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VPX Pro - Dual Battery Configuration Question

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nuckolls.bob(at)aeroelect
Guest

Posted: Sun Jul 10, 2011 8:44 am Post subject: VPX Pro - Dual Battery Configuration Question

My requirements are:  Ability to have both batteries on main bus for additional cold cranking capability  
Ability to isolate the second battery to the endurance battery bus  
Ability to charge the isolated battery 



 In looking at the recommendations in the Vertical Power manual, Dual battery Option #1 meets the first two requirements. Option #2 meets the last two requirements. So my question is will a hybrid design, like Option #3 meet all requirements? Are there any negative attributes with having two current paths when the aux battery contactor is closed?

 [img]cid:.0[/img] 



       

      Option 1 is the simplest way to add a second

      battery which is why it is featured in Figure Z-30.

      If you want to a battery maintainer for both

      batteries, a maintainer plug that puts the

      two batteries in parallel for storage takes

      care of the 'charging' issue.



      You need to think through the failure modes

      and the precise way in which the duties of the

      two batteries are partitioned during an alternator

      out condition. Do an energy study for the two

      duties and make sure the batteries are sized for

      your endurance goals (x number electro whizzies for

      y hours of operation) assuming also that you're going

      to periodically cap-check the two batteries for

      insuring those goals are achievable.



      The precise manner in which you add the second battery

      is not terribly important. The care with which you

      craft and maintain Plan-B is very important. This

      pre-supposes that your engine is electrically dependent

      and/or you're going to spend a lot of time in situations

      were the dark panel syndrome causes you to break a

      sweat. 



      Given the way 99% of OBAM aviation flights are conducted,

      and assuming that you have one mag on the engine, then

      Plan-B might be something like this . . .



  http://aeroelectric.com/Pictures/Misc/Vacination_for_Dark_Panel_Syndrom.pdf 



      for a whole lot less weight, a ton more reliability

      and lower cost of ownership. This has been my personal

      Plan-B over the last 30 years and 1000+ hours. It

      works good every time and in any airplane I rent. 



 

   Bob . . .

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rleffler

Joined: 05 Nov 2006
Posts: 680

Posted: Sun Jul 10, 2011 6:34 pm Post subject: VPX Pro - Dual Battery Configuration Question

Bob,

 

I understand and appreciate your comments, but you didn’t address my questions regarding Option 3.  I understand your opinion on KISS.  But I was attempting to understand is there are any negative attributes with having two current paths when the aux battery contactor is closed on Option 3?  I believe I understand the complexities and how to perform for a Plan B.

 

My concern for option 1, is that I will never truly know the state of both batteries since they both are online.  I only want to link both batteries for occasional starts in cold weather when I may need a stronger battery.  So 99% of the time, I’ll leave the battery isolated.  I then need a mechanism to ensure that the Aux battery is charged.

 

I understand that I truly will never know the exact length the aux battery will last, but I will know that I can get x% of its rated value.  Then it’s just a question of how conservative I want to be with the numbers.  In reality, it’s head for the nearest airport and stop the flight even though I know I may have longer time on the aux battery.

 

Thanks,

 

Bob



[img]cid:image003.jpg(at)01CC3F50.6D4C43F0[/img]

 

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Robert L. Nuckolls, III

Sent: Sunday, July 10, 2011 12:41 PM

To: aeroelectric-list(at)matronics.com

Subject: Re: VPX Pro - Dual Battery Configuration Question

 



My requirements are: Ability to have both batteries on main bus for additional cold cranking capability 
Ability to isolate the second battery to the endurance battery bus 
Ability to charge the isolated battery 

In looking at the recommendations in the Vertical Power manual, Dual battery Option #1 meets the first two requirements. Option #2 meets the last two requirements. So my question is will a hybrid design, like Option #3 meet all requirements? Are there any negative attributes with having two current paths when the aux battery contactor is closed?

      

     Option 1 is the simplest way to add a second

     battery which is why it is featured in Figure Z-30.

     If you want to a battery maintainer for both

     batteries, a maintainer plug that puts the

     two batteries in parallel for storage takes

     care of the 'charging' issue.



     You need to think through the failure modes

     and the precise way in which the duties of the

     two batteries are partitioned during an alternator

     out condition. Do an energy study for the two

     duties and make sure the batteries are sized for

     your endurance goals (x number electro whizzies for

     y hours of operation) assuming also that you're going

     to periodically cap-check the two batteries for

     insuring those goals are achievable.



     The precise manner in which you add the second battery

     is not terribly important. The care with which you

     craft and maintain Plan-B is very important. This

     pre-supposes that your engine is electrically dependent

     and/or you're going to spend a lot of time in situations

     were the dark panel syndrome causes you to break a

     sweat. 



     Given the way 99% of OBAM aviation flights are conducted,

     and assuming that you have one mag on the engine, then

     Plan-B might be something like this . . .



http://aeroelectric.com/Pictures/Misc/Vacination_for_Dark_Panel_Syndrom.pdf 



     for a whole lot less weight, a ton more reliability

     and lower cost of ownership. This has been my personal

     Plan-B over the last 30 years and 1000+ hours. It

     works good every time and in any airplane I rent. 



  Bob . . .

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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:

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_________________
Bob Leffler
N410BL - Phase I
http://mykitlog.com/rleffler

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