Hi Ferg,
I thought about this a lot while designing my panel. In the end I
decided to go with a 150 amp continuous, 500 amp peak switch from a
marine supplier. Same idea as you: have it mounted on the firewall side
and drilled a hole through the instrument panel where I can insert a RED
key. Panel comes off in under 1 minute.
ON-OFF markings for everyone to notice when leaving the aircraft or
during emergency landings. However, I have it mounted on the co-pilot
side, within view of the pilot. Saves me the special long key through
the instrument panel to reach the firewall in case things get heated up
in the cockpit. If I manage to get the battery mounted starboard forward
engine compartment the lead between battery and starter will be
extremely short (under 1 foot), saving weight and giving full voltage on
starting my 912S. I have a classic engine mount and installed the
standard engine starter.
Without the battery solenoid (more prone to failure than a big size
marine switch believe me!) it saves me at least 1 ampere of load on the
electrical system which I designed to draw no more than 2.5 without
strobes then (5 amp with single strobe). I have Microair transceiver and
Transponder pair).
Furthermore, I have glider wings in the waiting and need to keep the
current down while gliding. So I have a 3 way panel master avionics
switch planned which has 3 modes: OFF - ON - GLIDER. The glider
essential bus services only essential electronics and will draw less
than 1.5 amps/hr. That gives me 3 hrs glider flying without draining the
16 AH main battery too much for a secure start. It would be easy to
power the glider essential bus with a small NIMH battery (RC Car 10
cell) I take home after flying. Cost me maybe $40 at the most. Marine
switch was $30. You can start a truck with this. RNuckols is, I agree,
an absolute must read.
Christoph
@223 Wolfville, Nova Scotia
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Fergus Kyle
Sent: Wednesday, April 08, 2009 6:18 PM
Subject: Europa-List: Battery disconnect.........
Cheers,
I for one am indebted to OCBaker and RNuckolls for the exchange
of
views recently - prompted by a question of battery disconnect under
load.
This is must-read material for all us newbies in the build status.
My question is prompted by the above. I have built a coming
monster
due to wanting to populate it with amateur radio "electro-whizzies" (as
Bob
says). This brought me to wondering how I can reduce longterm demands on
current supply. I have a 914 which requires constant electrons for
electrical fuel pumps. I added an SD20S but a 100watt HF transceiver can
eat
20amps easily, I know (car history).
This led to the idea that the master contactor wants an amp or so all
its
life - that is a lot of juice - a thousand amp-hours if I don't prang.
SO I
installed a racing car cutoff switch instead on the firewall with an
eleven-inch wooden key through a hole on the instru panel. If you can
recognize the hole for what it is, you might steal the machine by
fabricating my key.
My question is:
Have I done a useful thing? What is the expected useful life of a fairly
simple (and supposedly rugged) device compared to these usual
contactors?
[Price was also a pleasantry].
Expectently, Ferg
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