Should I charge my Tesla every day and night?
One of the first questions every mindful electric vehicle owner asks after receiving their EV is: how often do you have to charge a Tesla? Is it best to fill up the battery every night? Or are there negative consequences to frequent charging that might increase energy consumption or harm the battery in the long term? What are the pros and cons of frequent charging?
We took a look at all the factors, so you don’t have to, and here is what we found.
Tesla’s Official Stance on Charging Frequency
The Tesla owner’s manual for a Model S says in no uncertain terms, “the most important way to preserve the battery is to LEAVE YOUR VEHICLE PLUGGED IN when you are not using it.”
It also states that “there is no advantage to waiting until the battery’s level is low before charging.”
The instructions are more or less identical for the Model 3, X, and Y, and share similar guidance for how often you need to charge your Tesla’s battery.
However, while there are many beneficial reasons to plug in your Tesla every time you get home, there is definitely a bit more nuance to consider if you want to maximize your battery life and have optimal charging for your EV.
This article will explore the benefits of daily charging, as well as the financial costs, so that you can determine how often you have to charge your Tesla for the best results.
Benefits of Charging Your Tesla Daily
The most obvious reason to charge every day is to increase the range available to you at the start of any given trip. The longer you drive without plugging in your Tesla, the less electrical charge you will have left.
However, according to the Federal Highway Administration, the average American only drives 37 miles per day, far less than the range of a fully charged Tesla.
The Standard Range Plus version of the Model 3, which has the lowest range estimation of any car that Tesla currently offers, gets an EPA estimated 250 miles of range on a full charge. This is enough for the average American to drive nearly a full week before depleting their battery completely. If this was all there was to consider, you could skip several days before charging and likely never run into problems.
However, the range contained in a brand-new battery charged to 100% is not the range you should rely on every day. As a Tesla ages, its battery capacity slowly drops, approaching a 10% reduction after 185,000 miles according to crowd-sourced data.
Lithium ion batteries are also damaged when they spend time in the very high and very low ends of the charge spectrum. For this reason, Tesla ships EVs with a maximum charge limit of 90% by default, and recommends you stay above 20% at all times.
Additionally, Tesla’s computer and auxiliary systems can use up a small amount of battery every day the car sits idle.
These restrictions might make it seem like you should charge your Tesla as often as possible to keep your battery healthy, but it’s not quite so simple.
Even with high mileage degradation, on a low range model, following strict battery health instructions, you only need to charge your Tesla about once every four days if you drive average amounts.
There is one more thing to consider about how often you have to charge your Tesla, and it should not be overlooked. Tracking your charge-level across multiple days and remembering to plug in requires a lot of mental effort. It can be easier for some people to just plug in whenever and wherever they arrive, always keeping the battery at a maximum charge.
However, for those who want to truly optimize the battery life of their Tesla, as well as manage the costs of electricity, then there are a few more things to consider before deciding how often you need to charge your Tesla.
How Does Daily Charging Affect Tesla Battery Health & Electricity Costs?
One drawback to charging your Tesla every day, especially in cold climates, is that you will increase the amount of energy you lose to preconditioning. The colder it gets, the quicker these losses will add up.
Preconditioning is the term for heating the battery to the optimal temperature for charging. This happens every time before a battery is able to accept a charge.
You can save on electricity costs by charging your Tesla once for a long duration, rather than multiple short periods of charging time. This reduces electrical costs because you avoid unnecessary preconditioning for your Tesla battery.
Verified EV owners on a Tesla Owners forum have noted significant savings. Some have elected to drive longer between charges during colder months due to the noticeable utility cost savings.
Another drawback to charging your Tesla too often is an increase to your battery’s cycle count. This concept is pretty nuanced, so let’s define a few terms first:
A battery’s cycle count is the number of times it is charged and then discharged, regardless of the energy used.
A battery’s depth of discharge, or DoD, is the percentage of full capacity each cycle uses.
There are many different battery formulae used across the world that still qualify as lithium-ion, but generally speaking, increasing your depth of discharge can get more total life out of your battery.
At 10% DoD, a lithium-ion battery can be expected to endure about 15,000 cycles before its capacity drops to 70% of new, while at 20% DoD, that number drops to 9,000 cycles.
However, since each cycle in the latter case gets double the range (20% vs. 10%), the battery in that scenario gets the equivalent of 18,000 cycles at 10% DoD, and is therefore healthier and lasts longer.
10% of a Tesla’s range is somewhere between 25 to 35 miles, which is right around what the average person drives in a day, meaning charging your Tesla every other day will get more life out of your vehicle.
That said, as your discharge depth ramps closer and closer to a full 100%, it actually gets significantly worse for your battery health. This should also be considered when deciding how often you need to charge your Tesla.
20% DoD produces the most full cycle equivalents before degrading to 70% of new capacity
Many EV owners also pay for electricity on a time-of-use rate schedule, meaning their prices fluctuate based on the time, day, and season in which they use electricity.
If this describes you, and you typically charge your Tesla at home after work, then you could be paying the highest utility rates to charge your Tesla during hours of peak pricing.
For example, weekend rates typically offer reduced rate schedules, meaning delaying a charge from Friday to Saturday could save you a significant amount of money on your utility bill. Fortunately Optiwatt offers a free app that will automatically schedule your Tesla to charge during off-peak rates
So How Often Do You Have to Charge a Tesla?
In the end, Tesla's official guidance to plug in your car as often as possible is designed to keep maximum range under the hood.
However, EV range is only one consideration. Tesla owners who want to maximize the long-term health of their battery, as well as reduce their electricity costs, need to consider all of the elements to fully optimize their EV.
Tesla owners can further optimize for your wallet and battery health by plugging in slightly less often than daily.
Charging your Tesla once every two or three days in off-peak electricity pricing periods will cost less and increase the lifespan of your lithium-ion battery.
You can save costs on charging your Tesla by reducing preconditioning time and maximizing the use of regenerative braking.
The lifespan of your battery will also be extended by lowering your cycle count and increasing your average depth of discharge.
When it comes down to it, only you can decide how often you have to charge your Tesla based on your individual needs. We have laid out the primary benefits and drawbacks of plugging in daily, and hopefully they are helpful in steering you towards an optimal schedule for your situation.
Whether you want to maximize ange at your fingertips, reduce your utility costs, or further reduce your environmental impact, Optiwatt is always there to help.