EV Batteries Never Actually Reach 0% Charge
Electric vehicles have a finite distance that they can travel on a full charge. Once you reach the upper limit of said range, the battery capacity will begin to creep ever closer to the 0% mark. At this point, you should receive beeps and buzzes reminding you to plug in the battery.
Related article: Why do EVs use Lithium-ion batteries?
If you continue to ignore these warnings, the vehicle will eventually run out of juice and come rolling to a stop. But do you know that despite the system telling you there’s 0% charge left, an EV battery’s charge never depletes to zero? That’s because there’s a built-in safety “guard rail” that prevents Lithium-ion or Lithium polymer batteries from dropping below a certain level.
There’s circuitry connected to the battery pack that prevents the voltage from dropping below safe levels and in turn, prevents damage to the battery. If things do go south, there’s a good chance the battery is permanently dead, unable to be charged again. Now, there is specialty equipment that can help revive dead batteries, but you’ll also need someone who knows what they’re doing to solve this problem.
The EV’s battery protection system will always make sure that there’s a safe amount of residual charge left over, preventing any permanent damage to the battery. That said, you shouldn’t run the battery below 10% of its available charge. This way you lengthen the lifespan of the battery and minimize the chances of there being any degradation in the near future.
Related article: Why do EVs lose range over time?
Thankfully, lithium batteries have a low self-discharge rate. If left unused for a lengthy period, they do not lose much of their charge. It’s a similar story with smartphones. Some are still usable despite being kept in storage for more than a year.
Lithium batteries are a little tricky to work with but are far superior to other alternatives. They offer a better energy to size ratio, high voltage, long service life and low self-discharge rate. That’s why, despite the inherent drawbacks, they still power most EVs on the road today.
