Carl Froehlich
Well Known Member
I'm helping an RV owner complete a conditional inspection. He has dual six cylinder Lightspeed ignitions installed.
As I'm guessing with most Lightspeed installs, he has a standard electrical (one battery, one alternator) system, with the added dedicated backup aux battery for the Lightspeed igntion exactly as Klaus depicts in his instructions.
While the install does have a selector switch to monitor main or aux battery voltage, it does not allow for measuring aux battery voltage with the main battery out of the system. As a result, the aux voltage reading is either the aux battery itself, or the voltage from the diode isolated feed from the main power system. As such, unless the main battery has been disconnected, the aux voltage reading does not detect a failed aux battery.
I did a simple check of the aux battery by measureing voltage across the battery terminals with the master switch off. The battery showed 2.3 vdc. In short, this batttery has been little more than a brick for a long time, and if the main battery system failed the engine would have stopped.
Lesson learned. If you are flying around with a Lightspeed install and using Klaus' backup power design, spend the $20 and replace the backup batttery every year. If you are not flying with Lightpseed and are considering installing an electronic igntion, consider pMag. If you must fly with Lightspeed, there are far better, two battery power distribution schemes you should consider.
Carl
As I'm guessing with most Lightspeed installs, he has a standard electrical (one battery, one alternator) system, with the added dedicated backup aux battery for the Lightspeed igntion exactly as Klaus depicts in his instructions.
While the install does have a selector switch to monitor main or aux battery voltage, it does not allow for measuring aux battery voltage with the main battery out of the system. As a result, the aux voltage reading is either the aux battery itself, or the voltage from the diode isolated feed from the main power system. As such, unless the main battery has been disconnected, the aux voltage reading does not detect a failed aux battery.
I did a simple check of the aux battery by measureing voltage across the battery terminals with the master switch off. The battery showed 2.3 vdc. In short, this batttery has been little more than a brick for a long time, and if the main battery system failed the engine would have stopped.
Lesson learned. If you are flying around with a Lightspeed install and using Klaus' backup power design, spend the $20 and replace the backup batttery every year. If you are not flying with Lightpseed and are considering installing an electronic igntion, consider pMag. If you must fly with Lightspeed, there are far better, two battery power distribution schemes you should consider.
Carl