lgrant2000
Active Member
Aviators;
On my O-235 (Falconar F-12), I've installed a Ford EDIS4 module, a 2nd gen Ford wasted spark coil, trigger wheel, sensor bracket with 3 CPK sensors and, finally, a 3 position rotary switch to go from 0*-25*-33* with the engine running. Of course, the engine is started on the 0* and that setting actually advances to 10* as soon as the engine rpm reaches 400 rpm. The timing is immediately moved to 25* after the engine starts. So far I've run this home brew E.I. along side of a healthy Slick mag with impulse coupling. At 2700 rpm one E.I. system consumes just a little over 1 amp to run the EDIS4 and coil. I've got about 16.5 hours on it now and the setup seems very reliable and accurate.
I'm now finishing up the installation of the same home brew E.I. for the other set of plugs and, with that, I want to add a cigar box size 12V battery for backup. I'm running a Suzuki Samurai (Denso) 55 amp alternator and (hang on to your hat) a Deka 12V lawn tractor battery (sealed) - 360 amps & 300 CCA. I have about 100 hours on this setup with no electrical problems (steam gauges) - the battery was on another project for about a year and the engine was started occasionally. I've owned this battery about 3 years now and it seems very healthy - purchased from Lowe's.
Side note: while running 2 mags I installed a VDO electric tach (3.125") that is also suitable for a diesel with no ignition system. The tach is capable of taking ignition signals but the mag signals are dirty so I wired it into the stator in the alternator (like a diesel application) and, with an optical tach, adjusted it to be right on the money. Very smooth operation and very cost effective.
So now I need a wiring diagram for the second battery. I plan to keep it on a trickle charger on this battery in between flights (or simply test for 12.6V as part of the preflight). I would like to use the second battery to:
1. help start the engine;
2. have it receive charging from the alt;
3. continuously supply power to one set of plugs - no other devices or appliances.
And that brings up a lot of thinking about electrical failures. No doubt the alt is the most common point of failure. I've thought about a perm magnet alternator and decided to not go that route. The 20 amp John Deer pm alt has some possibilities but I hate to monkey with a stable setup. I have a "low volts" idiot light and an amp meter. And of course an ALT master switch. Based on the very low incidence of battery fires in modern automobiles, I do not have an over voltage crowbar or an over voltage instrument. Rhetorical question: After the engine has run for 10 minutes and the existing battery is recharged, the sudden amp meter read out of significant amps being produced would be an indication of an over voltage situation, would it not? If the alt is suddenly producing 50V, then I'm thinking that would show up on the amp meter?
We could write books about electrical failures in aircraft and, accordingly, I do not propose that we do that. For now I just want redundancy on the different sets of plugs and a battery that will get me on the ground in case of the loss of the main electrical system. Any help with a wiring diagram would be much appreciated.
Thanks for reading this "too long" post.
Larry
On my O-235 (Falconar F-12), I've installed a Ford EDIS4 module, a 2nd gen Ford wasted spark coil, trigger wheel, sensor bracket with 3 CPK sensors and, finally, a 3 position rotary switch to go from 0*-25*-33* with the engine running. Of course, the engine is started on the 0* and that setting actually advances to 10* as soon as the engine rpm reaches 400 rpm. The timing is immediately moved to 25* after the engine starts. So far I've run this home brew E.I. along side of a healthy Slick mag with impulse coupling. At 2700 rpm one E.I. system consumes just a little over 1 amp to run the EDIS4 and coil. I've got about 16.5 hours on it now and the setup seems very reliable and accurate.
I'm now finishing up the installation of the same home brew E.I. for the other set of plugs and, with that, I want to add a cigar box size 12V battery for backup. I'm running a Suzuki Samurai (Denso) 55 amp alternator and (hang on to your hat) a Deka 12V lawn tractor battery (sealed) - 360 amps & 300 CCA. I have about 100 hours on this setup with no electrical problems (steam gauges) - the battery was on another project for about a year and the engine was started occasionally. I've owned this battery about 3 years now and it seems very healthy - purchased from Lowe's.
Side note: while running 2 mags I installed a VDO electric tach (3.125") that is also suitable for a diesel with no ignition system. The tach is capable of taking ignition signals but the mag signals are dirty so I wired it into the stator in the alternator (like a diesel application) and, with an optical tach, adjusted it to be right on the money. Very smooth operation and very cost effective.
So now I need a wiring diagram for the second battery. I plan to keep it on a trickle charger on this battery in between flights (or simply test for 12.6V as part of the preflight). I would like to use the second battery to:
1. help start the engine;
2. have it receive charging from the alt;
3. continuously supply power to one set of plugs - no other devices or appliances.
And that brings up a lot of thinking about electrical failures. No doubt the alt is the most common point of failure. I've thought about a perm magnet alternator and decided to not go that route. The 20 amp John Deer pm alt has some possibilities but I hate to monkey with a stable setup. I have a "low volts" idiot light and an amp meter. And of course an ALT master switch. Based on the very low incidence of battery fires in modern automobiles, I do not have an over voltage crowbar or an over voltage instrument. Rhetorical question: After the engine has run for 10 minutes and the existing battery is recharged, the sudden amp meter read out of significant amps being produced would be an indication of an over voltage situation, would it not? If the alt is suddenly producing 50V, then I'm thinking that would show up on the amp meter?
We could write books about electrical failures in aircraft and, accordingly, I do not propose that we do that. For now I just want redundancy on the different sets of plugs and a battery that will get me on the ground in case of the loss of the main electrical system. Any help with a wiring diagram would be much appreciated.
Thanks for reading this "too long" post.
Larry
