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Odyssey % of charge

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rparigor(at)SUFFOLK.LIB.N
Guest

Posted: Tue Feb 14, 2006 12:27 am Post subject: Odyssey % of charge

If the charging system is not working does anyone have an approximate % of

remaining capacity versus voltage for a Odyssey PC680 or similar?



What is a safe lower voltage limit one can discharge a PC680 to and not

cause permanent battery damage?



Thx.

Ron Parigoris

alexpeterson(at)earthlink
Guest

Posted: Tue Feb 14, 2006 4:53 am Post subject: Odyssey % of charge

 	  Quote: 	
		   

 

 If the charging system is not working does anyone have an 

 approximate % of remaining capacity versus voltage for a 

 Odyssey PC680 or similar?

 

 What is a safe lower voltage limit one can discharge a PC680 

 to and not cause permanent battery damage?

 

 Thx.

 Ron Parigoris


	


Go to their website, there is a complete pdf for downloading.



Alex Peterson

RV6-A N66AP 714 hours

Maple Grove, MN

nuckollsr(at)cox.net
Guest

Posted: Wed Feb 15, 2006 5:12 am Post subject: Odyssey % of charge

At 08:22 AM 2/14/2006 +0000, you wrote:



 	  Quote: 	
		  



If the charging system is not working does anyone have an approximate % of

remaining capacity versus voltage for a Odyssey PC680 or similar?



What is a safe lower voltage limit one can discharge a PC680 to and not

cause permanent battery damage?


	


    I guessing . . . but when most folks ask this question,

    the goal is to deduce some sense of how long the battery

    will run certain pieces of equipment given it's present

    state of charge.



    Keep in mind that voltage versus capacity deductions are

    only valid for a battery that is not loaded. Further the

    numbers are only approximate and most valid after the

    battery has been sitting static (neither loaded nor

    charged) for hours.



    Finally, any deductions you might make for endurance must

    be guided by knowing the battery's present CAPACITY as

    well. Knowing the voltage alone is like driving an

    unfamiliar vehicle with a gas gage calibrated as

    E - quarter - half - three quarters - Full. You have

    some sense of percentage of fuel remaining but without

    knowing the capacity of the tank, there's no way to

    deduce range and present rate of consumption.



    Know that ALL lead-acid technologies are 95% used up

    at 11 volts for a 12-volt battery. See:



http://www.aeroelectric.com/Pictures/Curves/Capacity_vs_Voltage.gif



    This is a curve for a big biz jet battery where we see

    that for "light" loads (1 to 2x of capacity), the discharge

    voltage has a sharp "knee" that increases the negative

    going slope as it crosses 11v/22v line.



    This particular battery is capacity rated at CC levels

    of discharge i.e., it's a 37 a.h. battery that will give

    100% of rated capacity at 74 amps of discharge (typical

    for rating bizjet batteries that have a 30 minute emergency

    requirement). If one were to discharge this battery like

    most of the rest of the industry does (20 hour rate) then

    it would probably exhibit a capacity on the order of

    50 ampere-hours.



    Check out this curve from the datasheet on a Panasonic

    33 a.h. battery:



http://www.aeroelectric.com/Pictures/Curves/LA1233_Panasonic.gif

    Again, note the shape knee in the curve as it dives

    through 11 volts . . . all used up. In this case, the

    battery is not specifically rated for emergency power

    service in airplanes - it couldn't be called a

    33 a.h. device. If we run up the 30-minute line to

    11 volts, we find that the battery would have to be

    rated as a 26 a.h. device if intended for that kind

    of service.



    The only way to KNOW how long your battery will perform

    certain duties during alternator out operations is to

    track the battery's capacity. I.e., load it with the

    anticipated endurance loads and see how long it takes

    to get down to 11.0 volts. I'm guessing this is the number

    you were hoping to deduce with the answer to your original

    question. A pure voltage measurement is not a useful

    anticipator of performance when the alternator is off

    line.



    Bob . . .

nuckollsr(at)cox.net
Guest

Posted: Fri Feb 24, 2006 6:21 am Post subject: Odyssey % of charge

At 05:30 AM 2/24/2006 -0800, you wrote:



 	  Quote: 	
		  



Robert L. Nuckolls, III wrote:



 >     HERE'S THE POT HOLE - THE 30 MINUTE DISCHARGE CURVE

 >     OF 26.4 AMPS SAYS THE CAPACITY IS 26.4A X 0.5 HOURS

 >     OR 13.2 A.H., NOT 26 A.H.

 >

 >     I SHOULD HAVE CAUGHT THAT . . . A 33 TO 26 REDUCTION

 >     IN APPARENT CAPACITY FOR A 15X LARGER DISCHARGE

 >     RATE DIDN'T RAISE THE FLAGS. FOUND IT WHILE ARCHIVING

 >     THE POST.



Welcome to Peukert's exponent. If you know the capacity at two different

discharge rates you can interpolate or extrapolate the capacity off the

battery at other discharge rates.


	


   Yeah . . . sorta. I'm working on that question along with the

   notion that owning one of those super-charge-all smart battery

   chargers is a good thing to do to. I'll give you all a forecast

   on present findings:



   An $80 smart charger and $??$ capacity meter are not well suited

   to our ultimate design goals (1) know that the battery is mission

   capable every time we walk up to the airplane and (2) have tools

   requiring minimum expense and user time/attention to track that

   capability. None of the devices I cited above do a very good job

   of meeting those goals. An article on alternative hardware proposals

   is in the works.



   Bob . . .

      < What is so wonderful about scientific truth...is that >

      < the authority which determines whether there can be   >

      < debate or not does not reside in some fraternity of   >

      < scientists; nor is it divine. The authority rests     >

      < with experiment.                                      >

      <                            --Lawrence M. Krauss       >

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Fri Feb 24, 2006 7:15 am Post subject: Odyssey % of charge

Robert L. Nuckolls, III wrote:



 	  Quote: 	
		      An $80 smart charger and $??$ capacity meter are not well suited

    to our ultimate design goals (1) know that the battery is mission

    capable every time we walk up to the airplane and (2) have tools

    requiring minimum expense and user time/attention to track that

    capability. None of the devices I cited above do a very good job

    of meeting those goals. An article on alternative hardware proposals

    is in the works.


	


Having a smart energy monitor is necessary in a system where you will

have irregular charge/discharge cycles and want to know how much is left

in the battery. If you always recharge the battery to full every time,

you can have a much simpler energy monitor that isn't quite so smart.



The biggest issue as I see it is that you need to make sure you don't

overcharge the battery in summer but that you do actually charge the

battery in winter. That implies temperature compensation.



-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

_________________
Brian Lloyd
brian-yak at lloyd dot com
+1.916.367.2131 (voice) +1.270.912.0788 (fax)

I fly because it releases my mind from the tyranny of petty things . . .
- Antoine de Saint-Exupery

william.p.dube(at)noaa.go
Guest

Posted: Fri Feb 24, 2006 9:20 am Post subject: Odyssey % of charge

State-of-charge meters, like the Link-10 

<http://www.xantrex.com/web/id/97/p/1/pt/5/product.asp> add up the 

amp-hrs in and out (in a fancy manner)  to figure the state-of-charge. 

If the battery is damaged or worn out, (or the unit loses track of what 

has happened lately,) the remaining capacity displayed is incorrect.



The high-tech battery testers like 

<http://www.batterymart.com/battery.mv?p=ACC-SB-300>  often use the 

impedance of the battery to judge its health. If you measure voltage, 

current, and temperature, and play them against each other, you can 

estimate the state-of-charge and the health of the battery. This is more 

what you want for an aircraft instrument. The key is measuring impedance 

(along with an estimate of OCV) and comparing it to what had been 

measured before under similar conditions.



Robert L. Nuckolls, III wrote:



 	  Quote: 	
		  



At 05:30 AM 2/24/2006 -0800, you wrote:



  



>

>

>Robert L. Nuckolls, III wrote:

>

>    

>

>>    HERE'S THE POT HOLE - THE 30 MINUTE DISCHARGE CURVE

>>    OF 26.4 AMPS SAYS THE CAPACITY IS 26.4A X 0.5 HOURS

>>    OR 13.2 A.H., NOT 26 A.H.

>>

>>    I SHOULD HAVE CAUGHT THAT . . . A 33 TO 26 REDUCTION

>>    IN APPARENT CAPACITY FOR A 15X LARGER DISCHARGE

>>    RATE DIDN'T RAISE THE FLAGS. FOUND IT WHILE ARCHIVING

>>    THE POST.

>>      

>>

>Welcome to Peukert's exponent. If you know the capacity at two different

>discharge rates you can interpolate or extrapolate the capacity off the

>battery at other discharge rates.

>    

>



   Yeah . . . sorta. I'm working on that question along with the

   notion that owning one of those super-charge-all smart battery

   chargers is a good thing to do to. I'll give you all a forecast

   on present findings:



   An $80 smart charger and $??$ capacity meter are not well suited

   to our ultimate design goals (1) know that the battery is mission

   capable every time we walk up to the airplane and (2) have tools

   requiring minimum expense and user time/attention to track that

   capability. None of the devices I cited above do a very good job

   of meeting those goals. An article on alternative hardware proposals

   is in the works.



   Bob . . .

      < What is so wonderful about scientific truth...is that >

      < the authority which determines whether there can be   >

      < debate or not does not reside in some fraternity of   >

      < scientists; nor is it divine. The authority rests     >

      < with experiment.                                      >

      <                            --Lawrence M. Krauss       >

nuckollsr(at)cox.net
Guest

Posted: Fri Feb 24, 2006 9:27 am Post subject: Odyssey % of charge

At 07:14 AM 2/24/2006 -0800, you wrote:



 	  Quote: 	
		  



Robert L. Nuckolls, III wrote:



 >    An $80 smart charger and $??$ capacity meter are not well suited

 >    to our ultimate design goals (1) know that the battery is mission

 >    capable every time we walk up to the airplane and (2) have tools

 >    requiring minimum expense and user time/attention to track that

 >    capability. None of the devices I cited above do a very good job

 >    of meeting those goals. An article on alternative hardware proposals

 >    is in the works.



Having a smart energy monitor is necessary in a system where you will

have irregular charge/discharge cycles and want to know how much is left

in the battery.


	




    Agreed . . . but how does this happen on an airplane and how

    often might one expect to encounter it?  . . . and are there

    less complicated and more positive ways to achieve the desired

    mission/maintenance conditions?



 	  Quote: 	
		  If you always recharge the battery to full every time,

you can have a much simpler energy monitor that isn't quite so smart.


	


    Yup.

 	  Quote: 	
		  The biggest issue as I see it is that you need to make sure you don't

overcharge the battery in summer but that you do actually charge the

battery in winter. That implies temperature compensation.


	


    Agreed . . . and it's not clear that we have really practical

    ways to achieve that. The LR-3 from B&C offers a battery temp

    sensor option. But it's not clear to me that this option will

    produce really meaningful differences in battery performance for

    most of our fellow airplane drivers.



        Bob . . .



      < What is so wonderful about scientific truth...is that >

      < the authority which determines whether there can be   >

      < debate or not does not reside in some fraternity of   >

      < scientists; nor is it divine. The authority rests     >

      < with experiment.                                      >

      <                            --Lawrence M. Krauss       >

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Fri Feb 24, 2006 12:48 pm Post subject: Odyssey % of charge

Robert L. Nuckolls, III wrote:



 	  Quote: 	
		  > Having a smart energy monitor is necessary in a system where you will

> have irregular charge/discharge cycles and want to know how much is left

> in the battery.

 

 

     Agreed . . . but how does this happen on an airplane and how

     often might one expect to encounter it?  . . . and are there

     less complicated and more positive ways to achieve the desired

     mission/maintenance conditions?


	


Oh, I agree that you don't need a complex energy monitor nor do you need

a fancy charger. OTOH, I have had experience with batteries failing due

to overcharge in hot weather and failing to charge properly in cold weather.



 	  Quote: 	
		  > If you always recharge the battery to full every time,

> you can have a much simpler energy monitor that isn't quite so smart.

 

     Yup.

 

 

> The biggest issue as I see it is that you need to make sure you don't

> overcharge the battery in summer but that you do actually charge the

> battery in winter. That implies temperature compensation.

 

     Agreed . . . and it's not clear that we have really practical

     ways to achieve that. The LR-3 from B&C offers a battery temp

     sensor option. But it's not clear to me that this option will

     produce really meaningful differences in battery performance for

     most of our fellow airplane drivers.


	


I believe that this is one of the key reasons why current crop of

"sealed" AGM aircraft batteries have such a poor service record. Flooded

cell batteries shrug off overcharge by just boiling off excess water

which gets topped off by the owner or mechanic. AGMs build up pressure

in the case and valves open and relieve the pressure, letting the water

go to the atmosphere. The AGM battery, having no excess

electrolyte/water, quickly quits working. I have never had an AGM

battery (Concorde especially) survive longer than two years in a

standard aircraft electrical system.



Brian Lloyd

brian-yak(at)lloyd.com

nuckollsr(at)cox.net
Guest

Posted: Sat Feb 25, 2006 2:46 pm Post subject: Odyssey % of charge

At 12:48 PM 2/24/2006 -0800, you wrote:



 	  Quote: 	
		  



Robert L. Nuckolls, III wrote:



 >> Having a smart energy monitor is necessary in a system where you will

 >> have irregular charge/discharge cycles and want to know how much is left

 >> in the battery.

 >

 >

 >     Agreed . . . but how does this happen on an airplane and how

 >     often might one expect to encounter it?  . . . and are there

 >     less complicated and more positive ways to achieve the desired

 >     mission/maintenance conditions?



Oh, I agree that you don't need a complex energy monitor nor do you need

a fancy charger. OTOH, I have had experience with batteries failing due

to overcharge in hot weather and failing to charge properly in cold weather.



 >> If you always recharge the battery to full every time,

 >> you can have a much simpler energy monitor that isn't quite so smart.

 >

 >     Yup.

 >

 >

 >> The biggest issue as I see it is that you need to make sure you don't

 >> overcharge the battery in summer but that you do actually charge the

 >> battery in winter. That implies temperature compensation.

 >

 >     Agreed . . . and it's not clear that we have really practical

 >     ways to achieve that. The LR-3 from B&C offers a battery temp

 >     sensor option. But it's not clear to me that this option will

 >     produce really meaningful differences in battery performance for

 >     most of our fellow airplane drivers.



I believe that this is one of the key reasons why current crop of

"sealed" AGM aircraft batteries have such a poor service record. Flooded

cell batteries shrug off overcharge by just boiling off excess water

which gets topped off by the owner or mechanic. AGMs build up pressure

in the case and valves open and relieve the pressure, letting the water

go to the atmosphere. The AGM battery, having no excess

electrolyte/water, quickly quits working. I have never had an AGM

battery (Concorde especially) survive longer than two years in a

standard aircraft electrical system.


	


     It would be interesting to put a battery black-box on those

     airplanes. I'm working a design for just such a critter with

     one of my associates at RAC. It's a matchbook sized module that

     installs in the head-space of an AGM battery. For a period of three

     years, it will measure and record battery voltage and temperature

     every 10 seconds.



     When a battery craps in warranty, the owner recycles the battery

     through local channels and sends the 0.5 ounce module back to the factory.

     For batteries out of warranty, the owner gets a discount on a

     new battery if he returns the black-box along with his order.



     I expect this product to yield very revealing data both about

     materials and processes used to craft good batteries along with

     detailed insight into the battery's experience up and until

     the time of failure/replacement.



     This is a desperately needed tool for closing the loop in the

     consumer/supplier relationship for batteries. So much bad blood

     has flowed and much opportunity for improvement lost for lack

     of data. The vast majority of discussions/deductions/accusations

     about battery life has been floobydust from the customers,

     interested observers AND manufacturers. A crapped battery is exceedingly

     difficult to deduce life history from a simple teardown inspection.

     Nobody is deserving of kudos or cabbages because there are no data

     from which understanding can grow.



     Bob . . .

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Sat Feb 25, 2006 3:40 pm Post subject: Odyssey % of charge

Robert L. Nuckolls, III wrote:



 	  Quote: 	
		        It would be interesting to put a battery black-box on those

      airplanes. I'm working a design for just such a critter with

 ...

      This is a desperately needed tool for closing the loop in the

      consumer/supplier relationship for batteries. So much bad blood

      has flowed and much opportunity for improvement lost for lack

      of data. The vast majority of discussions/deductions/accusations

      about battery life has been floobydust from the customers,

      interested observers AND manufacturers. A crapped battery is exceedingly

      difficult to deduce life history from a simple teardown inspection.

      Nobody is deserving of kudos or cabbages because there are no data

      from which understanding can grow.


	


Wow! I haven't heard anyone use the term Floobydust since my days

building analog amps back in the mid '70s.



But I think the battery manufacturers know a lot about how their

batteries live and die. It shouldn't be too hard to understand their

data and apply it to batteries in aircraft.



-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

nuckollsr(at)cox.net
Guest

Posted: Sat Feb 25, 2006 6:47 pm Post subject: Odyssey % of charge

At 06:27 PM 2/25/2006 -0800, you wrote:

 	  Quote: 	

Robert L. Nuckolls, III wrote:

 >      It would be interesting to put a battery black-box on those

 >      airplanes. I'm working a design for just such a critter with

 > ...

 >      This is a desperately needed tool for closing the loop in the

 >      consumer/supplier relationship for batteries. So much bad blood

 >      has flowed and much opportunity for improvement lost for lack

 >      of data. The vast majority of discussions/deductions/accusations

 >      about battery life has been floobydust from the customers,

 >      interested observers AND manufacturers. A crapped battery is 

 exceedingly

 >      difficult to deduce life history from a simple teardown inspection.

 >      Nobody is deserving of kudos or cabbages because there are no data

 >      from which understanding can grow.

Wow! I haven't heard anyone use the term Floobydust since my days

building analog amps back in the mid '70s.

    I think that's a Bob Pease original . . . I didn't hear it until

    I became an avid reader of his monthly columns probably in the

    80's . . . a good term I think for labeling intellectual babble

    masquerading as fact.

 	  Quote: 	
		  But I think the battery manufacturers know a lot about how their

batteries live and die. It shouldn't be too hard to understand their

data and apply it to batteries in aircraft.

   In the lab, yes. Lightbulbs are the same way. I just finished

   a song and dance routine to the FAA hand-cranked organ to subsitute

   #327LSV (25,000 hour) lamps for the #327 (4,000 hr) in some places

   on our airplanes. Seems customers are seeing a few hundreds of

   hours . . . and since the L1011 went into the Everglades a few years

   back, crews are forbidden to diddle with lightbulbs in flight, if at

   all. So the low-life lamps are a serious regulatory dispatch item

   and they're hoping that the better rated lamps will alleviate the

   problem. The question not asked and answered was how lamp cycling

   affects life and can we REALLY expect a 6x increase in lamp life

   with the substitution?

   I think we've made the FAA happy but now I'm starting more tests

   on my own to do some cycle testing with the two part numbers side-by-side

   for relative service life comparisons. I would not be surprised to

   discover performance that falls far short of the customer's (and my

   boss's expectations). At least I might be able to forewarn them as

   opposed to waiting for a followup call from a surprised and unhappy

   customer. If we called GE and asked how long their #327 will last in

   our airplane, they wouldn't have a clue. You call Enersys or Concord

   with the same question, they'd be silly to attempt a considered answer

   because there's no data upon which one might consider. Further, they

   have no idea how you will use/abuse their product.

   I've discussed the battery black-box with a manufacturer who has

   heartily endorsed the idea . . . both as a lowered cost warranty

   adjustment tool but as a device for getting real numbers about

   how their products are treated over LONG periods of time . . . not

   in a laboratory or short term flight test program.

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