Reference

Emergency Battery Power Supply

• Can I perform the capacity check in the field?

  The capacity check requires a bench power supply capable of 5A constant voltage output and an electronic load. Apply 28 VDC to the input, apply a 4.5A constant current load to the output, remove input power, and confirm the unit sustains output for a minimum of 48 minutes. Full procedure is in Section 4.4.3 of the installation manual.

• Can the MD835-1 be installed in any location in the aircraft?

  The unit must be installed in a 1/4 ATR avionics rack. It should not be installed adjacent to fuel lines, tanks, flammable fluids, engine firewalls, or sources of ignition. Avoid locations subject to standing or direct water exposure. The optional vent kit (P/N 9017983) is recommended for installations in poorly ventilated compartments

• Does the MD835-1 require external cooling?

  No. The unit requires no internal or external cooling. It incorporates internal thermal monitoring and protection circuits and is designed to operate across a wide temperature range

• How do I perform the pre-flight self-test on the MD835-1?

  With the unit armed, press and hold the TEST position on the panel-mounted switch. A green TEST annunciation confirms the unit has a minimum of 80% capacity available and that the internal heater and temperature monitoring are operational. If the test fails, remove the unit, recharge it, and perform a full capacity verification before flight.

• Is the MD835-1 a direct replacement for the Jet PS-835?

  Yes. The MD835-1 is a direct form, fit, and function replacement for the L-3 Avionics / Jet PS-835 Series, using the same 1/4 ATR rack mount and 13-pin ARINC-style connector. No rack or wiring modifications are required.

• What connector does the MD835-1 use?

  The MD835-1 uses a 13-pin ARINC-style connector. The correct mating connector is ITT Cannon DPXB-13-33S-0001 or equivalent. McFarlane stocks MCI P/N 9016600-2 as the compatible mating connector for the MD835-1.

• What happens if the MD835-1 fails the capacity check?

  If the unit fails to sustain 48 minutes of output at 4.5A, it must be removed from service. The internal cells are not user-replaceable. Contact True Blue Power for overhaul, exchange, or replacement

• What maintenance does the MD835-1 require?

  A pre-flight remote self-test should be performed before each dispatch. A full capacity verification is required every 24 months. After any in-flight use of the emergency power supply, a full capacity check should be performed before returning the unit to service.