An Electric Vehicle is all about choosing the right battery for you. Not the best one in the market, but Right one for your vehicle build. You need to choose from cost, mileage, and performance.
E-bikes, commonly referred to as electric bikes, are bringing about a revolution in the automobile sector. The battery that an e-bike uses is fundamental to its entire design. It can be difficult to choose the proper battery because battery technology is continually improving.
While range is the main determining criterion, additional elements including battery type and cell structure are also crucial. The final battery pack size depends on the desired range for your electric vehicle (EV).
The intended performance and range cannot be achieved if the battery pack does not fit the powertrain, and there is also an increased danger of harming the batteries or the drivetrain parts. But how to decide which battery is the best for your vehicle build?
By the end of this article, you will know which one.
Let us first take a look at this table to understand the basic comparison between different batteries.
| Name | Li-ion | Na-NiCl2 | Ni-MH | Li-S | Unit |
|---|---|---|---|---|---|
| Maximum Charge | 75 | 84 | 85 | 80 | Ah |
| Nominal Voltage | 323 | 289 | 288 | 305 | V |
| Stored Energy | 24.2 | 24.2 | 24.2 | 24.2 | kWh |
| Maximum Voltage / Minimum Voltage | 339/308 | 275/304 | 274/302 | 290/320 | V |
| Initial Charge | 100 | 100 | 100 | 100 | % |
| Number of Cells per Cell-Row | 12 | 12 | 20 | 26 | – |
| Number of Cell-Row | 17 | 30 | 20 | 1 | – |
| Internal Resistance charge/discharge | 1/1 | 1/1 | 1/1 | 1/1 | Ω |
| Operating Temperature | 33 | 270 | 36 | 30 | °C |
| Specific Heat Transition | 0.4 | 6 | 0.4 | 0.08 | W/K |
| Specific Heat Capacity | 795 | 950 | 677 | 1650 | J/kg*K |
| Mass of Battery | 318 | 457 | 534 | 173 | kg |
| Battery Price | 297* | 495* | 396* | 248* | $ |
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Consider the Parameters to choose the Right Battery for Electric Cars:
Here we mentioned the top 10 Ways to Choose the Right Battery For Electric car Build.
- Speed
Voltage! The higher voltage of your Battery System is equal to the faster EV can go. Thus, speed is a way to choose the right battery for electric car build.
- Distance and Trade-Off
As with ICE, EVs require more fuel as they go farther. This will affect how far you can travel on a single charge.
Pack KW rating, speed, temperature, aerodynamics, hills, driving conditions, driving styles, Vehicle weight, and several other factors need to be considered in the distance question.
The Simple formula for determining distance is: ( KW of pack / wh/m ) = Distance.
*note: Adjustments are needed for this formula*
And hence distance is a way to choose the right battery for electric car build.
- Watt-Hour per Mile (Wh/m)
The Simple rule of thumb for vehicles is:
Small Vehicle 250-300wh/m
Small Pickup 350-400wh/m
Calculation – Volts x (Amp Draw / MPH ) = Wh/m
- Battery Pack Size (KW):
Battery pack size is mentioned as a parameter for a way to choose the right battery for electric car build.
A voltage of Pack x Amp-Hour rating of battery = KW
As an illustration, let’s try to choose a battery pack for an e-bike with a 48V, 1kW motor, a top speed of 40 km/h, and a needed range of 100 km. Using an assumed DoD of 0.85 for Li-ion batteries.
= (Range * Motor Rating / Depth of Distance) / Speed
= ( 100*1000 / 0.85 ) /40
= 2.95kWh (approx.)
Battery rating = Kilowatt hr/48V =61Ah
Consequently, the vehicle would require a 48V, 61Ah battery. The battery pack for bikes or scooters can be chosen similarly.
- Required driving range
The final battery pack size depends on the desired range for your electric vehicle (EV). As a result, you must choose the theoretical range that will be required to translate this into the capacity in kWh.
This is an important necessity to keep in mind when constructing the battery pack. The battery capacity you require depends on the distance between charges you want to have.
A Tesla vehicle, for instance, requires 0.2 kWh per kilometer. To calculate the capacity needed for a car, multiply the necessary number of kilometers by 0.2 to get the desired range. That will give you a general idea of the minimum capacity of your battery pack. And hence it’s a way to choose the right battery for electric car build.
- Battery power calculation
The kind of batteries you’ll need to utilize in the battery pack depends on how much power you want the EV to have. The maximum discharge current of the batteries is determined by the peak power that the motor requires from the battery pack.
The motor’s continuous power consumption when the EV is in use determines the batteries’ continuous discharge current. You need to ask yourself these questions before moving forward:
- What is the motor’s maximum power output?
- What is the maximum current that the motor will draw?
The answers to these two questions determine the battery pack’s maximum discharge output.
- How much electricity will you always consume?
This will decide the batteries’ constant current.
The Values will be the maximum discharge values for each battery if you intend to connect all of them in a serial string with one in parallel (module).
The maximum discharge current of the battery pack must be determined if two or more batteries are linked in parallel to one another by multiplying the discharge currents by the number of paralleled batteries.
We have two examples for you to make the calculations clear.
Battery power calculation – Example 1
20 batteries serial, 1 battery parallel
Peak discharge: 30A per battery
Continuous discharge: 15A per battery.
Max discharge power of the battery pack = 1 battery parallel x 30A = 30A
Continuous discharge power of the battery pack = 1 battery parallel x 15A = 15A
Battery power calculation – Example 2
20 batteries serial, 4 batteries parallel
Peak discharge: 30A per battery
Continuous discharge: 15A per battery.
Max discharge power of the battery pack = 4 batteries parallel x 30A = 120A
Continuous discharge power of the battery pack = 4 batteries parallel x 15A = 60A
To quickly determine the number of modules you need to fit in your battery pack for your needed power output, utilize this Power Battery calculator.
- The temperature of the operating environment and battery type
The temperature is also known as the parameter or a way to choose the right battery for electric car build.
What range of outside temperatures are you going to utilize the EV in? The chemistry of the batteries will be impacted if the battery pack must operate at temperatures below 0 °C.
Both lithium-ion (Li-Ion) batteries and lithium-iron-phosphate (LiFePO) batteries are appropriate battery chemistries for electric vehicles. The working temperature range for Li-Ion batteries is between 10 and 60 degrees Celsius.
The operational temperature range for LiFePO batteries is -10 to 60 degrees Celsius.
LiFePO batteries are best suited for applications where operating temperatures below zero degrees are typical and there is no room for supplementary systems like a heating element.
| Battery Type | Min Temp | Max Temp | Unit |
|---|---|---|---|
| (Li-Ion) | 10 | 60 | °C |
| (LiFePO) | -10 | 60 | °C |
Li-Ion batteries are the most suitable for situations where the temperature is not a concern or low power is drained from the battery pack (causes a temperature rise).
The battery with the highest energy density currently on the market is lithium-ion. The energy density, including the weight and volume of these additional devices needed to keep the batteries within their operating temperature range, is still higher than when using LiFePO cells.
This indicates that Li-Ion batteries are typically preferred.
It’s crucial to maintain the batteries within their operating temperature range for both chemistries. The battery pack’s lifespan and capacity will be impacted if the batteries are utilized outside of this range.
When the battery temperature exceeds 60 degrees Celsius, it becomes dangerous because fires and explosions are more likely to occur.
- Spatial constraints for the battery pack
Your choice of battery chemistry will also depend on the amount of space that is available for the battery pack. Compared to LiFePo, Li-Ion battery chemistry offers a better energy density. As a result, larger LiFePo batteries will be required to produce the same amount of energy as Li-Ion batteries.
When constructing your battery pack, the available space is a crucial consideration. Frequently, the shape of the box where the battery pack is housed is extremely perplexing. You can select the battery or module you’re going to utilize after you know how much power is needed.
If so, you also know how many batteries or modules must be connected in parallel to generate the appropriate amount of power. The number of batteries that are connected in parallel must be shown as a plural in the rows of batteries or modules.
Otherwise, connecting all of the batteries will be challenging.
The total capacity and power of your battery pack are determined by the voltage. The required voltage is known if the other drivetrain elements, such as the motor and controller, have previously been selected.
The voltage is calculated as the sum of all batteries that are connected in series.
Here are some formulas to figure out the battery pack’s capacity and power:
Capacity = capacity per battery x nos of batteries connected in parallel x nominal voltage
Peak power = peak current per battery x nos of batteries connected in parallel x nominal voltage
Continuous power = continuous current per battery x nos of batteries connected in parallel x nominal voltage
You may determine what each battery configuration will mean for the size of your battery pack using these formulas.
- Reserve capacity
The amount of time a battery can deliver its maximum amperage before fully draining is known as its reserve capacity. The battery is more likely to survive an event like the lights remaining on while you are inside a store the higher the minute rating.
- Warranty
A car battery’s warranty can differ between manufacturers. Others give a prorated warranty that only allows for partial payment. Some warranties include a free replacement for the duration of the guarantee. Additionally, some warranties could combine these two different kinds of warranties.
When evaluating batteries, pay close attention to the warranty’s fine print to determine whether it is a full replacement guarantee or a prorated warranty. This will have a significant impact on how you assess each battery.
Top Battery Packs in use
Homebrew 18650 Packs
Pros: the ability to customize voltage, capacity, and packaging.
Cons: requires a lot of work and may be more expensive than alternative solutions.
eBay E-bike Packs
Pros: Complete solution, ready to use, and fairly sturdy
Cons: Limited packing options and potential problems with present restrictions
RC Flight Packs
Pros: rapid delivery, lightweight
Cons: Expensive, needs to be handled carefully, and requires a charging solution.
Power Tool Packs
Pros: They’re tough, easily hot-swappable, and you already have some.
Cons: Expensive, inefficient in terms of space, proprietary connectors.
Key Takeaways
- Way to choose the right battery for electric car build (EV) is particularly important.
- We have more battery options now than ever before, and as capacities and power outputs continue to rise, we continue to see new and more innovative electric vehicles than ever before.
- The battery type you use will depend on the vehicle you are trying to build, your performance and range, and your capabilities and willingness to build or purchase.
- The space availability for a battery pack is also important.
- Voltage! The higher voltage of your Battery System is equal to the faster EV can go.
- By researching the relevant factors, and choosing carefully, you can pick the best battery for the special vehicle.
- Checking the Warranty is equally important.
- Operational Temperature and Environment play an important role.
- Almost all batteries have Pros and Cons, so choose what’s right.
- Do your research and study before making a decision.
FAQs
What should be the selection criteria for a battery in an electric vehicle?
The desired power and range for your electric car should be your main considerations when selecting the battery. The battery pack’s design is determined by the required power and range. It’s also critical to have room for a battery pack.
Which batteries are best for electric vehicles?
The best batteries for electric vehicles are often lithium-ion batteries. Because lithium-ion batteries store a lot of energy, enabling electric cars to travel farther, they are the best. This increase in the range may be rather substantial.
How do I choose an electric motor battery?
Verify each of the products you chose is nominal voltage:
The typical operating range for electronics (microcontroller, motor controller power, etc.) is 9V–12V. Some can function at 3.3 or 5 volts.
Actuators, such as DC gear motors, stepper motors, and servos, typically run between 6 and 12 volts.
Sensors typically run on 5V.
Which battery can be preferable for EV applications?
The solid-state battery is one of the most promising technological advancements. The technique is comparable to lithium-ion batteries, except the electrolyte is solid rather than liquid. Faster charging times, higher power, and cheaper production will all be offered by solid-state batteries.
What are the main types of batteries mostly used in cars?
Value-regulated, gel cell, dry cell, and deep cycle batteries are the four primary types of automobile batteries. The most advanced design at the moment is value-regulated batteries. Due to its advanced valve design, this type of battery varies from conventional sealed flooded wet cell batteries.
Who is the leader in EV battery technology?
Contemporary Amperex Technology Co.
CATL leads the list of EV Battery Manufacturers in the World. It was the world’s biggest electric car battery maker, for the fifth year running, in 2021.
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