Mailing List flyrotary@lancaironline.net Message #38111
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Battery
Date: Tue, 26 Jun 2007 13:12:40 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
A bit smaller than most used in the RV series of aircraft.  Apparently if only cranking power is the concern, an amazing amount of energy can be had in a small package.  But, if staying power is required (such as alternator failure) then most of the smaller batteries I have checked out don't provide more than 15-20 minutes at a normal all-electric load.
 
I started out with two 22 lb concord batteries that were huge - I then went to two Odyssey 680 batteries at 14 1/2 lbs each.  These were about 1/2 the volume of the concord.  I now fly with one PC 680 battery which at 14 1/2 lbs seems to provide a good balance between light weight, cranking power and staying power. 
 
So for cranking your battery might do just fine - but, I would look at the Amp hours you wish to have as a back up emergency reserve and size your battery according to that.
 
Ed
 
----- Original Message -----
Sent: Tuesday, June 26, 2007 11:57 AM
Subject: [FlyRotary] Battery

My battery box in my kit will require a battery about 5 1/2" X 6". That seems pretty small to me. Is that about average for aircraft batteries?

Bob Mears
Supermarine Spitfire

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