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
From: Valin & Allyson Thorn
[mailto:thorn@starflight.aero]
Sent: Wednesday, May 06, 2009 6:52
PM
To: Lancair
Mail List (lml@lancaironline.net)
Subject: 28VDC Ground Power Supply
Options
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