Negative pulse charger

Lead-acid batteries have a history of more than 100 years, and they have begun to adopt the old viewpoints and operating procedures all over the world: the charge and discharge rate is 0.1C(C is the battery capacity) and the service life is longer. In order to solve the problem of fast charging, Mr. Max, an American, published his research results to the world in 1967, charging with a pulse current greater than 1C rate, and discharging the battery during intermittent charging. Discharge is beneficial to eliminate polarization, reduce the temperature of the electrolyte, and improve the ability of the electrode plate to accept charge.

Some scientific and technological workers in China around 1969, according to Mr. Max's three laws of the successful production of a variety of brands of fast charger. The charging cycle process is as follows: high current pulse charging → cutting off the charging path → discharging the battery briefly → stopping discharging → connecting the charging path → high current pulse charging......

Around 2000, some people used this principle in the electric car charger. During the charging process, the charging path was not cut off, and the battery was short-circuited with a small resistor to discharge. Since the charging path is not cut off at the time of the short circuit, an inductance is connected in series in the charging path. Generally in 1 second short circuit 3-5 milliseconds (1 second = 1000 milliseconds), because the current in the inductor can not jump, short circuit time, can protect the power conversion part of the charger. If the direction of the charging current is called positive, the discharge is naturally negative, and the term "negative pulse charger" has appeared in the electric vehicle industry, and it is said that it can extend the battery life and so on.

Three-stage charger

Electric car charger

In recent years, electric vehicles have generally used the so-called three-stage charger. The first stage is called the constant current stage, the second stage is called the constant voltage stage, and the third stage is called the trickle stage. From the perspective of electronic technology, for batteries, the first stage is called charging current limiting stage, the second stage is called high constant voltage stage, and the third stage is called low constant voltage stage. When the second stage and the third stage are switched, the panel indicator lights change accordingly. Most chargers and the second stage are red lights, and the third stage is green. The mutual conversion between the second stage and the third stage is determined by the charging current, which is greater than a certain current to enter the second stage and less than a certain current to enter the third stage. This current is called conversion current, also called turning current.

Early chargers, including chargers for advanced cars, although they also changed lights, were actually constant voltage and current limiting chargers, not three-stage chargers. Generally, this kind of stable voltage value is about 44.2V, which is not bad for the battery of high specific gravity sulfuric acid at that time.

Three key parameters of the three-stage charger

The first important parameter is the low constant voltage value of the trickle phase, the second important parameter is the high constant voltage value of the second phase, and the third important parameter is the conversion current. These three important parameters are related to the number of batteries, the capacity of the battery, the temperature, and the type of battery. In order to facilitate everyone's memory, the following is a very common electric bicycle (three 12V series of 10Ah batteries) used in the three-stage charger as an example of a brief introduction:

First, the low constant voltage value of the trickle phase is discussed, and the reference voltage is about 42.5V. This value will make the battery high water loss, easy to make the battery heat deformation; this value is not conducive to the battery fully charged. This value is lower than 41.5V in the south; The gel battery is lower than 41.5V, such as a little lower in the south. This parameter is relatively strict and cannot be greater than the reference value.

Secondly, the high constant voltage value of the second stage is discussed, and the reference voltage is about 44.5V. This high value is conducive to rapid and sufficient charging, but it is easy to cause the battery to lose water, and the current will not come down at the later stage of charging, resulting in heating and deformation of the battery; this low value is not conducive to the rapid and sufficient charging of the battery, and is conducive to the transition to the trickle phase. Although this value is not as strict as a value, it should not be too high.

After discussing the conversion current, the reference current is about 300 mA. This high value is conducive to battery life, not easy to heat deformation, but not conducive to the rapid battery full charge; this value is low (to the outside) is conducive to adequate charge, but due to a long time high voltage charging, easy to make the battery water loss, so that the battery heat deformation. In particular, when there is a problem with some batteries, when the charging current does not drop below the turning current, the good batteries will also be damaged. The given reference value has a certain range, positive and negative 50 mA and even 100 mA are allowed, but not allowed to be less than 200 mA.

There are many cheap flyback chargers with high constant voltage value of 46.5V, low constant voltage value of 41.5V and turning current greater than 500 mA.

If it is a charger for four 12V batteries, that is, a 48V charger, the first two parameters are the aforementioned voltage reference value divided by three multiplied by four. The high constant voltage value is about 59.5V, and the low constant voltage value is about 56.5V.

If the battery is larger than 10Ah, the current value of the third parameter is appropriately increased. For example, the 17Ah battery can be as large as 500 mA.

Electric car charger

Buy a new charger to check the three important parameters of the three-stage charger, the user can generally measure the third stage of the low constant voltage value. The method is to connect the battery, add mains power to the charger, and measure the output voltage of the charger with the 200V DC voltage file of the digital multimeter. The other two parameters, high constant voltage value and turning current, generally require special tools to measure.

Add some correct charging methods: 1, change the green light and then charge for 2-3 hours. 2. The principle is to charge (charge) frequently (charge) lightly, and charge after 50% each time. Don't charge too frequently. This will shorten the battery life. 3. If you don't ride for a long time, you should charge it regularly (1 month). 4, long-term shallow discharge of the battery, 3 months or so, for a deep discharge, is the so-called light recharge, is conducive to the activation of long-term immobile material in the deep part of the battery. The meaning of light is to ride until the controller battery undervoltage protection action.

Need to remind customers a few points: 1. Generally, after a new battery is put into use for 8-10 months, the battery should be inspected and maintained. 2. Generally, the chargers matched with advanced cars are screened and usually do not need to be tested. However, for non-matched chargers purchased on the market separately, the aforementioned three parameters must be tested. 3. There is a thyristor charger without power frequency transformer. It directly rectifies the mains power to charge the battery. The current can reach 30A and the voltage is adjustable from 12V to 80V. Before the mains power is effectively cut off, do not touch the battery. Customers who use this type of charger for freight three rounds should pay special attention to safety.

Features of Colin Charger (Relationship between Colin Charger and Battery)

Features: It can effectively extend the service life of lead-acid batteries