How Batteries Work: Slow vs. Fast EV Charging
The omnipresence of battery technology in our day-to-day life has made people much more aware of “batteries” as technological marvels that require care and maintenance. So it’s no surprise that these discussions are making their way to electric vehicles and EV chargers. Any vehicle represents a substantial investment, and people are right to want to know how to help their batteries — which lay at the very core of their EV’s function — last as long as possible. In large part, these concerns center on how charging speed affects batteries.
Here, we hope to educate both drivers and potential EV charger owners about how various charging speeds affect batteries. To do that, however, we need to understand charging speeds and batteries themselves. Let’s take a look at how a slow charge and fast charge affect your car’s battery.
EV Charging Speeds
Generally speaking, EV charging comes in three different speeds: level 1, level 2 and level 3 — also called direct current fast chargers (DCFC). While level 4 chargers are hitting the market, they’re still not widely tested.
Level 1 chargers are something you’re intimately familiar with. In fact, they’re mostly just regular residential outlets. They’re inexpensive but slow, often taking 40-50 hours to completely fill an all-electric battery.
Level 2 chargers are equipment specific to charging EVs and are the most common form of EV charger. They can fill an all-electric battery in roughly 4-10 hours. Regardless, we can consider both level 1 and level 2 chargers as “slow” chargers.
Level 3 (DCFC) chargers are the high-end option. They’re most common on high-traffic roads where people need to get in and out fast, and can get a battery from zero to 80% in as little as 20 minutes.
How Chargers (and Batteries) Work
Where electricity is concerned, charging speed is directly related to charging volume, which is directly related to heat. Think of it like filling a cup of hot coffee. If you drip it in drop by drop, you’ll fill slower, but the heat will have time to dissipate into the air and surrounding materials. If you just dump the whole steaming pot into the cup, however, it’s likely to burn you.
Batteries are the same way. This means that, where charging speed is concerned, the primary issue is temperature. If the batteries don’t have decent cooling systems, they’re going to be damaged when the temperature exceeds a certain level: roughly 104 degrees fahrenheit. Both cold and hot conditions can affect battery charging and overall performance. Below-freezing temperatures or hot weather make certain battery conditioning technology necessary. Both active and passive cooling systems exist, with active being more effective but coordinatingly more expensive.
It’s important to note that charging and draining a battery will always degrade it, in the same way, that engines and computers and anything else will degrade over time. Nothing can last forever, and while batteries seem to magically fill with invisible energy, the laws of physics still apply. Luckily, a degrading battery can be maintained by repairing damaged cells, and this can extend the life of an EV battery for years and years.
Outside Factors
So we’ve established that the main concern is heat. If a fast charger is going to do damage to your car’s battery beyond the usual degradation that comes with use, it will likely be heat-related.
As such, there are two major outside factors to consider: ambient temperature and your individual EV’s cooling systems. In parallel to gasoline vehicles, you’ve probably noticed that you’re much more likely to see broken-down vehicles on the side of the road in hot weather, and those vehicles are more likely to be heavy and old.
The same is true with these batteries but in regard to life span. As such, the outside temperature and your own vehicle’s battery cooling systems should both be considered when deciding what kind of charger to use.
So…What’s the Breakdown?
Where level 1 and 2 chargers are concerned, there’s little to no risk posed to your battery by charging speed. Unless you live in the Arizona desert, both are likely to keep your battery well within its specified charging temperatures. Level 3 chargers may pump in electricity much more quickly, but they are still designed to keep your vehicle within its operating temperature (which depends on environmental factors like weather, too). The good news is that we haven’t yet seen scientific evidence that battery degradation caused by charging heat causes an early breakdown of the battery.
What Charger To Install on My Property?
Unless you live in an extremely hot area, concerns about battery damage are unlikely to be the deciding factor in what charger you get. More likely, factors like installation costs and business needs will play a role in your choice. If you have questions about what level charging station is right for your business, connect with an expert on our team today!
Sources
Forbes - Electric Cars Can Fast-Charge Safely, but Range Still Dives at Speed
U.S. Department of Transportation - Electric Vehicle Charging Speeds