> that the rear position will cause." "You will also save some weight and
> a lot of expense." !!
The voltage drop on the length of cable from the underside of the baggage bay
to the engine with a rotax engine up front is so low as to be a non issue. The
resistance of a 2AWG cable is .156 ohms per thousand feet with a 35c
temperature rise rated current of 100A. Even if the Rotax engine drew 70A on
starting, the drop over ten feet of that wire would be negligible. Remember,
we're not turning over a Lycoming here!
Even coming down to 4AWG, at .249 ohms per 1000 feet and a current rating of
72A you'd be hard pushed to measure the drop due to the wire.
It's very convenient that 4AWG is the same diameter as 16mm diameter welding
wire because I followed Bob Nuckoll's advice and used 16mm welding wire for my
main feed lines from my aft mounted battery. The welding wire is much more
flexible, is considerably lighter due to a different covering, is made to be
used in hazardous environments and cost me all of USD3 as a offcut length from
a local welding shop.
I have already put a 20A dummy load on the front and, at three degrees of
precision, can't measure any voltage drop between the battery and the firewall.
I might add that one of my motives for putting the battery aft is because I
have an Airmaster CS prop going on the front, a secondary generator on the
vaccum boss and already have a 7Ah secondary system battery on the front of the
firewall. I have also allowed for that secondary battery to be placed aft if I
need to adjust the c of g.... the lead (as in Pb) may as well be serving some
useful purpose!
Tony
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