Does the 80% Charging Rule Still Matter? | EV Basics

Summary

The video script from 'EV Basics' discusses the '80% rule' for electric vehicle (EV) charging, which suggests charging to 80% to prevent battery degradation and slow charging rates post this point. It explains that while this guideline is beneficial for EVs with nickel-rich chemistry (NMC) batteries, it's less relevant for lithium iron phosphate (LFP) batteries, which can be charged to full without concern. The script also highlights the differences in charging recommendations between NMC and LFP batteries and emphasizes the importance of following the manufacturer's charging guidelines.

Takeaways

• 🔋 The 80% Rule is a guideline for electric vehicle (EV) owners to charge their batteries to 80% to improve the EV ownership experience and prevent battery degradation.
• 🚗 DC fast charging rates for EVs often slow down significantly after reaching an 80% state of charge, which is one reason for the 80% Rule.
• 📈 Battery degradation over time can be mitigated by capping the charge to around 80%, which is beneficial for preserving battery capacity.
• 🕒 The Hyundai Ioniq 5 can fast charge from 10% to 80% in 18 minutes, but takes nearly twice as long to reach 100% from 80%.
• 🎥 The script uses the analogy of a movie theater to explain why it's harder to charge the last 20% of an EV's battery, similar to finding a seat as the theater fills up.
• 🚧 Automakers recommend not charging to 100% regularly to help preserve battery health and potentially reduce warranty costs.
• 🛠️ The 80% Rule is not mandatory but is a smart practice, especially if the daily driving range does not require a full charge.
• 🔌 The type of battery chemistry in an EV affects charging recommendations; most US EVs use nickel-rich lithium-ion batteries (NMC or NCM).
• 🔄 Lithium iron phosphate (LFP) batteries, which are less common in the US, can be charged to 100% without the same degradation concerns as NMC batteries.
• 📚 Tesla recommends setting the charge limit to 100% for daily use for models with LFP batteries and to fully charge at least once a week if the car has been sitting.
• 📖 It's important to check the vehicle's owner's manual to determine the battery chemistry and follow the manufacturer's charging recommendations.

Q & A

What is the 80% rule for electric vehicles?

The 80% rule is a guideline that encourages EV drivers to charge their vehicles only up to 80% to help prevent battery degradation over time and to avoid slower charging rates that occur after reaching an 80% state of charge.

Why does charging an EV to 80% help with battery degradation?

Charging to 80% can prevent battery degradation because it avoids the slower charging rates that occur after reaching an 80% state of charge, which can be stressful for the battery and lead to reduced capacity over time.

How does the charging time differ between 10% to 80% and 80% to 100% for the Hyundai Ioniq 5?

For the Hyundai Ioniq 5, it can DC fast charge from 10% to 80% in about 18 minutes, but it takes nearly twice as long, 32 minutes, to go from 80% to 100%.

What are the two main types of lithium-ion batteries used in electric vehicles today?

The two main types of lithium-ion batteries used in EVs are Nickel-Manganese-Cobalt (NMC) and Lithium Iron Phosphate (LFP).

Why might the 80% rule not apply to all electric vehicles?

The 80% rule might not apply to all EVs because it depends on the battery chemistry. For instance, LFP batteries can be charged to 100% regularly without the same concerns for degradation as NMC batteries.

What does the acronym 'NMC' stand for in the context of electric vehicle batteries?

NMC stands for Nickel-Manganese-Cobalt, which is a type of lithium-ion battery chemistry commonly used in electric vehicles.

What is the recommendation for charging a Tesla Model 3 with an LFP battery?

For a Tesla Model 3 with an LFP battery, Tesla recommends setting the charge limit to 100% for daily use and fully charging to 100% at least once a week if the car has been sitting for more than 7 days.

How often should you fully charge an electric vehicle with an LFP battery according to Ford's recommendation for the Mustang Mach-E?

Ford recommends setting the maximum charge level to 100% and charging to 100% at least once a month to maintain range accuracy for the Mustang Mach-E with an LFP battery.

What is the role of Michelin Defender LTX Platinum tires in the context of the video?

The Michelin Defender LTX Platinum tires are advertised in the video as an ultra-premium option for heavy-duty vehicles like the Tesla Cybertruck or RIVIAN R1T, designed to last twice as long as their predecessor with a 70,000-mile warranty and roadside assistance.

What is the significance of the 80% rule in relation to DC fast charging?

The 80% rule is significant for DC fast charging because it suggests that drivers should avoid charging all the way to 100% using this method, as it can take a long time to reach the last 20%, regardless of the battery chemistry.

How can viewers find the right Michelin Defender LTX Platinum tire for their vehicle?

Viewers can find the right tire for their heavy-duty vehicle by visiting Michelin's website, scanning the onscreen QR code, or clicking the link provided in the video description.