One of the biggest problems with Tesla vehicles up to this point may have just been fixed with this new feature on the Model Y that Tesla decided to hide from us until now. Let’s talk about it.
Tupac once said “California knows how to party” but what about the rest of the country? See, Tesla vehicles are made in California, and many people have claimed that Teslas are designed with the typical California climate in mind, where it’s pretty much warm year round. So when someone like me who lives in the Midwest where it gets below freezing in the winter, driving a Tesla can be somewhat scary because of “range anxiety” which means you’re worried about running out of battery before reaching your destination.
In cold winter conditions an electric vehicle can lose up to 40% or more of its estimated range. In February I was on a road trip in my Model 3 and lost 50% of my estimated range while driving highway speeds when it was around 30 degrees Fahrenheit outside. I pulled in my driveway with 4 miles of estimated range remaining. I had a little range anxiety.
But why do electric vehicles lose so much range in cold temperatures? It’s mostly due to three things: colder air which means more drag, energy loss from heating the battery, and the energy used to warm up the vehicle’s cabin. All Tesla vehicles prior to Model Y, warm the cabin through something called a resistive heating system where electricity is sent through a resistive heating element, which creates heat that’s blown out of the air vents. A resistive heating system does not produce heat unless the heat is turned on. Think of it like you’re running a space heater that’s plugged into the wall in your house. It’s immediate heat as soon as it’s turned on. This is unlike in a gasoline vehicle which uses some of its waste heat to heat the cabin.
An electric car doesn’t have as much waste heat as an internal combustion engine vehicle which is why resistive heating is commonly used. This means for an EV (like my Model 3) to warm up the cabin, energy from the battery must be used which of course decreases the estimated range. An interesting thing to know, however, is electric resistance heating is considered 100% energy efficient in the sense that all the incoming electric energy is converted to heat. For example, in the Model 3, S, and X, one unit of electricity turns into an equal unit of heat thus 100% efficiency.
So you may be thinking: Well it doesn’t get any better than 100% efficiency, right? Well, actually there is something better. It’s called magic. No not really. It’s called a heat pump, and the Model Y is the first Tesla to have one. In the manual it says “Model Y uses a heat pump to maximize efficiency; therefore, your air conditioning compressor and external fan may run and make noise even when the outside temperature is cold and your vehicle is heating or Supercharging”
So what is a heat pump and how is it better than resistance heating? A heat pump can be thought of as an air conditioner that has the ability to work in reverse. An air conditioner works by using refrigerant to trap the heat inside of an area, then move it outside. A heat pump works in exactly the same way, only it has a reversing valve which allows it to reverse the flow of the refrigerant and heat an area when it’s cold out.
Heat pumps help efficiency because they move heat rather than generate it. The electricity is used by the compressor to send refrigerant around the system and capture the heat from outside, then bring it inside. It can do this because the refrigerant has an extremely low boiling point. And the best part is a heat pump can typically produce around 3kW of thermal energy for every 1kW of electrical energy resulting in an “efficiency” of 300%. I used air quotes for efficiency because according to the law of physics it’s impossible to have an efficiency greater than 100% because you can’t create energy from nothing. So instead, it’s expressed as a Coefficient of Performance or (COP) rather than efficiency.
So this “300% efficiency” sounds awesome, right? Well, there’s a catch. Heat pumps are usually not effective below a certain temperature range and typically don’t work well in extremely cold temperatures. However, heat pump technology has recently improved, and in some cases can be rated for outdoor temperatures as low as -4°F. So why is the Model Y’s heat pump so important? Well, as you can guess by now, a heat pump should be able to heat the cabin while using less energy which should lead to longer battery range when driving in cold temperatures compared to all the other Tesla models. This is a huge advantage! Actually an article by GreenCarReports claimed that in New York City at 14 degrees, an EV’s heat-pump-based system offered up to a 30 percent improvement in driving range. It’ll be interesting to see how the Model Y winter range improves compared to the other Tesla models. The only downside to a heat pump is it’s slower to heat compared to resistive heating.
Even though the Model Y is the first Tesla to have a heat pump, some other EVs including the Nissan Leaf have already had it as an option for a while now. So if heat pumps are really that much better than resistive heating, why didn’t Tesla implement this before the Model Y? Most likely it was because a heat pump adds cost, complexity, and weight. But for a Tesla, which already has an air conditioner, a heat pump seems like a no-brainer because the added complexity would be pretty minimal. And it seems with the Model Y Tesla finally decided that it was worth it. After all, Teslas are going out to all parts of the world where there are actual real winters instead of just sunny California.
I guess the biggest questions now are: where does the heat come from in the Model Y heat pump and does the Model Y always use a heat pump or does it alternate between heat pump and resistance heating? From the Model Y manual it looks like it could be taking excess heat from the motor and battery, which would probably make it efficient even in extremely cold temperatures which would be nice. Teslas already have the ability to use the motors to heat the battery, and if the heat pump is powerful enough it can potentially heat both the battery and the cabin.
Either way, I can’t wait to see how the Model Y handles driving in the winter. It sounds like it will be the best Tesla for that task. I can’t wait to get mine and I’ll be doing a lot of videos about it so be sure to subscribe so you don’t miss out on those. What do you think about this new feature? Let me know in the comments below. If you enjoyed this video please be sure to give it a thumbs up. My name is Andy. Thank you for watching and I’ll talk to you in the next one.