Balancing for A123 cells  
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All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> A123Racing Support >> Balancing for A123 cells
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Balancing for A123 cells - 8/14/2007 10:56:39 PM   
dcnpaulk


 

Posts: 10
Joined: 5/30/2007
From: New Milford, NJ, USA
Status: offline 		I would like to know how ESSENTIAL balancing of cells is for an A123 pack. Now I assume that it would always be NICE to do, but how necessary is it? Since A123 cells don't have the tendency toward spectacular self-immolation that LiPos do, is it more a matter of efficiency than safety? I have read some statements that A123's are quite stable and do not get out of balance enough to worry about. OTOH, the deWalt packs have some cell management system built in which I assume is some sort of balancing. A123 racing charger has built-in balncing in their charger, as do the new FMA chargers. So how important is it? Brian or anyone?

Paul K.
       Post #: 1

RE: Balancing for A123 cells - 8/15/2007 4:11:17 PM   
A123 Racing


 

Posts: 101
Joined: 8/25/2006
From: Hopkinton, MA, USA
Status: offline 		Hello Paul,

This is a tough question to answer.

There certainly is an advantage to balancing on every charge, this is why the Sonic Charger always balances. The advantages are:

Optimal Performance (Each cell will be charged to its required voltage, yielding optimal capacity)
Optimal Cycle Life (The cells have all be charged properly and they are not abused. Cell abuse will decrease cycle life)
Safety (Without balancing there is a much greater risk of cell failure do to extreme unbalance)

I would recommend that anyone using a pack without a balancing charger follow the guidelines below.

1. Charge and Balance the pack you are using, either manually or with a balancing module. Use a volt meter to ensure that it balanced properly.
2. Use the pack in your vehicle (whatever that may be) until end of discharge (recommended 2.0V / cell cutoff)
3. Charge the pack again and check the balance of the pack with a volt meter. It is important to check the balance of a pack when it is near 3.6V/cell. Due to the flat discharge curve of our batteries state of charge is extremely difficult to analyze below 90% charged.
4. If the pack is still balanced then you can proceed with some more cycles. It is recommended to repeat these steps at 5, 10, and 20 cycles, assuming the pack stays balanced. This should give you an idea on how often you need to balance.
5. If the pack is still balanced at the end of the 20th cycle and at least every other 20th cycle. This will help prevent future divergence.

Please let me know if you have any other questions.

Power . Safety . LiFe

Brian



(in reply to dcnpaulk)
       Post #: 2

RE: Balancing for A123 cells - 8/20/2007 2:03:01 AM   
Night_prowler26



Posts: 1061
Joined: 3/11/2003
From: PowderSprings, GA, USA
Status: offline 		We use them and all tho most time we do Balance them it is not a need to, we do cause we have the equipment do to it, I myself never balance them when charge them I have a 4 cell pack i have been flying in a plane. only time it gets balanced is when My father charges it. even then its always in perfect balance

_____________________________

Mini Edge 540,BP Edge 540 profle ,MST, E rustler ,With DX2.0. /GF"S-E Pede, Blade CX,Slow stick A123 Batts all the way!

(in reply to A123 Racing)
       Post #: 3

RE: Balancing for A123 cells - 9/6/2007 5:27:18 PM   
closetguy


 

Posts: 746
Joined: 7/5/2004
From: berlin hts, OH, USA
Status: offline 		i need to know where i can get the balance charge lead for the Sonic charger.i bought four cells and going to make the packs up.i did not know this before hand or else i would have bought the pre made packs instead. i am new to this hitec battery stuff so go easy.
ENJOY!

(in reply to Night_prowler26)
       Post #: 4

RE: Balancing for A123 cells - 9/8/2007 1:22:19 AM   
everydayflyer



Posts: 890
Joined: 8/21/2005
From: Buchanan, GA, USA
Status: offline 		A 123 Racing sells the balancing leads.

I build my packs from DeWalt cells. Presently I have 2-3S / 5 -4S / and 2- 5S. most have balancing leads either Poly Quest or thunder Power however they reall do not get much out of balance.

Some of the Heli flyer using 20S packs never add balancing leads.

Charles

< Message edited by everydayflyer -- 9/8/2007 1:26:53 AM >

(in reply to closetguy)
       Post #: 5

RE: Balancing for A123 cells - 9/8/2007 1:26:15 AM   
Red Scholefield



Posts: 4743
Joined: 12/8/2001
From: Newberry, FL, USA
Status: offline 		If you make up your own packs put on FMA CellPro balancing plugs and go with the CellPro charger - great combination. Been using one for over a year now and am still getting 95% capacity after 160 cycles.

_____________________________

Red S. AMA 951
R/C Battery Clinic
www.rcbatteryclinic.com

(in reply to everydayflyer)
       Post #: 6

RE: Balancing for A123 cells - 10/12/2007 5:42:42 PM   
Rate1



Posts: 499
Joined: 7/19/2004
From: Stockholm, SWEDEN
Status: offline 		How to know when it is time to land before an A123 RX pack is about to give in (depleted)? Purhaps a stupid question, but I am all new to this and just read that A123 packs keeps current just untill depleted then it just drops very fast.

_____________________________

<--- This is my dog, Capt Morgan, and he has propably more flight hours than you.

(in reply to Red Scholefield)
       Post #: 7

RE: Balancing for A123 cells - 10/12/2007 6:08:39 PM   
everydayflyer



Posts: 890
Joined: 8/21/2005
From: Buchanan, GA, USA
Status: offline 		Time your flights.

You could use a higher LVC but then it may be triggered prematurly under a WOT burst.

I tried 2.5 to 2.0 volts per cell in 0.1V steps and gave up. I use 2.0 now on most things and even 1.6 per cell at times.

Charles

(in reply to Rate1)
       Post #: 8

RE: Balancing for A123 cells - 10/12/2007 6:12:30 PM   
Rate1



Posts: 499
Joined: 7/19/2004
From: Stockholm, SWEDEN
Status: offline 		ok, sounds easy enough. But this still leaves some guessing and rule of thumb over it.

LVC??? Sorry but I am a forigner..., what does that mean?

< Message edited by Rate1 -- 10/12/2007 6:13:46 PM >

_____________________________

<--- This is my dog, Capt Morgan, and he has propably more flight hours than you.

(in reply to everydayflyer)
       Post #: 9

RE: Balancing for A123 cells - 10/12/2007 9:02:06 PM   
everydayflyer



Posts: 890
Joined: 8/21/2005
From: Buchanan, GA, USA
Status: offline 		LVC Low Voltage Cutoff. As in where the ESC tells the motor to stop and save power for the receiver and servos.

I doubt he has more flight hours than I unless he was abanded in a cargo hole.

I have logged more than 18 flight hrs. on on aircraft in the past 20 days and that is only one of the 3 I have been flying durning that time frame.
First statrted flying R/C in 1963.

(in reply to Rate1)
       Post #: 10

RE: Balancing for A123 cells - 10/12/2007 9:07:23 PM   
Rate1



Posts: 499
Joined: 7/19/2004
From: Stockholm, SWEDEN
Status: offline 		Cool...

Myself are looking for the best bang for the buck RX pack for my Extra 300 kit 25%. OS 200-FS on soft mount, 6 digital servos where 5 is high torque. Est weight 11,5 lbs 72" wingspan. I plan to run them on 6V and have 5 Amps into RX.
This is my biggest plane so far and have alot to learn and figure out inorder to equip it right and good. I am trying to save as much weight as possible but still have enough capacity for a days flying.
In my research I found these A123 and obviosly it sounds intresting.

Where to get these A123 custom made though? I guess I would need a pack with 18g lead and deans connector.

< Message edited by Rate1 -- 10/12/2007 9:09:49 PM >

_____________________________

<--- This is my dog, Capt Morgan, and he has propably more flight hours than you.

(in reply to everydayflyer)
       Post #: 11

RE: Balancing for A123 cells - 10/13/2007 12:04:12 AM   
everydayflyer



Posts: 890
Joined: 8/21/2005
From: Buchanan, GA, USA
Status: offline 		http://bigerc.com/index.php?cPath=21&osCsid=d1a2834d30b5078a7deb3e6cdb591c65

(in reply to Rate1)
       Post #: 12

RE: Balancing for A123 cells - 10/13/2007 2:54:28 AM   
Rate1



Posts: 499
Joined: 7/19/2004
From: Stockholm, SWEDEN
Status: offline 		Cheers...

_____________________________

<--- This is my dog, Capt Morgan, and he has propably more flight hours than you.

(in reply to everydayflyer)
       Post #: 13

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