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Can you help me do math?

UnknownUnknown
edited November -1 in Model 3
Because I'm an idiot.

My question is this - how much am I spending preconditioning the car (warming the cabin) to ~72F for 1 hour? Just a best guess is all I'm asking.
~40F in my garage.
Here's how much I pay per my Xcel Energy statement (MN)

Electric/kWh per Day 70.2
Electric/Cost per Day $9.58

I'm just curious how much warming the battery is costing me every day (ROUGHLY).

TIA
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Comments

  • jimglas_98269389jimglas_98269389
    edited November 2019
    Not much
  • andy_connor_eandy_connor_e
    edited November -1
    For 1 hour?

    ≤ 6kWh
  • UnknownUnknown
    edited November 2019
    what is that in $?
  • andy_connor_eandy_connor_e
    edited November -1
    And you're paying roughly 13.6 cents per kWh, so ~$0.8188/day.
  • andy_connor_eandy_connor_e
    edited November 2019
    Sorry less than or equal to 81 cents per day.
  • UnknownUnknown
    edited November -1
    GTFOH! Sweet. There goes that worry.
  • UnknownUnknown
    edited November 2019
    and THANK YOU
  • UnknownUnknown
    edited November -1
    shit, I might as well prewarm for 2 hours. 2 bucks.
  • andy_connor_eandy_connor_e
    edited November 2019
    For future reference, you listed kWh and $ usage per day

    So $9.58 / 70.2kWh = $0.136/kWh

    Cabin heater is a 6kW heater running for 1 hour so thats a maximum of 6kWh you could use.

    $0.136 x 6kWh = $0.818
  • andy_connor_eandy_connor_e
    edited November -1
    Ya its only $2. But its $60 every month. or $720 per year for a preheated cabin.
  • UnknownUnknown
    edited November 2019
    Gotcha.
    Strange my statements don't say/show the $0.136/kWh. Why make me do math....
  • andy_connor_eandy_connor_e
    edited November 2019
    Thats why there are forums. You're welcome.
  • UnknownUnknown
    edited November 2019
    Agreed. It can add up. But in my mind for some odd reason I was ready to hear $5/day for an hour of cabin warming. So less than $1 was awesome to find out.
    I'll never really prewarm for 2 hours...Just was happy how little it did cost for 1 hour.
  • EffopecEffopec
    edited November 2019
    Cost depends on your electric pricing. For me it's about $0.10/kWhr, so 6 kWhr is about $0.60.

    Next question is why are you running it for an hour? The cabin should warm up within about 5 minutes. If you use the new "finish by" charging strategy you can use your charging to warm the battery. I'm not Minnesota cold (garage is usually in the 50's on cold mornings), but even if it finishes charging close to an hour before I leave I generally don't have any regen dots when I leave. Now if I can just get the timing a bit better I'll be all set. I put in finish by 7:30 & it has been done between 6:20 and 7:00 every day so far. I don't care if it goes all the way to my set point, so I'll probably move the finish line to a bit later to be sure it is pretty warm when I leave.
  • andy_connor_eandy_connor_e
    edited November 2019
    No worries. After yesterdays 15 degree temperatures, leaving work i definitely can see the benefit of preheating my cabin for even just 5 minutes.
  • UnknownUnknown
    edited November 2019
    And it wouldn't be for a full year. Probably ~5 months. So $300/year.

    but I love regen that much :)
  • UnknownUnknown
    edited November 2019
    @Effopec

    If I do nothing I have 0 regen (all dots) when I start driving.
    If I prewarm + charge for 1 hour before leaving I get about half or more regen back (~50% or less dots). For less than $1/day I'll take that improvement.
  • UnknownUnknown
    edited November 2019
    ***I should mention this is after the car sits all night in the freezing cold. Taken from someone else on here a 'cold soaked battery'
  • andy_connor_eandy_connor_e
    edited November 2019
    Even this week when it was 12 degrees in the morning my garage was about 55 degrees. So i can imagine i shouldnt have a horrible time with cold battery packs.
  • hokiegir1hokiegir1
    edited November -1
    And really -- while that's the max on the heater, my TeslaFi preconditioning losses are *significantly* less than that for 30 minutes to an hour (usually .1 kwh, though there was one morning it was 1.1kwh used), so you'd be looking at closer to 30 cents/hour "real world".
  • UnknownUnknown
    edited November 2019
    garage insulated to some degree? I am planning on doing mine just to help my car :)
  • UnknownUnknown
    edited November 2019
    @hokie

    Back to 2 hours of prewarm for 60 cents! :)
  • andy_connor_eandy_connor_e
    edited November -1
    Ya definitely to some degree. There are typical cinder blocks up to i think 2'-6", but from there its insulated drywall. Garage is also underneath the house, raised ranch style, and there are ducts that run into the garage despite that i have the vents closed. Even better my main panel is directly next to where i park so a charger installation will be a breeze.
  • andy_connor_eandy_connor_e
    edited November -1
    I'll take the 2 hours for 60 cents plz
  • hokiegir1hokiegir1
    edited November 2019
    With our 1.5 cents/kwh TOU plan here, it's well worth it to me. ;)
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