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Charge based on Time capabilities

Discussion in 'Model S: Battery & Charging' started by jeffro01, Jun 18, 2015.

  1. jeffro01

    jeffro01 Active Member

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    Okay so I've read a few things here and want to make sure I understand this. I searched but didn't seem to find a complete picture of what I was looking for so if I missed it then my apologies.

    I have a TOU plan from PG&E for EVs and my off-peak rate is .09/kWh. In my volt I can put into the scheduler what times my peak, mid-peak, and off peak are and tell the car to ONLY charge during off peak unless manually over ridden. So every night at 11PM my Volt charges and goes until it's finished. On the flip side it also will stop at 7AM when my mid-peak kicks in should I be charging on 120V (which is rare).

    What options do I have with the Model S? It's my perception that the charge scheduling functionality isn't nearly as robust in the Model S as it is in my Volt but I don't want to make assumptions.

    Naturally my primary goal here is not be drawing energy when it's costing me .43/kWh during peak, but only when it's costing me .09/kWh during off peak... While it'll be rare that the car will need more than the 8 hours of off peak every night (week days) to charge, I want it cut off at 7AM when the mid-peak kicks in.

    Am I being to overly analytical here?

    Thanks,
    Jeff
     
  2. Max*

    Max* Autopilot != Autonomous

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    The car allows you to select when to START charging, but not when to complete charging.

    I've heard VisibleTesla desktop application allows that, but I've never tried.
     
  3. Rocky_H

    Rocky_H Member

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    You're not being overly analytical, but you are correct that the Tesla charge scheduling is not quite as detailed as with some other EVs. The Tesla lets you pick a scheduled start time, and that's it. You can't pick an ending cutoff time. But if you start your charging after 11PM, I would think it would reach your charge limit within a few hours and be done well before 7AM.

    - - - Updated - - -

    Oh, good point about Visible Tesla. Yes, I'm pretty sure it can do that, because it's not using the car scheduling. The program can access the functions of the mobile app and a few additional things, so just as you could manually use your phone to tell it to stop charging before 7AM, the Visible Tesla program I think can use a time on your computer to tell the car to stop charging.
     
  4. nh-srt8

    nh-srt8 Member

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    For someone that also came from a Volt the scheduling of charging needs improvement. My TOU plan is 7pm - 11am M-F and all day at the weekend and holidays. I have to manually initiate the charge during a weekend if I plug in before 7pm. I could "program" the settings through Onstar and simply plug in and it would know based on the time if I was in the TOU window and automatically start the charge.
     
  5. MichFin

    MichFin Member

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    Also, one worry I have on this is that Tesla will draw power throughout the day for keeping the computers running. I haven't gotten a bill yet but with my volt the 30 KWH I used during peak time was as expensive as the 250 KWH I used at off peak for a month.

    I'm afraid to see what it's going to be for the Tesla 85D.
     
  6. mknox

    mknox Well-Known Member

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    The car does draw the battery down a bit through the day, but will only draw shore power to top itself up once it reaches a certain threshold. My observation is that it will top up once it has dropped about 2.5 kWh from the set point. If you have your timer set for, say, 10:00 PM, the car will schedule the charge, but not actually draw shore power until 10:00 PM so you don't have to worry about drawing shore power during peak periods.
     
  7. BFCobra

    BFCobra Member

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    Jeffro01,

    Are you 240v or 120v? At 240v 30amp, I never run past 3 or 4 in the morning. I have PG&E EVA rates which 11pm to 7am are at around 9 cents/kWh. Charge rate at 240v 30amp with the travel charger is about 23 miles/hour of charge. At 120v 12amp it is more like 3 miles/hour of charge. So if you are 120v, you can go well past the 7am rate increase. I just ran an appropriate sized wire, 50amp rated, from a Dryer plug in the laundry room, through PVC conduit, into the garage. So Tesse gets plugged in about every other day, and stays between 150 to 234 miles of range usually.

    On a trip to SoCal it got as low as 35 getting into the Supercharger at Atascadero. The more nervous part was the speedo range said 50, but the nav was freaking out as we left San Luis Obispo from a stop, that "RED Warning" must stop for charge now, "you do not have enough charge to reach your destination". Nav range appears to look at a shorter period of battery use, and was forecasting that demand load as being needed for the balance of the trip. The speedo range was more correct. But it sure got the wife going..... I had charged at Oxnard, gone back to Thousand Oaks, then to Atascadero. On highway 154, nav warned me to slowdown to make my destination, so I did. Basically, it seems to ask you to slowdown, if it forecasts battery life at your destination is under 8%. I played with it and got it to go under and over 8%, with the slow warning coming each time under 8% forecast as we drove through Santa Ynez area north of Santa Barbara. I got it come on 3 times, so pretty sure 8% is their perimeter. Oxnard is not well mapped, and two of Model S's were driving around looking for it. If you're in that area, its across the parking lot from the Whole Foods.

    Just got the 6.2.4.239 upgrade night before last. Looking forward to a trip to the east bay this weekend to see what that does to the nav forecasting....
     
  8. jeffro01

    jeffro01 Active Member

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    Thanks for all of the answers.

    My current charger is 240v at 30amps which is more than the Volt can do as it's limited to 3.3/kWh. I plan on getting the HPWC even though I can only put it on a 50amp breaker as the house service is only 125amps and the cost to upgrade the house service to 200amps is well, obscene... I want the Tesla HPWC because we'll still have the Volt so I'll use the Tesla HPWC for the Tesla and plug the volt into our current EVSE as needed.

    Never thought about the weekends... Fudge a duck... :) Oh well... :) Manually overriding from my app isn't that big of a deal but naturally I'd rather have a better scheduler.

    I think I need to just break down and get solar...

    Jeff
     
  9. davewill

    davewill Member

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    There's no harm done if you wait until 11PM even on the weekend. Don't bother to override unless you need it...which would apply to the weekdays, too.
     
  10. jeffro01

    jeffro01 Active Member

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    Indeed... :)

    Jeff
     
  11. m6bigdog

    m6bigdog Member

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    I agree, the HPWC is the best method to perform daily charging duties because it is the most robust and safest method.
    Yes, the charging schedule is simple however, the Tesla has a lot of range and you will not keep it charged above 70-80% most of the time and if you are heading out of the area on a road trip the first Superchargers are all less than 100 miles away in every direction.

    I live in the Bay Area also, have solar (7.3kW system averaging 1MW/mo. over the last 36 months) and have been using E-6, TOU and until I got my Tesla last month and got a True-up credit (@ $.04 kWh) of between $75-100 annually with a monthly $8 grid hook-up cost ($4 electric & $4 gas).
    I paid for my system out of my savings and it is the best investment I ever made!!
    IMHO, don't lease a system, I would take out a home equity loan if necessary as the payback is quick, 5-6 years and the total savings is huge over the +25 year life of the system.
    I just switched to EVA and I shall see how that affects the total cost of electricity since I will be putting an additional +/- 12kWh during off-peak hours into the Tesla on a daily basis.
    I have also contemplated installing another 4-6 panel to offset the EV charging as the actual panel installation cost seems high but there is nothing like generating your own power and managing the EV charging cost for the long term.
     
  12. jeffro01

    jeffro01 Active Member

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    Who did you get your solar installation from? Me personally, we need a new roof before we put on solar or else it'll just have to be taken off again when we actually do replace the roof in a couple of years or so. We get tons of sun here with plenty of roof space available for quite a large array, combined that with the Tesla Powerwall, we could pretty easily be net 0 users with the likely hood of being paid by PG&E...

    I have never quite been a fan of the lease model for solar simply because it makes it much more complicated to sell your house with a solar lease involved and there is a more than reasonable chance we'll want to sell at some point...

    Thanks,
     

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