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Re: Europa-List: Re: Is there any reason to have a separate battery and

Subject: Re: Europa-List: Re: Is there any reason to have a separate battery and
From: Gilles Thesee <gilles@elixiraircraft.com>
Date: Sat, 16 May 2020 02:05:28
Le 15/05/2020  23:33, William Daniell a crit:


Will,

There is a law in physics measurements : the more parameters you 
measure, the more you scratch your head^^!

That said, you wrote that your bus - or battery - voltage remained 
within the "green" limits during each of the events. So no reason to 
suspect the voltage regulator.

The only item capable of supplying more than the 21 amps of the 
alternator is the battery, but while doing this its voltage would sag 
due to internal resistance (Cf Ohm's law for a generator). 70 amp is no 
trifle.

So the main probabilty is an ammeter artefact. The best way to measure 
currents is with a Hall effect sensor, as the shunt may induce side 
effects in your circuits with high currents.

But first things first, without independent and reliable voltage and 
possibly current measurements or logging, no assumptions can be made.


Concerning disconnecting the battery while running, not sure it would be 
a safe thing to do, especially in flight :


-- 
Best regards,
Gilles
http://contrails.free.fr
http://lapierre.skunkworks.free.fr


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