Matronics Email Lists :: View topic - Battery Cranking Amps

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Battery Cranking Amps

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Fri Jan 22, 2010 10:10 am Post subject: Battery Cranking Amps

Anybody have a method for determining cranking amps necessary for a specific engine? Mine's a 10.5:1 350in 6 cyl

I found this site with a CCA calculator and other useful engine stuff.



http://www.bgsoflex.com/auto.html



Trusting but verifying.



John

N20DG

Joined: 02 Jan 2008
Posts: 61
Location: lancaster, texas

Posted: Fri Jan 22, 2010 10:54 am Post subject: Battery Cranking Amps

Would like to look at this site but this is what I get when I log onto  it

 "You don't have permission to access /auto.html on this server. "

 Thanks

 Dick

  

  In a message dated 1/22/2010 12:13:47 P.M. Central Standard Time,  jonlaury(at)impulse.net writes:

  	  Quote: 	
		  -->    AeroElectric-List message posted by: "jonlaury"    <jonlaury(at)impulse.net>



Anybody have a method for determining    cranking amps necessary for a specific engine? Mine's a 10.5:1 350in 6    cyl

I found this site with a CCA calculator and other useful engine    stuff.



http://www.bgsoflex.com/auto.html



Trusting but    verifying.



John





Read this topic online    here:



http://forums.matronics.com/viewtopic.php?p=282917#282917===============================================

_-=   = Use   utilities  Day  ================================================               - MATRONICS WEB FORUMS  ================================================             - List Contribution Web Site  sp;                             ===================================================



	


  [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Jan 22, 2010 11:24 am Post subject: Battery Cranking Amps

At 12:10 PM 1/22/2010, you wrote:

 	  Quote: 	
		  



Anybody have a method for determining cranking amps necessary for a 

specific engine? Mine's a 10.5:1 350in 6 cyl

I found this site with a CCA calculator and other useful engine stuff.



http://www.bgsoflex.com/auto.html



Trusting but verifying.


	


   The "cranking amps" ratings of batteries are generally

   not high on the priority of items in system design goals.

   Weight, size, ease of installation, cost of ownership,

   and other features usually set decision process in

   OBAM aircraft. Cranking amps for an engine is pretty

   whispy too . . . it depends on tightness of the engine,

   temperature, viscosity of oil, motor efficiency, gear

   ratios, wire sizes, etc.



   In other words, I'll suggest you start with a 3 x 6 x 6"

   SVLA, 17-20 a.h. battery with expansion room for upsizing later. See

   how that fits with YOUR notions of satisfactory performance.

   A new battery that size will get your engine going with

   about any of the modern starters. The question that drives

   an up-sizing decision is how often you need to replace the

   battery for the environment and missions you fly.



   MOST builders are happy with that size battery.



   Bob . . .

mrspudandcompany(at)veriz
Guest

Posted: Fri Jan 22, 2010 11:56 am Post subject: Battery Cranking Amps

I was able to get right on without a problem.  

   

Roger  

   

     

Would like to look at this site but this is what I get when I log onto it  

    

"You don't have permission to access /auto.html on this server. "  

    

Thanks  

    

Dick  

    

   

      

In a message dated 1/22/2010 12:13:47 P.M. Central Standard Time, jonlaury(at)impulse.net writes:  

  

  [quote]--> AeroElectric-List message posted by: "jonlaury" <jonlaury(at)impulse.net>



Anybody have a method for determining cranking amps necessary for a specific engine? Mine's a 10.5:1 350in 6 cyl

I found this site with a CCA calculator and other useful engine stuff.



http://www.bgsoflex.com/auto.html



Trusting but verifying.



John





 [b]

N20DG

Joined: 02 Jan 2008
Posts: 61
Location: lancaster, texas

Posted: Fri Jan 22, 2010 12:45 pm Post subject: Battery Cranking Amps

Must be an AOL thingy - went to firefox and loaded OK

 Thanks

 Dick

  

  In a message dated 1/22/2010 1:58:19 P.M. Central Standard Time,  mrspudandcompany(at)verizon.net writes:

  	  Quote: 	
		  http://www.bgsoflex.com/auto.html

	


  [quote][b]

jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Fri Jan 22, 2010 9:09 pm Post subject: Re: Battery Cranking Amps

 	  nuckolls.bob(at)aeroelect wrote: 	
		  At 12:10 PM 1/22/2010, you wrote:

 	  Quote: 	
		  

	


      In other words, I'll suggest you start with a 3 x 6 x 6"

   SVLA, 17-20 a.h. battery with expansion room for upsizing later. 

   Bob . . . 	




Per your suggestion of using smaller batteries to make a lightweight Z14, I looked at the Odyssey PC 310. With two of them I'd have 620 amps for 5 seconds (wondering how many engine start trys I get). According to the website that I linked in my original post, I need 427amps to spin my 6cyl 350 in. engine. The PC310 (6lbs) is an 8AH battery with a 25 amp discharge capability of 9 minutes. Two of them gets me about 1/2 hr (at) 12 amps, which is what my 2 no frills battery buses and E bus need. Having 2 alternators makes me OK with this minimum size battery bank and this light weight Z14 weighs less than the Z19 with 2 17AH batts by about 10 lbs.



What am I overlooking



John

earl_schroeder(at)juno.co
Guest

Posted: Sat Jan 23, 2010 7:10 am Post subject: Battery Cranking Amps

Hi John,

You wrote in part:

Per your suggestion of using smaller batteries to make a lightweight Z14, I looked at the Odyssey PC 310. With two of them I'd have 620 amps for 5 seconds (wondering how many engine start trys I get). 



What am I overlooking?



Check the size of the battery terminals.  Some that I've tried were too small to accept the wire size required to carry starter current requirements.  For instance, some would only accept a 6-32 size screw or a 1/4" push on tab.  Earl

nuckolls.bob(at)aeroelect
Guest

Posted: Sat Jan 23, 2010 10:35 am Post subject: Battery Cranking Amps

At 09:06 AM 1/23/2010, you wrote:

 	  Quote: 	
		  

<earl_schroeder(at)juno.com>



Hi John,

You wrote in part:

Per your suggestion of using smaller batteries to make a lightweight 

Z14, I looked at the Odyssey PC 310. With two of them I'd have 620 

amps for 5 seconds (wondering how many engine start trys I get).



What am I overlooking?



Check the size of the battery terminals.  Some that I've tried were 

too small to accept the wire size required to carry starter current 

requirements.  For instance, some would only accept a 6-32 size 

screw or a 1/4" push on tab.


	


   The 310 is pretty light even in pairs. Limited

   cranking ability due to high internal resistance.

   Even with two paralleled, total battery resistance

   about twice that of a 680.



   That doesn't mean it won't work for YOUR airplane

   and the environment in which you crank the engine.

   There ARE small batteries with low internal resitances.

   Bill and I tested a 10 a.h. Gates product about 15 years

   ago that gave us five, 10-second cranking cycles on a

   room temperature, hi-compression engine with 1 minute

   waits between attempts.



   So there is potential for a pair of light weights

   to step up to the task . . . the 310 may or may

   not be a good choice. You'll have to tell us.



        Bob . . .

                    ////

                   (o o)

    ===========o00o=(_)=o00o=========

    < Go ahead, make my day . . .   >

    < show me where I'm wrong.      >

    =================================

jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Sun Jan 24, 2010 5:01 pm Post subject: Re: Battery Cranking Amps

OK I'm abandoning my holy grail search for a lightweight Z-14. I don't want to spend $300 for 2 PC310's to find out that they won't crank my engine. I think I'll settle for Z-13/8 (with a 40amp stby; $350 less money, more amps and a 4.5 # penalty over the B&C PM alts that don't fit my Franklin engine) and I'll use a single PC680. I have accomodation for another 680 should I decide that I need the redundancy. A single 680 gives me about 45 mins with my Ebus load (longer than the dual 310's). I still save 7+ lbs over Z-19 and I like having the second alternator better than a second battery. 



No matter how frequently I tested my batteries, I know that with no alternator, I'm not going to be comfortable with a vague notion of how long I've got. I would head for an airport immediately. With a second alternator and battery reserve,  a primary alternator failure, becomes a bother rather than something I have to make a go/no-go decision about.



Other than the size of the alternator, and using two B&C LR-3 VR's, I see nothing in Z13/8 that I would change. 



Any observations/refinements appreciated.



John

jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Sun Jan 24, 2010 5:05 pm Post subject: Re: Battery Cranking Amps

 	  earl_schroeder(at)juno.co wrote: 	
		  Hi John,

Check the size ng?of the battery terminals.  Some that I've tried were too small to accept the wire size required to carry starter current requirements.  For instance, some would only accept a 6-32 size screw or a 1/4" push on tab.  Earl 	




Thanks Earl. You're right. The PC 310 use an M4 screw (#8-32 equiv). There's a pad for more contact, but the screw is pretty small to get decent clamping force applied.



See the previous post.



John

kevann(at)gotsky.com
Guest

Posted: Mon Jan 25, 2010 6:55 am Post subject: Battery Cranking Amps

I have a two alt one batt(pc680) syatem in my 914 powered Europa. I change 

out the battery every other year. I modified our Subaru Legacy to take the 

680. The two year old 680 cranks the Subaru fine for two years till I get a 

new one for the plane.



Kevin

---

jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Mon Jan 25, 2010 9:43 am Post subject: Re: Battery Cranking Amps

 	  kevann(at)gotsky.com wrote: 	
		  I have a two alt one batt(pc680) syatem in my 914 powered Europa. I change 

out the battery every other year. I modified our Subaru Legacy to take the 

680. The two year old 680 cranks the Subaru fine for two years till I get a 

new one for the plane.



Kevin

--- 	




Thanks Kevin.

I've often thought that with the numbers of people that subscribe to the List and who monitor this forum, there's got to be a market for 1 or 2 year old AGM batteries like the Odysseys for those who opt for a two battery system like Z19 or 14 and are in their first year. 

It always pained me thinking of tossing a perfectly good $100+ battery.

Your Subaru adaptation is a good way to get some use out of a normally superfluous batt.

J



Do not archive

klehman(at)albedo.net
Guest

Posted: Mon Jan 25, 2010 12:01 pm Post subject: Battery Cranking Amps

That is actually a nice thing about z-14 with small batteries such as 

the Dekka units. Flog them until cranking is noticeably slower. See 

which one is dead and put the new one on the most critical side. They 

are still $100. batteries but they are fully consumed when replaced.

Ken

jonlaury wrote:

 	  Quote: 	

 kevann(at)gotsky.com wrote:

> I have a two alt one batt(pc680) syatem in my 914 powered Europa. I change 

> out the battery every other year. I modified our Subaru Legacy to take the 

> 680. The two year old 680 cranks the Subaru fine for two years till I get a 

> new one for the plane.

>

> Kevin

> ---

 Thanks Kevin.

 I've often thought that with the numbers of people that subscribe to the List and who monitor this forum, there's got to be a market for 1 or 2 year old AGM batteries like the Odysseys for those who opt for a two battery system like Z19 or 14 and are in their first year. 

 It always pained me thinking of tossing a perfectly good $100+ battery.

 Your Subaru adaptation is a good way to get some use out of a normally superfluous batt.

 J

 Do not archive

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p 83361#283361

Display posts from previous:

	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