Tag: rechargeable battery

How to Determine the Real Range of an Electric Scooter and its Battery

Before jumping into the Physics of it, you can access our online calculator here to determine the range of an electric scooter battery.Batteries are the lifeblood of any electric vehicle. They are not only their most expensive individual component of a vehicle, but they also define their range and performance. How are they characterised and what do their specifications mean for you, the rider?

Typically batteries are defined by 3 basic specifications, Voltage (V), Amp-hours (Ah) and Watt-hours (Wh).

Let us start by describing Voltage and Amps. Voltage and Amperage are characteristics of electric systems that can easily be understood by using the analogy of water flowing in a pipe. Voltage is akin to water pressure, the more voltage the more ‘pressure’ there is in the current. The Amperage is akin to the flow rate, or the amount of water that is flowing through the pipe. The more Amperage, the more current is ‘flowing’.

The Amps being akin to how much water is flowing, the Amp-hours (Ah) are therefore akin to how much water there is in the tank. 1 Ah is basically the ‘amount of electricity’ equal to 1 Amp of flow for 1 hour.

FuroSystems Battery Range Water Analogy

If a battery were simply a water tower, the Voltage is the water pressure (height of the tower) and the Amp-hours is the amount of water in the tank.

Now, how does all this relate to the range of an electric vehicle (electric bike, electric scooter)? The range is directly proportional to the amount of energy stored in the battery. The total energy capacity of a battery is defined in Watt-hours (Wh). Just like Amp-hours, a battery with 1 Wh capacity can provide 1 Watt of power for 1 hour.

You can easily calculate the Watt-hours (Wh) from the Voltage (V) and the Amp-hours (Ah):
Wh=V x Ah

And therefore, the range a battery can provide is directly linked to its Voltage and its Amp-hours. It is a common misconception that a battery’s capacity is measured with Ah. The capacity of a battery is actually measured by Wh which is equal to V x Ah. This means that a 48V battery with 8.8AH capacity (48×8.8 = 422Wh) is actually much larger and will provide longer autonomy than a 24V battery with 12AH (24×12 = 288Wh).

FuroSystems Battery Range Water Analogy Part 2

To sum up, whenever you want to compare batteries with regards to range, ensure you are not comparing Ah or V. You should be comparing Wh. And the Wh can easily be calculated from V x Ah.

Lithium-ion Batteries vs Hydrogen Fuel Cells in Electric Vehicles

Today, most electric vehicles use batteries, often based on Lithium-ion or Lead-acid chemistry. These batteries allow storing energy that was produced away from the vehicle and subsequently use that energy to create mechanical motion and make an e-bike, car or motorcycle move forward. Hydrogen Fuel cells, a rather old technology, created in 1839 by Sir William Grove and refined through the years, also allow storing energy in the form of hydrogen to power electric vehicles. Like a battery, a fuel cell harnesses a chemical reaction to produce energy in the form of electricity. More specifically, Hydrogen fuel cells generate electricity, water and heat from hydrogen and oxygen.

 

Fuel cells consist of an anode and a cathode surrounding an electrolyte called a synthetic polymer membrane which separates hydrogen and oxygen while only permitting the passage of certain ions (H+ or protons). Hydrogen atoms enter the fuel cell at the anode where they are stripped of their electrons. These electrons travel through the vehicle’s circuit to the cathode in the form of electricity. The positively charged hydrogen atoms (or protons) travel through the membrane to join with the oxygen and the electrons in order to eventually form water. Each individual fuel cell produces relatively low amounts of current and voltage and, like lithium-ion cells, therefore need to be stacked together in series and in parallel to reach the target voltage and max current required by the vehicle they are powering.

 

Hydrogen Fuel Cells vs Lithium-ion Batteries - Detailed functioning of a Hydrogen Fuel Cell

 

The beauty of hydrogen fuel cells is that you get electricity, heat and (potable) water as outputs with hydrogen and oxygen as inputs. Oxygen is abundant in the atmosphere while hydrogen is the most common element in the universe. However, hydrogen tends to bond very easily with other elements. Therefore, it has to be artificially isolated before being usable as fuel through processes that are quite expensive and energy-consuming.

 

Hydrogen used in fuel cells has the energy to weight ratio ten times greater than lithium-ion batteries. Consequently, it offers much greater range while being lighter and occupying smaller volumes. It can also be recharged in a few minutes, similarly to gasoline vehicles. However, Hydrogen fuel cells also come with a lot of drawbacks. First of all, hydrogen is mainly obtained from water through electrolysis which is basically a reversed fuel cell and takes electricity and water to produce Hydrogen and Oxygen. The source of this electricity can range from renewables to coal depending on where you are in the world, hence hydrogen extraction can be very clean or dirtier than a typical gasoline car. Nowadays, sadly, it is more likely to be the latter simply because of the way the majority of the electricity is produced on Earth.

 

Other issues are that storing hydrogen as a gas is expensive and energy-intensive, sometimes as much as half the energy, it contains, and even more so when it is stored as a liquid at cryogenic temperatures. In addition, it is highly flammable, tends to escape containment and reacts with metals in a way than renders them more brittle and prone to breakage. Eventually, although it is everywhere around us, hydrogen is hard, dangerous and expensive to produce, store and transport.

 

Fuel cells can also only operate with water, not steam nor ice. Therefore, managing internal temperatures is essential and heat has to be constantly evacuated through radiators and cooling channels which add considerable amounts of weight. Restarting in cold temperatures can also be very complicated and impractical in locations that often experience temperatures below freezing point.

 

Detailed functioning of a Hydrogen Fuel Cell

To conclude, hydrogen fuel cells offer a potentially very clean, energy-dense and easy to recharge energy source for vehicles and other systems, but are currently complicated, expensive and dangerous to operate. In comparison, Lithium-ion batteries, although less energy-dense and slower to recharge, are as clean, much cheaper, easier and safer to handle. More specifically, cylindrical lithium-ion cells like those used in the SIERRA and the FX are very stable and safe to use. In the future, once the technology is sufficiently developed and the drawbacks mentioned above addressed, hydrogen could be a great solution to increase range and decrease charging time in electric vehicles. But for now, lithium-ion technology is the best solution to offer very practical and high-performance e-bikes and other vehicles.

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