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912 ULS starter

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icrashrc

Joined: 16 Mar 2006
Posts: 247
Location: Mishawaka, In

Posted: Sun Apr 05, 2009 11:39 pm Post subject: 912 ULS starter

Has anyone measured the current draw of the Rotax 912 HD starter? I'm researching battery options and i wasn't smart enough to check mine before we started disassembly. Thanks,

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Scott

www.ill-EagleAviation.com

do not archive

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Mon Apr 06, 2009 8:30 am Post subject: Re: 912 ULS starter

I have an 18 Amp Hour battery in my Kolb that has been starting my 912-S for 3 years without a problem.  I live in Florida, so I cant tell you weather it would work in cold weather or not.



Mike

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"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

by0ung(at)brigham.net
Guest

Posted: Mon Apr 06, 2009 10:09 am Post subject: 912 ULS starter

I have an 18 Amp Hour battery in my Kolb that has been starting my 912-S for

3 years without a problem.  I live in Florida, so I cant tell you weather it

would work in cold weather or not.



Mike

 	  Quote: 	
		  >>>>>>>>>>>>.


	


I have a 18 amp hour that starts the 912 in 20 deg temps.



Boyd

icrashrc

Joined: 16 Mar 2006
Posts: 247
Location: Mishawaka, In

Posted: Tue Apr 07, 2009 5:54 pm Post subject: Re: 912 ULS starter

Thanks for the info on the size battery you're using. I was hoping someone had actually tested the amp draw of the starter while cranking. Not something one would normally check but I've never been called 'normal'!

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Scott

www.ill-EagleAviation.com

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John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Tue Apr 07, 2009 6:03 pm Post subject: 912 ULS starter

> Thanks for the info on the size battery you're using. I was hoping 

someone had actually tested the amp draw of the starter while cranking. Not 

something one would normally check but I've never been called 'normal'! 

[Laughing]

 	  Quote: 	
		  

 --------

 Scott


	


Scott:



This is the battery I use in my mkIII and 912ULS:



http://www.odysseybatteries.com/battery/pc545.htm



john h

mkIII

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John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Wed Apr 08, 2009 4:25 am Post subject: Re: 912 ULS starter

I believe the typical draw while cranking the 912ul is about 75 amps. I'm going to check mine today and will report back. 912ULS may be different.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Wed Apr 08, 2009 1:38 pm Post subject: Re: 912 ULS starter

I don't know where I got the "typical draw while cranking the 912ul is about 75 amps." from but it was way off for our 912UL per testing this morning.



Using clamp on ammeter I got ~13 amps current during cranking our 912UL at about 45-50F OAT.



I hope this figure helps with at least a ballpark guestimate.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

by0ung(at)brigham.net
Guest

Posted: Wed Apr 08, 2009 8:10 pm Post subject: 912 ULS starter

Using clamp on ammeter I got ~13 amps current during cranking our 912UL at

about 45-50F OAT.



 	  Quote: 	
		  >>>>>>>>>>>..


	


I have never seen a clamp on dc amp meter.



Boyd

icrashrc

Joined: 16 Mar 2006
Posts: 247
Location: Mishawaka, In

Posted: Thu Apr 09, 2009 2:21 am Post subject: Re: 912 ULS starter

DC clamp-on meters may not be a dime a dozen but they are easy to find. I have one as well. I just don't have the entire system to use it on at the moment...

 

Thanks for checking your 912ul. You may want to check the calibration and/or settings on your meter. Somehow i think your estimate of 75 amps is closer to reality. I would hate to think i ran 6 ga cable to the starter when 18 ga would have worked just fine!

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Scott

www.ill-EagleAviation.com

do not archive

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Thu Apr 09, 2009 4:26 am Post subject: Re: 912 ULS starter

Scott,



The Rotax 912 Installation manual states that the regulator is rated for 75 Amps continuous and that is where my aging memory got the 75 A number. The #6GA wire is what the installation manual calls for too, I believe. The manual also states that the battery required is 18AH.



My clamp on meter is nearly new. Compared to two other meters I've tested it against recently, it is accurate, so 13 Amps cranking current is what I'm getting. I suspect it would be a bit higher in colder weather and a little less in the summer.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

herbgh(at)nctc.com
Guest

Posted: Thu Apr 09, 2009 5:06 am Post subject: 912 ULS starter

Unless the meter had a peak and hold ability...it did no read the 

initial in rush current to the essentially stalled motor.. To get the 

motor turning takes a multiple of 15 amps for a fraction of a 

second..maybe longer... Marginal wire side coupled with necessary 

long runs and a marginal battery ...is always a problem... Herb

At 05:21 AM 4/9/2009, you wrote:

 	  Quote: 	
		  



DC clamp-on meters may not be a dime a dozen but they are easy to 

find. I have one as well. I just don't have the entire system to use 

it on at the moment...



Thanks for checking your 912ul. You may want to check the 

calibration and/or settings on your meter. Somehow i think your 

estimate of 75 amps is closer to reality. I would hate to think i 

ran 6 ga cable to the starter when 18 ga would have worked just fine!



--------

Scott



www.ill-EagleAviation.com



do not archive





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http://forums.matronics.com/viewtopic.php?p 38454#238454

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Thu Apr 09, 2009 5:35 am Post subject: Re: 912 ULS starter

The 912 installation manual also shows a 300A peak (1 second max) for the regulator. 



I was reading continuous cranking amps, not peak starting current.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

herbgh(at)nctc.com
Guest

Posted: Thu Apr 09, 2009 5:50 am Post subject: 912 ULS starter

The regulator should no be in the circuit when starting...  I was 

thinking about the current draw when starting motors...  couple of 

seconds......     Ohms law ... The fractional resistance of a 

conductor becomes appreciable at high currents which results in a 

proportionate voltage drop....      Herb

At 08:35 AM 4/9/2009, you wrote:

 	  Quote: 	
		  



The 912 installation manual also shows a 300A peak (1 second max) 

for the regulator.



I was reading continuous cranking amps, not peak starting current.



--------

Thom Riddle

Buffalo, NY

http://riddletr.googlepages.com/sportpilot-cfi

http://riddletr.googlepages.com/a%26pmechanix



A complex system that works is invariably found to have evolved from 

a simple system that works.

   - John Gaule





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p 38480#238480

ElleryWeld(at)aol.com
Guest

Posted: Thu Apr 09, 2009 3:52 pm Post subject: 912 ULS starter

You can buy one from a Snap-on tool dealer you just  lay the meter on the wire  if the wire is the right size it will snap on to  it and you can also get one to test your charging system  from snap-on I  have both of these meters in my Tool box that I have been using for years and  they are a great rig to have 

  

 Ellery in Maine 

  

  In a message dated 4/9/2009 12:10:42 A.M. Eastern Daylight Time,  by0ung(at)brigham.net writes:

  	  Quote: 	
		  -->    Kolb-List message posted by: "b young"    <by0ung(at)brigham.net>

Using clamp on ammeter I got ~13 amps    current during cranking our 912UL at

about 45-50F    OAT.



 	  Quote: 	
		  >>>>>>>>>>>..


	


I have    never seen a clamp on dc amp meter.



Boyd  ======================== the  ties  Day  ================================================               - MATRONICS WEB FORUMS  ================================================             - List Contribution Web Site  sp;                             ===================================================



	


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