On Tue, 28 Dec 2004 17:43:57 +0000 (UTC), Aaron Coolidge
wrote:

snip

Don't forget that the charging voltage for a lead-acid battery is *supposed*
to be modified by ambient temperature, with a higher voltage at lower temps.
This is commonly done with a thermistor in the voltage regulator. Even
the mechanical (vibrating relay) regulator in my 1977 Datsun has temperature
compensation.

Good point, the battery dudes suggest a difference in regulated
charging voltage with varying battery operating temperatures, which
can vary from ambient temps.


That said, 13.6V is probably OK. If you check the volts on the battery
terminals you'll probably get a little more than the 13.6V on the avionics
bus, because the battery is wired to the alternator with heavier wires.

Another good point, voltage drop between a GA aircraft main bus and
the avionics bus is not uncommon.

Regards;

TC