Electrical systems, 14v or 28v


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Well-Known Member
Mar 30, 2004
S36 Kent, WA
Not being a pilot (yet) and having familiarity with various aircraft, and not having specs for the electrical systems for different aircraft available to me, I have a few questions...

I know there are 14 and 28 volt systems out there. What existing aircraft use 14v and what aircraft use 28v?

For a homebuilt (say a small twin, 200hp ea) what would be the best choice for a power system, 14 or 28v?

14v is common to automotive applications. But 28v cuts down on wire sizes, and is common to most military equipment (ex. a military diesel chev blazer is 28v).

When I look at instruments in the aircraft spruce catalog I usually see both options. Personally I would lean toward the 28v system, but I'd like to hear what others think.


Well-Known Member
Jan 30, 2003
Jupiter, Florida
28 v versus 12v

Tom - Dieselfume -
While in large airplanes, the lighter wire would save a bit of weight over the longer runs, this is not so true in our more modestly sized aircraft.

The 28v battery is, by necessity, much heavier than a 12v battery. With short cable runs, you are using mainly 16 and 18 ga wire anyway, no matter what size battery you have, and the weight savings is nil at best.

Hope this helps.