Cold Weather Questions

Looking through the trip videos in this youtube channel should answer your charging questions. He shows stats from OBD2 dongle so you can clearly see the battery temperature, SOC, and charging rates. In summary, battery needs to reach about 25C/77F temperature before it will accept maximum charge rate regardless of SOC. Those kind of temperatures are almost impossible to achieve through normal driving if ambient temperatures are much lower. The optional winter package includes a battery heater that somewhat speeds up warming the battery during charging but it's still very slow. Be prepared for most of your session to be at the <55 kW rate before reaching 70+ kW towards the end when battery gets hot from charging (assuming you have not reached the ~55% SOC step down).

 

Thanks, all. Though I'm surprised to hear that even after driving on the highway from 100% down to 10% SOC, you can't count on 70+ kW charging speeds while charging back up to 40-50% SOC. It would seem that a few hours of highway driving would warm the battery enough, even in 20-30 degree F ambient temps. Anyway, thanks.

 

My experience driving at highway speeds for 2 hours at -9C ambient resulted in a battery temp at 12C when I stopped for a fast charger(250Kw) with 16% SOC. It took 26 minutes for battery heater to raise the battery temp to 25C at which point the DC max delivery was 78 Kw/h with an indicated 51% SOC. The charge rate stepped down to 58 Kw/h when it hit a SOC at 55%, battery temp was 28C at that point. According to my measurements if I did not have a battery heater my max charge rate under similar driving conditions and ambient temperature would have never exceeded 43 Kw/h for the entire charge session. So while the battery heater is not as fast as the Teslas( they can start pre heating before arrival at supercharger) it still made an appreciable difference in time and cost per DC charge session over a similar vehicle without a battery heater.

 

Teslas have an effective ~7 kW battery heater when idling their dual motors while parked. The dedicated ~1-2 kW battery heaters in other EVs pale in comparison and are the reason it takes so long to reach optimal charging temperature. The fact that Teslas can start pre-conditioning their battery while navigating to a charger is just icing on the cake.

When I was doing a long trip at ~50F, I observed the same long ramp up (20+ minutes) before battery reached maximum charging temperature. I don't have the battery warmer so can't say how much it would have helped if at all. You have to keep in mind that the charging process itself also generates a lot of heat even without the battery warmer present.

The good news is that once your battery gets hot, the large thermal mass will keep it hot for a long time after you resume driving. Chances are that you will still be at optimal charging temperature by the time you reach your next charger. That was my experience driving at ~80mph in 40-50F ambient. So the slow charging speeds are mostly a problem for your first stop. The key is to make more short stops and resume driving when the charging speed decreases.

 

I’ve heard stories about kias front wheel drive causing issues on ice and snow. These include poor traction at initial throttle usage with wheels spinning. Also on icy roads and full Regen on there have been issues with braking and full Regen 3 and ABS system.
I’m also considering a model 3 RWD so I’m curious if anyone has driven both in poor winter conditions and icy slippery roads. Everything works well in summer but it’s winter that puts these cars to the test. Snow tires are required by law. Range is same for both so this question is not about winter range or how it significantly decreases in cold weather.


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I live up a hill in Vermont. and my street is a 90° right is also blind and uphill again. My neighbors have front wheel drive or four wheel drive. I use studded winter tires. You can carry a fair amount of speed going up the first hill, but to make the turn, you have to slow down to avoid skidding, and to see if the road is clear. the niro's big advantage over an ICE car, is that it doesn't stall, so it will continue to try. Success is based on driving skill and driving conditions. failure is most often a result of conditions that are not suitable for driving

 

What about the Regen and interference with abs braking system. Does this exist?


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ABS works if you provide enough force on the brakes. I remember being concerned about regen when I first began to drive on snow and ice. After I got used to the car and studded tires, it did not seem to be a problem. I think I am in regen 1 or 2 most of the time the winter. In the summer, I am in region O, because it is most efficient to coast. The brake pedal uses regen anyway, except for panic stops. Feel the rotors after regen 2 (cold) or region O brakes (warm or hot). Niro does really well, the battery weight helps.

 

That’s helpful. Thanks


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As a new Niro ev owner I’m not sure how the battery heater works. If the car is sitting out in the cold does the battery heater kick in when the vehicle turns on? Does it try and maintain a certain battery temp even when the car is not in use? Do I need to set the car to turn the battery warmer on? Little instruction in the manual
Thanks

 

This is a great explanation from a Kona foum member nzkiwi68
I will just cut and paste as follows:

1. You only get the "Winter Mode" on/off menu option if your EV has the battery warmer fitted.
2. The BMS will use the battery warmer to heat the battery whilst plugged into a charging connector, regardless of winter mode off or on, according to the battery temperature automatically.
3. Winter Mode ON will heat the battery whilst driving if the battery gets very cold. I've read others say at under -10 deg C.

So point 3 is really what 'Winter Mode" is all about, heating the battery whilst driving in very cold conditions for 2 reasons;

• At very cold temperatures (under -15 Deg C) the BMS will drastically reduced the power output from the battery to a very low 35 kW. With Winter Mode ON, the battery warmer will prevent the battery from becoming too cold and thus continue to allow full power output from the car, at the expense of reduced range (because the 2 kW battery heater is used whilst driving)
• Because the battery was heated during driving, fast DC charging is possible at higher rates immediately, because the battery has not allowed to get too cold. Without winter mode ON, the battery heater would come on when plugged in to charge, but obviously it will take time to heat up the battery and allow the faster DC charging rates. So winter mode ON helps faster DC charging rates, only useful at low temperatures and again at the expense of range as the battery warmer operates whilst driving.

 

Thanks so much for this. I just discovered this forum and was trying to find exactly this description. That now leaves me with only this question. What, exactly, is the function of the winter package/heat pump? How does it affect range and charging times if at all?

 

Well the winter or cold package is typically the inline 2Kw battery heater, heat pump and associated software to control these. As discussed the battery heater helps maintain full motor power and speeds up DC charging(modestly) in very cold temperatures. Heat pump is basically reverse air conditioning and uses available byproduct heat energy in the cooling circuit available from the motor, inverter, electronics and in ambient air to heat your inside cabin. It is much more efficient than a resistive heater. At ideal external temperatures/peak efficiency it can return as much as 3 time more heat energy than a comparable powered resistive heater. Its effective operating range is approximately between -7C and 15C. It looses efficiency as the ambient temperatures drops, below ~ -7C the resistive becomes more efficient with a 1:1 heat to energy return and the car stops using the heat pump. Up until that point it may use the heat pump alone or in combination with the resistance heater depending on outside/inside temperatures and how much heat is requested by the user or auto HVAC settings. The official claim is that heat pumps can improve range up to 30%. Again that assume ideal conditions for peak efficiency.(ie you enjoy full cabin heat all the time and only drive around when its +5C) From my experience during shoulder winter temperatures(-5 to +5C) the heat pump functionally extends the car's range by around 10% There are just too many variables to give you an exact number.

 

This is very helpful. The only thing that I have done is to check the four read outs on the central display that split out drive energy, HVAC energy, electronics, and battery conditioning, which by the way I have never seen registering anything. As one drives, the heat pump starts out at 1.5 to 2 kWh draw, but after about twenty minutes, it drops down to .35 Kwh to .6 Kwh. Some of this is due to the cabin being brought up to temperature, but the rest is due to the heat pump's effectiveness. Also, fan energy seems to be registered under electronics.

The are add-on OBD devices which register battery temperature, which have helped educate me on what is realistic to expect in charging speeds at cold temperature. The battery starts off at low nighttime temperature, so if one starts a trip at say 9 or 10, the battery might be 5°C colder than the daytime temperature. driving a 100 or so miles does not do much, so you first charging session will be slow, but the battery will get into the 20°C to 25°C ranges at the end of the session. This will help the next changing be faster. Anyway, cold gate is a problem, but maybe only less than 10% of the time

 

Thank you very much for your reply. You have been very helpful.

 

We have a feature request for Hyundai/Kia for adding an option to manually preheat the battery before DC charging, and thus minimize the coldgate. Asking local dealers individually was not yet successful, so trying another channel as a petition. Please sign if you are interested. Thanks for signing and/or sharing. We have currently 426 people after 5 days.

https://www.change.org/p/kia-motors-global-add-manual-battery-preheating-for-kia-e-niro-ev-my19-21-hyundai-kona-electric



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Leaf owner chiming in here. I've experimented on slippery roads trying to throw the Leaf off. On acceleration the moment the car detects any wheel slip you can instantly hear the traction control braking the spinning wheel. If it's really slippery it cuts power to the motor. I have found this sometimes works against you in deep snow as the power cut can cause you to bog down.

I mostly drive in the "B" mode which provides strong regeneration. The moment the car detects a skid or slip it cuts the regen off completely. Regen is also quite limited at the upper states of charge when it's really cold out. I never charge to full any how unless the next day's run demands maximum range. All in all the Leaf is a real trouper in the cold. I use the heated seats and steering wheel to minimize use of range killing heaters.

The stock tires on the Leaf are designed for mileage not traction and I imagine it is the same with other EVs. They are not merely inadequet in the cold. They are downright useless. Winter tires further reduce range but give me the grab to haul my way through just about anything.