Cessna's Pawnee plant engineers had never designed an electrical system with two alternators. And never would they again! Why they didn't use the proven system the 400 series aircraft uses probably has something to do with "Not Invented Here Syndrome" and rivalry between the two production plants.
Whatever the reason, the dual alternator charging system on our 337's is a Rube Goldberg like design. The alternator electrical outputs are not placed in a parallel circuit where they may be properly managed by the regulators.
The Electrical Upgrade Package includes two used regulators pulled from a 400- series twin ($595 - 30 day warranty through me), or two new regulators from Cessna($1495 - 90 day warranty through Cessna). Also included are specific installation instructions and diagrams, including the addition of the parallel circuit wire. Finally, there is a sample 337 form that has been approved many times by many FSDO's. Your A&P can use it to file the 337 for the upgrade.
Kit installs in about an hour.
Blinking alternator lights will be a thing of the past.
Please let me know if I may be of assistance.
Last edited by mshac : 09-07-22 at 07:23 PM.
|