Date: Wed, 23 Sep 1998 09:52:29 -0400
From: Lynda Frantz <LFrantz@compuserve.com>
Subject: Battery capaticance
Sender: Lynda Frantz <LFrantz@compuserve.com>
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Now that we all agree that the battery is a big capacitator and has
potentially great noise filtering qualities the question is; How can we use
this feature of the battery to maximum advantage?  

I identified the historically noisy devices that are in our craft  like
strobes, alternators, and hydraulic pumps.  I'm sure we have all  flown
badly wired aircraft in the past and could hear one or all of  these
devices through our headset.  We definitely don't want to hear these
devices in our finely built  Lancairs.  So, I wired all of these noisy
devices directly (actually through circuit breakers) to the battery rather
than to the power distribution bus.  All the other clean devices are wired
directly to the power distribution bus through their respective circuit
breakers.  So what's the difference, isn't the noisy stuff still connected
via the battery bus to the power distribution bus?  Yes, but the resistance
between the noisy device and the battery/capacitor/filter  is many times
less than if the power distribuion bus were inbetween. 

Perhaps someone else could explain this better than I.  In any event, look
for my pictorial wiring diagram in the Dec/Jan issue of the Lancair Network
News.  It features a 3 1/2 bus system, a battery direct bus (the +  lug of
the battery), power distribution bus, radio bus and essential bus.  And I
do not have any zips, pops, clicks, or hummms comming through my headset!

Jim Frantz
Jim@Angle-of-Attack.com