Heard of the 80/20 or 20/80 charging rule? It means always keeping your electric vehicle (EV) charged above 20%, and never topping it up over 80%. We’ll explain how this works and why it’s important.
If you’re new to EVs, it’s natural to want to fully top up. But there’s a good reason for the rule, and 80% is usually more than enough for most journeys.
We’ll show you how it’s more efficient and how it’s better for your battery. And we’ll give you some EV charging tips.
- Why not charge my EV to 100% every time?
- EV charging for an everyday journey or a longer trip
- Why it’s best to keep 20% charge, and stop at 80%
- Charging slows down after 80%
- What this means for Scheme customers
- It’s about confidence, convenience, and EV battery care
Why not charge my EV to 100% every time?
Charging to 100% makes sense for your phone, laptop, and devices at home. But for an EV, regularly charging to the max can put stress on your EV’s battery.
When a battery is charged, used, and recharged, that’s one charging cycle. No battery lasts forever, but an 80% charging habit puts less stress on the battery.
EVs are designed to last, with battery management systems to help your battery work properly. But if you want your battery to last even longer, the 80/20 rule can help a lot.
If you’re curious about your battery’s health, you can check it to get an idea of how well your battery is lasting.
EV charging for an everyday journey or a longer trip
Most daily drives need far less than 100% charge to get you where you need to be. A school run or driving to an appointment is likely to use well under 80%.
For longer trips, it’s OK to charge your EV up to 100% because it’s an occasional trip and not a regular habit. If you did this all the time, your battery would feel the pressure.
We know what it’s like: you’ve got a long distance to cover, and you need that peace of mind to know you’ve got as much charge as your EV can handle. So charge up fully before you set off.
Why it’s best to keep 20% charge, and stop at 80%
Keeping your electric car charged above 20% helps keep your battery healthy and makes sure you never break down because you’ve run out of charge. Keep that 20% in reserve. You never know when you might need it.
Another great reason to do this is that you’ll save a lot of time.
Think about the time you spend charging at home or on the go. Then imagine spending one-fifth less time doing that.
Here’s a top tip: some EVs let you set an 80% limit on charging, so it automatically stops once it hits 80%. That means you can enjoy your rest stop in peace, and you’ll never accidentally go over. Your dealer can tell you more. Or read your vehicle’s handbook.
Charging slows down after 80%
You might think your EV charges at a consistent speed, but it actually changes from beginning to end. It’s known as the charging curve.
Your battery starts to charge much more slowly once it crosses over 80%, because the electrons coming in have to work harder to find space. Simply put, your battery charges more easily when it’s still a little empty, rather than nearly full.
Using the 80/20 rule might help look after your braking system too. If you leave your battery a little room, it can take in energy from regenerative braking.
It’s great for your bank balance too. You’ll save money if you turn the 80/20 rule into a habit. So always quit while you’re ahead and stop at 80%.
What this means for Scheme customers
If you’re on the Scheme, we’ll support you with charging. We’ll arrange a home chargepoint and a standard installation as part of your lease, or give you access to the BP Pulse network.
75% of EV owners charge at home and find it convenient. So having a home chargepoint installed, if you meet our criteria, can give you a lot of peace of mind.
Whether you’re charging at home or on the go, we’ll help you feel confident on your daily journeys and supported on your longer trips.
It’s about confidence, convenience, and EV battery care
We hope we’ve shown you how impactful the 80/20 rule can be. It’s all about giving you confidence and convenience. And helping you look after your EV.
Remember, EVs are growing in popularity. National Energy System Operator predicts there will be up to 37.4 million EVs on the road by 2050. That’s a lot of people who will be new to charging, who could all use this 80/20 rule.
If everyone uses the 80/20 rule, there will be fewer queues at charging stations and more chargepoints will free up sooner. It gets you and others back on the road quickly and gives you time back for other things.
Lastly, remember to set that automatic 80% charging limit we mentioned. It’s very handy and it means you can relax while you charge.
Sign up for our electric car series
It’s our exciting email series for anyone looking to learn more about electric cars. We’ll explain how they work and show you what life with one could look like. You’ll get one email each week for eight weeks.
