"Roger Long" wrote in message
.. .
My outlook is probably effected somewhat by watching the motorcycle size
battery in my plane start the 160 HP, high compression, engine briskly on
even below zero days.

Most aircraft batteries (even if motorcycle size) are AGM or gel. High
energy density for their size. Also, I assume that you preheat your engine
on your aircraft prior to starting.. All aircraft I have piloted require
preheat prior to starting to minimize excessive wear while the oil
decides to be useful. So most aircraft engines are not actually started at
zero temps.

BTW the 1,2 Both switch is an anachronism that I'll be ditching as soon as
I can get the boat back to Maine and overhaul the whole system.

Agreed. An antiquated concept.

There are very inexpensive battery management and charging systems now
that charge the batteries while leaving them isolated from each other for
normal loads.

Not exacty inexpensive but worth it.

--

Roger Long


Doug
s/v Callista