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Emergency Battery Power Supply

The TS420 Emergency Battery Power Supply simultaneously provides one primary power output and three lighting power outputs. Pitot/Static ports or optional electrical input provides the ability to work in automatic mode without pilot intervention. Buy Now


  • Provides 18 volts of rechargeable power for Mid-Continent products, lighting or critical avionics
  • Arms at the beginning of flight, recharges during flight, activates instantly upon power loss and turns off after flight
  • Powers LED or incandescent lighting at 5, 14 or 28 VDC
  • Remote, mini-annunciation switch controls test and manual operations
  • Field-replaceable battery modules
  • Quality Mil-Spec connectors included
  • Designed and built in Wichita, Kansas USA
  • Two-year limited warranty
  • FAA TSO Certified


Model Number TS420
Part Number MD420
National Stock Numbers (NSN) 6130-01-564-7588
Capacity 1.0 Ah (0.05C) at 25°C
Input Power 10 – 32 VDC, 0.25A nominal,
4.0A max (14 VDC) / 2.0A max (28 VDC)
Output Power 18 VDC nominal, 1.6 amps max
Weight 3.2 lbs
Dimensions 3.35” H x 6.75” L x 3.38” W
Maintenance Annual capacity check
Field-replaceable batteries
Mating Connectors 25-pin female D-Sub (MD25F20JVL0 or equivalent) — battery control unit
9-pin female D-Sub (MD9F20JVL0 or equivalent) — annunciator
Remote Test Switch Remote, mini-annunciation switch controls test and manual operations
Annunciator Lighting LED backlighting, automatic internal dimming
Battery Charging Automatic recharging when main power is present
Compatibility Provides 60 minutes or more of backup power to Mid-Continent’s Electric Attitude Indicator Model 4200 or 4300 and lighting power for two additional instruments (5, 14 or 28V)

Battery run time will vary depending on total power load and battery charge status
Certification FAA TSO-C4c certified
RTCA DO-160E qualified


TS420 Product Flier

Installation Manual
IM 9016391

Technical Drawings
OL MD420
OL MD420-1

Service Bulletins
SB MD421-01