• Why is the power of the E-Vehicle getting less and less when it is obviously not riding? Is this normal?

    First, the battery has a self-discharge phenomenon. it  means the battery is naturally placed there, and its power will gradually decrease if no electrical appliances are connected. This is because there are some impurities and deposits in the electrolyte of the battery, which will lose part of the power when the battery is internally circulated.

    Self-discharge is a normal phenomenon. If there is only self-discharge, it will take a long time to use up the battery power.                                                                           

    But the actual situation is that now E-Vehicles are equipped with remote control alarms and other devices. These devices are connected to the battery, which is equivalent to the existence of an external discharge circuit, and these circuits are still in a state of high power consumption. As an example-the alarm , there is usually a discharge current of 6 am or even 8 am.                                                                                                                                                                                                             

    In such a case, even if we turn off the power of the E-vehile and  unused, the power of the battery will gradually decrease. Taking a 48V12Ah battery (0.576 kWh) and an 8am alarm as an example, the alarm consumes 0.0092 kWh every day, and the battery will be exhausted within  60 days.
  • The E-Vehicle is fully charged. Why does it lose 2 grids as soon as it accelerates? One grid of electricity is lost when climbing the slope. Why is it full at the top of the slope?

    In daily life, we sometimes encounter such a situation: when the E-Vehicle is charged and goes out, the electric power will be reduced by 2 grid as soon as it is accelerated; When encountering a steep slope, the power is reduced by 1 grid when climbing, and it shows full power at the top of the slope.                                             

    In fact, this is because the power display function of electric motorcycles and electric bicycles is still in the original state, just like the mobile phones in the past. Today's smart phones generally use percentage to display power. When charging, the amount of electricity increases, and when using electricity, the amount of electricity decreases. There will not be 85%, 76% and 85% at once. This power display method is called SOC (state of charge).                                                                                 

    Although SOC is a good technology, it has not been widely used in the field of electric two-wheelers due to high cost and technical difficulty. The commonly used method is to display the power according to the corresponding relationship between the load current and the voltage. However, the voltage and current of the E-Vehicle are not static, but fluctuate, which is also the main reason for the inaccurate power display of the existing method.                                                                                                   

    For example, when the load current is 10 amps and the voltage is 48V, it shows that the power is full; As soon as it accelerates, the current increases to 15 amps, the voltage becomes 47V, and the power is reduced by 1 grid; When going downhill, the load current is only 3 amps, and the voltage changes back to 48V or even 49V. At this time, the power will display full grid again.                                                                                                                                                                                                 

    If we use the load voltage as the criterion to display the power, the fully charged state will appear when the car is parked, making it impossible for us to accurately judge the charging timing; if we use the voltage at the time of parking as the criterion, it will appear that as soon as we ride on the car, the power will be reduced. The case of falling to the bottom.

    In order to improve the situation of inaccurate power display, we can use dual-mode power display, and use different voltage curves to display the power when it is under load and when it is stopped. But most fundamentally, the application of the SOC display method should be promoted, so that the E-Vehicle's power display can be as accurate as that of a smartphone.
  • Why do E-Vehicles catch fire, always when charging-lead-acid battery ?

    The main reasons for the fire of lead-acid battery during charging include the following three points.

    1, The charger with high temperature 

    Now the common E-Vehicle chargers on the market are open style, and the shell is mainly made of plastic parts. When the fan of the charger fails, or the air duct is blocked by other objects, the heat generated by the charger cannot be dissipated in time, and the temperature will rise sharply,  then causing accidents such as fire.       

    If the user still has some  habits, such as wrapping the charger in a windshield or quilt, or placing some flammable items under the charger, it will greatly increase the probability of fire.              
    2, the internal circuit of E-Vehicles is aging

    When the E-Vehicle is charging, a higher voltage will be generated inside,  the air will also be ionized. If the E-Vehicle happens to have some internal damage at this time, and the  ionized substance produced by air ionization ignites between the positive electrode and the negative electrode, the electric spark will easily cause a fire if it hits the non-flame-retardant substance next to it.
    E-Vehicle chargers are specially designed to charge E-Vehicles. However, in real life, some users will mix chargers, which may cause the insulation damage of the charger plug, which will cause high voltage to be generated when the E-Vehicle is charging, increasing the risk of fire.                                                                                 

    3, There are some problems with charger                                                                                                                                                                                                         

    There is a fault in the charger itself, such as the voltage "running away", the original 48V voltage suddenly increases to 70V, or even 80V, which will also cause the charger and battery to overheat, eventually causing a fire accident.
    All in all, compared with lithium batteries, lead-acid batteries are relatively safe, and there are not many actual accidents. As long as you choose high-quality products and use them correctly, you don't have to worry too much.
  • Why is lithium battery easy to catch fire when charging? Is there any way to avoid it?

    Compared with lead-acid batteries, lithium batteries are more prone to explosion and fire accidents, mainly because their electrolytes are different. The electrolyte of lead-acid batteries is generally an aqueous solution, which is not easy to catch fire; while the electrolyte in lithium batteries is organic matter, we can directly understand it as gasoline which is flammable.
    So why can lead-acid batteries use aqueous solution, while lithium batteries use relatively dangerous organic matter as electrolyte?
    Simply put, it is because the maximum ionization voltage of the two is different.The highest ionization voltage of aqueous solution is 2V, which is far from enough for lithium battery.In order to improve the electric energy density, lithium batteries must use organic matter as electrolyte.When the organic electrolyte is sealed in such a narrow space as the battery, there will be a high risk of explosion and fire.   
    Why is it easy to cause lithium batteries to explode and catch fire when charging? The destruction of the SEI film (the solid electrolyte membrane) of the negative electrode is one of the main reasons. Same as lead-acid batteries, lithium batteries are also divided into positive and negative electrodes. The positive electrode is generally a transition metal oxide of lithium, and the negative electrode is graphite and carbon. 
    When the SEI film on the surface of the negative electrode is destroyed, the carbon and lithium compounds generated during charging cannot react normally, and huge heat is generated inside the battery. When the temperature rises, the positive electrode of the lithium battery will automatically release oxygen. When the three combustion conditions of "temperature rise, the presence of flammable substances, and the presence of oxygen" are met, the probability of explosion and fire rises sharply. 
    It is precisely because the positive electrode of lithium battery will automatically release oxygen when the temperature rises, so we can't put out the fire by isolating oxygen, that is to say, dry powder fire extinguishers are useless. Therefore, lithium battery fire is very dangerous.   
    So how to  solve the safety problem of lithium batteries? This is a systematic project, which needs to be carried out from the battery design, to the battery  protection board, and then to the charging. Therefore, users who have purchased a lithium battery vehicle must use the battery in accordance with the regulations, avoid some charging items prohibited in the manual, and recommend that you conduct a battery safety inspection about once a year to prevent problems before they occur. 
    Luyuan's BMS battery management system can check whether the lithium battery is damaged. If there is a problem, charging is automatically disabled. If you encounter the situation that the lithium battery cannot be charged, please do not continue to forcibly charge the battery by short-circuiting the BMS board. Instead, you should go to a special store or maintenance office to find the reason for the inability to charge, and then prescribe the right way to solve the problem.
  • What's the detail situation that the E-vehiles mileage increase when Summer comming?

    E-Vehicles do not run as far in winter as in summer. The main reasons are as follows. 
    1,The capacity of the battery decreases as the temperature drops, and it also recovers as the temperature rises. If a group of batteries can discharge 12AH at an ambient temperature of 25°C (battery ampere hours represent the capacity of the battery, represented by the letters AH, the larger the number of ampere hours, the greater the capacity of the battery), 10°C may only be able to Discharge 10AH of electricity. When it reaches -20°C, because the temperature is too low, the chemical reaction cannot proceed normally, and the battery  cannot discharge electricity.
    In summer, as soon as the temperature rises, the battery capacity will gradually recover, and the endurance will naturally increase. Therefore, the phenomenon of "E-Vehicles don't run far in winter than in summer" will appear. 
     2,In winter, when riding, the wind resistance caused by thick clothes is relatively large, the power consumption of E-Vehicles increases and the endurance decreases.   
    Most people can think of the above two reasons. The third reason is that there may not known by most people,   that is, the temperature is low in winter, the air density will rise, and objectively, the wind resistance will also increase. 
    Because air has weight, and the resistance of air is proportional to the weight of air. When the temperature drops, the hot air runs up, the cold air sinks, the air density increases, and the wind resistance increases.  
    In addition to the above three main reasons, there are other secondary reasons such as the decrease of tire pressure in winter, which leads to the increase of road resistance.
  • What is the best time to charge?

    It is a good question to charge the E-Vehicle when it has the best amount of electricity left. It is also a focus of our research. The depth of discharge is used to describe the power consumption of the battery. It represents the percentage of the battery discharge capacity and the rated capacity of the battery. For example, if the battery discharge depth is 80%, then the remaining capacity is 20%. 
    Generally speaking, after considering all factors, the discharge depth of most lead-acid batteries on the market is about 80%. In other words, charging is best when the remaining 20% of the power is available. If conditions permit, it can also be charged when the discharge depth is 60%, that is, the remaining 40% of the power.  
    It should be noted that the discharge depth should not be too deep. It is more dangerous to wait until the depth of discharge is 100%, that is, when the battery is completely dead before charging. Because we cannot guarantee that the battery will be charged as soon as the battery is dead, and sometimes we just forget that "deep discharge without charging", also known as "depleted storage", will damage the battery and seriously shorten the life of the battery. 
    Because the battery's electrolyte is in a very dilute state when it is stored without enough electricity. At this time, the electrolyte will be hydrolyzed, causing serious corrosion of the positive plate of the battery, which may eventually lead to the rupture of the grid of the battery. So we do not recommend recharhing the battery  after  running out of power. 
    All in all, the depth of discharge of the battery is 80%-60%, that is, it is most appropriate to charge when the remaining 20%-40% of the battery is charged. Correct charging habits can effectively prolong the service life of the battery and ensure that the cycle life of the battery can reach more than 500 times.
  • The brake pads wear out quickly, and the more the brake is used, the less sensitive it is. What is the reason? How to solve it?

    Whether it is national standard, provincial standard or enterprise standard, the evaluation of the quality of the safety part of the brake is based on the braking distance of the new car. The problem is that the braking performance of new cars is generally good, but due to the rapid wear of braking friction materials, the braking is not so sensitive after a period of time. 
    Then the question comes again. Why do friction materials wear so fast? This is determined by the two characteristics of friction materials, wear resistance and temperature characteristics. 
    Braking is a process of converting mechanical energy into thermal energy. If the temperature characteristics of the friction material are not good enough, when we brake frequently, the temperature of the brake will rise sharply, which will change the friction coefficient of the brake pads and accelerate and intensify the wear. 
    In fact, when the brake is slightly worn, we can adjust it in some small ways.
    But many times, before we can adjust, the brakes are almost worn out. For example, the takeaway brother uses the vehicle and the brake function very frequently. When he realizes that he needs to adjust, the brake pads have been worn out.  
    So what is the fundamental way to solve the problem of rapid wear of brake materials? In fact, it is very simple, that is to improve the grade of the brakes. Using materials with low wear characteristics and good temperature stability to make brakes, such as the ceramic brakes that have been used in all Luyuan models at present, can shorten the braking distance by 30% and prolong the service life by 5 times. Ceramic brakes, through the introduction of ceramic additives, have greatly improved the wear resistance and temperature characteristics of friction materials, making them more wear-resistant and safer. So that whether it is a new car or an old car, it can brake steadily.
  • The E-Vehicle goes and stops. The problem lies in this invisible place!

    When it comes to the four major parts of E-Vehicles, many people can think of batteries, chargers and motors, but they are not familiar with the last one - the controller. In fact, for E-Vehicles, this thing that many people are not familiar with is crucial. It is the command system of E-Vehicle, which is equivalent to the heart or brain of E-Vehicle. The controller is indispensable for the normal operation of the motor. The controller pushes each coil winding in the coil, so that the motor can produce alternating magnetic field and rotate. In addition, the detection image of hall in the motor also needs to be sent to the controller, and then the controller ensures the continuous and good operation of the motor through calculation and feedback.
    In this process, it will involve a set of driving system with MOS transistor, MOS FET and hall image detection as the core. This drive system is very important for E-Vehicles. If there is a problem with this system, there will be situations described at the beginning of the article, such as unable to run with electricity and the car stops as soon as it goes. Therefore, choosing a good controller is very critical. 
    However, the common controllers on the market are prone to various small problems. What is the reason? The main reason is that, like chargers, motors, etc., the controller of an E-Vehicle is also a heat-generating system.  
    As mentioned above, there is a MOS tube in the controller, which will pass a large current during operation. It is well known that the current has a thermal effect, which will cause the temperature inside the controller to rise. The higher the temperature, the greater the power consumption, the greater the power consumption, the higher the temperature, which creates a vicious circle, and eventually the controller becomes hot, and in severe cases, the MOS tube will be burned, causing the controller to fail to work normally.
    And the controller is generally installed at the rear of the E-Vehicle, next to some plastic parts and wires. The charger often heats up and becomes hot, which will also lead to the aging of these plastic parts and wires, and even the destruction of the insulation, and in more serious cases, a short circuit will occur. Therefore, to ensure the safety of E-Vehicles, it is very important to choose a good controller.
  • I went to replace it with a new batterys as the electric motorcycle didn't run far. But it still not as far as the new car. Did I buy a fake battery?

    When the mileage  of E-Vehicles decreases, most users may choose to replace the battery. However, in many cases, the consumers  will find that the mileage of the E-vehicle is still not as good as previous one. At this time, users will have a question: did the battery  merchant  replace the fake battery for the E-vehicle? 

    It was found that the battery was actually a good battery after  battery capacity was tested with a discharge meter. Somehow, it didn't run as well as previous while the new battery replce for the new E-vehicle. Some careful consumers  will also check the tires, brakes and other parts. The E-vehicles cann't run as same mileage as previous one while all parts work well.

    At this time, we have reason to suspect that there is  80%-90% problem of  the internal efficiency of the motor is reduced which leads to the decline of endurance.
    There are three parts related to "magnetism" in the motor, namely permanent magnet, copper wire and iron (silicon steel sheet). Copper and iron will not change, but high temperature will lead to irreversible demagnetization of the permanent magnet, and water vapor will lead to oxidation and rust of the permanent magnet, reducing the internal efficiency of the motor further. At this time, the range of E-Vehicles with new batteries can not reach the same as that of new E-vehicle.

    Moreover, this kind of "running too far" is still a vicious circle: the shorter the distance, the more easily the E-Vehicle will heat up when climbing a hill or carrying a load, and the hotter it is, the less it will run. In such a situation, many consumers will feel that the car is no longer good, and will choose to trade in the old for a new one, which is one of the reasons why the service life of E-Vehicles is not long. But neither changing the battery nor changing the car is the solution to the fundamental problem.

    In fact, the most effective and fundamental is to reduce the internal temperature of the motor while it is working and prevent water from entering the motor. The specific measures include establishing a good water vapor exchange system and strengthening the surface treatment of permanent magnet materials.





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