Matronics Email Lists Forum Index Matronics Email Lists
BBS Forum Interface to the Matronics Email Lists
 
 Get Email Distribution Too!Get Email Distribution Too!    FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Rotax 912iS Electrical Charging System

 
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> AeroElectric-List
View previous topic :: View next topic  
Author Message
cluros(at)gmail.com
Guest





PostPosted: Sat Sep 08, 2018 6:37 pm    Post subject: Rotax 912iS Electrical Charging System Reply with quote

This question is specifically in relation to the Rotax 912iS stock electrical system. Lane A and B voltages are rock steady at 14 V, but the volt sensor on the Dynon Skyview is seeing 13.5 - 13.7 V. The aircraft is wired exactly as per Rotax installation instructions and follows their wire size recommendations. I'm going to stick a voltmeter on the battery tomorrow and see what the actual voltage at the battery is while the engine is running but if it confirms the Dynon reading I'm concerned the battery is never going to be charged.

The strange thing is the Dynon Skyview default for this engine's voltage output has 13.5 in the middle of the green band. For a Lycoming or Continental I put the green band at 14-14.5
Is anyone here familiar with the 912iS? If this is how the system is designed, what are the implications for an Odyssey PC680 that spends most of it's waking life at 13.5 V?
Thank you all,
Sebastien


- The Matronics AeroElectric-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List
Back to top
nuckolls.bob(at)aeroelect
Guest





PostPosted: Sun Sep 09, 2018 8:54 am    Post subject: Rotax 912iS Electrical Charging System Reply with quote

Quote:

The strange thing is the Dynon Skyview default for this engine's voltage output has 13.5 in the middle of the green band. For a Lycoming or Continental I put the green band at 14-14.5


An SVLA battery should be run at no less than 14.0
and no more that 14.8 with 14.4 being the nominal
"target". Anything below 14.0 has a high probability
of failing to top off the battery after a significant
discharge. This has nothing to do with the make/model
of the engine.


Quote:
Is anyone here familiar with the 912iS? If this is how the system is designed, what are the implications for an Odyssey PC680 that spends most of it's waking life at 13.5 V?

If true, that battery is seriously under-served for
charging.

Your proposal to investigate battery terminal
voltage while in flight is a good move. Keep in
mind just because a certain voltage is recorded
at one place in a system, it's not a sure bet
that the same voltage will be recorded elsewhere
even tho both points are connected with copper
pathways. There are subtle but significant voltage
drops in system wiring. Further, if the readings
are taken with two different instruments, it's
possible that they may not be calibrated to the
same accuracy.

Irrespective of engine, the voltage regulator's
prime directive is TAKE CARE OF A BATTERY. Given
that there's a lot of copper monkey-motion between
the regulator and battery, the regulator's electronics
can only ASSUME that it knows what battery voltage
is.

For SVLA batteries, voltage in cruising flight with
a fully charged battery should be in the 14.2 to
14.6 range. If the alternator is off for any
reason, the battery voltage will fall quickly to
something under 13.0 volts. when the battery falls
to 11.0 volts, it has probably less than 5% of
it's maximum capacity remaining.


Bob . . .


- The Matronics AeroElectric-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List
Back to top
Display posts from previous:   
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> AeroElectric-List All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Powered by phpBB © 2001, 2005 phpBB Group