Is Slow Charging Bad For Your Tesla? 

The process of charging electric vehicles has happily come a long way in recent years.

Where we once had little choice about how long our cars needed to stay plugged in for, today we can take our pick between trickle charging, fast charging, rapid charging, and so-called “supercharging”.

But, as a Tesla driver, you’re probably wondering which approach is best for your car’s battery. Plus, if your options are limited, you may crucially want to know, is slow charging bad for your Tesla?

Let’s address this issue fully so that you can enjoy peace of mind.

The Tesla Take On Charging Speed

Tesla’s design team is pretty smart when it comes to what they create and their battery setups align with that standard. Ultimately, the brand recognises that different drivers will use their EV in different ways, and will likely have varying access to charging station types. Some people have a supercharging point just around the corner, while others don’t have access at all. Some people drive their car only over relatively short distances, while others rely on being able to run close to the full range that the Tesla provides.

The result of this variability is that Tesla’s engineers have created charging systems able to charge-up at various rates both efficiently and safely.

Tesla provides pretty clear guidance on how to maximise battery life, including keeping the battery between 20% and 80% as a rule of thumb and only pushing it above 90% when planning a particularly long journey. 

The only exception is if you have a Tesla kitted out with a lithium iron phosphate (LFP) battery rather than a lithium-ion (Li-ion) battery—in which case, pushing up to 100% is A-OK and should actually be done at least weekly.

That’s all well and good, I hear you say, but what about the speed of charging? Is slow charging bad for your Tesla, or is it advantageous when compared to fast charging? Well, the answer isn’t quite black and white. There are certain circumstances that might lead you to lean one way or the other, so let’s explore exactly what those are.

What Are My Tesla Charging Options?

We mentioned that Teslas can be charged at different speeds. This includes what is commonly known as “Level 1” charging, which is when the car is plugged into a standard single-phase household outlet. This can be considered slow charging or trickle charging, and depending on the power supply and battery size, fully charging a particularly low Tesla battery may take days to accomplish.

Next, we have a “Level 2” charging outlet, which would operate at 3-phase and either come from a purpose-built wallbox installed in your home, or a Fast Charging station located out and about. 

Stepping further up in speed, we find Rapid Charging stations, which are increasingly and conveniently to be seen at service stations, malls, and within city centres due to their ability to get drivers powered-up and on the road again in anything from mere minutes up to a couple of hours depending on their unique charging needs. 

Finally, as a boon for us Tesla Drivers, we have our go-to car-makers network of exclusive Supercharger stations, which are reserved for us and us alone. Once again depending on battery size, these speedy destinations can probably take your Tesla from 20% to 80% in around 20 minutes.  

Is Slow Charging Bad For Your Tesla?

When a battery is charged very quickly, the process generates a lot of heat. If left unchecked, that rise in temperature can lead to damage which shortens the lifespan of the battery. That said, Teslas are fitted with battery-monitoring and charge-controlling systems that keep a close watch on your battery’s condition at all times and adjust charging rate or kick in a cooling system as required.

In contrast, slow charging doesn’t generate that intense heat, which you’d think would make it the better option. However, it turns out that extended charging duration can also very slightly reduce battery lifespan by altering the chemical makeup within the battery itself. With this in mind, some would argue that there’d be a loss of performance with constant trickle charging, but this is likely to be negligible.

It’s definitely worth noting that if your Tesla battery has already taken some hard knocks due to over-draining, slow charging does indeed become the best option. A battery that is not in great shape will be more vulnerable to the impacts of fast charging, so opting for a slower charge may help you mitigate ongoing degradation.

The last consideration to make in deciding how fast or slow to charge your Tesla is electricity usage. For some, living in an area with lower nighttime rates may make it very appealing to be able to fully charge their car within that narrow and cheaper power window. It’s also worth noting—even if you pay the same rate 24 hours a day—that slow charging is less efficient than fast charging, so overtime, you’ll use more a tiny bit more power overall and your EV’s running costs will be higher.

At the End of the Tesla-Driving Day

So what does all of this tell us? At the end of the day, Teslas are fantastically designed to adapt to faster or slower charging rates and intelligently modulate your charging sessions through self-protective functions as required. 

A damaged battery may benefit from slower charging – though it is of course better to avoid battery damage in the first place by not repeatedly draining your battery from 100% to near zero.

The best thing that you can do is adhere to Tesla’s battery care recommendations, and if you do that, you should be rewarded with a decent battery lifespan and a positive driving experience all round.