Cessna 400 Series Voltage Regulator Upgrade Kit

[CRDedrickson]

I came across this post and it might be related to an issue I have with low voltage when at idle. I have accepted that at low RPM (~1000) there may be insufficient voltage to charge the battery, but this always resolves at higher taxiing RPM and certainly always in flight.

My understanding is that the voltage regulators adjust the alternator field current to maintain the set voltage. Should I be able to achieve rated charging voltage at idle, nominally 1000 RPM? I don't think this should adversely affect the scenarios, but I'll mention that the alternators were upgraded to 60 amp units by a prior owner. I am seeking to understand if this low voltage at low RPM is a design limitation, or if there is a remedy (voltage regulator adjustment or model change)?

My most recent interest in this voltage is because I've added an electric air conditioning system that requires a voltage in the 24 +/- area to prevent an unplanned battery drain. So, at idle and while taxiing, the AC system may shut down. The system is Peter Schiff Aero's SOFIE system. It provides up to 18,000 BTU and rejects heat to the outside by liquid antifreeze piped to the condenser located in the rear engine compartment. The cycle is a freon system with electric compressor for the evaporator in the cabin.

Russ Dedrickson
N8CV 1973 T337G Pressurized Super Skymaster, standard TSIO-360 Continentals