With competitive price and timely delivery, Energyland sincerely hope to be your supplier and partner.
Some time ago I wrote my list of ‘Top Ten EV Urban Myths That Deserve To Die’. Even as I wrote it, I knew it wouldn’t be the end of EV urban myths: I might have covered ten of the ‘best’ and put them to bed, but I was sure more would come along to replace them. Or, as I will show here: be recycled in subtly different forms.
The ‘new’ one I am referring to is what I will call here the 80/20 ‘rule’. This myth says that batteries should never be charged beyond 80% or discharged below 20% lest ‘irreversible damage’ occur.
Another slightly different version of this “rule” suggests that if EV batteries can’t be taken safely above or below these limits, then they are really only 60% of their stated size/driving range.
So where has this nonsense come from? Like all good urban myths: it is based loosely on a couple of pieces of information that have been taken out of context, and are borne out of “rules” that might equally apply for an internal combustion engine (ICE) vehicle.
For instance, we have long been told when driving petrol or diesel vehicles that:
So what is the significance of the 80 per cent charging limit?
80% is the recommendation for normal day-to-day charging of non-LFP EV batteries, which are still found in most EVs. (More on the other main lithium battery chemistry type, LFP, later).
For longevity of EV batteries, it is considered best not to stress them unnecessarily by charging to 100% every time you plug-in. For today’s EV battery sizes, it is also completely unnecessary to charge to 100% on a regular basis. Even charging my Kona electric to 80% for daily driving, I still only need to charge once every two to three weeks.
It is also worth pointing out that the early EVs with smaller batteries were almost always charged to 100%, and their batteries did not ‘die’ early as a result. Many are still going with those original batteries, albeit with reduced range. To give an example, my 13-year-old iMiEV is still on its original battery with a reliable 70km of its original 110-ish km range left.
The corollary to the above is that you will not ‘irreparably’ damage the battery by occasionally charging to 100% when needed. (For instance, when leaving home for a long trip). So yes, the top 20% of the battery is available for use when needed, it is not ‘lost’.
The other reason for only charging to 80% is when you’re at a DC fast-charger. The physics of battery charging is that the time for an EV battery to charge from 0% to 80% is very roughly the same as it takes to go from 80% to 100%.
(LFP chemistry batteries start slowing at slightly higher percentages, but the effect is much the same: DC charging slows as you near the top of the charge).
This means that if you don’t need that last 20%, don’t waste your time (and potentially delay others waiting for that charger) by staying there. Get moving and, if you need, do one extra stop during the day for 20 minutes or less to get that 20% when the battery is at 40 or 50% and the charging speed is much faster.
(For long trips, 20 minute stops are a must every 2 to 3 hours anyway and even an 80% charged battery will go for well longer than that).
Why no lower than 20%?
As mentioned earlier, this is similar to the recommendation for ICE vehicles. In the case of EVs, it:
Again though, the advice is (just like not always charging to 100% or going below ¼ in a fuel tank): be kind to your battery and charge at a reasonable low point. Like the old ¼ (or 25%) tank, for EVs that point is now generally suggested as 20%, but most EVs won’t even begin to start warning you until around 10%.
If by the way you do reach 5% or below, just recharge it as soon as practicable on arrival and no harm will have been done there either.
As a final note: the only true way to flatten an EV battery below its absolute minimum is to park at a low point and then leave it that way without recharging for weeks to months as it will slowly self-discharge to a dangerously low level. Even then, the car will at a certain point defensively shut all systems down to slow the process.
Summing up: just like the top 20% of the battery, the bottom 20% is also not ‘lost’. It is there if you need it, but just like an ICE car: don’t drive till the low fuel light turns on before refilling!
Batteries are still an evolving technology – especially lithium chemistry ones. However lithium batteries have reached a certain level of maturity where changes are incremental rather than revolutionary.
After all, a quick look at the hundreds of billions of dollars being spent on lithium battery manufacturing plants is all you need to realise that the EV industry does not expect a revolutionary ‘killer app’ battery to turn up any time soon. (Unless you’re Toyota, but that’s more to do with finding excuses to not build battery electric cars than reality!)
All the advice I’ve referred to above is what is recommended for cars with standard lithium ion battery chemistries like NMC (nickel manganese cobalt) or NCA (nickel cobalt aluminium).
As the chemistries evolve, some of these recommendations have altered. One recent innovation in lithium battery chemistry is the LFP (lithium-iron-phosphate) battery. In LFP batteries, the cathode material is replaced with iron and phosphorus instead of the nickel or cobalt in NMC or NCA formulations.
As these materials are cheaper and in more plentiful supply, LFP batteries are cheaper to produce. However, LFP batteries still only represent an incremental change in lithium batteries.
They still contain lithium and are still considered a ‘wet’ battery chemistry. (As opposed to the much talked about … but yet to be commercialised … ‘dry’ lithium chemistry batteries).
However, being cheaper to produce and not containing cobalt, they are being adopted by some manufacturers in an effort to reduce EV manufacturing costs as well as being one way to avoid the issues surrounding cobalt mining.
LFP also has the advantage that the charge rate slows at a slightly higher charge level than other lithium ion ones to ramp their charge rate down more slowly after 80%.
However, they too after 90-ish percent charge at little more than a 7kW AC charger would offer. It has also been suggested (and recommended by Tesla) to regularly charge LFP batteries to 100%. It would seem therefore they are slightly more robust and capable of this treatment if you so wish to regularly charge to that level.
LFP batteries also have their downsides, the main one being they are less ‘energy dense’ (that is for the same kWh, they weight more/are bigger as compared to other chemistries) meaning LFP is unsuited to large battery packs where space for the battery is at a premium.
Tesla for instance use LFP for their Standard Range Model 3 and Model Y, but still use NMC chemistry for the Long Range packs.
Like all good urban myths, the ‘80/20 rule’ has a real sounding basis that in fact does not stand up to scrutiny. It is in fact an attempt by some EV doubters to increase the FUD (Fear, Uncertainty and Doubt) around EV adoption to slow the transition by restating in other terms the long-dead myths about EV batteries not lasting or not having enough range.
Unfortunately, the public is not yet fully up to speed on EV technology and are therefore susceptible to cleverly designed disinformation campaigns such as this one.
EV batteries in fact do last well and are quite robust, whatever the chemistry used. They also have high quality battery management systems fitted to ensure they are maintained within the manufacturers set voltage, temperature and charge/discharge limits.
The batteries are also well able to deliver the driving ranges stated in the WLTP or US EPA range figures. (If not the NEDC ones – but that’s another story!)
A side issue is whether LFP or other lithium ion chemistries (like NMC or NCA) are a ‘better’ choice. The proponents of each tech will ty to convince you that theirs is better – but in reality, it is a bit like choosing between QLED, ULED, OLED, 4K or 8K TVs. Each battery technology has slight advantages over the others, but not enough to say any of them is the ‘one’.
Bryce Gaton is an expert on electric vehicles and contributor for The Driven and Renew Economy. He has been working in the EV sector since 2008 and is currently working as EV electrical safety trainer/supervisor for the University of Melbourne. He also provides support for the EV Transition to business, government and the public through his EV Transition consultancy EVchoice.
This article was originally published February 21, 2023 and was updated March 13, 2024.
Electric vehicles (EVs), whether they are new or used, are typically long-term investments made with the intention of driving and enjoying the car for several years. How you choose to care for and maintain that investment will significantly impact the lifetime cost, experience, and overall value of your vehicle.
One of the most significant expenses in an EV, accounting for nearly one-quarter of the cost of an EV, is the battery. Certain habits can cause battery degradation to occur, which will ultimately decrease its lifespan.
To ensure your vehicle’s battery longevity and receive the most value from your EV long-term, you’ll want to be familiar with EV battery charging best practices. In this article, we’ll explore how to maintain your electric car’s battery health with key EV battery charging best practices and EV charging tips.
The following factors comprise essential elements of EV charging best practices that will help optimize your battery’s performance and efficiency, as well as prolong its life. We discuss each of these in more detail below.
Slow charging versus fast charging.
Minimum and maximum battery charge.
Driving habits.
Climate conditions.
EV battery charging best practices are essential to learn and implement, particularly regarding the tradeoffs between fast and slow charging.
When it comes to EV charging, there are three levels of charging to consider: Level 1 EV Charging, Level 2 EV Charging, and Level 3 EV Charging, also referred to as DC Fast Charging (DCFC).
Level 1 EV charging utilizes a 120V AC outlet and is easily accessible for a majority of drivers, as this type of outlet is a standard outlet in any home, multifamily, or commercial building outfitted with electricity. While this type of outlet is convenient to access at home or on the go, it charges at very slow rates due to the low output in voltage.
You can expect a Level 1 charger to add approximately three to five miles of range per hour of charging, depending on the make and model of the electric vehicle. As a result of this slow rate of charging, Level 1 EV charging can lead to an extended battery life by preventing a battery from regularly overcharging or receiving high-levels of energy on a consistent basis.
However, with a full charge often taking over 50 hours, many EV drivers find this level of EV charging is insufficient to meet their daily driving needs.
Level 2 EV charging stations are a preferred method of charging for many people as they can charge an EV up to ten times faster than a Level 1 EV charger, making it an ideal option for overnight charging.
Depending on the make and model of the electric vehicle as well as the EV charger, Level 2 charging adds 12 to 80 miles of range per hour of charging. These units run on 240V AC power through a dedicated circuit and require a certified electrician with the correct EV charger installation experience to install the appropriate hardware and wiring, as well as make any needed panel upgrades depending on the current available capacity and EV charger needs.
Level 2 EV charging stations use a higher level of power than Level 1 EV chargers but are equipped with “smarter” technology to communicate with the computer and technology inside of your electric vehicle to ensure your EV battery does not overcharge or overheat, and degrade as a result of these things over time.
Additionally, installing a smart Level 2 EV charging station that memorizes your schedule and daily driving needs can also calculate when you need your EV to be fully charged and when electricity is the most cost effective, so you never start your day with less battery range than you need and you can maximize your savings with at-home EV charging.
For more information you can read our blog discussing the differences between Level 1 and Level 2 EV charging.
Level 3 EV charging stations, or Direct Current Fast Chargers (DCFC) are a commercial-grade method of EV charging as they require 480V DC power and are significantly more expensive to purchase and install. Commonly found along major roads and in grocery stores, malls, and other quick stops, these charges offer high-powered, rapid-charging speeds and boast a full charge often in 30 minutes to 1 hour making them convenient for charging your EV while traveling or topping off an EV battery.
DC Fast Charging Stations are the only charging method to utilize DC, or direct current, energy. Using DC allows these chargers to directly power the vehicle battery, whereas Levels 1 EV chargers and Level 2 EV charging stations must convert the energy from AC to DC within the vehicle, slowing down the charge time of the EV battery.
While Level 3 EV charging stations provide the fastest battery charge, consistent use of Level 3 EV charging has been shown to increase battery degradation for electric vehicles by an average of 3-5% over 50,000 miles.
Related Reading: What Is A Level 3 EV Charger?
Lithium-ion batteries work better when they are used and charged in partial cycles, in other words, not completely depleted or fully charged.
Consequently, the best charging practice is to charge the battery at different stages, optimally keeping its level between 20% and 80%. Similarly to how the overuse of fast charging stations can decrease battery life, so can consistently allowing your battery to drain to 0% or continually overcharging the battery to 100% when it’s not needed.
One way to keep your battery charging in the optimal range is to utilize a smart panel or smart EV charger to maintain charging within a certain range. Some EVs may also come with these limits established as a baseline setting for charging capacity. Another benefit to keeping your battery charge at no higher than 80% is that it leaves the capability to generate and store energy through regenerative braking, which can help extend your EV driving range.
Consistently having a fully charged or fully drained battery can affect its life, particularly during long-term storage when the vehicle sits with the EV battery at extremely high or low levels of charge for extended periods of time. If you need to keep your EV in storage, make sure to charge the battery at least once every three months. Keeping the EV battery level consistently between 20-80% is the best way to prevent damage during long-term storage, especially if the vehicle will also be exposed to extreme temperatures during that time.
Most batteries are designed to last a minimum of 200,000 miles or more, so battery damage or extended use will not always require battery replacement. However, battery lifespan can fall somewhere between eight and twelve years in more extreme conditions. Depending on the situation and extent of damages, a repair may be possible to bring your battery back to standard working order.
One way to make this less expensive repair choice available is to follow EV battery charging best practices diligently. In particular, repeatedly leaving your lithium-ion battery fully charged at 100% or completely depleted at 0% can cause the worst damage, so it’s best to avoid doing so, and frequently using rapid charging can also result in increased EV battery degradation over time.
While most EVs require very little battery maintenance, some models rely on a liquid coolant to manage battery temperature. You should have a professional check coolant levels regularly and ensure that this system is still working properly to prevent overheating.
The maximum lifespan of your EV battery will vary based on the vehicle’s make and model. Check the maintenance recommendations of your EV’s manufacturer to get a better idea of how many charging cycles your battery is rated for.
How you drive your EV can also impact its battery life. Rapid acceleration and harsh braking negatively affect your battery. Accelerating slowly and maintaining a consistent speed, as well as easing into stops, maximizes your battery range. Respecting the posted speed limits will also help enhance your EV’s battery health and range, as you will have a lower risk of needing to rapidly slow down to turn or avoid traffic.
EV range can also vary widely based on the driving environment. Regenerative braking can capture an average of 22% of the energy used when driving. This percentage can exceed 30% when driving in an urban environment with frequent stops, but it can be as low as 6% when driving on the highway where you are generally less likely to make frequent stops.
How you charge your EV when driving long distances is another factor affecting battery life. Planning ahead is a good practice, and with many attractions and hotels now including EV charging as an added amenity, it is more convenient to find Level 2 EV charging stations during daytime venues or for overnight charging while you also rest and recharge.
Ideally, well-planned trips should minimize the need to frequently fast charge your EV in favor of Level 1 EV chargers or Level 2 EV charging. Combining meals, venues, and hotel stops with EV charging can provide ample time to replenish your EV battery, especially if you plan ahead to make the most of your stops.
Weather is another significant consideration for optimal charging. Extreme temperatures can substantially impact any vehicles range, and it’s especially important for EV drivers to be mindful of how the weather conditions can affect an EV battery’s life and charging capability.
Cold weather can reduce your EV’s range by as much as 25% when driving at 70 mph. However, your range can be reduced by half when making short trips with frequent stops. Cold temperatures decrease battery resistance, which results in less power being available. Using energy to heat the cabin is another factor that affects range in the winter.
Warm weather can have a similar effect on battery performance. Range typically decreases by 5% at 90°F and can drop by as much as 31% once temperatures exceed 100°F. Driving with the AC on further contributes to reducing the range.
Parking your vehicle in the shade or in a temperature-controlled garage and pre-cooling it while still charging and before driving can help maximize the battery’s range in the summer. In the winter, you can protect your EV’s battery from extreme temperatures by charging indoors, pre-heating the cabin while still charging, and relying on heated seats rather than the cabin’s HVAC system for heat to help increase your vehicle’s range in cold weather. One unique difference with electric vehicles is that they can remain plugged in and charging while they are turned on and warming up or cooling off, helping you to conserve battery range while driving.
A malfunctioning EV charger can cause damage to your battery by not regulating the level of energy sent to the vehicle, or other harmful situations. When plugging in at home, this damage can add up over multiple charging sessions and significantly reduce the vehicle’s range over time.
You can prevent accidental damage to your battery by maintaining your charging equipment. You should perform regular visual inspections of your EV charger, look for signs of rust or damage, and keep the charging ports clean.
If you use a connected or smart charger, your charging data can reveal changes in performance and help identify potential problems. You should also have a professional test your charging equipment regularly to make sure the energy output is adequate for your vehicle’s battery and that the wires and internal connections are continuing to properly function.
Beyond damaging your electric vehicle and EV battery health, an improperly installed EV charger that used incorrect materials or wasn’t maintained properly over time and began to degrade can lead to electrical fires, melted components, severe damages, and more. Working with an experienced licensed electrician who has the proper training and certifications for EV charger installation to install and service your EV charger will help ensure your EV charger is safe and efficient for years to come.
When relying on public charging locations, your best option is to pick a charging network with a reputation for actively maintaining chargers and performing regular charging tests.
One final tip is to check your EV owner’s manual for the manufacturer’s recommendations for optimal charging, operating, and any instructions for repairs or replacements.
Your owner’s manual should provide additional tips and suggestions to further address EV charging and ensuring the health of your vehicle and EV battery for years to come. For example, certain vehicles offer a “sleep” mode that places them in an optimal state for storage. Your owner’s manual will also tell you where to check for any software updates that will increase your battery’s range and can provide additional information on how the carmaker is working to advance your EV’s range and functionality.
Remember, while technology is designed to provide added convenience to our lives, you will need to do your part in providing the maintenance and support your EV needs to perform optimally. Following these best practices will help keep your electric vehicle in excellent shape and ready to meet all your driving needs.
While planning for travel is vital, 80% of charging is done at home, generally overnight. Installing a Level 2 EV charger at home makes this manageable and straightforward and it’s important to work with a reliable, certified electrician who will ensure you have all the information and hardware needed to optimize your charging capabilities and ensure your vehicle is maintained for years to come.
As the largest network of certified EV charger installers in North America, Qmerit is the most trusted EV charger installation partner recommended by automakers, EV charger manufacturers, utilities, businesses, and homeowners alike.
But don’t just take our word for it. Rated #1 in customer satisfaction, Qmerit’s experienced network of certified electricians has installed more than 450,000 EV charging stations in homes and businesses across the U.S. and Canada!
Give us a call at (888) 272-0090 or complete our online EV assessment to find out why we’re North America’s most trusted EV charger installation service provider today!
For more information, please visit home residential inverters.