US Model Subfreezing Weather tips? (<10 F)

Discussion in 'Clarity' started by DC1, Jan 21, 2019.

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  1. DC1

    DC1 Member

    Recently the weather has been very cold here in the Northeast US. I understand Canadian models have dedicated battery heaters, but since we don't have that where I am (MA), trying to figure out how to manage charging and driving more effectively.

    Charging is happening super slow for me the past couple days with single digit Fahrenheit temps. Yesterday, it took about 20% longer than usual to charge my car, and it was about 15 degrees F outside. Today, it's about 2 degrees F outside, and it's taking more than 100% longer.

    Lurking on a Tesla forum, it seems like the Tesla 3 doesn't have a battery heater either, and they were saying that you should drive around to heat up the battery and charge it right away after parking the car to take advantage of the warm battery.

    Does that mean that in very cold temps, we Clarity PHEV drivers should be using Hybrid mode as much as possible?

    (Edit for clarification: The slower charging that I've seen this is with our charger at office, not at home. I wonder if charging at home at 110v will behave slower like I saw at the 240v charger at work?)
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  3. AlAl

    AlAl Active Member

    It appears the car will kick you into HV mode whenever cabin temps reach stupid low numbers and are looking for heat. Learned that this morning, after the engine roared to life the moment I started the car..
  4. Viking79

    Viking79 Well-Known Member

    The engine will start in very cold weather around 0 F if the car is cold, doesn't seem to be related to air temp, more battery temp or possibly heating demands. So car will use HV if necessary. If you charge at home and work it might keep the battery warm enough not to start when you leave.

    Charging in cold is slow to protect the battery, it charges around 3.8 kW in my garage around 20 or 25 F, but once the battery warms as it charges it will jump to 7.2 kW. I have never charged the Clarity outside in the Cold, so it is likely it will drop even slower. 110 V shouldn't be impacted as it is always slow :)

    The battery seems to protect itself no matter what you do, but plan on longer charge sessions during winter.
  5. Today it was pretty cold for TN, with a high in the mid-30’s.

    We did our first drive across the mountains at these temps, and for most of the trip the regen would not exceed 2 or 3 chevrons. Battery was about 50% and we were driving in HV/SPORT mode until close to home. I assume this has to do with not allowing excessive regen from charging a cold battery too quickly.

    That sound right?
  6. KentuckyKen

    KentuckyKen Well-Known Member

    Charging in colder temps takes longer because the battery can’t take as many kW per unit time. So it slowly ramps up that power instead of going straight to the maximum. The colder the battery pack the lower the initial charging rate and the longer it takes to ramp up to the maximum rate.

    Here are two charging graphs to demonstrate. The first is at high 50s F, and the second at low 40s in my garage. No way to monitor battery temp but I charge in the middle of the night so it has had some time to equilibrate to garage temp.

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  8. insightman

    insightman Well-Known Member Subscriber

    The charging process generates heat in the battery, so you can park your Clarity with a partial charge and then schedule it to complete charging just before you want to drive the car. The battery will be warm even though you don't have the Canadian advantage.
  9. Claire Green

    Claire Green Member

  10. DC1

    DC1 Member

    Normally when charging at the office, I could always count on reaching 100% within 3 hours. Today, after four hours of charging when I was ready to go home, it was only at 51% charged.

    It’s been plugged in at home and has reached 85% a few mins ago, so I think either having driven home helped it to warm up or maybe it just is not so noticeable at 110v because it’s always slow.

    I hadn’t seen any charging time degradation down to around the 20s before. Only when it stayed for prolonged periods of sub 15 degrees the last couple days did this phenomenon happen to me. Max EV range the past couple days is less than 30 miles too. I think tomorrow will go up to a balmy 20+ degrees so all will be well again. :)
  11. KentuckyKen

    KentuckyKen Well-Known Member

    The car being driven outside in cold temps then comes into the warmer garage. The car and battery are colder than the garage and it takes some time for it to warm up (equilibrate) to the same temperature of the garage. (Think thermal mass) That’s why I set the timer to charge later in the early morning of the next day. This lets the battery warm up to garage temp which is a little warmer than outside. And as @insightman mentioned it also may help to have the battery warmer from the charging just before I drive out in the morning. Not sure how much any of that really helps, but it can’t hurt. No cheaper charging at night here in coal country so that’s not an incentive.
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  13. Concur with the low temperatures increasing charging times. My biggest gripe is the spray nozzles on the wiper arms. I would be prepared for a washer tank refill if the salt trucks are out. The top of the windshield never gets clean. I attached my Juicebox charge session at 2F.

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  14. DC1

    DC1 Member

    Yes, I had to refill my washer tank today. Haha.

    It was about 5 F this morning, but preconditioning working great made it a slightly nicer morning. :)
  15. The Gadgeteer

    The Gadgeteer Active Member

    Totally new here. Been reading up in the Clarity Plug in. Just about ready to pull the trigger and buy one. Anyway, I like to crank the heat in the winter and drive we my coat off. I know unlike a pure ICE heat comes at a big mileage cost. If it is cold enough I am willing to take some mileage hit. What I want to know is will the Clarity PHEV take advantage of the engine heat when it is running? Would I get more heat in HV or Sport mode?
  16. craze1cars

    craze1cars Well-Known Member

    Yes to first question. Engine heat does provide heat to the cabin with Clarity.

    2nd question is too open-ended to answer. HV vs Sport mode is not really an either-or choice. You can be in BOTH HV and Sport mode at same time, or EV and Sport mode, or EV and non-sport, or HV and non-Sport. And no matter what mode you put the car in...if your climate control is set to 70 degrees, the interior of the car will reach and maintain 70 degrees, and the engine will do whatever it needs to do in order to accomplish this.

    I'm much like you...I buy extra gas and electricity if needed to be comfortable year-round and I hate driving with a bulky coat on. So coat gets tossed in the back seat if I'm going to be driving more than about 5 minutes and I also dislike seat heaters, so I crank the cabin heat like I would in any other car. And this car keeps me comfy like any other car, and I just let the engine run if it chooses to. I chose drive modes exclusively based on how I want to drive and how far I'm driving, and heat concerns do not come into the equation.
    Last edited: Jan 24, 2019
  17. DC1

    DC1 Member

    Based on my experience this week, the Clarity is totally fine in prolonged sub 10F weather. The only difference was "charging time" which otherwise was not affected much until prolonged weather in sub 20F temps. (About 20% slower in sub 20F, and maybe 50% slower in sub 10F.)

    As for how well heating works in general, it's fantastic and doesn't take away as much of the battery charge as you might have gathered from the discussion here. BTW, I always use the preconditioning in the winter mornings and love getting into the car which has no problems getting to interior temps of 70F and higher. Even in sub 10F temps, preconditioning works equally as quickly (probably used up about 3-4% more battery charge than in warmer temps.)

    But to answer your questions of whether the car will take advantage of the engine heat, I would assume yes. But I don't think it's that important of a factor.

    In my experience, the Clarity PHEV is better in cold weather than any ICE car I've owned. Yes, I definitely drive with my winter coat off and you can too. :)
  18. MNSteve

    MNSteve Well-Known Member

    Agreed. And frankly, I don't much care, as I put my comfort above burning a bit of gasoline. After all, it wasn't even an option before I bought this car.

    Preconditioning. Yes. Use it. But be aware that preconditioning using a level 1 charger (like the one supplied with the car) is much less robust than what you will see when using a level 2 charger. It is for exactly this reason that I have a L2 charger wending its way through delivery channels to me at this moment. Preconditioning with the L1 charger is still worth doing, as you will get immediate heat and you won't have used as much of your EV range preheating the fluid used for heating. But in my experience it doesn't change the interior cabin temperature very much. Just setting your expectations.
  19. The Gadgeteer

    The Gadgeteer Active Member

    Great info, thank you all. I have located a couple of Clarity Plug Ins in my area. I am leaning towards the black although all the colors look great. Leaning towards the Touring although I am not sure it warrants the added price.
    Back to heating.... I figure I will be getting so much better mileage with the Clarity PHEV anyway if I lose some miles due to climate control so be it. I have read that AC take much less a toll on range than heat. That makes sense being the heat is electric resistance heat. If the Clarity takes advantage of any engine heat that would be great since I am likely to need the run the engine some during my typical drives anyway.
    My attached garage doesn’t get that cold because of the lack of insulation in the wall between the house and the garage. So I start off somewhat preconditioned as it is. The electric heat is probably almost instant. I should be in good shape to leave my coat in the back seat until I arrive at work.
  20. The Gadgeteer

    The Gadgeteer Active Member

    Has it been determined whether or not the Clarity will use engine heat if available or only in extremely low temperatures? For example if the engine is on anyway because of HV, HV Charge, or 0 EV miles left will the climate control system leverage hot engine coolant produced by the engine since it is running? I have read the Clarity will start the engine to warm the coolant in extremely cold temperatures to use hot engine coolant but doesn't say if it will use "opportunity" heat if the engine is running anyway and there is a call for heat.
  21. MNSteve

    MNSteve Well-Known Member

    I have observed that if the outside temperature is below about 10°F that the engine will start. This has happened often enough for me to be pretty confident that it is programmed behavior - that the algorithm says, "It's too damned cold to pull cabin heat out of an already-degraded battery; let's just recognize that and use waste heat from the engine."

    It seems to be a safe bet to assume that if waste heat is available, that it will be used. I believe I am using ICE heat [nice term] when I am on the road in HV mode; it would be silly to use gas to generate electricity to then send through the resistance element to make cabin heat. On the other hand, how many "safe bets" have we made on the operation of this vehicle that have turned out to be wrong.
  22. ab13

    ab13 Active Member

    If I recall, the system heats the engine coolant for the cabin heater. The heater draws the heat from the engine coolant by heat exchanger. So you can heat the coolant by engine heat or electrical heater. That should mean as long as the coolant is warm enough, it doesn't need electrical heat.
  23. The Gadgeteer

    The Gadgeteer Active Member

    what I read was a valve opens up and allows coolant from the engine into the heater core. No heat exchanger other than the core itself being a fluid to air heat exchanger.

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