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parallel batteries on maintainer

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raymondj(at)frontiernet.n
Guest

Posted: Sun Jan 13, 2013 8:47 pm Post subject: parallel batteries on maintainer

I am set up to use 1           maintainer to keep 4-5 or more batteries charged             over the winter.  How can I tell if I've exceeded the capacity of the maintainer?                Will the voltage drop?  How much of the total amperage                       of the charger is available for                         maintaining the batteries?                          One of my charger/maintainers is                           rated 6amps.  I can't imagine any reasonable number                               of batteries needing that much                                 current to be kept                                   topped up.  The batteries are at                                   outside temp                                     (currently below 0deg                                           F). Is this a factor I need to                                           consider?

                                             

                                             Thanks for                                               any information/opinions/warnings.

                                                 

                                                 do not                                                   archive                                                   

                                                    [quote]-- 

Raymond Julian

Kettle River, MN.



"And you know that I could have me a million more friends,

and all I'd have to lose is my point of view." - John Prine [b]

bobnoffs

Joined: 04 Jul 2012
Posts: 132
Location: northern wi.

Posted: Mon Jan 14, 2013 4:37 am Post subject: parallel batteries on maintainer

my experience in my cild barn last winter is that it works poorly or not at all. i think it is because one marginal battery always calls for power and the others don't get the right voltage. anyway, this year i bought a bunch of harbor frt. maintainers and every battery gets its own.

  bob noffs

 n. wi.

On Sun, Jan 13, 2013 at 10:46 PM, rayj <raymondj(at)frontiernet.net (raymondj(at)frontiernet.net)> wrote:

 [quote]                    I am set up to use 1           maintainer to keep 4-5 or more batteries charged             over the winter.  How can I tell if I've exceeded the capacity of the maintainer?                Will the voltage drop?  How much of the total amperage                       of the charger is available for                         maintaining the batteries?                          One of my charger/maintainers is                           rated 6amps.  I can't imagine any reasonable number                               of batteries needing that much                                 current to be kept                                   topped up.  The batteries are at                                   outside temp                                     (currently below 0deg                                           F). Is this a factor I need to                                           consider?

                                             

                                             Thanks for                                               any information/opinions/warnings.

                                                 

                                                 do not                                                   archive                                                   

                                                     	  Quote: 	
		  -- 

Raymond Julian

Kettle River, MN.



"And you know that I could have me a million more friends,

and all I'd have to lose is my point of view." - John Prine 



ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List

tp://forums.matronics.com

_blank">http://www.matronics.com/contribution



	


[b]

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Jan 14, 2013 5:57 am Post subject: parallel batteries on maintainer

At 10:46 PM 1/13/2013, you wrote:

  	  Quote: 	
		  I am set up to use 1 maintainer to keep 4-5 or more batteries charged over the winter.  How can I tell if I've exceeded the capacity of the maintainer? 	


   Not possible to do with batteries that are capable of

   being maintained.  A smart charger-maintainer (SCM) has

   two phases of operation (1) top off the battery's state

   of charge and (2) support the battery at a voltage just

   above the open-terminal voltage for the battery in

   storage. The 'effort' required to do (1) has some battery

   size issues associated with it. Obviously, a maintainer

   with a 1 amp charge rate will take longer to top off a

   32 a.h. battery than for a 17 a.h. battery.



   Once top-off is achieved, the SCM will switch output

   voltage to some level too LOW to deliver a practical

   charge to a battery but just HIGHER than the battery's

   normal open circuit resting voltage. For the SVLA battery,

   OCV is on the order of 12.8 to 13.1 volts depending

   on room temperature. So a MAINTENANCE voltage on the

   order of 13.2 to 13.5 volts is called for. See:



  http://tinyurl.com/b4td78b



   In the maintenance mode, the LOAD on the SCM is

   equal to the SELF DISCHARGE current built into

   the battery itself. Given the very long self life

   of SVLA batteries, this means that self discharge

   currents are very low.



  	  Quote: 	
		  Will the voltage drop?  How much of the total amperage of the charger is available for maintaining the batteries?  One of my charger/maintainers is rated 6amps.  I can't imagine any reasonable number of batteries needing that much current to be kept topped up.  The batteries are at outside temp (currently below 0deg F). Is this a factor I need to consider? 	


   No and no. At lower temperatures the OCV of the

   battery goes down but the self discharge rate

   goes down too. Here is an excerpt from an essay

   on battery management I found at:



  http://tinyurl.com/bys7ty6



 ---------------------------



 Few batteries do not die a natural death  most batteries are murdered. They are murdered by owners that charge them improperly, cycle them too deeply, let them sit discharged for too long, or store them at too high a temperature. Since our UPS units have built-in controllers and the units are rarely deeply discharged, the primary battery killer is heat.



 Batteries are electrochemical machines. Chemical reactions govern how they work and chemical reactions govern how they fail. Chemical reactions exist within a battery that cause them to discharge just sitting in storage. Other chemical reactions cause them to form crystalline lead sulfate. Both of these reactions are accelerated by temperature according to the Arrhenius equation, which I state in Equation 1.

 Eq. 1 [img]http://s0.wp.com/latex.php?latex=kA+cdot+e-E_aR+cdot+T&bg=ffffff&fg=333333&s=2[/img]  



 [img]cid:.0[/img]



 where  k is the rate of the chemical reaction  
Ea is the activation energy.  
R is the R is the universal gas constant.  
T is the absolute temperature in °K.  
A is a constant.  

 Equation 1 tells us that increasing temperature produces an exponential increase in reaction rate. Let’s examine how this reaction rate affects a battery that appears to just be sitting there  it actually is experiencing an internal chemical reaction that is discharging the battery. I also want to examine a common rule of thumb for electrical engineers.



   A battery at a temperature of T+10 °C self-discharges

  twice as fast as the same battery at a temperature of T. 



 [/b] Is this rule true? If it is true, the customer that I mentioned earlier who stored his batteries at 50 °C would see his batteries discharged in his warehouse within about two and half months. At that point, the sulphation process begins. His batteries were dying right before his eyes.



 ----------------- end of excerpt -----------------



 So the short answer to your question is first place each battery

 in turn on the SCM and allow it to top off. Then place the array

 of batteries in parallel with each other and connected to the

 SCM. Storing the batteries in a cold location is beneficial

 to the general health and well being of the battery's chemistry.

 The number of batteries in the storage array has no practical

 limit.



 

 

   Bob . . .

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nuckolls.bob(at)aeroelect
Guest

Posted: Mon Jan 14, 2013 6:04 am Post subject: parallel batteries on maintainer

At 06:35 AM 1/14/2013, you wrote:

my experience in my cild barn last winter is that it works poorly or 

not at all. i think it is because one marginal battery always calls 

for power and the others don't get the right voltage. anyway, this 

year i bought a bunch of harbor frt. maintainers and every battery 

gets its own.



  bob noffs



   The bit I just posted on the use of a single maintainer

   for an array of batteries assumes that the batteries are

   capable and worthy of maintenance. In other words, the

   candidates for storage are reasonably well known for

   their state of useful capacity. A battery that is damaged

   and in need of recovery (suffers from light, short term

   sulphation) needs to be attended to and tested for useful

   capacity before adding it to an array of batteries already

   know to be worthy of retention in anticipation of future

   service.



   A battery badly sulphated is not recoverable. Placing

   crippled batteries in parallel with topped-off, good

   batteries will degrade if not negate the benefits of the

   maintenance mode.

   Bob . . .

raymondj(at)frontiernet.n
Guest

Posted: Mon Jan 14, 2013 9:10 am Post subject: parallel batteries on maintainer

raymondj(at)frontiernet.n
Guest

Posted: Mon Jan 14, 2013 9:40 am Post subject: parallel batteries on maintainer

Greetings Bob Noffs,

             

             I bought 6+ of the HF battery maintainers and was planning on                   doing the same thing.  In the process I started looking at the voltage provided by them and was surprised to find that NONE of the                       units I had provided more than                         about 12.75 volts.  Some were as                           low as 12.4.  As I understand the process it is necessary to provide a voltage higher than the OCV to                               the battery in order to                                 offset the internal process.  My conclusion is that                                     the maintainers would only keep the                                     batteries charged to a level which                                         would result in                                           an OCV lower                                             that the maintainer voltage                                           and less then 100% charge.                                                Given that the maintainer                                               I'm now using                                                 is at 13.5 volts in maintenance                                                   mode I                                                     don't think 12.75 or                                                     less is                                                       acceptable for                                                       maintaining                                                         my batteries.

                                                         

                                                         

                                                         Just                                                           my experience,                                                           hope you find                                                           it useful.                                                                                           

                   	  Quote: 	
		  Raymond Julian

Kettle River, MN.



"And you know that I could have me a million more friends,

and all I'd have to lose is my point of view." - John Prine 	
       On 01/14/2013 06:35 AM, bob noffs wrote:

     

     [quote]       my experience in my cild barn last winter is that it works         poorly or not at all. i think it is because one marginal battery         always calls for power and the others don't get the right         voltage. anyway, this year i bought a bunch of harbor frt.         maintainers and every battery gets its own.

        bob noffs

        n. wi.

         

       

       On Sun, Jan 13, 2013 at 10:46 PM, rayj <raymondj(at)frontiernet.net (raymondj(at)frontiernet.net)>         wrote:

          	  Quote: 	
		              I am               set up to use 1                   maintainer to keep 4-5 or more batteries charged over the winter.  How can I tell                     if I've exceeded the capacity of                       the maintainer?  Will the voltage drop?  How much of the total amperage of the charger is available for maintaining the                                 batteries?  One of my charger/maintainers is                                   rated 6amps.  I can't imagine any                                       reasonable number of batteries                                       needing that much                                         current to be                                           kept topped up.  The batteries                                           are at outside temp (currently below                                             0deg F). Is this                                                   a factor I need to                                                   consider?

                                                     

                                                     Thanks                                                       for any information/opinions/warnings.

                                                         

                                                         do                                                           not archive 

                                                                     	  Quote: 	
		  -- 

Raymond Julian

Kettle River, MN.



"And you know that I could have me a million more friends,

and all I'd have to lose is my point of view." - John Prine 



ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List

tp://forums.matronics.com

_blank">http://www.matronics.com/contribution



	
           

         

	
     [b]

raymondj(at)frontiernet.n
Guest

Posted: Mon Jan 14, 2013 10:07 am Post subject: parallel batteries on maintainer

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Jan 14, 2013 10:23 am Post subject: parallel batteries on maintainer

At 11:39 AM 1/14/2013, you wrote:

 Greetings Bob Noffs,



 I bought 6+ of the HF battery maintainers and was planning on doing the same thing.  In the process I started looking at the voltage provided by them and was surprised to find that NONE of the units I had provided more than about 12.75 volts.  Some were as low as 12.4.  As I understand the process it is necessary to provide a voltage higher than the OCV to the battery in order to offset the internal process.  My conclusion is that the maintainers would only keep the batteries charged to a level which would result in an OCV lower that the maintainer voltage and less then 100% charge.  Given that the maintainer I'm now using is at 13.5 volts in maintenance mode I don't think 12.75 or less is acceptable for maintaining my batteries.



 

 Just my experience, hope you find it useful.   



    I tried a couple of HF devices about 5

    years ago that purported to be smart-charger-maintainers

    but found their performance disappointing. Don't

    recall the details now. I've not tried them again

    since.



    Your note prompted me to take a peek at the two

    Battery Tenders and one Schumacher 1562A charger

    maintainers currently plugged into walls around

    here.



    Batteries not connected but recently topped off

    were running 12.7 to 13.1 at 55F in the wood-shop

    with two other batteries on SCMs were being held

    at 13.4 (Battery Tender) and 13.58 (1562A).



    In the house I have two batteries sitting open

    12.95 and 13.01 and one on a Battery Tender

    at 13.45 volts.



    For the moment, my peronal stable of battery

    maintenance tools seem to be functioning as

    advertised. There's a handful of Schumacher

    products here and perhaps another one coming.

    

    I put a 12 a.h. battery on the cap meter for

    discharge. I'll use the discharged battery to stroke

    one of these chargers and see if they purr, snarl

    or just lay there.



    Thanks for the narrative.



 

   Bob . . .    [quote][b]

raymondj(at)frontiernet.n
Guest

Posted: Mon Jan 14, 2013 10:25 am Post subject: parallel batteries on maintainer

Bob,

         

         Thanks for the very educational reply.               Always appreciate having my                 plans reviewed, rather than                 waiting 'till spring to find out I'm wrong.  

                     

                     Understand the prohibition on                       including crippled batteries in the process.  I                       will be charging the batteries on                         a non maintainer capable charger then checking the OCV 24 hrs                             after the end of charging and will not try                             to maintain batteries which don't show at least 12.9V.

                                 

                                 Thanks                                     again.

                                       	  Quote: 	
		  Raymond Julian

Kettle River, MN.



"And you know that I could have me a million more friends,

and all I'd have to lose is my point of view." - John Prine 	
       P.S.  Matronics doesn't like something in your email when I try to       include it in a reply.

     

      [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Jan 14, 2013 10:28 am Post subject: parallel batteries on maintainer

 	  Quote: 	
		  Understand the prohibition on including crippled batteries in the process.  I will be charging the batteries on a non maintainer capable charger then checking the OCV 24 hrs after the end of charging and will not try to maintain batteries which don't show at least 12.9V. 	


   Sounds like a plan . . .



 

 

   Bob . . .    [quote][b]

skywagon

Joined: 11 Feb 2006
Posts: 184

Posted: Mon Jan 14, 2013 11:23 am Post subject: parallel batteries on maintainer

Hi Ray,

 I also have used the HF cheapie maintainers...maybe a  dozen or so.

  

 I also found that some were either floating at too high or  too low of a voltage.  I believe the ideal is about 13.1 - 13.3 volts in  the maintenance mode.

  

 What I found, at lease in the older units, that the back  plastic plate could be carefully cut loose using an exacto knife or similar to  pop the glue joints.  The simple circuit board contained a small  potentiometer that had a dab of RTV on the pots center wiper.  The glue  could be picked off to the point that the wiper could be adjusted a small  amount.  I found that rotating the center wiper CCW a very small  amount would increase the float voltage & CW to lower.

  

 The final setting of the center wiper can be only  determined after the load battery has stabilized, so it is a bit of a trial and  error.  You could use a load that has a fixed resistance and determine the  final setting much quicker.

  

 Later, I decide to drill a hole in the plastic case that  lined up with the pot.

  

 However, I suspect these Chinese designs change over time  and I do not know if the above steps will work on later versions of the HF  unit....David

  

   

 [quote]   ---

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Jan 14, 2013 11:49 am Post subject: parallel batteries on maintainer

At 01:21 PM 1/14/2013, you wrote:

 Hi Ray,

 I also have used the HF cheapie maintainers...maybe a dozen or so.

  

 I also found that some were either floating at too high or too low of a voltage.  I believe the ideal is about 13.1 - 13.3 volts in the maintenance mode.

  

 What I found, at lease in the older units, that the back plastic plate could be carefully cut loose using an exacto knife or similar to pop the glue joints.  The simple circuit board contained a small potentiometer that had a dab of RTV on the pots center wiper.  The glue could be picked off to the point that the wiper could be adjusted a small amount.  I found that rotating the center wiper CCW a very small amount would increase the float voltage & CW to lower.

  

 The final setting of the center wiper can be only determined after the load battery has stabilized, so it is a bit of a trial and error.  You could use a load that has a fixed resistance and determine the final setting much quicker.

  

 Later, I decide to drill a hole in the plastic case that lined up with the pot.

  

 However, I suspect these Chinese designs change over time and I do not know if the above steps will work on later versions of the HF unit....David



     Good data. One could also hook the device to

     the SCM test rig I just posted. cycle the charger

     into the maintenance mode, drop the bench supply

     to 13.2 volts then adjust the pot for 10 mA of

     current flow into the load.



 

   Bob . . .    [quote][b]

raymondj(at)frontiernet.n
Guest

Posted: Mon Jan 14, 2013 12:46 pm Post subject: parallel batteries on maintainer

Greetings David,

         

         I opened several of of the little black boxes and                 none had anything that was adjustable                   inside.  New design I suppose.  

                     

                     I                           don't have the electronics skills yet to do an                           analysis of the little black box.                              I've just put them away figuring at some                             point I'll design a new black box to attach                                 the 15VAC transformer.  Just one more thing on                                     my list of things to do.

                                                   

                                                   Thanks                                                     for the note.                  

               	  Quote: 	
		  Raymond Julian

Kettle River, MN.



"And you know that I could have me a million more friends,

and all I'd have to lose is my point of view." - John Prine 	
       On 01/14/2013 01:21 PM, David Lloyd wrote:

     

     [quote]                            Hi Ray,

       I also have used the HF cheapie           maintainers...maybe a dozen or so.

        

       I also found that some were either           floating at too high or too low of a voltage.  I believe the           ideal is about 13.1 - 13.3 volts in the maintenance mode.

        

       What I found, at lease in the older units,           that the back plastic plate could be carefully cut loose using           an exacto knife or similar to pop the glue joints.  The simple           circuit board contained a small potentiometer that had a dab           of RTV on the pots center wiper.  The glue could be picked off           to the point that the wiper could be adjusted a small amount.            I found that rotating the center wiper CCW a very small           amount would increase the float voltage & CW to lower.

        

       The final setting of the center wiper can           be only determined after the load battery has stabilized, so           it is a bit of a trial and error.  You could use a load that           has a fixed resistance and determine the final setting much           quicker.

        

       Later, I decide to drill a hole in the           plastic case that lined up with the pot.

        

       However, I suspect these Chinese designs           change over time and I do not know if the above steps will           work on later versions of the HF unit....David

        

                       

       [quote]         ---

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