Don
Well Known Member
While attending Oshkosh I heard Greg Richter (sp? - the Blue Mountain guy) give a talk on aircraft wiring for smart people. He made a strong case for using a 28v system. His argument is most electronics (radios and efis's...efii?) work on either and will stop working at 9.6v more or less. If you lose your alternator he argues that you'll have a lot longer use of your electrical system as your battery drops from 24v to 9.6v than you would if you had a 12v system. Actually he thinks 48v is ideal but 24v is the best you can readily do now. He also argues that you can save 6-10 lbs of wire using 24v and the lighter guage wire required.
I'm midway along with the fuselage and nearing a point where I need to finalize my wiring plans but early enough that I can change plans without any real impact (other than maybe a little money). I've got a set of Whelen position lights and strobes that are 12v that's my only real 12v electrical investment so far and I'm sure I could sell them for near what I have in them if I go 24v. But as I look around, the light weight alternators seems to be 12v (though I'm sure if l look harder I can find a 24v). The LED lights I've been thinking of switching to for weight and other reasons are strictly 12v. So right out of the gate I seem to be heading uphill. I believe my planned radios and purchased EFIS (a dual GRT Series 1) can operate on either.
So, this not is too long but my questions are:
1. Am I right that 12v systems are predominant today? This includes the assumption that putting together a 24v system will involve more scrounging and searching.
2. Is there a simple way to get a 12v system to last longer in the event of a battery failure other than adding a second battery?
3. Other than night flying, I don't really see an electrical failure as a big issue. About the biggest concern would be loss of the GPS and I expect I'd have a handheld that would suffice for getting me to an alternate airport. If all else fails there's always the chart and pilotage to get me to an airport. Does anyone see something I'm missing?
My inclination at this point is to resign myself to the 12v system and finish the airplane. In theory, Greg appears right. In practice, he may be right in the future. For now theory and practice don't seem to agree.
Don
I'm midway along with the fuselage and nearing a point where I need to finalize my wiring plans but early enough that I can change plans without any real impact (other than maybe a little money). I've got a set of Whelen position lights and strobes that are 12v that's my only real 12v electrical investment so far and I'm sure I could sell them for near what I have in them if I go 24v. But as I look around, the light weight alternators seems to be 12v (though I'm sure if l look harder I can find a 24v). The LED lights I've been thinking of switching to for weight and other reasons are strictly 12v. So right out of the gate I seem to be heading uphill. I believe my planned radios and purchased EFIS (a dual GRT Series 1) can operate on either.
So, this not is too long but my questions are:
1. Am I right that 12v systems are predominant today? This includes the assumption that putting together a 24v system will involve more scrounging and searching.
2. Is there a simple way to get a 12v system to last longer in the event of a battery failure other than adding a second battery?
3. Other than night flying, I don't really see an electrical failure as a big issue. About the biggest concern would be loss of the GPS and I expect I'd have a handheld that would suffice for getting me to an alternate airport. If all else fails there's always the chart and pilotage to get me to an airport. Does anyone see something I'm missing?
My inclination at this point is to resign myself to the 12v system and finish the airplane. In theory, Greg appears right. In practice, he may be right in the future. For now theory and practice don't seem to agree.
Don