If we use electric bicycles, we find that the lithium battery of the electric car is often bad, sometimes not long after the replacement, the battery is bad again. If you always encounter such a situation, then you need to hurry to understand the six kinds of damage to the electric car battery life culprit.
First: "small horse-drawn car" phenomenon
Currently on the market, the majority of electric bicycle drive power 300W or more, or even up to 350 - 360 w, but a large number of electric bicycle manufacturers and dealers in order to reduce costs, the pursuit of profits, the configuration of the battery and motor power does not match, most of which is 10Ah power lithium battery.
According to the calculation of 350W drive power, the average current of drive is 350W/48V=7.3 (A), while the actual new 10Ah (according to the discharge rate multiplier technology of conventional battery) battery discharge is 7.0A, and the range is only 90-95min. 6-DZM-12 battery discharge strength is 7.0A, and the discharge time is about 110-115min.
The actual limit of the battery's output tool exceeds the power of the electric motor of the electric bicycle. The phenomenon of a small battery dragging a high power motor is usually called "small horse-drawn car". The "small horse-drawn car" phenomenon leads to accelerated battery capacity decay, a significant drop in vehicle mileage, and a lack of power, leading to constant user complaints and affecting the reputation of the vehicle and the battery. Therefore, once the configuration of the vehicle is determined, it is necessary to choose the appropriate battery specifications. For example, when the motor power is 300-350W, at least need to be equipped with 48V/14Ah or more lithium batteries for electric bicycles, such as failure to reach the capacity, at least according to the drive power of 300-350W. configuration of the corresponding lithium cell discharge multiplier, so that it can meet and can reach the motor drive power, strictly speaking, in addition to reach the benchmark power configuration, the battery The power of the battery needs to leave a certain amount of margin, so that the transient or short time may appear higher output power demand, such as electric car load climbing, the battery needs to have a higher current output, if the battery power only matches the motor, it may be in the half-slope of the battery due to overcurrent circuit break protection led to the electric car midway stop, there may be danger.
Second: the brake is too tight phenomenon
This phenomenon is very common in electric vehicles with large batteries.
Due to the high capacity of the battery, the electric vehicle itself must become heavier. Therefore, the entire vehicle is shipped from the factory, in order to ensure reliable and safe braking when the vehicle is running, the brake brakes are adjusted tighter, resulting in a high idling current and increased power consumption since the electric bicycle.
Take an electric bicycle with a 48V350W motor as an example. Generally speaking, the normal reactive current is within the range of 1.0±0.1, but currently, we are approaching the market with a maximum reactive current of 1.5 or even 2.0, resulting in an increase in battery load and a reduction in the mileage of the e-bike during operation.
An effective solution is to detect the no-load current after the vehicle is assembled and adjust the brake brake to the proper position.
In addition, here to remind everyone: everyone in the daily use of electric vehicles, it is best to brake calibration every half month or so on the brake.
Third: the phenomenon of power consumption of the controller
Brushless motor is currently equipped with a lock, switch control circuit electrical main circuit, the advantages of this structure, one is to reduce the lock load, can reduce the cost of the lock, the other is to avoid lock through the high current, reduce the lock power consumption heat, and extend the service life.
But the disadvantage is: easy to cause the battery over-discharge. According to actual measurements in the market, after locking the car, the controller's power consumption current is generally around 15-25mA, the minimum of 5mA, the maximum power consumption current (especially vehicles equipped with anti-theft alarm device) is about 150mA.
Power consumption current of 100mA, for example, 20Ah battery can only be used for 12 days and nights. Long-term sustained power consumption leads to many car volume dealers before the sale of electric vehicles. The battery is found to have no remaining power. By this time the battery is usually already over-discharged and protected.
An effective solution is to disconnect the connection between the generator and the vehicle when storing the vehicle, or to replenish the power in time. So, because it seems to be common for the control side to appear. When the electric vehicle is not used for a long time, it is necessary to disconnect the link between the vehicle and the battery. Nowadays, the new electric bicycle and electric motorcycle have independent switches for disconnecting the battery and the vehicle, or the battery can be removed in its entirety.
Fourth: the controller's current limit of arbitrary amplification
Through market sampling tests, the current electric bicycle manufacturers produce vehicles, especially luxury electric bicycles, the controller current limit value is generally too large. As we all know, increasing the current limit directly affects the battery life. This is usually the battery life that is chosen to be sacrificed at the beginning of the design to control manufacturing costs.
To make the vehicle "more powerful". Often want to increase the current limit value by increasing the controller, and ignore the motor efficiency at the current limit value, which is similar to the case of small horse-drawn car.
Fifth: the power box is too tightly sealed, the power fuse heat phenomenon
The current market for full use of electric bicycle power box is mostly closed, the battery charging, especially at the end of charging can produce a certain amount of hydrogen and a small amount of oxygen gathered in the top of the power box, which makes the power box a safety hazard, these flammable materials in the presence of sparks or overheating can lead to fire and explosion.
Generally speaking, "battery explosion" actually means "generator explosion". And fuse (especially installed in the power box), because it is a long time high current through, so the fuse holder heat loss elasticity, resulting in poor contact, thermal softening causes the power box ABS plastic melting, generating sparks, it may lead to the power box explosion. Therefore, the design should be considered in addition to waterproof, but also consider the smooth flow of air in the power bank to avoid some of the problems caused by airtight.
Sixth: charger parameters drift
The first is the cold state and hot state parameters drift, where the maximum voltage value of the hot state is lower than the cold state by 0.1V-0.35V. The cause of this problem is the improper selection of electronic components or inadequate aging conditions.
The second scenario is when the charger is carried in the car, due to on-board vibration causing the charger to drift. This parameter drift has a high probability of occurring and can be fatal to the battery. It is recommended to explain to the user when selling the vehicle why the charger should not be carried along and to take appropriate anti-vibration measures for the internal structure of the charger.
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