N130WN
Well Known Member
My RV-7 project (night VFR, dual AFS 4500 with internal battery, VP-X) has dual Lightspeed plasma II ignitions. I'm weighing my options as far as the electrical system goes, and I find that I like this approach, from the Lightspeed web site:
Sounds good to me -- no unnecessary complexity, cost or weight. But, I have never heard of anyone here using this approach. Many projects, even those with only one electrically dependent EI, have backup alternators and/or batteries. Whats wrong with the simple approach above?
-Is a back-up battery necessary?
If you are using a battery to start your engine, you have sufficient energy to run an ignition system for several hours after an alternator failure. Therefore, a back-up battery is not required when running a dual electronic ignition system. Once the system is running, less than 5V are required to maintain operation, giving a further safety cushion. At this low power level, most other electrical equipment will have long stopped functioning giving the pilot adequate warning.
Sounds good to me -- no unnecessary complexity, cost or weight. But, I have never heard of anyone here using this approach. Many projects, even those with only one electrically dependent EI, have backup alternators and/or batteries. Whats wrong with the simple approach above?