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  #61  
Old 02-21-2017, 01:00 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 6,356
Default You have to know the details........

Quote:
Originally Posted by Driftdown View Post
Seems like a tradeoff . . . oil pressure verification for more cranking power.
I question . . . just how much more cranking power does that really add up to?

With a Skyview already on, not only do we see oil pressure immediately . . but prior to actual crank, we can see the battery power available.
On the D180 RV-12's, the EFIS was switched by the Avionics switch (which is why it was on during start).

On Skyview RV-12's, the the screen is not controlled by the Avionics switch so the switch can be off for start and still see all necessary engine info...
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Scott McDaniels
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RV-6A (aka "Junkyard Special ")
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  #62  
Old 02-21-2017, 01:03 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Originally Posted by AirHound View Post
RVBuilder-

What kind of experience? I'd like to avoid expensive repairs? At least those known by others. Thanks!
Cranking the engine with low battery voltage (particularly with early engines that did not have soft start) is hard on the starter sprag clutch and can lead to early failure. It is expensive to repair because of the required engine removal and opening up of the back of the engine.
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  #63  
Old 02-21-2017, 01:12 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by RFSchaller View Post
A typical battery is about 25 amp-hours capacity. Cranking power is in the 100 amp range while avionics pull about 7 amps. Seems like the avionics load during a typical start is insignificant.
AMP hour rating is only slightly connect to cranking amps rating.

The cold cranking amps available is directly connected to the actual voltage of a batter at any given moment and the published rating is with the battery fully charged.

With a low battery voltage on your car, it is entirely possible for head lights on or off to mean the difference between whether it will actually start or not.........
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  #64  
Old 02-21-2017, 02:50 PM
Driftdown Driftdown is offline
 
Join Date: Jan 2011
Location: Clearwater, Florida
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Quote:
Originally Posted by rvbuilder2002 View Post
On the D180 RV-12's, the EFIS was switched by the Avionics switch (which is why it was on during start).

On Skyview RV-12's, the the screen is not controlled by the Avionics switch so the switch can be off for start and still see all necessary engine info...
Got it. Thanks.
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  #65  
Old 02-21-2017, 05:24 PM
2johns 2johns is offline
 
Join Date: Apr 2008
Location: Great Falls, Montana
Posts: 66
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exceptions, exceptions! Operating legally under sport pilot rules I have flown my RV 12 up to 14,000 feet. It was still climbing 400 fpm when I stopped.
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  #66  
Old 02-21-2017, 06:10 PM
AirHound AirHound is offline
 
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Location: OFallon IL now, everywhere before
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Quote:
Originally Posted by rvbuilder2002 View Post
Cranking the engine with low battery voltage (particularly with early engines that did not have soft start) is hard on the starter sprag clutch and can lead to early failure. It is expensive to repair because of the required engine removal and opening up of the back of the engine.
Would a 2010-11 ELSA engine have soft start? And what is considered minimum volts to crank?
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Last edited by AirHound : 02-21-2017 at 06:16 PM.
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  #67  
Old 02-21-2017, 08:54 PM
Mich48041 Mich48041 is offline
 
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Probably. Look for yellow labels on the ignition modules.
Quote:
Would a 2010-11 ELSA engine have soft start?
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  #68  
Old 02-22-2017, 11:28 AM
AirHound AirHound is offline
 
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What is a ballpark Minimum battery voltage before damage to starting system!
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