Electric Vehicle battery charging is a key aspect of owning & operating an EV. An EV battery’s charging is the process of replenishing the EV’s power source, essential for keeping it on the road. Charging options range from slow, convenient methods using standard household outlets to faster setups requiring specialized equipment, often found at public EV charging stations. In this blog, EVJoints answers some important questions related to EV charging:
What is BMS in an EV?
Battery Management System (BMS) is the nerve centre of an EV’s battery which monitors & controls its performance. It ensures that any operation out of the battery’s safety limit is prevented. It continuously manages input voltage & temperature, and monitors the battery’s State-of-Charge (SoC). (An EV battery ‘State-of-Charge’ (SoC) represents the remaining charge in the battery.)
What is the best percentage to charge an EV?
Most EV batteries perform best when kept between 20% and 80% capacity. Dropping to 10% or below regularly can strain the battery. It’s better to plug in at 20% to avoid dipping too low. Waiting until 10% won’t ruin the battery immediately, but it’s riskier if you misjudge and run out of charge.
Should I charge my EV to 100% every night?
EV owners should avoid charging their EV to 100% every night. Charging to 80% is usually enough for daily driving, and it’s gentler on the battery. Charging to 100% generates more heat than charging to 80%. This heat generation can damage the battery, leading to reduced efficiency & capacity over time.
Fast charging pumps a lot of power into the battery quickly, generating heat & stress. EV batteries handle this fine up to about 80%, but beyond that, the charging rate slows down to prevent overworking the cells. Pushing to 100% regularly with fast charging can speed up degradation, reducing the battery’s capacity over time.
What is the 80/20 rule for EVs?
The 80/20 rule for EVs is a guideline for managing battery charge to optimize lifespan & efficiency. It suggests keeping your EV’s battery between 20% & 80% capacity most of the time. EV owners should try and not let battery charge drop below 20%, and also not charge it past 80%.
This rule comes from how lithium-ion chemistry works. Keeping the charge in this range (20%-80%) minimizes wear and tear.
Is it okay to drain the EV battery to 10%?
EV owners should avoid draining the battery to 10%. Dropping to 10% is ‘deep discharge’ territory, and while it won’t kill your battery in the short-term, doing it often can stress the battery and accelerate capacity loss over time.
What is the EV battery charging curve?

The EV battery charging curve describes how the charging speed of an EV’s battery changes as it fills up.
From 0% to around 60-80%, the EV charger delivers a steady current. This is the fast charging phase and the battery charges quickly.
Past 60-80%, the EV charger slows down to avoid over-stressing the cells. That last 20% can take almost as long as the first 80%.
Is frequent slow charging bad for EVs?
No, frequent slow charging isn’t bad for EVs. In fact, it’s generally better for the battery than frequent fast charging. Slow charging, by using a Level 1 or Level 2 EV charger at home, puts less stress on the battery compared to DC fast-charging at public EV charging stations.
Is frequent fast charging bad for EVs?
Frequent fast charging can accelerate battery degradation over time compared to slow charging. DC fast-charging pumps in a lot of power in batteries, generating heat. High temperatures are a key driver of EV battery degradation. If you fast charge regularly, you might see considerable battery capacity loss sooner. Fast charging once or twice a week is acceptable. Modern battery management systems (BMS) are good at dealing with such habits. Fast charging is okay if you need it but go for slow charging whenever possible.
Conclusion:
An EV owner’s charging habits can affect the battery’s long-term health. It’s a straightforward yet evolving technology that’s central to the EV experience.
For more insights on EVs & EV charging, visit EVGuide by EVJoints.