Charger AZU-108 - one of the most common solutions for restoring the performance of lead-acid batteries 12 V. This device, developed back in Soviet times, is still actively used in garages, service stations and car parks due to its simplicity, reliability and maintainability. However, not all owners know how to properly operate AZU-108, connect it to the battery or fix typical breakdowns.

In this article we will look at technical specifications device, we will provide connection diagrams, tell you about the nuances of charging different types of batteries (maintained and unmaintained), and also give step-by-step instructions for diagnostics and repair. We will pay special attention to safety issues - improper use of the charger can lead not only to battery failure, but also to a fire or explosion.

Technical characteristics of AZU-108: what you need to know before buying

Charger AZU-108 belongs to the class transformer chargers with manual current adjustment. Its main parameters:

  • 🔋 Supply voltage: 220 V (single-phase network)
  • 🔌 Output voltage: 12 V (for charging batteries)
  • ⚡ Maximum charging current: 8 A (adjustable)
  • 📏 Dimensions: 220×150×180 mm
  • ⚖️ Weight: ~5 kg
  • 🔄 Operating mode: continuous (with breaks for cooling)

The device is intended for charging lead-acid batteries with a capacity of 40 Ah up to 100 Ah. It's important to note that AZU-108 doesn't fit for lithium-ion (Li-ion) or gel (GEL) batteries - their charging requires special voltage and current control algorithms.

One of the key advantages of the model is the ability step current regulation (via a switch on the case), which allows you to select the optimal mode for batteries of different capacities. However, the lack of automatic shutdown when fully charged requires user control.

📊 What battery capacity do you charge most often?
Up to 50 Ah
50–75 Ah
75–100 Ah
Over 100 Ah

Connection diagram of AZU-108 to the battery: step-by-step instructions

Incorrect connection of the charger may result in short circuit, battery damage or even fire. Follow these instructions to avoid errors:

  1. Disconnect the battery from the vehicle's on-board network. Remove the negative terminal first, then the positive one. This will prevent voltage surges in the machine's electrical system.
  2. Clean the battery terminals from oxides and dirt. Use sandpaper or a special brush. Poor contact leads to overheating and unstable current.
  3. Connect the charger:
    • 🔴 Red wire (“+”) - to the positive terminal of the battery.
    • ⚫ Black wire (“–”) - to the negative terminal.
  • Set the charging current. Optimal value - 10% of battery capacity. For example, for a battery 60 Ah the current should be 6 A.
  • Connect the AZU-108 to a 220 V network. Start charging and monitor the process every 1–2 hours.

    • ⚠️ Attention: Never connect the charger to the battery if it is installed in a car with the ignition on. A power surge can damage electronic control units (ECUs).

    Clean the terminals from oxides|Disconnect the battery from the on-board network|Check the electrolyte level (for serviced batteries)|Set the charging current (10% of the capacity)|Connect the wires according to polarity-->

    Battery capacity (Ah) Recommended charging current (A) Approximate charging time (hours)
    40–50 4–5 8–10
    55–75 5.5–7.5 10–12
    80–100 8 12–14

    Typical malfunctions of AZU-108 and ways to eliminate them

    Despite the simplicity of the design, AZU-108 may fail due to overloads, power surges or natural wear and tear of components. Let's look at the most common breakdowns and methods for repairing them.

    1. The charger does not turn on

    If when connecting to the network indicator does not light up and there is no output voltage, the reasons may be as follows:

    • 🔌 Broken power cord. Test the wire with a multimeter in circuit test mode.
    • 🔧 Fuse failure. B AZU-108 Usually the fuse is installed on 10 A (located on the board or in a holder on the case).
    • 🔄 Breakdown of the diode bridge. Check the diodes with a tester - in good condition, they only pass current in one direction.

    2. The charger gets hot or emits a burning smell

    Overheating transformer or power elements - a sign of a serious malfunction. Possible reasons:

    • 🔥 Interturn short circuit in a transformer. Needs rewinding or replacement.
    • 📉 Exceeding the maximum current. Make sure the switch is set to the correct position.
    • 🔌 Poor contact at solder joints. Inspect the board for any blackened or peeled traces.

    ⚠️ Attention: If after 10–15 minutes of operation the device body becomes hot (more than 60°C), unplug it immediately. Continued use may result in fire.

    How to check a diode bridge with a multimeter?

    1. Set the multimeter to diode test mode (diode icon or "Diode Test").

    2. Connect the probes to the diode terminals in the forward direction - the device should show a voltage drop (~0.5–0.7 V for silicon diodes).

    3. Swap the probes - the screen should show “1” (break). If the readings are the same in both directions, the diode is broken.

    3. Charger outputs low voltage or current

    If at the exit AZU-108 voltage is lower 10 V or the current does not correspond to the set value, check:

    • 🔋 Transformer condition. Measure the voltage on the secondary winding - it should be within 14–16 V.
    • 🔄 Current regulator. The switch contacts may have oxidized - clean them with alcohol or WD-40.
    • 📊 Filter capacitors. Swollen or leaking capacitors must be replaced.
    💡

    If you are not confident in your soldering skills, contact a specialist to replace the diode bridge or capacitors. Poor repairs can lead to a short circuit.

    Modernization of AZU-108: how to improve the device with your own hands

    Basic version AZU-108 It does not have reverse polarity protection, automatic shutdown when fully charged and other modern functions. However, the device can be modified:

    1. Adding reverse polarity protection

    To protect against incorrect terminal connections, install reverse current relay or a Schottky diode with a high forward current (for example, SB560). Connection diagram:

    

    Battery (+) ——[Schottky diode]—— Charger (+)
    

    Battery (–) —— Charger (–)

    The diode will only pass current if the polarity is correct. If you connect it back, the circuit will break.

    2. Installation of ammeter and voltmeter

    To control the charging process, you can build in digital indicators (for example, modules based TM1637). They will show the current current and voltage, which will help avoid overcharging.

    3.Automatic shutdown when fully charged

    The easiest way is to use voltage relay, which will break the chain when it reaches 14.4 V (for lead-acid batteries). A more advanced option is a microcontroller (for example, Arduino) with current and voltage sensor.

    ⚠️ Attention: Any modifications must be made taking into account electrical safety. After modification, check the device with a multimeter before connecting it to the battery.

    Comparison of AZU-108 with modern chargers

    AZU-108 inferior to modern pulse chargers in a number of parameters, but also has advantages. Let's look at the key differences:

    Parameter AZU-108 Modern pulse memory (for example, Bosch C3)
    Type Transformer Pulse
    Weight ~5 kg 0.5–1.5 kg
    Automatic shutdown No Yes
    Reverse polarity protection No (needs improvement) Yes
    Price 1 500–3 000 ₽ 3 000–10 000 ₽
    Maintainability High Low (often beyond repair)

    AZU-108 remains relevant for garage use due to the possibility of repair and low cost of spare parts. Modern devices are more convenient, but their repair is often not economically feasible.

    Safety when working with AZU-108: what not to do

    Working with chargers and batteries requires precautions. Errors can lead to electric shock, battery explosion or fire.

    • ⚡ Do not connect the device to the network without a load (without a battery). This may damage the transformer.
    • 🔥 Do not smoke or use open flames near the battery being charged. When charging, hydrogen is released, which is explosive.
    • 💧 Do not allow moisture to enter the device body. Work in a dry environment.
    • 🔌 Do not leave the charger unattended for long periods of time. Optimally monitor the process every 1–2 hours.

    ⚠️ Attention: If the battery has started boil (intensive outgassing), immediately reduce the charging current or turn off the device. Continuing charging in this mode will lead to destruction of the battery plates.

    💡

    AZU-108 does not have built-in overcharge protection, so be sure to monitor the voltage at the battery terminals. The optimal value for full charging is 14.4 V.

    FAQ: Frequently asked questions about AZU-108

    Is it possible to charge a maintenance-free battery using AZU-108?

    Yes, but with caution. Maintenance-free batteries are sensitive to overcharging, therefore:

    • Set the current to no more than 5% of capacity (for example, for 60 Ah — 3 A).
    • Control the voltage - do not exceed 14.4 V.
    • Use a timer to ensure you do not exceed the charging time (usually 10–12 hours).
    Why does AZU-108 spark when connected to a battery?

    Sparking occurs due to:

    • Bad contact on the terminals - clean them of oxides.
    • High current when connecting - first connect the wires to the battery, then plug the device into the network.
    • Diode bridge faults — check the diodes with a multimeter.

    If the sparking is strong and accompanied by a burning smell, turn off the device immediately.

    How to check the functionality of the AZU-108 without a battery?

    For diagnostics:

    1. Connect to device output incandescent lamp on 12 V (for example, from a car headlight).
    2. Set the minimum current on the regulator.
    3. Plug in the device and the lamp should light up. When you change the position of the control, the brightness should change.

    If the lamp does not light or flickers, check the transformer and diode bridge.

    How to replace a burnt out transformer in an AZU-108?

    Suitable analogues:

    • TS-180 (from old TVs, requires rewinding the secondary winding).
    • TPP-277 (used in power supplies for industrial equipment).
    • Any transformer with power 150–200 W with output voltage 14–16 V.

    When replacing, make sure that the new transformer can withstand up to 10 A.

    Is it possible to use AZU-108 to charge 6-volt batteries?

    No, AZU-108 designed only for 12 V. For charging 6-volt Battery required:

    • Rewind the secondary winding of the transformer (reduce the number of turns).
    • Or use a step-down voltage converter.

    Without modification, connecting a 6-volt battery will damage the battery.