Matronics Email Lists :: View topic

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 Equalizers

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Dec 15, 2009 10:28 pm Post subject: Battery Equalizers

At 10:12 AM 12/14/2009, you wrote:

Thanks Bob, in your response, you indicated a lack of familiarity 

with battery equalizers and their functioning:



"I'd not encountered this style of "equalizer" before . . .  A study 

of it's ratings suggests that the device contains a switchmode power 

supply designed for charging 12v batteries from a 28v source."

Does anyone else on the list have any experience with these 

units?  The advertising and claims suggest they're designed to extend 

the lives of batteries wired in series by shuttling power between the 

two batteries (bi-directionally) to ensure they always have the same 

voltage.  Folks use these extensively in electric vehicles and for 

maintaining long strings of batteries for storing energy derived from 

solar power in stand-alone systems.  Anyone with some experience to 

share with the list?



   The term "battery equalizer" is a really broad brush

   with which to draw a schematic or write a description

   of how it functions.



   The folks doing development work on Li-Ion aircraft

   batteries have already described a host of "electronic

   enhancements" to make sure that each one of the relatively

   small bundles of energetic chemistry are not mistreated to

   destruction . . . or worse yet, catastrophic failure.

   This is a worry for the electrically enhanced vehicle

   business too.



   Equalization COULD be nothing more than precision

   shunt regulators that prevent voltage in any single

   cell from rising above some not-to-exceed levels.

   It COULD be an array of such devices individually

   commanded from some smart device like a micro-controller.



   The "equalizer" we were discussing seems to be a single

   precision power supply designed to simply offset the

   effects of loading the lower half of a two battery

   string. In this case, each string has twelve cells

   divided into two sections . . . equalization philosophy

   is therefor coarser.



   The ideal "equalizer" for a pair of six-cell batteries

   array might be a pair of switch-mode chargers feeding

   each battery independently . . . each capable of

   sourcing the highest anticipated load on each battery.



   I'm not trying to be obtuse but until one identifies

   and understands exactly how any particular "equalizer"

   is designed to function, and matches the knowledge

   with design goals for the system, sharing of experiences

   may not be all that useful.



   Exactly how would you like to use two 12v batteries

   in a 28v system?

        Bob . . .

                    ////

                   (o o)

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

    < Go ahead, make my day . . .   >

    < show me where I'm wrong.      >

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

- 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

dfritzj(at)yahoo.com
Guest

Posted: Wed Dec 16, 2009 10:39 pm Post subject: Battery Equalizers

Bob,

 The planned use for the battery equalizer is to allow the charge state of the two batteries in a 24V system to equalize after one battery is used (via the center tap) to run the 12V hydraulic pump.  My thought is that the battery will easily supply the 20A load for 30 seconds or so to required to raise the gear, after which the equalizer will act to direct energy to it in order to bring its charge state up to equal that of the other battery.  The particular unit I've chosen is called PowerCheq and appears to be designed for just such an application.  It's produced by a company called Power Designers, here's a link to the manual for the unit:  

  

 http://www.evsource.com/datasheets/powercheq/powercheq_operations_manual.pdf

  

 and here's a link to a white paper on its design and testing:

  

 http://www.fleetcareequipment.com/files/phatfile/PowerCheqPaper_MotivePower.pdf

  

 I'm not a Double-E, so I welcome comment from you and others out there regarding the usefulness of such a beast.

  

 Dan



         [quote][b]

- 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

bgray(at)glasair.org
Guest

Posted: Wed Dec 16, 2009 11:10 pm Post subject: Battery Equalizers

I’ve come into this thread on the back end, but why not just change the hydraulic powerpac to 24V?  

     

Bruce

 www.Glasair.org   

  

--

- 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

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Dec 27, 2009 11:01 am Post subject: Battery Equalizers

At 12:36 AM 12/17/2009, you wrote:

  	  Quote: 	
		  Bob,

 The planned use for the battery equalizer is to allow the charge state of the two batteries in a 24V system to equalize after one battery is used (via the center tap) to run the 12V hydraulic pump.  My thought is that the battery will easily supply the 20A load for 30 seconds or so to required to raise the gear, after which the equalizer will act to direct energy to it in order to bring its charge state up to equal that of the other battery.  The particular unit I've chosen is called PowerCheq and appears to be designed for just such an application.  It's produced by a company called Power Designers, here's a link to the manual for the unit:  

  

  http://www.evsource.com/datasheets/powercheq/powercheq_operations_manual.pdf 

  

 and here's a link to a white paper on its design and testing:

  

  http://www.fleetcareequipment.com/files/phatfile/PowerCheqPaper_MotivePower.pdf 

  

 I'm not a Double-E, so I welcome comment from you and others out there regarding the usefulness of such a beast. 	


    Dan,



    I've been pondering your request. I'm having

    trouble wrapping my head around a design task

    that increases weight, complexity and cost

    of ownership to side-step an ordinary procurement

    task to swap 14v equipment out in favor of 28v

    equipment.



    I suspect there are few if any folk who have

    implemented the equalized split battery architecture

    to achieve a quasi-dual voltage system. My only

    experience with a tapped battery scheme involved

    a pusher design that needed electric augmentation

    of cooling on the ground. The builder ran a pair

    of 14v fans off the top battery . . . another

    pair on the bottom battery.



    Unfortunately, the airplane crashed before

    the wisdom of the experimental architecture could

    be evaluated.



    You're a the leading edge of the investigation

    for what you've proposed. Were it my airplane, I

    would swap the parts out and stay with an all

    28v system.



    Bob  . . .     [quote][b]

- 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

dfritzj(at)yahoo.com
Guest

Posted: Tue Dec 29, 2009 3:53 pm Post subject: Battery Equalizers

Bob et al,

I appreciate the architecture advice and will take it into consideration.  Unfortunately, I'm on a work-driven building hiatus that'll probably keep me from doing any work on the Velocity for at least a couple years, so I won't be able to give any solid feedback on the usefulness of a battery equalizer in this setup for a while.  In the meantime, I can do a quick trade study to look at the cost and parts count between the multiple bus setup and replacing the hydraulic power pack and associated control circuits.



I don't know if you looked at the link to the white paper in my previous post or not, but in it the author shows significant experimental improvement in battery life using an equalizer in a series string of batteries.  As I need a 24V system in my aircraft anyway and will be using two batteries in series, it makes  sense to me to take advantage of these improvements if in fact the claims are true.  Have you (or anyone on the list) looked at the white paper and/or have any knowledge or experience in the use and efficacy of these equalizers (regardless of whether I keep my multi-bus setup or not)?



Thanks,

Dan



         [quote][b]

- 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

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Jan 05, 2010 3:30 pm Post subject: Battery Equalizers

 	  Quote: 	
		  	
At 05:26 PM 12/29/2009, you wrote:

 Bob et al,

 I appreciate the architecture advice and will take it into consideration.  Unfortunately, I'm on a work-driven building hiatus that'll probably keep me from doing any work on the Velocity for at least a couple years, so I won't be able to give any solid feedback on the usefulness of a battery equalizer in this setup for a while.  In the meantime, I can do a quick trade study to look at the cost and parts count between the multiple bus setup and replacing the hydraulic power pack and associated control circuits.



 I don't know if you looked at the link to the white paper in my previous post or not, but in it the author shows significant experimental improvement in battery life using an equalizer in a series string of batteries.  As I need a 24V system in my aircraft anyway and will be using two batteries in series, it makes sense to me to take advantage of these improvements if in fact the claims are true.  Have you (or anyone on the list) looked at the white paper and/or have any knowledge or experience in the use and efficacy of these equalizers (regardless of whether I keep my multi-bus setup or not)?



    Dan,



    The IDEAL equalizer will, no doubt, make the 12v tap

    on a 24v battery look transparent to the rest of

    the system . . . including batteries.



    By "ideal" we mean equalizers that are about as

    capable as the batteries themselves . . . very

    low impedance and capable of carrying what ever

    loads are imposed at the tap. 



    As soon as you choose an equalizer smaller than

    anticipated loads, then the lower battery MUST

    make up the difference. Yes, it's just for a short

    time and the too-small equalizer will fix things

    back up once the loads go away. Nonetheless, this 

    means that the bottom half of the battery is

    treated differently than the top half.



    Terrible thing to do? Don't know. I have no experience

    with it in the distinctly aviation environment

    where batteries are protected against deep cycle

    and monitored for minimum capacity. How does one

    integrate a less than idea equalizer into the

    battery maintenance protocols?



    My gut feeling is that you'll be happier in the long

    run with a conversion of your 14v hardware to 28v 

    hardware and forget the equalizer. But should you

    choose to conduct this experiment, you will become

    the go-to guy for guidance on how good an idea it

    is.



    Bob . . .

        [quote][b]

- 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

dfritzj(at)yahoo.com
Guest

Posted: Sat Jan 09, 2010 2:05 pm Post subject: Battery Equalizers

Thanks Bob,As I mentioned, it'll be a while before I can get back to work on the Velocity, but when I do, I'll report whether I decide to maintain the center-tap scheme or not and how well it works if I do.

Dan



           [quote][b]

- 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

nuckolls.bob(at)aeroelect
Guest

Posted: Sat Jan 09, 2010 5:17 pm Post subject: Battery Equalizers

At 03:16 PM 1/9/2010, you wrote:

 	  Quote: 	
		  Thanks Bob,

As I mentioned, it'll be a while before I can get back to work on 

the Velocity, but when I do, I'll report whether I decide to 

maintain the center-tap scheme or not and how well it works if I do.


	


   Very good! Hope your project doesn't

   have to languish too long!



        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

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