flyrotary@lancaironline.net Mailing List Archive

Joe,

Which Bob Knuckles system?  Z19?

I realize Ed is happy with one battery, but I like two batteries.  The THUNK of relays all popping open and the realization of "I turned off the alternator, and voltage dropped way too low.... followed with LAND NOW!" would have convinced Ed to have put the second battery back in! It sure got my attention on why two batteries is a good thing!(Great Story, but I'll let Ed tell it!)

So two batteries, and a BIG RED LIGHT with "low voltage" will go on my panel.

I did the spread sheet with 17AH batteries and flying
 time. Add in Night, and no place to easily land.... two batties seem like a good trade off.  My biggest shock was the FORD style contactor needed 1Amp draw to remain closed.  Shutting down non essential, but leaving contactors, PDF, ECU and coils....   System draw is around 15 Amps. 17AH implies you'd have an hour, but at 15Amp draw... more like 30-40 minutes, hence two batteries as 1 hour flying time makes finding a landing strip a little easier.  

Tom

From: Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors
 in aircraft <flyrotary@lancaironline.net>
Sent: Monday, August 22, 2011 11:20 AM
Subject: [FlyRotary] Re: Batteries

Joe, I started out using two Concord 25AH RGB each weighing 22 lbs for a total of over 44 lbs of battery (some joked I could get home by using the start to crank the prop {:>)) !   I then transition to two Odyssey PC-680 17AH batteries each weighing 14 lbs for a total of 28 lbs.  Then after 6 years of flying with two batteries and never using the second one - except to help crank on a cold morning, I removed one of them.  Have now been flying for over 4-5 years with one Odyssey 14lbs.  I swap it out every two years.

Ed

--------------------------------------------------
From: <jskmberki@windstream.net>
Sent: Monday, August 22, 2011 11:59 AM
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Batteries

> What size an type of batteries are required for the rotary?  I am leaning toward using 2 batteries and use Bob Nuckols system.  Thanks for any help.
> 
> Joe Berki
> Limo EZ
> 
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