To calculate the time it will take to charge an electric vehicle, use the following Formula.
Charge time = (battery capacity) / (charge power ×.9)
In other words, the time it might take to charge in hours is equal to the size of the battery in kilowatt-hours divided by the charging power times .9, which is the average power efficiency.
For example, let’s estimate the time to charge a 2019 Tesla Model 3, which has a 50 kWh battery capacity, using a 3.7 kW home charger.
charge time =(50 kWh) / ( 3.7 kW×.9@)
charge time = (𝟓𝟎 𝒌𝑾𝒉) / (𝟑.𝟑𝟑)
Thus, it will take about 15 hours to charge a Tesla Model 3 to total capacity using a 3.7 kW charger.
A battery often has a partial charge, and charging from 0 to 100% is unnecessary. It’s also possible to charge to a partial capacity, lowering the time needed to charge.
Most home chargers are 7.7kWh or smaller, while public chargers are usually fast or rapid chargers in the 11kW to 50kW range. It’s also becoming more common to see chargers delivering 100kW of power or more.
How to calculate EV battery charging?
The only big argument against using electric vehicles, at least from a user’s point of view, is the time it might take to charge its batteries. For a worldwide population regularly filling up a tank of petrol and diesel in minutes, waiting for hours to fill their vehicles fuel can sound like a big no. it is then essential for electric vehicles and two-wheelers to have a particular charging time, ideally as low as possible.
So how does one determine the right charging time for their electric vehicle? It cannot be evident for some to manage their EV’s daily charging from various charging options and the different charging rates they enable. Here, we try to solve this problem for good.
The solution appears from simple science that controls electricity flow in circuits. A few factors and a couple of formulas are all you need to know the required charging time your vehicle will take, determined by the charging option you choose. So without any wait, here is how to calculate the charging time of your electric vehicle every time.
Charging time calculation:
Let us first revisit the keywords in the equation to understand EV charging dynamics easily. Don’t fret if you are unfamiliar with this, as there are just a few to remind.
Battery capacity:
The total quantity of charge a battery can hold. They are denoted in kilowatt-hours or kWh.
Charging Power:
The speed through which a charger can charge a battery. Symbolized in kilowatts or kW. And some basic ones.
Voltage:
It is the variation in electric potential between two points.
Current:
Current is the rate of flow of electric charge of an EV.
Now, to determine the time your EV will take to charge, there are only two formulas you need to utilize. The first one is to count the power of your charger from its Voltage and Current readings. It goes like this.
Formula 1st:
Power = Voltage x Current
You can identify the voltage reading of the charger with a Volts or “V” unit attached to it. Likewise, the Current tasks are discerned with the unit Ampere or “A.”
Hence, once you calculate the power of a charger, calculating the charging time is as easy as
Formula 2nd:
Charge time = battery capacity / Power (x power component)
The power aspect indicates how order energy is conveyed from the charger to the electric vehicle. It is the arrangement of real Power to Evident Power to account for energy wastes while charging. For AC chargers, this usually is at 0.8, although for DC chargers, the moderate lies around 0.9.
You can group both these equations to make:
Charge time = EV battery capacity / (Voltage x Current x power component)
For more accuracy, let us see this with an example:
Nexon EV Max, the most current EV by Tata Motors, comes with a 40.5kWh battery. It has a standard 3.3kWh AC charger and a premium 7.2kWh wall-mounted AC charger. To determine the charging time for Nexon EV Max with both these chargers, we use
Charging time 1st = 40.5/ (3.3kWh x 0.8) = 15.3 hours
Charging time 2nd = 40.5/ (7.2kWh x 0.8) = 7 hours
The Nexon Electric vehicle Max would thus go 0 to 100% capacity in just over 15 hours, using a 3.3kWh charger. Likewise, a 7.2kWh charger will charge the car entirely in 7 hours.
Note that some chargers include the requirements in Voltage and Current. Then, you can calculate the charger’s power using Formula 1st, which should be a more accurate representation of charger power than the depicted figure (in this case, 3.3kWh).With that, you can calculate the charging time for your electric vehicle using any charger.
EV Power Calculation:
If you are familiar with the vehicle, you are probably familiar with the concept of power. Power gives the vehicle acceleration and maintains a vehicle at a given speed. Spontaneously power is the product of torque and RPM, so while torque can be multiplied through gearing (by lowering rpm), power is unconventional of gearing.
On the electrical side of things, with lower power, it is essential to know that Voltage times Amps = Watts. This is only an estimate of rapid power. This is the quantity of power that flows through an electrical circuit. This does not inform us how long this power can be utilized. Power is calculated in metric units as watts (W) or kilowatts (1kW=1000W). Technically there is no difference between power given by an Internal Combustion Engine or an electric motor. However, because the torque curves are so different, just balancing the peak power of the two motors isn’t enough. The peak power of an EV is typically decided by the controller, as long as the batteries and motor can handle that power.
How fast can an electric Vehicle be Charged?
Electric vehicles are gaining popularity quickly, but some considered buyers remain unsure. One significant purpose is that charging EVs is slow. While drivers today are regularly filling their gas tank in below five minutes, EVs, depending on the size and requirements of the battery, generally take at least 30 minutes to get 80% charged at the fastest charging stations.
In five to 10 years, however, far faster charging might be possible. Companies are blooming with new lithium-ion battery materials and “solid-state” batteries, which are more reliable at faster-charging speeds. They could place recharge rates of 20 minutes or less within reach.
While a group of scientists recently planned a lithium battery prototype that, under laboratory circumstances, can recharge more than 50% of its capacity in just three minutes—and do so thousands of times without significantly lowering. The researchers say this could cover a path toward batteries that can recharge fully in as little as 10 minutes.
Although, there are still science and engineering challenges to overcome before ultra fast-charging EV batteries are technically valuable and economical. And some experts question whether EVs can be charged quickly in the future we want—at least with the current electric grid.
12V Battery charging time:
A 12-volt battery might take up to 12-24 hours to charge fully. When recharging your battery, be sure that if it gets too hot while you’re charging it, you need to stop charging. It should not get too warm above 125 Fahrenheit.
Preferably, slow charging your batteries is the best option. Of course, the rate differs depending on the battery you’re setting and its capacity. A 12-volt EV battery, for instance, takes a while to charge. Fast charging for this kind of battery isn’t justified. Ten amps are the recommended current. This is a slow charge. Twenty amps are already fast charging. Repeated fast charging might overcharge your battery. This may lower the battery’s service life in the long run.
To determine how long it’ll take to charge your battery, you need to know your battery’s storing capacity and your charger’s output charge current. A 100aH battery accused by a 10A charger will be fully charged in 10 hours.
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