<craig.ellison2@verizon.net>
>
> ...The directions with the UMA unit say to place the shunt
> between the voltage reg and the + side of the battery.
>
That will tell you whether the battery is being charged, but some may
prefer reading only total load on the bus. However, reading the
latter will not tell you if the battery is discharging because of too
much load vs. RPM. This can be dangerous for IFR at night in
instrument conditions, so I believe reading current in/out of the
battery is the common case in production planes.
In reading system load, even for just day VFR, you may never know when
the day will come the engine won't start at some little airport where
the facilities are closed. Although adding a voltmeter will tell us
something, but that requires interpretation since the voltage reading
can be a function of battery charge condition at any point in time.
Reg,
Fred F.
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