Thank you all for your helpful advice on and off the list.  The LML people are a great resource.

 

Our Legacy is still under construction.  We want to be able to do system testing before the engine is installed and without the engine running after it is.  Our desire for a power supply sized around 50A is because we’re about to begin testing of an all electric air conditioning system we’re developing for the Legacy in partnership with an aircraft A/C company.  The whole system sits behind the seats, there is no P-51 air scoop, and we get the cold air in front of the pilots.  Oh, and for the winter or if you want to off-load 40 lbs, it can be removed in less than 5 minutes.  Anyway, I digress…J  The A/C system running at steady state pulls about 30A between the compressor, condenser fan, and evaporator blower. 

 

We’d also like to eventually do simple EMI testing.  With all the avionics on we’ll cycle other components like gear, lights, and A/C looking for interference.  We’re planning on a Garmin G900X integrated avionics system and it pulls about 15A max intermittent (for 28V system). 

 

The cheapest approach is a good size battery with a serious charger to get power for brief periods of time.  We want to do some long duration testing so we’ve decided to get a StartPac Portable Power Supply Model 53050 which can provide 50A continuously at 28.5 VDC, with over voltage and over current protection.  ACS price is $896. 

We’re planning to add two Odyssey batteries to the set up to provide more surge capacity and ensure good power quality.  We’re assuming we can work a setup where the StartPac power supply just looks like the power coming from the alternator and the batteries (2 Odyssey 12V in series) with a voltage regulator in there somewhere…  We still have some homework to do and welcome more advice from the DC power distribution gurus out there on the best way to set this up.

 

Thanks,

 

Valin

 

Legacy in work

Hot & Humid Houston, Texas

 

http://www.starflight.aero/legacy

 

 

Hello LML gang,

 

Could I get some advice on the best way to get a 28 VDC 50 Amp power supply set up in our hangar?  On the web I’ve seen $5000 ground power units that can be plugged into our hangar’s AC power outlets to solve the problem…  Surely there’s a cheaper way to do this.  Anyone know of a more affordable source?  Maybe a couple of 12V car batteries ganged together with a battery charger in there somewhere. 

 

Suggestions?

 

Thanks,

 

Valin Thorn

Legacy

Texas

 

http://www.starflight.aero/legacy