20NKBN-25-TD-U3

20NKBN-25-TD-U3 aircraft battery for onboard DC systems

The 20NKBN-25-TD-U3 is an aircraft nickel-cadmium battery used in onboard 24 V DC electrical systems. It is intended for autonomous engine start, APU start, emergency power supply, and ground operation when the main power sources are not available. The battery works as part of the aircraft DC network together with battery contactors, protection devices, charging circuits, busbars, and cockpit indication. It is not a converter or voltage regulator. Its job is to store electrical energy and deliver high current when the aircraft system requires it.

Starting and emergency power through 20NKBN-25-TD-U3

In service, the battery can supply high current for starter loads and support selected DC consumers in emergency modes. This is especially important before generators come online or when external power is not connected. The battery may be used for starting main engines or auxiliary power units, depending on the aircraft electrical design. Actual starting capability depends not only on the battery type, but also on charge condition, temperature, wiring resistance, contactor condition, and the load connected to the DC bus.

Marking structure of the 20NKBN-25-TD-U3 battery

The designation gives the basic battery type. "20" refers to the number of cells connected in series. "NK" identifies the nickel-cadmium electrochemical system. "B" means battery, while "N" refers to the pasted electrode design. "25" indicates the nominal capacity class. "TD" means the battery includes a thermal sensor for overheating indication. "U3" refers to the climatic version. This marking is important during procurement because similar aviation batteries may have the same voltage class but different capacity, thermal control, dimensions, or operating limits.

Aircraft application of battery 20NKBN-25-TD-U3

The 20NKBN-25-TD-U3 is used on aircraft and helicopters where this battery type is specified by the electrical system documentation. Typical applications include An-74, An-140, Il-62, Il-76, Il-86, Il-96, Tu-154, Tu-204, Mi-8MTV, Mi-171, and Ka-32 configurations. The exact installation should still be checked by aircraft documentation, because battery compartment layout, connector arrangement, charging system settings, and thermal indication wiring may differ by aircraft type, production series, or modification standard.

Identification and ordering checks for 20NKBN-25-TD-U3

Before ordering, the installed battery designation should be compared with the aircraft parts catalog, battery compartment documentation, or maintenance records. For a correct request, it is useful to specify the aircraft type, required battery condition, documentation, electrolyte status, and whether tropical or temperate climate requirements apply. The thermal sensor version should also be confirmed if the aircraft wiring uses battery temperature indication. The product is also known under alternative designation 20НКБН-25-ТД-У3.

Product Type: Aircraft nickel-cadmium battery
Function: Autonomous engine/APU start, emergency and ground DC power supply
Application / Where Used: Aircraft and helicopter onboard DC electrical systems
System / Installation Area: Battery compartment / 24 V DC onboard network
Compatible Aircraft / Equipment: An-74, An-140, Il-62, Il-76, Il-86, Il-96, Tu-154, Tu-204, Mi-8MTV, Mi-171, Ka-32, subject to aircraft documentation
Battery Type: Nickel-cadmium aircraft battery with pasted electrodes
Number of Cells: 20
Nominal Voltage: 24.0 V
Nominal Capacity: 25.0 Ah
Continuous Discharge Current: Up to 250 A
Starter Load Discharge Current Amplitude: Up to 650 A
Temperature Range for Charge and Discharge Characteristics: −20 to +50 °C
Operating Temperature Range with Performance Maintained: −60 to +60 °C
Vibration Resistance: 10–2000 Hz, 10 g
Impact Resistance: 12 g, 2–20 ms
Thermal Sensor: TD version, overheating signal above approx. +60…+70 °C
Weight With Electrolyte: Not more than 25 kg
Dimensions: 392 × 175.5 × 229 mm
Charge Retention: 30 days
Warranty Period in Cold and Temperate Climate: 5 years
Warranty Period in Tropical Climate: 3 years
Service Life in Tropical Climate: Not less than 3 years
Technical Documentation: Battery passport / aircraft battery maintenance documentation

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Warranty
All products are covered by a standard 6-month warranty.
Extended warranty is available upon request and is agreed individually; it may affect the final product price.