Negative pulse charger
Lead-acid battery has a history of more than 100 years, began to be universal along the old point of view and operating procedures: charge, discharge rate of 0.1C(C is the battery capacity) long life. In order to solve the problem of fast charging, Mr. Max, an American, published his research results to the world in 1967. He charged the battery with pulse current of more than 1C rate and discharged the battery during the interval of charging. Discharge is beneficial to eliminate polarization, reduce the temperature of electrolyte and improve the ability of the plate to accept charge.
Some Chinese science and technology workers in 1969 around, according to Mr. Max's three laws to make a variety of successful brands of fast charging machines. The charging cycle process is: large current pulse charging → cut off the charging channel → brief discharge to the battery → stop discharge → switch on the charging channel → large current pulse charging......
Around 2000, someone applied this principle to the electric car charger. In the process of charging, the charging channel is not cut off, and the battery is short-circuated with a small resistance and discharged. Because the charging path is not cut off during short circuit, the inductance is connected 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 short circuit time, can protect the power conversion part of the charger. If the charging current direction is called positive, discharge is naturally negative, electric vehicle industry has the term "negative pulse charger", but also said that can extend the battery life and so on.
Electric vehicle charger
In recent years, electric vehicles commonly use the so-called three-stage charger, a stage is called constant current stage, the second stage is called constant voltage stage, the third stage is called trickle stage. From the point of view of electronic technology for the battery: one stage is called charging current limiting stage, the second stage is called high constant voltage stage, the third stage is called low constant voltage stage is more appropriate. During the transition between the second stage and the third stage, the panel indicator light changes accordingly, most chargers, the second stage is red, and the third stage is green. The conversion between the second stage and the third stage is determined by the charging current, higher than a certain current into the second stage, and lower than a certain current into the third stage. This current is called conversion current, also called transition current.
Early chargers, including those that come with advanced cars, are constant-voltage current-limiting chargers, not three-phase chargers, although they also change lights. Generally, this kind of stable voltage value, about 44.2V, for the high proportion of sulfuric acid batteries at that time is acceptable.
Three key parameters of three-stage charger
One important parameter is the low constant voltage value in the trickle phase, the second important parameter is the high constant voltage value in the second phase, and the third important parameter is the conversion current. These three important parameters are related to the number of batteries, battery capacity Ah, temperature, and battery type. In order to facilitate your memory, the following is a very common electric bicycle (three 12V series of 10Ah battery) used for the three-stage charger as an example:
First, the low constant voltage at trickle stage is discussed. The reference voltage is about 42.5V. The high value will make the battery water loss, easy to make the battery heating deformation; This low value is not conducive to full battery charge. It is lower than 41.5V in the south; Colloidal batteries are lower than 41.5V, and a little lower in the south. This parameter is relatively strict and cannot be larger than the reference value.
Secondly, the high constant voltage value of the second stage is discussed. The reference voltage is about 44.5V. This high value is conducive to fast enough power, but easy to make the battery water loss, late charging current does not come, resulting in heat deformation of the battery; This low value is not conducive to the battery fast full charge, conducive to the trickle phase conversion. This value is not as strict as a single value, but it should not be too high.
The conversion current is discussed later, and the reference current is about 300 mA. The high value is conducive to the battery life, not easy to heat deformation, but not conducive to the battery fast enough power; This low value (amateurs) is conducive to sufficient power, but due to a long time of high voltage charging, easy to make the battery water loss, so that the battery heating deformation. In particular, when there is a problem with individual batteries, the charging current falls below the turning current, the good battery will be charged. A range of reference values is given, with plus or minus 50 milliamps or even 100 milliamps allowed, but not less than 200 milliamps.
There are many cheap flyback chargers on the market with a high constant voltage of 46.5V and a low constant voltage of 41.5V and a turning current greater than 500mA.
If there are four chargers with 12V batteries, i.e., 48V chargers, the first two parameters are the preceding voltage reference value divided by three times four. The high constant pressure value is about 59.5V and the low constant pressure value is about 56.5V.
If the battery is larger than 10Ah, increase the current value of the third parameter appropriately. For example, a 17Ah battery can be as large as 500 mA.
Electric vehicle charger
Buy a new charger to check three important parameters of the three-stage charger, users can generally measure the third stage of the low constant voltage value. The method is, do not connect the battery, add mains to the charger, use the digital multimeter 200V DC voltage file to measure the output voltage of the charger. The other two parameters, high constant voltage value and turning current, generally need special tools to measure.
Add some correct charging methods: 1. After the green light changes, continue charging for 2-3 hours. 2, the principle is shallow discharge (electricity) often charge (electricity), each time after the use of 50% charge, do not charge too frequently this will shorten the battery life 3, long-term do not ride, to charge a regular (1 month). 4, long-term shallow battery, 3 months or so, for a deep discharge, is the so-called light recharging, is conducive to the deep battery long-term immobile material activation. Glow means ride until the controller battery undervoltage protection action.
The customer needs to be reminded of several points: 1, the general new battery put into use 8-10 months, to check and maintain the battery. 2. Generally, the charger supporting advanced cars is screened, usually without testing, but the non-matching charger purchased separately on the market must be tested for the above three parameters. 3, there is a thyristor charger without power frequency transformer, direct rectifier mains for battery charging, current to 30A, voltage 12V-80V adjustable, not effectively cut off the mains before, do not touch the battery, freight three rounds using this kind of charging machine customers should pay special attention to safety.
Collin charger characteristics (Collin charger and battery relationship)
Features: Can effectively prolong the service life of lead-acid battery +
Principle: The main cause of lead-acid battery damage and the solution of Dongkoda