The car battery is the heart of the electrical equipment of the machine, and its performance depends on the quality of service. In harsh climates and frequent short trips, the battery often fails to regain charge, leading to plate sulfation and loss of capacity. To solve this problem, vehicle owners often turn to time-tested models of chargers, including: ZU-120 It holds a special place because of its reliability.
This device is a classic transformer rectifier that provides a stable charge current necessary for high-quality desulfation and recovery. lead-acid batteries. Unlike modern pulsed analogues, the ZU-120 is less susceptible to voltage surges in the network and is able to withstand significant overloads. That is why many motorists still prefer this model for regular maintenance of the battery.
In this article we will discuss in detail the technical characteristics, the principle of operation, as well as common malfunctions of this unit. You will learn how to properly operate the device so as not to damage the battery, and what precautions must be taken when working with high currents.
Technical characteristics and design features
The basis of the device is a powerful step-down transformer that converts the main voltage of 220 volts into a safe value for charging. The design of the ZU-120 is made in a metal body, which ensures effective heater Protecting internal components from mechanical damage. The weight of the device is significant, which is a direct consequence of the use of copper winding in the transformer.
On the front panel are an ammeter to control the current and a regulator of voltage or current, depending on the modification. The nominal output current of the device is up to 10 Amps.This allows you to charge batteries with a capacity of 40 to 190 Ah. This versatility makes the model suitable not only for passenger cars, but also for servicing trucks and special equipment.
An important element of the design is a system of protection against overpole, although in older models it may be absent or be implemented by a fuse. Modern versions are often equipped with electronic circuits that turn off the output when the terminals are not connected correctly. This is critically important, as the reverse current can disable the diode bridge.
⚠️ Before connecting to the network, be sure to make sure that the battery terminals are connected correctly: plus to plus, minus to minus. An error in polarity can cause the device to fail instantly.
Dimensions and weight of the device require stationary placement or the use of a durable stand. To carry the working device should only be for a special handle, avoiding jerks that can damage the internal soldering or a pointer indicator.
Operating principle and charging modes
The operation of the ZU-120 is based on the conversion of alternating current into direct current using a diode rectifier. The current passes through the transformer windings, where the voltage decreases, and then straightens. The resulting direct current is supplied to the terminals of the battery, triggering chemical reactions to restore the active mass of the plates.
There are two main modes of operation that can be implemented using this device. The first is direct current charging, when the current strength is fixed by the regulator, and the voltage increases as the battery is charged. The second mode is a constant voltage charging, where the current automatically decreases as the battery saturates.
For deep desulfation, a cyclic regime is often used, alternating charge and discharge. The ZU-120 performs this task well due to its ability to produce stable parameters for a long time. However, the user needs to independently control the process, since there may be no automatic shutdown at full charge in the basic models.
What is desulphation?
Desulfation is the process of removing lead sulfate from the surface of the battery plates. Sulfation occurs at deep discharge or long-term downtime, reducing the battery capacity. ZU-120 allows this process by supplying a low-voltage current for a long time.
The process is controlled through a built-in ammeter. At the beginning of charging, the arrow of the device shows the maximum value, which gradually decreases. When the current drops to the minimum values (about 1-2% of the battery capacity), the battery is considered fully charged.
Step-by-step instruction for operation
The correct sequence of actions when connecting the ZU-120 ensures the safety and efficiency of the procedure. Violation of the order of inclusion can lead to sparking and damage to the contacts. Always start by visually inspecting the device and checking the integrity of the wires.
First, connect the device clamps to the battery terminals, observing polarity. Red clamps are attached to a positive conclusion (+), black to a negative conclusion (-). Only after reliable fixation of the terminals can the device be included in the electric network 220V.
☑️ Algorithm of connection ZU-120
After switching on to the network, set the required charge current by the regulator. Usually, a value equal to 10% of the battery capacity is recommended. For example, for a 60 Ah battery, the optimal current is 6 Amps. During charging, the ammeter readings will change and adjustment may be required.
At the end of the charging process, first turn off the device from the network, and only after that disconnect the terminals from the battery. This sequence eliminates the possibility of a spark skipping near electrolyte vapors, which is especially important for the batteries being served.
⚠️ Note: It is strictly forbidden to open the charger circuit while it is on the network. This can cause a powerful spark discharge and damage the contact group.
Diagnosis and typical malfunctions
Despite its high reliability, the ZU-120, like any electrical device, is prone to breakdowns. Most often, users are faced with a fuse burnout or failure of the diode bridge. Symptoms of malfunction are usually manifested in the absence of ammeter readings or the characteristic buzzing of the transformer.
If the device is buzzing, but the current is not going, you should check the integrity of the output wires and the condition of the clamps. Contact oxidation is a common cause of conduction loss. It is also worth examining the brushes of the current regulator, if it is made in the form of a rheostat.
In the case when the ammeter shows a “throw” of current immediately after switching on, most likely, there was a short circuit in the output chain or a breakdown of the rectifier diodes. Requires the disassembly of the hull and multimeter all the elements of the circuit.
| Malfunction | Probable cause | Elimination method |
|---|---|---|
| No reaction, no lights. | The safety lock burned. | Replacement of the fuse |
| A powerful transformer hum | Closing or overloading of turns | Load check, transformer repair |
| Current is unregulated. | Regulator or rheostat malfunction | Replacement of variable resistor |
| The ammeter shows 0. | Chain break or instrument failure | Checking contacts and the ammeter itself |
For self-repair, a minimum set of tools is needed: screwdrivers, passages and multimeters. Before starting work, be sure to disconnect the device from the network and give the capacitors time to discharge.
When the diode bridge is verted with a multimeter, a serviceable diode should ring only in one direction. If the vertebra goes in both directions or is absent at all, the diode requires replacement.
Safety and prevention
Working with chargers is associated with the risk of electric shock and chemical burns. The ZU-120 operates with high currents, so safety requirements are particularly stringent here. The charging room should be well ventilated, since rattles gas is released during the charge.
The body of the device during operation can heat up. This is normal for transformer circuits, but the temperature should not exceed 60-70 degrees Celsius. If the heating is excessive, you should take a break or check whether the ventilation holes are clogged with dust.
Regular prevention includes cleaning the contacts of oxides and checking the tightening of the screw joints inside the housing. Vibration during transportation can weaken the fastener, which will lead to heating of the contact areas and melting of the insulation.
⚠️ Warning: Do not leave a running charger unattended for a long time, especially if it does not have an automatic shutdown function. Monitor the temperature of the case and the state of the electrolyte in the banks.
Comparison with modern analogues
In the era of widespread pulse chargers ZU-120 looks archaic, but does not lose its relevance. Pulse models are compact, lightweight and often microprocessor-controlled, but they are sensitive to power quality and frost.
The ZU-120 wins in reliability and maintainability. Its simple scheme is clear to any radio amateur, and the safety margin allows you to use it in garage conditions, where the voltage in the network can "jump". It is also less susceptible to low temperatures.
On the other hand, the absence of complex charging algorithms requires the user to pay more attention and understand the processes taking place in the battery. For beginners, modern smart charging can be safer, but for professionals, the ZU-120 remains an indispensable tool.
The choice between the ZU-120 and the pulse charger depends on the operating conditions: for a garage and frequent use, a transformer model is better suited, and for rare trips and apartments - a pulsed one.
Frequently Asked Questions (FAQ)
Can I charge the ZU-120 gel batteries?
Yes, you can, but with caution. It is necessary to set the voltage to not exceed 14.4 V, as the gel batteries are afraid of overcharging and boiling. The process must be monitored constantly using an external voltmeter, since the built-in ammeter does not show voltage.
Why does the ZU-120 get hot when working?
Heating the transformer to 50-60 degrees is the norm for devices of such power. If the body is heated to temperatures at which it is impossible to hold the hand, or there is a smell of burning, immediately turn off the device. This may indicate an inter-turn circuit.
What current to set for a 60 Ah battery?
The optimal charge current is considered 10% of the battery capacity. For a 60-Ah battery, this is 6 Amps. Charging with such current will take about 10-12 hours until full recovery.
Can the ZU-120 be used as a power supply?
Theoretically, yes, because the output is direct current. However, it is not suitable for powering sensitive electronics due to the lack of stabilization and the presence of pulsations. It can only be used to power a powerful load, for example, lamps or engines.