Capacity & Cycling - What are you getting?  
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All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> Capacity & Cycling - What are you getting?
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Capacity & Cycling - What are you getting? - 12/18/2006 2:38:04 PM   
bob_nj


 

Posts: 3521
Joined: 12/3/2001
From: Vineland, NJ, USA
Status: offline 		My buddy gave me a couple of packs to check out because he said they didn't seem to be up to snuff.
They are relatively new 3300 NiMH's.

I've used 4 different chargers, and five different pieces of discharge equipment to log the results.

I can't get more than 2700 mAh out of them.
We sent them back to the seller, and he insists that his top dollar equipment is getting over 3300?

I've used two different Triton's, a Competition Electronics Turbo 35, and an Ace digital vari charger used to form
charge them after discharging.
I've discharged on the Triton's, Turbo 35, and four different Sirius Test dischargers.


Basically my questions are;

Should new batteries at least put out what they say if treated proplerly?

Are Triton's and the like accurate enough to give me good information?


Thanks and Happy Holidays_bob
       Post #: 1

RE: Capacity & Cycling - What are you getting? - 12/18/2006 4:42:02 PM   
Rodney



Posts: 4997
Joined: 12/8/2001
From: FL
Status: offline 		Are you testing to the same low voltage point the manufacturer is? This is typically 0.9 volts/ cell. Are you discharging at the same current the test are normally made at? This is typically 0.25C or less. Are you doing a slow charge before starting the cycle, this is a 16 hour charge at 0.1C? If not, and you get a lower value than the manufacturer lists, it is not surprising.

(in reply to bob_nj)
       Post #: 2

RE: Capacity & Cycling - What are you getting? - 12/18/2006 5:43:52 PM   
richrd


 

Posts: 803
Joined: 7/18/2005
From: Waterford, PA, USA
Status: offline 		After new batteries are cycled about five times with C/10 16 hrs charge and C/5 discharge to 0.9V they must meet capacity as stated. All my new batteries exceed some I am under the impressions that it’s your test or the batteries have been damaged. Also if the batteries are failing then you will get unpredictable fast charge peaks.
Rich

(in reply to Rodney)
       Post #: 3

RE: Capacity & Cycling - What are you getting? - 12/18/2006 9:24:17 PM   
bob_nj


 

Posts: 3521
Joined: 12/3/2001
From: Vineland, NJ, USA
Status: offline
quote:

I've used two different Triton's, a Competition Electronics Turbo 35, and an Ace digital vari charger used to form
charge them after discharging.


Yes I am form charging them as described above and below.
I was discharging the cells to .9v per cell and the vendor severely chastised me so I went to 1.1 as he recommended.
I'm discharging at C/5

Ask me some questions about my test and I'll explain what and how I am doing it.
I always keep records of what I do, and try to keep things as consistant as possible.

Thanks

(in reply to richrd)
       Post #: 4

RE: Capacity & Cycling - What are you getting? - 12/18/2006 9:41:15 PM   
laryboy



Posts: 723
Joined: 7/16/2003
From: wilmington, MA, USA
Status: offline 		put an ammeter into circuit when discharging to calibrate

(in reply to bob_nj)
       Post #: 5

RE: Capacity & Cycling - What are you getting? - 12/18/2006 11:03:13 PM   
bob_nj


 

Posts: 3521
Joined: 12/3/2001
From: Vineland, NJ, USA
Status: offline 		I used four different chargers, and seven different dichargers.
Can they all be wrong?

My original questions were;

Should new batteries at least put out what they say if treated proplerly?

Are Triton's and the like accurate enough to give me good information?


So,

What are you getting?

(in reply to laryboy)
       Post #: 6

RE: Capacity & Cycling - What are you getting? - 12/21/2006 2:29:51 PM   
pettit



Posts: 2198
Joined: 12/19/2001
From: Durham, NC, USA
Status: offline 		How long and what diameter are the wires on the battery leads and the charger leads?

If they are too long or too small a diameter, (or both!) they may allow an unwanted voltage drop that tells the discharger to stop discharging too early.

That will indicate less-than-full capacity.

Limit the lead length to 6" or so and never try to cycle a battery through a charge switch harness assembly.

There's too many connectors in series that may also cause an unwanted voltage drop.

I use 20 gauge wires, 6" long from the cycler to a connector (gold plated pins here too) and the lead on the battery is no more than 6" long itself.

_____________________________

Dick Pettit
Former Associate Editor, R/C REPORT Magazine
"Where Traditional Quality is a Thing of the Past"

(in reply to bob_nj)
       Post #: 7

RE: Capacity & Cycling - What are you getting? - 12/21/2006 5:17:33 PM   
JPMacG


 

Posts: 1191
Joined: 1/2/2002
From: Ivyland, PA, USA
Status: offline 		I have found that discharge rate affects capacity. Smaller discharge rates give higher capacity than higher discharge rates. Try discharging at C/5 or C/10 and see what you get.

(in reply to pettit)
       Post #: 8

RE: Capacity & Cycling - What are you getting? - 12/21/2006 5:20:04 PM   
Panzlflyer



Posts: 1960
Joined: 2/28/2002
From: Goldsboro, NC, USA
Status: offline 		Most manufacturers specs call for a 500ma discharge rate regardless of capacity...you can look it up at Sanyo or Panasonic for example and see how they arrive at their specs.

(in reply to JPMacG)
       Post #: 9

RE: Capacity & Cycling - What are you getting? - 12/22/2006 3:26:36 PM   
Geistware



Posts: 12946
Joined: 4/9/2002
From: Locust Grove, GA, USA
Status: offline 		A friend of mine had two 3300maH packs that would not come up.
There had a very colorful and graphical package on each cell.
We never got above 2900maH. Use them and enjoy.
I don't think the packs are as good as the Sanyo's that we are accustomed to.

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(in reply to Panzlflyer)
       Post #: 10

RE: Capacity & Cycling - What are you getting? - 12/23/2006 5:09:17 PM   
fossil



Posts: 381
Joined: 1/7/2002
From: Tullahoma, TN, USA
Status: offline 		This is just my experience and my opinion, A lot of it also depends on who makes the packs. Of all the Nimh packs I own if they are made of quality cells, which usually were made by well known companies charged and discharged to and above rated capacity. Every pack that I own that were acquired from lesser known companies ( most were off ebay) were always 300mh to 500mh short of rated capacity when charged & discharged. Most were still within 15% of rated capacity (if they were not I throw them away). That being said and again my opinion I have used these packs to fly some of my aircraft for years with no problems. I always check the voltage of battery with a meter with a load on it after every flight. I guess the old saying you get what you pay for works for batteries also.
fossil

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(in reply to Geistware)
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RE: Capacity & Cycling - What are you getting? - 12/24/2006 1:23:53 PM   
Smiff 24



Posts: 354
Joined: 10/26/2004
From: chatt, TN, USA
Status: offline 		Bob, im pretty basic about batts,but I know youve form charged the batts from your above posts.
but did the original buyer form charge them the first time ? Just wondering !

_____________________________

Hillbilly Racer

(in reply to fossil)
       Post #: 12

RE: Capacity & Cycling - What are you getting? - 12/24/2006 1:30:24 PM   
bob_nj


 

Posts: 3521
Joined: 12/3/2001
From: Vineland, NJ, USA
Status: offline 		I'm pretty sure he did.
When I didn't get veryspecific information here, I posted it elsewhere and got some interesting responses.
Seems that this particular brand has some issues, and nickel metal in general in their experiences tended to lose
capacity rather quickly over short periods of time, and low numbers of cycles.

General consensus was that this is the nature of the NiMH beast with a side note of migration to A123.

I'm not ready to make that switch yet, so I'm pondering my choices for a current need, and passing this info on to
my buddy.

Thanks for the response_bob

(in reply to Smiff 24)
       Post #: 13

RE: Capacity & Cycling - What are you getting? - 1/19/2007 12:21:43 AM   
danimal1965



Posts: 67
Joined: 2/24/2006
From: LILLOOET, BC, CANADA
Status: offline 		I've got a new 4200 smc wc pack and no where in the charge info(paper or website) does it say to form them at 420 mah for 10 hrs. it says charge 200 or 300 seconds(assuming they mean at 6amps) then dis-charge at "35"amps to 5.4volts then peak charge . Would the cells have been formed already(at SMC) being that they are matched? Dan.

(in reply to bob_nj)
       Post #: 14

RE: Capacity & Cycling - What are you getting? - 1/19/2007 8:25:51 AM   
bob_nj


 

Posts: 3521
Joined: 12/3/2001
From: Vineland, NJ, USA
Status: offline 		Those specs sound like racing characteristics. Sometimes the car guys do those kinds of tests to see how they stand
up under race conditions.

What is an smc wc pack?

(in reply to danimal1965)
       Post #: 15

RE: Capacity & Cycling - What are you getting? - 1/29/2007 5:15:59 PM   
danimal1965



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