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Mike,
I question the value/benefit of converting to the 65 AMP alternators. I have air-conditioning and a single 38 AMP alternator has no problem (in flight) producing the 20+ amps the entire electrical system plus air-conditioning is requiring. I would think the bigger alternators would just put more stress on the direct drive coupling and presumably reducing it's reliability. Or, did you covert to a belt driven system? (I think the O2's had those - and it would seem like changing the pulley ratios would be a simple way to solve the problem).
Even with the 38 AMP alternators, the power output at idle is inadequate. The mechanics tell me that this is symptomatic of IO360's, not just the Skymaster installation. Seems to me that the gear ratio that drives the alternators is wrong.
I recently converted to the 400 series regulators because I could not get the alternators to share the load. When idling, one would do all the work and the other would sit at 0 AMPS - even though the battery was discharging. Simply turning off the working alternator would cause the idle one to pick up the load, but they would not share the work if they were both online (on the ground, in flight they shared a little bit). So, under these circumstances, I'd have to run the engine with the "working" alternator at 1500 RPM on the ground.
Now after the conversion, I can run my air-conditioning and avionics with both engines running at 1200 RPM. Between the two alternators, there are enough Amps to run everything.
Can you see that both alternators are outputting Amps equally? Do you have the EI ammeter?
If I read your post correctly, it sounds like you shut down your radios manually to reduce the rear engine temp? I doubt you'd be able to see any temp benefit from reducing the electrical load (if that was your intent). And besides, if that were what you were trying to do, then shutting off the rear alternator would have been the way to do it (thus reducing 100% of the alternator load on the rear engine). Regardless, I think your only recourse in that case is shutting down the rear engine. And when trying to start the rear, you probably want the front engine at a high RPM (and therefore lots of amps available) so you don't experience that shutdown glitch which scrambles your radios frequencies and the brains of all the electronics on board. I had the problem previously and I had to one by one pull and reset various circuit breakers to get things like the JPI, Shadin, and autopilot out of their brain-dead states.
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