Additional alternator for 914

by Tony Renshaw

Oct 27, 2023

I want to not have to be discretionary in my use of electricity and with the 914 having electric fuel pumps I reckon it might be smart to consider a 2nd alternator. I believe there is a blank up front on the crankcase for one.....I would like to hear from anyone who has first person experience with using one please? 

Thanks in anticipation.

  • up

    John Austin

    Would it not be a lot simpler and cheaper to just have a dual battery system with the 2nd battery isolated from the primary battery so that in the event of an alternator or primary battery failure, you'll have reserve power until you can safely land?

    John

    N750A

    6

    Oct 28, 2023

    Load Previous Replies
    • up

      Jasper F Stemple

      I'm a bit late to the party but here is my build with a 914.  Many things take less power than it would first appear.  For example a Trig radio requires a 5 amp breaker but only pull about 1/2 amp continuous.  The fuel pumps are listed below as well.  As you can see my build came up with some room to spare.  The tablet chargers are still a bit of a question on what they'll draw continuously.

      18 amps availab
      0.5
      ACK 406/121.5 MHZ E-04 ELT Just a wild guess.
      1
      Trig ty 91 radio w/ harness .2A continuous 2A when transmitting
      0.45
      Trig tt22 transponder w/ harness
      0.1
      Trig tn72 gps position source
      2
      iLevil AP, just a guess, calls for a 3A breaker
      0.2
      GRT engine monitor
      4.2
      2 chargers for small tablets
      0.5
      2 small pc fans for cooling tablets, combined <1A
      1 heater fan .3A (heater fan and cooling fans won't be run at same time)
      1.5
      Aero LED nav/strobe/pos
      1.7
      Aero LED landing light
      2.1
      12v Aux for phone charging etc
      1.7
      2 rotax fuel pumps page 14. 1.7A/ea if individual. 1.5A/ea if running both.
      0
      electric elevator trim tab 2A breaker on friends plane
      0
      electric flap actuator 5A breaker on friends plane
      15.95

      1

      Feb 17