Does The Weather Affect EV Batteries?

Post date: 19-Apr-2020 10:13:40

If you already own an EV you know that the rated range which is how far you can travel on a single charge really doesn't ever pan out to be as advertised hi I'm Ben Psalms with Tesla Nomex and I have a special episode for you today I'm here in Brooklyn with the team that makes Tesla which is the Fitbit for your Tesla app.

And we're looking into what effects battery range and driving efficiency when it comes to efficiency for a Tesla it's kind of similar to gas cars and really any other car basically the idea is what do you expect to get out of the fuel or energy your car has versus what you actually get so if your Tesla is telling you that you'll get 200 miles on a charge and you only get 180 miles on that charge that's about 90 percent efficiency conversely if you got 210 miles on that 200 mile rated charge that would be 105 percent efficiency.

So in this way your car can be wildly inefficient or easily get over a hundred percent depending on some key variables EVs and ice cars are similarly affected by things like hills however that's where the similarities end most EV stuff like Tesla's have regenerative braking which slows the car down and recharges the battery at the same time this reduces wear on your brakes as well as giving you extra range on your charge this is extremely helpful when you're headed down mountains where your car can actually regenerate tons of power.

In fact the world's largest EV does this exceedingly well the e dumper as it's known is a 45-ton dump truck that travels up a mountain in Switzerland 20 times per day then it loads up with 60 tonnes of rock and travels back down the hill during this process the dump truck actually generates more energy than it takes to go back up making it a net positive energy vehicle that gives back to the grid more than it takes now you're not likely to see those kind of results in your Tesla or any other regular EV but some folks in Colorado regularly get upwards of 200 percent efficiency due to the routes that they travel.

The way Tesla measured this is by looking at the distance traveled versus the rain difference reported in the Tesla API this can get a bit tricky so I'll spare you the details and suggest you check out the app where you can see the efficiency for every trip you take as well as other factors like phantom drain but basically it goes back to the math that I previously told you if the car is saying you get 200 miles and in fact you get 210 then you divide those two and you see that you're now at about a hundred and five percent efficiency.

When looking at the data from all the cars in the fleet it became immediately obvious that the correlation between temperature and efficiency was quite strong this means that if you're in a colder climate you'll likely get less range out of your car than folks in warmer climates for those of you living in these areas this is a no-brainer you already know this it wasn't until we analyze this data however that we realized it also affects warmer climates.

In fact over 80 degrees Fahrenheit seems to have a negative impact on driving efficiency similar to what you see when you go below 45 degrees on the other end of the spectrum now both of these may seem obvious that you're using your heating and cooling but there's more going on than just what's on the interior of the car that could be affecting your driving efficiency.

With this data we've been able to uncover a few key insights around what can really help you with your driving efficiency wind seems to have a pretty strong impact on what we call phantom drain this is how much energy your battery losses just sitting there this is again due to temperature but even over a short period of time in a cold windy area it can really zap the energy from your Tesla so if you have the chance avoid parking in a windy area.

If you're in a crowded street in a more urban area that's going to be much better than in an open field or in a really big parking lot where the wind can reduce the temperature even further and affect that phantom drain meaning you're just gonna be losing miles while your car is sitting there another insight we had was that when the temperature goes below 50 degrees Fahrenheit efficiency really falls off a cliff and the surprising thing about that is that 15 degrees Fahrenheit isn't really that cold.

Now when it is below that you need to be conscious of your driving habits and your charging the data we have suggests that you'll lose an 10 to 20% with a median efficiency of around 60% overall in these temperatures below 50 so if your Tesla is reporting a 200 mile range only expect to get about 120 miles on that charge and make sure that you plan your trips accordingly and the last thing we've learned is about charging times.

Again it has to do with temperature and the data we have suggests that in colder temperatures you can wait almost twice as long to charge to fill up your battery with that same amount of energy if you're using a level 3 charger like a supercharger and are going to top up in about 45 minutes like you would normally you may need more like an hour and a half so depending on how cold it is and a few other factors you are gonna have to take a lot more time to charge up.

Now the data we have for this varies greatly so it's hard to say exactly what to expect but the trend is pretty clear as the temperature drops charging times go up if you live in a warmer climate like I do you might be thinking well why does this matter and the truth is that there are a lot of different things that can affect your driving efficiency as time goes on we're going to continue to monitor all the different metrics we have to understand what really affects range and efficiency for your EV.

If you don't have it already go to the link in the description down below and download tez lab for either your iOS device or your Android device and start getting a clearer picture of the health of your car and one last note if you're a model 3 reservation holder living in a colder climate I'm gonna recommend that you go with the longer range battery I know it may seem like an expensive upgrade but the data we have here and plus just talking to Tesla owners in these colder climates really points to big impacts on your driving efficiency and your overall range.

So while it may seem like a lot to pay just for those extra miles in the colder months they're really gonna come in handy I'm curious what you think do you will live in a colder climate or a really hot climate have you seen that affect your efficiency and your driving.