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Aside from the slight savings in weight, the only significant difference

between 12 and 24 v. is in the alternators.  The only ones I have been
able to find, produce 60amps regardless of the voltage.  So for 12v. you

have 600 watts available to power everything on the plane, with 24v.
1200.

On the IV the hydraulic pump draws 500 watts. That leaves 100 watts,
which is less than an average com draws when transmitting.
To say nothing of all the other whistles and bells that you have
probably installed. Imagine being on an IMC approach at night, (landing
lights, nav lights in addition to everything else) and having the
alternator fuses blow when you put down your gear.

OK, maybe you shouldn't take that risk, but situations like that do
occur, often without forewarning.

IMHO the alternator should be to handle normal operations, excepting
starting, without drawing on the battery.  What would you do if you had
a battery failure?

It is true that almost all equipment is available in 12v, but the same
is true for 24v. when you're looking at new equipment.  With the amount
of electronics being put on planes, the trend will inevitably be towards

24v.

After reading the Lancair information on the matter, my order was for
12v.  When I found out how much the hydraulic pump drew, I changed to
24v., which Lancair did at no penalty.  Thanks, Lance.

John Herminghaus
LIV-P     I-VVVV

P.S. According to an Oildyne graph, the 12v. pump draws slightly more
than 50 amps at 1000psi.

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Please send your photos and drawings to marvkaye@olsusa.com.