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Prime charging on a timer

Discussion in 'Prime Plug-in Charging' started by IABoy987, May 21, 2020.

  1. IABoy987

    IABoy987 Member

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    Was unsure to post here or Technical forum. Moderator can move topic if there is a better forum.

    I know that the Prime can be programmed to start charging at what ever time the owner desires, and that there is an "over ride" setting on screen if car needed charging at other times.

    As I will be having an electrician install a dedicated 120V 20A outlet, it occurred to me, why not also install one of those ubiquitous gray box mechanical timer made by Intermatic to start charging at night during cheaper off load period. That way I don't need to fiddle with the programming, or remember to turn off over ride. The only power would be the minuscule clock motor power rather than the plugged-in charger brick standby idling until next charging time (yeah I know, just unplug it every time, doofus, but that also wears out outlet contacts over time.)

    Unless I missed it, I did not read anything specific in the manuals that says you must plug in charger first then cord into car, nor a warning that doing this reverse order might cause problems, stress equipment, or injury. As an experiment, I plugged charger to car then charger into 120V outlet. After a few seconds, the charging light lit, and several hours later the car was charged. But this was just one time experiment. Of course if there was a power failure then power resumes, the charger brick would have to be able to start up under the car battery load, unless owner remembered to unplug car until power came back on.

    :) And as an aside, I have really appreciated the help Prime members have done answering a newbie's Prime technical question. I hope I will get smart enough that I can contribute some useful answers......someday!;)
     
    #1 IABoy987, May 21, 2020
    Last edited: May 21, 2020
  2. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    It does not work that way. Just because you plug the Prime into power or in this case supply it power with it already plugged in, does not trigger a charging event. You have everything you need to accomplish this task right inside your car. Plug it in and set the schedule to start charging at specified time or set it to finish at a certain time.

    Time to read, read, and read some more and then "fiddle" as you say. It's not hard, but you do need to do the reading homework. ;)

    PS, I have mine set to finish charging by 4:30am, 7 days a week. It does this well. If I don't plug it in, it doesn't charge. Power outages are a fact of life and will interrupt your schedule. Short of having a large UPS, there's little you can do about that.
     
    #2 Mark57, May 21, 2020
    Last edited: May 21, 2020
  3. mr88cet

    mr88cet Senior Member

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    You beat me to it, Mark57: The problem with that theory is the default is to wait for a timed charge.

    To take advantage of your external timer, you’d have to remember every time to tell it to charge immediately, and the result you’d get would just be a less-flexible version of what you’d get if you’d set up a timed charge in the car.
     
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  4. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    Also, charging at 120V generally takes 5.5 hours so as long as your cheap off hours time slot is longer than 5.5 hours, just set a schedule to finish just before your cheap TOU ends. Example TOU is at least 6 hours long and ends at 7am. Set a schedule to be finished at or a departure time of 6:30am to 7am. Doesn't matter if that's when you're going to drive it. If you need to drive it sooner, set it to finish sooner, etc. All it needs is to be plugged in about 6 hours before your schedule is set to end, or more.
     
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  5. Bob Comer

    Bob Comer Active Member

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    I have my car set to finish charging a half hour before I leave, and it works quite well! If I need an immediate charge, I plug the plug into the car, unplug it, and plug it in again. It's just a way to trigger immediate charge without having to do it while in the car.
     
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  6. IABoy987

    IABoy987 Member

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    Just for sake of a very friendly argument, how is this different than right now I go out to the car after 9PM (start of time of day night low cost period) and plug in charger and green LED lights, than plugging car in when I get home and car starts charging based on registered time start of 9PM? On one hand I don't need to fiddle with programming (which isn't that hard I know), or charging starts when power turns on with a timer? I am still plugging and unplugging cords no matter what.
    (wish forum emojis had one with question marks above its head)
     
  7. Bob Comer

    Bob Comer Active Member

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    Well, I only plug in one time a day, and unplug 1 time a day and the brick stays plugged in to the wall all the time. So it's basically the same as your extra timer, only it costs nothing extra and the charging schedule works wherever I am.
     
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  8. IABoy987

    IABoy987 Member

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    That's definitely a plus 1 !! Had not considered that point if we were on travel and I plugged in car somewhere else. In that case though you would use the Charge Now button. That brings up an interesting point, how do "Primers" handle overnight charging say at hotel/motel/guest home where an outdoor outlet is not available or out of the charge cords 25 foot reach? Manuals seem to strongly warn against any extension cords even if they are over rated amperage/wire gauge capacity.
     
  9. Salamander_King

    Salamander_King Senior Member

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    Using the charge schedule timer in the car is as simple as setting a clock. You can set up multiple events, so if you have different time of departure, it's easy to set it up. I have M-F 6 AM departure, and Sat-Sun for 9 AM departure. As for your question about use of extension cord, although the manual warns against the use, using heavy gauge (at least 12, but preferably 10) pure copper extension cord that is shortest for the required distance should pose minimal risk. I have used 12 gauge extension cord for over two years, and recently switched to 10 gauge extension cord.
     
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  10. EdPalmer42

    EdPalmer42 Member

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    I've never used the charge scheduler. I plug the car in and it immediately starts charging. The OP's idea of using a timer is exactly what I would do.

    Also, note that the brick doesn't draw any more power than the clock motor would. The entire charging cord is basically the world's most over-engineered extension cord!
     
  11. mr88cet

    mr88cet Senior Member

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    It’s different, and I think most would say “easier,” because you don’t have to:
    * Tell it to (and remember to tell it to) “charge now,” (again that’s not the default, although I think I recall that you can make that the default), and
    * You don’t have to (and don’t have to remember to) go out at 9PM to plug it in.

    Instead you plug it in when you’re already at the car anyway, after finishing your daily commute, or last errand of the day.
     
  12. Tideland Prius

    Tideland Prius Moderator of the North
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    I'm confused by the posts from the two of you. From my understanding, if you don't have a charge timer event, the car will start charging when power is supplied (whether it's plugging into a live outlet or whether it's plugged in and the timer to the outlet triggers the outlet to go live overnight when the costs is lower).

    In addition, if you have a charge timer event, wouldn't the car just default the next charging event when the power is supplied? Or are you guys saying that the charging event is triggered not by the power supply becoming live but by the physical action of plugging in the car? If it's the latter, then I see what you guys mean by his idea not working since he'd have to physically go out to the car and unplug/plug it back in when the timer turns the power on.

    However, this can also be achieved by plugging into the car first before plugging the other end of the cable into the outlet and I know this works since I've done it two or three times. Based on my experience, his timer idea should work and doesn't require him to physically plug the car in again.

    Now in terms of charging events, if he wants to not fiddle with the car's charge timer (so he's always in "charge now" mode), then his timer idea should still work.
     
  13. Hicksite

    Hicksite Member

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    Is the default really to wait for a timed charge? I have never set up or used a timed charge, always just plug the cable into the power outlet and then into the car and charging starts immediately and continues until finished. I don't have to "tell it to charge immediately" each time I do this.
     
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  14. john1701a

    john1701a Prius Guru

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    If there is an obvious benefit to having that electricity available (avoid engine startup for short trips, cabin conditioning, etc), just use Charge-Mode.
     
  15. Tideland Prius

    Tideland Prius Moderator of the North
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    If you have a "charge event" (e.g. M-F 7am), then yes. Either press "charge now" on the 11.6" MID, select "charge now" in the 4.2" MID or plug/unplug/plug your charging cable. (i.e. plug it in twice in succession)
     
  16. Tideland Prius

    Tideland Prius Moderator of the North
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    Use the engine. It's a Gen 4 Prius and it's ridiculously fuel efficient. I was only able to charge 3 times on a road trip last summer (including the initial home charge... so I guess 2 more full public charges) and drove over the Cascades and the total trip mpg was 65mpg.
     
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  17. jerrymildred

    jerrymildred Senior Member

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    I thought I read somewhere that the correct sequence for connecting the EVSE is to plug it into the wall first and then the car. But I can't find it now. However, the instructions are consistent in describing the sequence as:
    1. Plug it into the wall
    2. Plug it into the car
    3. Unplug it from the car
    4. Unplug it from the wall
    As for the timer, The would change that sequence and greatly complicate things. Using the car's scheduler, I can come home, plug in immediately, and it will charge at the time I'm planning for. If I want to charge immediately, I can either hit the "charge now" button when turning off the car or, if I decide later to make a special trip, just plug it in twice as already described. If I had the outlet on a timer, I'd be likely to have conflicts with that which would be much harder to over ride than the car's scheduler.
     
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  18. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    I can't speak for what mr88cet said, but you have to go back to the convoluted circumstance the OP setup for us to answer. He said no schedule set, no charge now set. He wants it plugged in to a dead wall socket that is powered on by an external timer. Just because the socket gets power the car will not start charging without a schedule or a charge now set.
     
  19. mr88cet

    mr88cet Senior Member

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    Ah, that may well be true, now that you mention it. I have never not had a “next charging event” scheduled.

    If for some reason you think it’s easier for the socket to do the timing, than for the car to do the timing, then OK.

    In fact, assuming you’re right about how it works there, then I can see an advantage of letting the socket do the timing for you: When you plug in at a grocery store, say, it will automatically “charge now.” I have all too often forgotten to se charge now when I plug in elsewhere.
     
    #19 mr88cet, May 21, 2020
    Last edited: May 21, 2020
  20. Rob43

    Rob43 Senior Member

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    Just a 120v outlet ?

    Give great consideration to a side by side 120v & 240v outlet, you'll get a better deal. If you hire your electrician to come back later to install a 240v outlet, you'll really wish you'd done it the first time.



    Rob43
     
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