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I am adding extra alternator on my 912/100. Does any one have a wiring diagram of how to wire it? Two batteries? Two regulators? I have the book electrical connection but not sure on wiring. Should I use both alternator and a regulator set at 11.5 v so it will on charge a single Battery or batteries? Should I also use seperate switches for the mags? Do you use a 40 or 50 fuse in the main wire between battery and starter. Thanks
In the book AeroElectric Connection written by Bob Nuckolls are schematics and equipment lists that show you how to do exactly what you are looking to do.
I have the book and cd,but the one for rotax is for the Dynamo and single battery.someone said there is a drawing z-11 which I can not find. Z-16 is the 912/914,z-14 has the right side of the drawing but not the left side. Am I missing something?
Look at single page figure Z12 single battery, dual alternator or for true redundancy two page figure Z14 dual battery, dual alternator,
Can you send me the left page for z-14? For some reason I can not find it thanks
My scanner is not working, so as soon as it works, I will send it.
GIZMOS,
I believe that the entire Aeroelectric Connection book is available online, free.
The online version
http://www.aeroelectric.com/articles.html
Downloadable PDF
www.aeroelectric.com/Book/AEC_R12A.pdf
Gizmos,
We installed the auxillary alternator on our S7 and found the most useful information to be in the data sheets (about 20 pages) that came with the Auxillary alternator kit.
From what I gather, not many of us add the aux alternator and fewer yet go to a true dual electrical system . In our case, The decision was based on the need to provide more amperage for the electrical load of the aircraft than what the integral alternator was capable of RELIABLY producing. The integral alternator advertised max amperage is listed as more than it is capable of providing reliably under continuous draw. According to the data sheets from Rotax included with my add on kit - a person should not expect the integral alternator to reliably deliver more than 12-15 amps @ 13.8 volts. Likewise, the aux alternator - while called a "50 amp" should not be asked to contuniously provide more than 40 amps. That's one thought.
#2 - The data sheets also provide that the integral alternator normally operates at a fraction of a volt lower than aux alternator. That has some relevance to the decision to go with either a single system linked to both alternators; or, a true dual system with each charging system working on a separate battery and buss and with the aircraft electrical loads dedicated to one or the other. If I understand the rotax data sheets correctly, with a dual alternator connected system most commonly used (two alternators, one buss, one battery), the aux alternator, with it's slightly higher operating voltage, will provide all the power generation till the load becomes sufficient to drop the system voltage to the operating voltage of the integral alternator. The problem being that if the continuous load is sufficient drop the voltage of the aux alternator, it is probably being overloaded beyond what it should be reliably expected to produce. Bottom line - with a dual alternator connected system (two alternators, one buss, one battery) the total amperage the system could be reliably expected to produce is 40 amps - which may very well be more than enough for anything a Kitfox needs.
#3 We decided to go with a true dual charging system. Each alternator connected to a separate buss and a separate battery. Our decision was based on: a) maximizing the total output (15 + 40 amps continuous) , B) Engineering a Dual system which could be cross tied so if one alternator puked & was disconnected, the entire system could be operated on which ever alternator was healthy, up to the limits of which ever alternator remained. Technically, the cross tie would not be necessary, as a person could operate without it but would not have the backup. C) The recognition that having either or both batteries to start provides some utility in extremely cold weather (which we seem to achieve in the winter) or ending up at a remote strip with one dead battery and the unlikely possibility of hand propping.
Hopefully not too much information - what I found most useful in doing the completely separate system is simply starting with the Data sheets for the dual alternator connected system (two alternators, one buss, one battery) and separating/adding components - wiring the integral alternator to essential components and the aux alternator to all the high draw stuff (the high draw stuff being the genesis of going down this path in the first place). They don't seem to provide much info on a true dual system since almost nobody uses that. It also helps to think of the aux alternator and system as if it is a standard auto system with it's separate field/stator hookups and integral regulator - I couldn't help but notice the extreme similarity between the Rotax aux alternator and a 40 amp Nippodenso unit found on 1982-1984 Toyota pickups - with the rear of the case rotated 90 degrees.
I am sure many would question adding weight and expense; but, you know, My wife and I can get on board with full fuel and 140# of camping gear and use much shorter runways than we ever could with lesser performing aircraft.:)
Fy well,
Very good info Dave.