A lot of people have bad habits, often people are not at home to put the electric car battery on the car, the air switch is not turned off, put a few months do not ride. When I came back a few months later, I found the bike had run out of battery and couldn't charge it. The charger is plugged in, but the light stays green, even if it is plugged in for 24 hours, because the battery voltage is too low, and the charger can't flush electricity into the battery if the output voltage is too different from the charger.


This situation is commonly known as the battery is "starved to death." The voltage of the battery is usually only about 5.6V, not more than 6V. For such batteries, most are replaced. But it's a shame to replace a set of hundreds of batteries, especially if they're just out of warranty.


Here are five good ways to save most of these starving batteries. Notice that most of them are not 100%.

First, series method. Another 12 volt battery with normal voltage is connected in series in the whole battery group. For example, the original car is 48V-20ah battery, then we have another 12V-20AH battery in series. The voltage of a 12V battery with sufficient power is about 13V. After series series, the voltage of the whole battery can be raised, and then the charger can be charged with its original charger. In this case, it can be charged into the battery. As soon as the charger turns green, remove the additional battery connected in series. Then recharge normally.


Two, parallel method. This method is a little bit more cumbersome. For example, the vehicle originally had 48V-20ah batteries, and we had another set of 48V-20ah batteries in parallel. You know that the voltages in a parallel circuit are the same, and the high voltage ends flow into the low voltage ends. This method is also used by many battery dealers to test batteries that have no charge at all. Then charging can also achieve the purpose of charging. It's similar to what happens when you have a battery in series. It's also going to raise the voltage of the whole group.


Low voltage charging method. Use a smaller model charger for charging. For example, a set of 60V-20ah batteries, then we use a 48V-20ah charger for charging. In most cases, it can be filled. The principle is similar to the first one, which makes the charging voltage closer to the voltage at both ends of the battery.


Four, single battery charging method. The single battery can be activated by charging it with a 12-volt motorcycle charger, but the charge is slow, generally taking more than 7 hours before the battery voltage slowly rises back to around 12V. If all single block charge is very time-consuming.


5. Special charger method. Day can charger it is automatic identification of battery voltage, no matter how many volts of battery voltage, can automatically identify the voltage, he can charge in. For example, the original car is 60V-20AH battery, now only 30V less than, it can still charge inside. As the voltage rises, it ADAPTS to a higher voltage and recharges the battery. Tailing, lvjia electric car, Jinpeng tricycle matching this brand charger.

In addition, how to activate the lithium battery "starved to death"? Laptop batteries or cell phone batteries


Battery activation is called "Power ruler Calibration" in lenovo Power Management software. When we used Everest for a PC, we found a "design capacity" followed by "full charging capacity." If the two values were the same, we found a "battery loss" score of 0 percent. Generally speaking, the "full charge capacity" of batteries that have just left the factory or have been placed for a long time without timely maintenance will be less than the "design capacity", and you will see that the battery loss is 1%. This means that the battery is not "fully charged", so we need to "fully charge" (charge the battery continuously for 12 hours or more after a full discharge) to fully "exploit" the battery's "potential". This full charge and discharge process is called "battery activation", lenovo Thinkpad and other power management software has a "power ruler calibration" function principle is similar.


I think some old tech batteries like NiMH need to be activated. The theory of lithium batteries is that they need to be activated because they need to form an SEI protective layer at the negative electrode. But this process is actually done in production testing. Personally, I think consumers' misunderstanding of batteries has led to such a service.


Your cell phone battery is "hungry" dead, can not turn on the phone to charge, then need to activate! First of all, the so-called starvation is the battery has been out of power or low battery caused by the battery can not be recharged phenomenon. Then the so-called activation at present there are two methods: one is to use universal filling 20 minutes or so can be activated. The second is to give the mobile phone repair shop has a more professional voltage slightly higher, such as 12 volt power supply to activate, specifically, the positive and negative power supply on the positive and negative batteries for dozens of seconds or even a few minutes to give it all electricity, get through it! Finally, it can be recharged with direct charge as before, whether it will have a significant impact on life is unknown.


Charge by instrument. (If the above way is not good, the battery is not faulty, you need to use the 'stable voltage power supply' activation, black wire connected to the negative battery, red connected to the positive battery, charging voltage reached 3.8V, you can use the device of lithium battery, the first time use without charging 12 hours, this is not necessary!

"Lithium battery" is a kind of battery with lithium metal or lithium alloy as anode material and non-aqueous electrolyte solution. Lithium metal batteries were first proposed and studied by Gilbert T. Lewis in 1912. In the 1970s, M.S. Wattingham proposed and began research on lithium-ion batteries. Due to the chemical characteristics of lithium metal is very active, the processing, preservation and use of lithium metal have very high environmental requirements. As a result, lithium batteries have not been used for a long time. With the development of science and technology, lithium battery has become the mainstream.

Lithium batteries can be roughly divided into two categories: lithium metal batteries and lithium ion batteries. Lithium-ion batteries do not contain metallic lithium and can be recharged. Lithium metal battery, the fifth generation of rechargeable battery, was born in 1996. Its safety, specific capacity, self-discharge rate and performance-to-price ratio are better than lithium ion battery. The lithium-metal battery is now being produced by companies in only a handful of countries because of its high technical requirements.


Battery life


Lithium-ion batteries can only be charged and discharged 500 times?

Believe that the vast majority of consumers have heard of, the life of the lithium battery is "500", 500 times more than the number of times, the battery will "die", many friends in order to be able to extend battery life, each time to charge when the battery run out completely, so really have a longer effect on battery life? The answer is no. Lithium-ion batteries have a life span of "500 cycles," which is not the number of charges, but the cycle of charging and discharging.


A charging cycle means that all the charge of a battery goes from full to empty, and then from empty to full, which is not the same as a single charge. A lithium-ion battery, for example, uses only half its capacity on the first day, and then recharges it. If it's still the same the next day, use half of the charge, and two total charges count as one charge cycle, not two. As a result, it may normally take several charges to complete a cycle. With each charge cycle, the capacity of the battery decreases a little. However, the reduction is so small that high-quality batteries retain 80% of their original capacity after multiple cycles of charging, and many lithium-ion products can still be used after two or three years. Of course, lithium battery life to the end is still need to be replaced.


The so-called 500 times, refers to the manufacturer in a constant discharge depth (such as 80%) to achieve about 625 times of charge, up to 500 charging cycle.


(80%*625=500) (factors such as reduction of lithium battery capacity are ignored)


However, due to various practical influences, especially the discharge depth when charging is not constant, the "500 charge cycle "can only be used as a reference battery life.


Correct view: lithium life and charging cycle of the completion of the number of times, and the number of charges is not directly related.


A simple understanding, for example, is that a piece of lithium battery uses only half its capacity on the first day, and then it is fully charged. If it's still the same the next day, use half of the charge, and two total charges count as one charge cycle, not two. As a result, it may normally take several charges to complete a cycle. With each cycle, the charge goes down a bit. However, the reduction is very small. High-quality batteries retain 80% of their original charge after many cycles, which is why many lithium-ion products are still in normal use after two or three years. Of course, lithium battery life eventually needs to be replaced.


Lithium battery life is usually 300 to 500 charging cycles. Assuming that the power provided by a complete discharge is Q, if the reduction of the power after each charging cycle is not considered, the lithium battery can provide or supplement 300Q-500Q power in its lifetime. From this, we know that if we charge each time with 1/2, we can charge 600-1000 times; If one third of each charge is used, 900 to 1,500 charges can be made. And so on, if the charge is random, the number of times is variable. In short, no matter how it is charged, a total of 300Q to 500Q of power is added, which is constant. Therefore, we can also understand: lithium battery life is related to the total charge of the battery, and the number of charges has nothing to do with. There is little difference between deep charge and shallow charge on lithium battery life.


In fact, shallow discharge shallow charge for lithium is more beneficial, only in the product power module for lithium calibration, deep charge is necessary. Therefore, the use of lithium electric power supply products do not have to stick to the process, all with convenience first, charging at any time, do not have to worry about the impact of life.


If lithium is used in an environment above the specified operating temperature, that is, 35°C or higher, the battery charge will be continuously reduced, that is, the battery will not be powered for as long as usual. If you have to charge your device at those temperatures, the damage to the battery will be even worse. Even if the battery is stored in a hot environment, it will inevitably cause damage to the quality of the battery. Therefore, it is a good way to prolong the life of lithium batteries to keep operating at the optimum temperature.


If the lithium battery is used in a low-temperature environment, that is, below 4°C, it will also be found that the battery life is reduced, and some mobile phones with original lithium batteries can not even be charged in a low-temperature environment. But don't worry too much, this is only a temporary condition, unlike the use in high temperature environment, once the temperature rises, the molecules in the battery heat up, and immediately return to the previous charge.


To get the most out of lithium-ion batteries, they need to be used regularly to keep the electrons flowing. If you do not often use lithium, please remember to complete a charging cycle to lithium every month, do a battery calibration, that is, deep deep charge once.


It's called "charge and discharge cycle". It's not equal to "charge times". Cycle means that the battery goes from full charge to full charge. Similarly, you go from full to full to full to full to full to full to full to full to full to full to full again, so you're charging twice. Therefore, the cycle is only determined by "how much power is released from the battery", and has nothing to do with "charge times".



And the nominal number of charge and discharge cycles does not mean that the battery is no longer usable, but that after doing so many cycles, the battery's ability to store charge decreases to a point,


For example, the nominal charge and discharge cycle of a lithium battery is "not less than 60% of the nominal capacity after 500 times".


That is, after 500 cycles, the battery can only hold 60% of the power of the new battery, which means the performance has dropped to a certain extent


Lithium battery has no fixed charge times limit, the regular manufacturers out of the battery can generally charge and discharge at least 500 times, and the capacity is maintained at more than 80% of the initial capacity, a day can be used for 2 years. It usually takes 1,000 recharges of a mobile phone battery to cause serious battery fatigue.



Mobile phone battery maintenance methods:


1, each time fully charged use, reduce the number of charging, improve the battery life.


2, do not fully discharge the battery, usually less than 10% need to charge.


3, use the original charger to charge, do not use universal charging.


4. Do not use your mobile phone while it is charging.


5. Do not overcharge. Stop charging when the battery is full.


Yes, according to the experimental results, the life of lithium battery is decreasing with the increase of charging times, and the general charging times of lithium battery is 2000-3000 times


Cycle is use, we are using the battery, care about the use of time, in order to measure how long the rechargeable battery can be used for such a performance, the definition of cycle number. Actual user usage varies greatly, because tests under different conditions are not comparable, and a comparison requires a standardized definition of cycle life.


Gb requirements of lithium battery cycle life test conditions and requirements: in the ambient temperature of 20℃±5℃ under the condition of 1C charging, when the battery terminal voltage to charge limit voltage 4.2V, to constant voltage charging, until the charging current is less than or equal to 1/20C, stop charging, use 0.5h~1h, Then discharge with 1C current to the termination voltage 2.75V, after the discharge, use 0.5h~1h, and then carry out the next charge-discharge cycle, until two consecutive discharge time is less than 36min, then consider the end of life, cycle times must be more than 300 times.


Interpretation of national standard provisions:


A. This definition specifies that the cycle life test shall be conducted in A deep charge and deep discharge manner


B. The cycle life of lithium battery is stipulated. In accordance with this model, the capacity is still more than 60% after ≥300 cycles


However, different cycles of the circulation system is very different, such as more than the other conditions unchanged, only change the constant-voltage voltage of 4.2 V to 4.1 V voltage for the same model of the constant pressure of the battery cycle life test, so the battery is not deep filling way, the final test number of cycle life can be improved by almost 60%. If the cut-off voltage is raised to 3.9V for testing, the number of cycles should be increased several times.



This cycle charge and discharge once less a life, we should pay attention to the definition of the charging cycle of lithium battery: a charging cycle refers to all the power of the lithium battery by full to empty, and then by empty charge to full process. And that's not the same as charging once. In addition, when we talk about the number of cycles, we can not ignore the conditions of the cycle. It is meaningless to talk about the number of cycles without rules, because the number of cycles is the means of testing battery life, rather than the goal!

48V lithium ion battery definition

Individual batteries on the market are generally around 3.7V, but there are many times when the operating voltage range is slightly larger than the obvious problem of insufficient voltage. At this time, the battery pack and modular battery that can improve the battery voltage will follow, and in many high-voltage batteries, 48V lithium ion battery has been widely used.

Compared with lead-acid battery, 48V lithium ion battery has the advantages of small volume, light weight, strong temperature adaptability, high charge-discharge efficiency, safety and stability, long service life, energy saving and environmental protection, etc.

According to the cathode material, 48V lithium ion battery can be divided into ternary lithium battery, lithium iron phosphate battery and lithium titanate battery.

48V lithium ion battery price

48-V lithium-ion battery is composed of multiple lithium cells combined in series and parallel, because if a single cell is 48-V lithium battery, the efficiency and life of the battery is not very good.

· 48V lithium ion battery price estimation formula

Price of single lithium battery cell x (3.6-3.7V *n= 48V) * M (number of parallel cells) + price of protective plate + shell price + price of auxiliary materials

Generally, the voltage of a single lithium cell ranges from 3.6 to 3.7V, and the price varies depending on the materials and processes used by lithium battery manufacturers.

48V lithium battery pack

48V lithium ion battery pack model table

48V lithium ion battery charger

48V lithium ion battery charger is specially used to charge the nominal voltage of 48V lithium battery charger. Lithium batteries have high requirements for chargers and need to protect the circuit, so lithium battery chargers usually have high control precision and can charge the lithium batteries at constant current and constant voltage.

The lithium battery charger has the function of overvoltage protection and temperature protection. The lithium battery charger is connected with the external current-limiting charging power supply and p-channel field effect tube, which can charge a single lithium battery safely and effectively. Its biggest characteristic is that it can achieve very low power dissipation without using inductance, and adopts 8-pin μMAX package. The charging control accuracy is 0.75%, which can realize pre-charging. The maximum charging time limit provides secondary protection for lithium battery. The floating charging mode of lithium battery charger can maximize the battery capacity.

47.5V 4A lithium iron phosphate battery charger

Input voltage: 100-240V,50-60Hz

Output voltage: 47.5V

Output current: 4A

Application: 13 41V lithium iron phosphate battery packs

Product size: 178*80*46mm

Product weight: 0.8kg/ PCS

Safety standard: UL1012 IEC60335 IEC61558

Certified: UL, cUL, GS, CE, ROHS, REACH, SAA, PSE, CCC

Features: with reverse connection/overload/overcurrent/short circuit/high temperature automatic protection function, parallel rail charging, automatically capture and track battery voltage, lock charging current, temperature rise sensing, step-down stay, color changing light-emitting diode display full charging status

48V lithium ion battery protection plate

48V lithium ion battery protection plate, namely the protective role of the circuit board. It is mainly composed of electronic circuits, which can accurately monitor the voltage of the cell and the current of the charging and discharging circuit at the temperature of -40℃ to +85℃, and timely control the on-off of the current circuit.

The lithium battery protection plate can protect the charge and discharge of the series and parallel battery pack, and detect the state of over voltage, over current, over temperature, under voltage and short circuit of each single battery in the battery pack, prolong the service life of the battery, and avoid the damage of the battery due to over discharge. Lithium battery protection plate is an indispensable part of lithium battery.

48V lithium ion battery BMS

48 v lithium-ion battery management system (BMS), through to detect the state of each monomer battery of lithium battery to determine the status of the battery system, and according to their status to lithium battery system adjustment and the corresponding control strategy implementation, implementation of lithium battery system and to ensure that the lithium battery charge and discharge of each monomer management system safe and steady operation.

48V lithium ion battery BMS features

The lithium ion battery management system consists of a management host (CPU), a voltage and temperature collection module, a current collection module and a communication interface module.

It can detect and display the total voltage, total current and reserve power of lithium ion battery pack; The voltage of any single cell and the temperature of the cell box; Maximum and minimum battery voltages, battery numbers, maximum and minimum temperatures, and charge and discharge quantities of battery strings.

4 Lithium ion battery host also provides alarm and control output interface, alarm and control output for overvoltage, undervoltage, high temperature, low temperature, overcurrent, short circuit and other extreme situations.

Provide RS232 and CAN bus interface, CAN directly read all information on the lithium battery management system on the computer.

Note for use of 48V lithium ion battery

If lithium ion batteries are stored for a long time, they should be kept in 50%-60% full charge state. They should be replenished once every three months and charged and discharged once every six months.

In the transportation process, pay attention to moisture and moisture, avoid extrusion, collision, etc., to avoid damage to the lithium ion battery.

Do not use or place lithium-ion batteries at high temperature (under hot sun or in a hot car). Otherwise, the batteries may overheat, catch fire, fail to function and shorten their service life.

Do not store in a place with strong static electricity or magnetic field. Otherwise, the battery safety protection device may be damaged, resulting in unsafe risks.

If the lithium-ion battery gives out peculiar smell, heat, discoloration, deformation or any abnormality occurs during use, storage or charging, remove the battery from the device or charger immediately and stop using it.

48V lithium ion battery vs. lead acid battery



Weight energy density



At present, the energy density of lithium battery is generally 200~ 260Wh/g, and the lea

48V lithium ion battery

1, 48V lithium ion battery charging matters needing attention

Charge strictly according to standard time and procedure.

Lithium battery factory is generally charged half state, the first use must be fully charged battery.

Use the original charger, the original charger supporting strong performance, moderate charging rate.

Do not always charge until the undervoltage protection circuit is active. The concept of recharging after completely discharging the electricity is not correct, the greater the discharge depth, the more times of use of deficient electricity, the shorter the service life of lithium battery.

2. How many kilometers does the 48V lithium ion battery run with full electric energy?

The battery life of 48V lithium ion battery is related to the capacity of the battery itself (Ah) and the motor power of the electric vehicle (W). Now the electric bicycle on the market in line with national standards generally uses 48V 12Ah lithium battery and 350W motor. With the development of battery technology, their theoretical endurance can reach 50km. The actual range depends on the weight of the passenger and the weight of the vehicle.

How many kilometers can a 48-V lithium-ion battery run on full electric energy depends on battery capacity, motor power and load capacity. Generally speaking, 48V 12Ah, 350W lithium battery can run 50km. 48V 20Ah can run 70km. The 72V 22Ah lithium battery has a range of 90 kilometers.

3. How many hours does it take to charge the 48V lithium battery?

Charging time doesn't have much to do with voltage;

Basically see the capacity of lithium ion battery and the power of the charger, charging time = lithium battery capacity ÷ charging current

For example, 48V 20Ah lithium ion battery uses a regular 48V 2A charger, so the theoretical charging time is 2 hours, that is, 20Ah÷10A=2h, but the actual charging constant flow constant voltage mode, in the last stream charging time is long, so under normal circumstances are about 3 hours. Similarly, the 48V 5A charger needs 20Ah÷5A=4h, but it also has trickle time, so it is about 5 hours.

4. How to do if the 48V lithium ion battery cannot be charged?

Charger output parameters are normal, voltage, current, etc.;

Whether the charger line is normal, whether the connection is broken;

Lithium battery is broken, you can test the battery open circuit voltage is normal;

? Consult lithium battery manufacturers.

5, 48V13 string and 14 string difference

Ternary is 13 or 14 strings, lithium iron phosphate is 16 strings

But ternary 13 series discharge platform is obviously lower than 48V, the speed is slow, 14 series is good

13 series full voltage 13*4.2=54.6V, rated voltage 13*3.7=48.1V, cut-off voltage 13*3.2 = 41.6V

Full voltage 14*4.2=58.8V, rated voltage 14*3.7=51.8V, cut-off voltage 14*3.2 = 44.8V

13 series can be better compatible with lead acid battery electric vehicle, lead acid battery electric vehicle normal is 12*4= 48V, up to the voltage 10.5*4 =42V

In addition, 48V 13 series and 48V 14 series charger voltage is not the same, can not be universal, some chargers can adjust the voltage can be universal.

What is energy density?


Energydensity refers to the amount of energy stored in a given unit of space or mass. The energy density of a battery is the amount of energy released per unit volume or mass of the battery. The energy density of a battery is generally divided into two dimensions: weight energy density and volume energy density.



Battery weight Energy density = battery capacity x discharge platform/weight, the basic unit is Wh/kg(watt-hour /kg)


Battery volume energy density = battery capacity x discharge platform/volume, the basic unit is Wh/L(watt-hour/liter)


The greater the energy density of a battery, the more energy can be stored per unit volume, or weight.


What is the monomer energy density?


The energy density of a battery often refers to two different concepts, the energy density of a single cell and the energy density of a battery system.


The cell is the smallest unit of a battery system. M cells form a module, N modules form a battery pack, which is the basic structure of the vehicle power battery.


The energy density of a single cell, as the name implies, is the energy density of a single cell.

According to "Made in China 2025", the development plan of power battery is clear: by 2020, the battery energy density will reach 300Wh/kg; By 2025, battery energy density will reach 400Wh/kg; By 2030, battery energy density could reach 500Wh/kg. This refers to the energy density at the level of a single cell.

What is the system energy density?

System energy density refers to the weight or volume of the whole battery system compared to the electric quantity of the whole battery system after the combination of single cells. Because the battery system contains the battery management system, thermal management system, high and low voltage loop, etc., which occupy part of the weight and internal space of the battery system, the energy density of the battery system is lower than that of the single energy density.


System energy density