~30 cents / kwh. Is he BS'ing me for trying to sell me a solar panel system ?

    let's say I am at 1,000 kwh/month now. Tesla S will add another 500 kwh/month, pushed me into tier 4 at 30 cents/kwh. does it matter if I charge EV at midnight - 6am, that all 500kwh. even though SCE say it is only ~12 cents then, doesn't that push 500 kwh of my regular usage into tier 4 anyway ? I am confused.

    2. how much does it cost to install a 2nd meter ? will you be able to stay within tier 1 on the new meter - to drive say 1,000 miles per month ?

    3. if you add solar panels, can it be wired to both meters ? or is that a dumb idea, only wire to primary meter ? what if I have 2 EVs, each pulling 500 watts, matching my household uses. or if one has a solar panel, it should always be 1 meter ?

    I am on Southern California Edison.

    thanks all for help....
  2. Zextraterrestrial

    Mar 11, 2010
    Humboldt/Los Altos
    standard tier or time-of-use?

    I count all my power drawn as $0.30 per kWhr since I hit the top tier @ around 1000 kWhr/month regularly.
  3. mulder1231

    mulder1231 Active Member

    Jan 1, 2012
    Menlo Park, CA
    Yeah, that's why I'm leasing a small 3kW solar grid-tied system from SolarCity, to take the top off so I can stay in the lower tiers for my regular PG&E bill. The system will offset the extra use by my Model S, plus hopefully a little bit more.
  4. shokunin

    shokunin P85 & S40

    Feb 28, 2012
    Irvine, CA
    Since you're mention tier 4/5 you're not on Time of Use (which has 2 levels/tiers on SCE TOU-D-TEV plan). It does not matter what time you use your kwh's, you are billed for your total usage. Moving to Time of Use plan would charge different rates based on peak, off peak, and super-offpeak.

    Not sure, it will depend on how that 2nd meter is tied into your house. Some have mentioned having to pull extra wires from the transformer to power the meter, others say they were able to install another meter tapped just before your main meter. You'll have to contact SCE for this.

    No, solar will only be tied to one meter, unless you install your system as 2 separate systems feeding both meters. The key with solar is to sell as much electricity back to SCE during peak hours when the rate per kwh is more expensive and then use those "credits" to offset the cost to charge during super off peak periods. You may sell edison 10kw's during the day and that would be equivalent to using 15kw during super off peak, net cost being zero.

    The cheapest electrical rate is using a second meter TOU-EV-1 which has roughly $0.13 kwh rate during off peak. However, the cost to install the 2nd meter and any monthly fees associated with a second meter may or may not be worth the $0.07 savings per kwh on the regular household + EV TOU schedule.

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