John,

I forgot to answer your = question. Each battery is connected independently to its own alternator through an = individual contactor. If one alt fails, I can shut it off by opening the = field (good argument for external regulated alt) and close the x-feed contactor to = connect both batteries in parallel. So, a failed alternator should be a = non-event… just open the field on the failed alt, flip the x-feed switch and = continue on to my destination.

Mark S. =

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of John Slade
Sent: Tuesday, January = 24, 2006 8:00 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Two Alternators?

Mark,

How do you charge the backup = battery? A diode? Got a part number?

I'm just switching a contactor = right now, but I'd like to isolate the backup.

Regards,

John

-----Original = Message-----
From: Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net]On Behalf Of Mark R Steitle
Sent: Tuesday, January = 24, 2006 8:21 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Two Alternators?

Doug,

I have dual alternators and dual = batteries per Aero-Electric Z-14 architecture. I’m using the small = 55amp ND units. They weigh about half of what the Mazda alternator weighs, = so I rationalized that there was very little weight penalty to using two alternators, but a significant safety improvement. With an = electrically dependent engine and all electric panel, I decided this was the way to = go for me. The cross-feed contactor connects both Odyssey batteries = during starting, so I am able to use smaller batteries than would be required = to start the 3-rotor with only one battery. Every annual, I plan on = replacing the main battery, rotating the 1 year old main battery to the aux position, = and move the 2 year old aux battery to my Goldwing motorcycle. That = way the main battery will be less than one year old, the aux battery will be 1 - = 2 years old, and the motorcycle battery will be 2-3 years old. = I’ll send you a picture off-line.

Mark S. =

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of DLOMHEIM@aol.com
Sent: Tuesday, January = 24, 2006 6:11 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Two Alternators?

I am debating the future use of = two batteries vs. two alternators and I was wondering if anyone in the group = has mounted a second alternator and if so if they had any pictures of its = mounting location, etc.

=

Thanks for the = information.

=

Doug Lomheim = RV-9A / 13B

OK City, = OK