Prius Prime HEAT Climate Prep with Charger Timer

Discussion in 'Prime Main Forum (2017-Current)' started by Michael Wood, Nov 13, 2020.

  1. Michael Wood

    Michael Wood Member

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    In New England, "Climate Prep" means heat. A/C is far less important to me, and I'm willing to endure some discomfort while I wait for my A/C to do its job in the summer. Winter time is a different story. "Climate Prep" is definitely something I'll be using a lot of in EV mode.

    First thing I do before setting my charge timer is set my climate control to the desired temp (example - 68 degrees). I'm not sure it matters where I leave the fan speed or what mode I leave the climate control system in (off or auto). I think that as long as the temp is set, that's the temp the "Climate Prep" will target. Then I turn the car off and set my charge timer making sure that "Climate Prep" is on.

    Next, exit the car and plug in the charge cable.

    Finally, LOCK the car with the key FOB. "Climate Prep" won't start unless the car is locked.

    That should do it. Did I miss anything?
     
  2. ForestBeekeeper

    ForestBeekeeper Active Member

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    I dont know. I have never heard of 'climate prep' before. I must give it a try.

    The heated seats heat up fairly quick, and within the first 2 miles I have heat coming out. The defrost usually works right before the windshield ices up completely.

    I have gone through many previous cars, that the windshields will rise up entirely, and then you have to park with the defrost on high, waiting for the windshield to clear up. But with our Prius Prime, I have never had to park and wait. Even at -20F.
     
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  3. Salamander_King

    Salamander_King Senior Member

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    I think leaving the A/C Auto ON will take care of the fan speed, but if you leave it Auto OFF, then whatever the fan speed you have set when you turn off the car will be the speed of the fan.

    You may read this long thread on climate prep to learn more about its use: Remote A/C & Climate Prep Quick Guide | PriusChat

    For me living in New England, the climate prep or the remote A/C on Prius Prime is just a waste of valuable electric energy. I don't usually use heat in my car unless the outside temperature is well below 32F. And at that low temperature, the heat pump is ineffective. It runs only 10 min before the departure time set on the charge schedule and it uses traction battery power for that 10min of heating. Since it stops as soon as you open the door, by the time I finish loading my bags and get inside, even if the warm air was in the cabin it escapes very quickly. Or since it stops at the departure time, if I don't leave on time, then prewarming is all wasted. I have tried using it several times, but at temperature I really want the cabin pre-heated which is usually below 20F, the heat pump does not heat up the cabin quick enough or does not run at all if it's below 14F, no matter what setting I use. So, after several tries, I quit using either climate prep or the remote A/C. Of course, YMMV, so please give it a try and see if it's worth it.
     
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  4. Tideland Prius

    Tideland Prius Moderator of the North
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    I found 68°F (20°C) a bit low for climate prep since the whole point is to warm the cabin using (mostly) wall power. 21-22°C (70-73°F) is good for me (above freezing temps) then lower to 20°C/68°F when I drive off and live off the residual heat.

    But otherwise, those steps look good to me.

    Whaaaaat? Climate prep is great in the winter (well as long as it's above -14°C). Since charging ends about 30 minutes prior to departure, I use climate prep to pre-heat the cabin and I'm assuming the battery as well. (Since it'll be using the battery and pulling power from the wall which will generate some heat within the battery + the cabin heat) rather than starting with a cold battery.
     
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  5. Michael Wood

    Michael Wood Member

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    If climate prep uses traction battery power I'd be inclined not to use it also....except for days when I make several short trips early in the day. I've heard both stories. I prefer the version where it uses wall power, which would be great, unless it's a myth. Is it confirmed that it's pulling juice from the traction battery? Tomorrow, I'll check my starting range to see if it's reduced.
     
  6. Salamander_King

    Salamander_King Senior Member

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    My understanding is that PRIME's HVAC runs only from the traction battery. What happens to the traction battery after the pre-conditioning all depends on how much battery charge is used to heat or cool the car. What I have read others reporting is that L2 EVSE will replenish used battery charge quick enough to bring the traction battery back to full. L1 EVSE may or may not replenish quick enough. If the traction battery charge can not be replenished quick enough, then you will have less than 100% at the departure time.

    upload_2020-11-16_21-41-22.png
     
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  7. Michael Wood

    Michael Wood Member

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    Good info. Thanks. What you said about L1 EVSE explains some strangeness I saw at the end of the charge process (with climate prep is on). The charge stopped (no lights on dash) about 30 mins before departure time, then climate prep started, then charging restarted at about departure time - I had 2 solid lights and 1 blinking on the dash. So I guess it was trying to top-off the charge prior to departure. However, I was running late so I left with slightly less than a full charge.
     
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  8. jerrymildred

    jerrymildred Senior Member

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    Cooling is much the same as what you're seeing with heat. It's just that cooling doesn't requite as much of a temperature change and there's no concern about it being too cold for the heat pump.

    I use L2 at home and have a power meter on that circuit. What I find with cooling on L2 in my garage is that when the A/C starts, charging stops. The current on my meter drops from 16A to just over half an amp. Once the time for the climate conditioning is ended, the charging resumes. It rarely gets done before departure time. And by then, much of the cooling is wasted. Most of what remains dissipates when we open the doors to put in our stuff and ourselves.

    At work, I park in the shade and use L1. Climate prep is totally ineffective. It uses way too much of the battery to get charged back up in a reasonable amount of time on L1 and the cabin is back up to its original temperature before the battery is finished charging -- IF I can even wait that long.

    In both scenarios, the A/C doesn't stay on long enough to chill the seats, consoles, dash, steering wheel and all the other mass inside the car, which continues to radiate heat. It takes a really long drive to get that much mass cooled down. Probably even longer for it to soak up the heat on a frigid day.
     
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