It is a classic bike to which are added:
– An electric motor which can be located in the front or rear wheel, in the crankset and sometimes offset by a pulley. The law limits its power to 250 W and its speed to 25 km / h,
– A battery which, depending on the technology used, provides more or less autonomy. A charger is supplied to supply it to the mains.
– An electronic controller which regulates the various components (integrated in the battery pack on the image opposite)
– A handlebar control unit, which is not necessarily present depending on the model, and which allows the user to adjust the assistance, to know the mileage …
SO WITH AN ELECTRIC BIKE, CAN I NOT PEDAL ANY MORE?
No, the legislation of the VAE (Electrically assisted bicycle) stipulates that the motor is only pedal assistance. The user must therefore always rotate the crankset to activate the electric assistance. Some models nevertheless offer a throttle system by handle without the need to pedal: This though, is not in accordance with the law.
DO ALL ELECTRIC BIKES WORK IN THE SAME WAY?
No, there are different types of electrical assistance:
– Assistance by rotation of the pedal: it is the least expensive and most common system. Located at the pedals, a sensor detects the rotation of the pedal and therefore the pedaling but not the pressure exerted on the pedal. The engine releases all of its energy instantly. A turn of the pedal is often necessary to ensure that the engine starts. We add to it, on certain models, a starting aid by handle which triggers the assistance without the need to pedal;
– Assistance by pressure sensor: The engine starts as soon as it senses the pressure exerted on the pedal. The more the user presses the pedals, the more the motor helps him, even if his pedaling rate is low. This system is particularly appreciated by sportsmen who have the feeling of keeping control of the cycle and of printing acceleration but it requires maintaining a continuous pressure on the pedals which is not always within the reach of amateur cyclists;
– Assistance by force sensor: it is the pedaling and its cadence which control the power of the motor. The higher the cyclist pedals, the more assistance he receives. This system makes hill starts easier. It is a system at a cost equivalent to that of the pressure sensor;
– Assistance by chain tension: Assistance is started by chain tension. This system is very reactive since the chain is tightened as soon as the foot is put on the pedal. It therefore favors hill starts but has the disadvantage of always having to press the pedals to move forward. The central positioning of the motor balances the bike.
ARE THERE SEVERAL LEVELS OF ASSISTANCE?
It actually depends on the models.
Some can offer up to 4 or even 5 levels of assistance adjustable via a control located on the handlebars while others, more basic, offer only one level.
WHAT ARE THE DIFFERENT TYPES OF BATTERIES?
Below, the three most common families of batteries in the electric bicycle industry.
– Lead batteries or the lead with gelled electrolyte (Pb) (from 80 to 200 €): low cost, good energy efficiency and without “memory effect” .They are less and less used nowadays. They have the disadvantage of a heavy weight (more than 10 kg), a limited maximum power (50 watt / h / kg approximately) and a sensitivity to negative temperatures (- 25 ° C). Their lifespan is of the order of 350 charge and discharge cycles.
– Nickel-metal hydride (Ni-Mh) batteries (from 200 to 400 €): marketed in the 1990s, they replace nickel cadmium (Ni-Cd) batteries. Significantly lighter than lead-acid batteries, they have a higher maximum power (around 90 watt / h / kg). If their lifespan is around 500 charge / discharge cycles, their self-discharge rate is important. Not to be used in winter, because they will be fully discharged in spring. They can be subject to a “memory effect” which then limits their capacity.
– Lithium-ion (Li-ion) batteries (from 300 to 500 €): they have a predominant place on the portable electronics market and currently equip most pedelecs. Their maximum power is around 120-150 Wh / kg and their weight is limited. They do not suffer from the memory effect and support loads greater than 800 cycles. Their disadvantage remains the high price and the risk of explosion if the electronics are poorly designed.
– Lithium-polymer (Li-Po) batteries (more than € 500): they represent a real technological leap since they are even more powerful than the previous ones (140 Wh / kg), which are also light insofar as their electrolysis in gel does not require tightening due to liquid electrolysis. In the event of overheating, they do not explode but consume themselves. Their disadvantage is a significantly higher cost than lithium-ion.
Tip – Calculation of the energy capacity of a battery:
Voltage x Amperage
Example on a 36 V – 10 Ah battery:
36 x 10 = 360 Wh or 0.36 kWh
So based on a cost of Kwh at 0.1350 € the price of the refill amounts to … 0.36 * 0.1350 = 0.05 € or 5 cts 🙂
I LIVE IN AN APARTMENT, HOW CAN I RECHARGE THE BATTERIES?
No need to have fun riding your electric bike up the stairs to charge it at home since 90% of the models have removable batteries that can be removed very easily to recharge at home on a traditional 220 Volt outlet.
DOES THE BATTERY RECHARGES ITSELF WHILE I PEDAL?
Some models have a dynamo which recharges the battery when pedaling or going downhill. However, the energy saving is minimal and you will not be able to fully charge the battery – except on a descent of 30 km 😉
Written by: https://www.little-dragon-bikes.eu/