A35 Standby Alternator odities?
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First and foremost, what a delight to fly this thing. Amazingly done!
During my flights I noticed that the standby alternator works a bit strange.
The load meter does not agree with what the tablet is saying. The meter shows 90A while the tablet shows 18A.
My hunch is that as the standby alternator only being able to supply 25A instead of 100A, the ALT LOAD meter displays the percentage w.r.t. the selected alternator (primary or secondary)Btw, I noticed that the standby alternator cannot turn on if the battery is turned off. Is this due to the standby alternator controller requires battery power to turn on?
So this is expected:
BAT: On
ALT: On
STBY ALT: On
-> transition ALT: Off
-> transition BAT: Off
Result:
Power on main bus, from the STBY ALTThis should work, as the mainbus has enough power, but the result is unexpected
BAT: On
ALT: On
STBY ALT: On
-> transition BAT: Off
-> transition ALT: Off
Result:
No power on main busThis is also expected, as the STBY ALT controller has no power to turn the alternator on. (No field excitation)
BAT: Off
ALT: Off
STBY ALT: Off
-> transition ALT: OnResult:
No power on main busFurthermore
Amazing work on the details of the STBY ALT illumination light, it matches the original perfectly
https://bandc.com/product/bonanza-standby-alternator-system-components-stc-pma/#regulator-controller -
Thanks for the kind words. I have recollections of flip-flopping between percentage of total load and absolute amps over the years as I've been sent conflicting information. Sometimes I wonder how much of my time is spent just reversing changes I made years ago when I forget the rationale one way or another. From a read of the POH's now, it seems that it should be in absolute amps.
I can go and test things later, but I'm not sure I completely follow your table of expected outcomes. In the first instance, the power would still come from the main alternator, since the standby will not be brought online unless the first fails. In the second instance, your initial conditions are the same as the first, but your expected outcome implies something else.
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As a fellow software engineer, I feel your pain. Conflicting documentation on the hardware, different revisions of the hardware, different revision of the documentation.... It's the burden of creating beautiful software, the modern magic.

Yeah...that table went through some revisions which didn't make it clear.
The difference between the first and second table is the order in which the battery and alternator are disconnected.Turning of the battery before the alternator will prevent the standby alternator from starting, this is unexpected as there should still enough bus voltage on the main bus when only running on the alternator.