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Old Feb 09, 2008, 07:10 PM
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NY State
Joined Jan 2007
2,833 Posts
I put this together today. It weighs about 180 on my inaccurate kitchen scale. I used quite a lot of tape! Not sure if it's overinsulated, but I doubt it's the end of the world if it is.
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Old Mar 12, 2008, 09:54 PM
D.G.B.
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Southington, Connecticut, United States
Joined Jun 2000
2,951 Posts
Lucien,MANY THANKS TO YOU .I feel more capable to tackle the job of building these packs.Also THANKS TO EVERYBODY who has contributed to this thread.Now off to do some A123 shopping

KOMET44
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Old Mar 20, 2008, 04:01 AM
Never fast enough...
Reman's Avatar
San Diego, CA
Joined Oct 2006
660 Posts
Anyone doing 7S A123 packs? If so, what kind of balancing taps are you using? I currently have 2 6S packs for my T-Rex 600 but Im looking to go with 2 7S packs with Thunder Power balancing taps if possible since I have the 1010C with A123 capability.

My 6S packs have Hyperion taps on them which are useless to me since I havent been able to find an adapter for my TP charger.

A little help?

Also, is anyone using the overcharge method to balance your cells?

http://www.modelelectronicscorp.com/...uct.php?pid=12
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Old Mar 20, 2008, 09:37 AM
Southern Pride
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Haralson County GA. USA
Joined Oct 2004
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http://www.rcgroups.com/forums/showp...2&postcount=65


TP balancing taps on a 7S

http://www.rcgroups.com/forums/showp...2&postcount=35

just one of many balancing solutions listed here

http://www.rcgroups.com/forums/showp...0&postcount=29


Adapters to go from PQ /Hyp. to TP are not that complicated I have made many pf them as I have used TP balancers for close to 3 years and have used PQ balancing connectors even longer.


My latest TP 5S (6 lead) mod. was to fit a Cell Pro 10 and match PQ and TP .

http://www.rcgroups.com/forums/showp...&postcount=381

A good source is Cheapbatterypacks.com


Charles
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Last edited by everydayflyer; Mar 20, 2008 at 09:45 AM.
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Old Mar 20, 2008, 12:34 PM
Never fast enough...
Reman's Avatar
San Diego, CA
Joined Oct 2006
660 Posts
Awesome, THANKS!

One more question...for anyone. Can heat from a soldering iron damage cells? I recently replaced a couple cells (they vented for unknown reason) in one of my 6S packs and after one flight Ive got two more that look bad (reading 2.7V as compared to 3.3 for the rest)

I'm using them in my heli in a 12S config. After 3 minutes the headspeed dropped off rapidly and I brought it down. Packs didnt seem to be excessively hot. But got em home and measured two of the cells at 2.7V. Is that a sign that they have been damaged? They were all at 3.6 before the flight. All the rest of the cells measure 3.3 right now.

BTW, Im using a 60 watt iron and really trying not to get the cell too hot but I really dont know how much is too much...

EDIT: Just charged the pack that seemed to be weak...Put back 1531mah before charger stopped and now I have one cell at 3.6, another at 3.7 and all the rest are at 3.3...does this sound normal?
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Old Mar 20, 2008, 02:29 PM
Southern Pride
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Haralson County GA. USA
Joined Oct 2004
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Quote:
EDIT: Just charged the pack that seemed to be weak...Put back 1531mah before charger stopped and now I have one cell at 3.6, another at 3.7 and all the rest are at 3.3...does this sound normal?
Sonds like a question I answered in another thread.

http://www.rcgroups.com/forums/showp...2&postcount=70
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Old Mar 20, 2008, 02:59 PM
Never fast enough...
Reman's Avatar
San Diego, CA
Joined Oct 2006
660 Posts
Yep, thanks!
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Old Mar 20, 2008, 03:39 PM
Jay Garcia
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Huntsville, AL
Joined May 2006
305 Posts
Has anyone used a 4S pack on something like a 3DHobbyshop Yak54 (47"). Seems like the A123 batteries would work nicely here. I have a Hyperion charger with the dataport so I can add the balancing unit. What rate can you realisticaly charge an A123 cell at? Is 3C really possible without degrading the battery performance?
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Old Mar 20, 2008, 03:43 PM
Southern Pride
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Haralson County GA. USA
Joined Oct 2004
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Some of my A123 fuled aaircraft

http://www.rcgroups.com/forums/showthread.php?t=734064

Extre Flight Yak 54E 4S, 3D hobby Shop Extra 300 4S and sometimes 5S, Sig Fazer 5S, Zero Gravity Pitts Python 5S, MUS 3S.

Forgot the charging rate question.

Within reason as high as your charger will go.
I charge A123 2300 mAh packs at 10 amps. all of the time.
I Zip Charge 3S packs at 15-20 amps. average .
http://www.rcgroups.com/forums/showthread.php?t=747911

Note Zip charged pack has over 400 flights on it now and it is beginning to lose a little capacity..


Charles
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Last edited by everydayflyer; Mar 20, 2008 at 03:54 PM.
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Old Mar 20, 2008, 03:46 PM
p-38
the colony tx
Joined Oct 2007
312 Posts
Quote:
Originally Posted by thermalking
Has anyone used a 4S pack on something like a 3DHobbyshop Yak54 (47"). Seems like the A123 batteries would work nicely here. I have a Hyperion charger with the dataport so I can add the balancing unit. What rate can you realisticaly charge an A123 cell at? Is 3C really possible without degrading the battery performance?
I charge my 4s at 8.0amps all the time.

1airborne
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Old Mar 21, 2008, 09:59 AM
Jay Garcia
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Huntsville, AL
Joined May 2006
305 Posts
I am confused about how the battery balance leads work.

With the batteries being in series and the balance leads hooked to each (+) terminal and one black lead soldered to the end (-) lead, the voltage would go as follows (Assuming a 4S pack)

black to lead 1 -> 3.6V
black to lead 2 -> 7.2V
black to lead 3 -> 10.8V
black to lead 4 -> 14.4V

How do balancers work with each cell independently. It seems that (black to lead 4) balancing would be balancing all four cells, and (black to lead 3) would be balancing 3 cells, etc.

The only way I see this could work logically is that cell 1 would have to balance then cell 2 could be balanced (assuming cell 1 is balanced) and so on and so on. Not sure if I just answered my own question, but any inputs would be appreciated.

Thanks,

-Jay
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Old Mar 21, 2008, 10:20 AM
Go ahead... Build it to crash!
Fuegodeth's Avatar
Conroe, TX
Joined Apr 2007
2,630 Posts
If you are going from the same black to each one, then yes, but lead 4 to lead 3 is pos and neg of a single cell. Lead 3 to lead 2 is the next cell, 2 to 1, and then 1 to black. By using the different wires, there are 4 different circuits with each going to 1 cell. Not sure if that's a good explanation. Hope it helps.
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Old Mar 21, 2008, 10:47 AM
Jay Garcia
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Huntsville, AL
Joined May 2006
305 Posts
That makes sense. I had not thought about the positive lead also belonging to the negative from the adjacent cell. Thanks for the input, I think I understand now.



Quote:
Originally Posted by Fuegodeth
If you are going from the same black to each one, then yes, but lead 4 to lead 3 is pos and neg of a single cell. Lead 3 to lead 2 is the next cell, 2 to 1, and then 1 to black. By using the different wires, there are 4 different circuits with each going to 1 cell. Not sure if that's a good explanation. Hope it helps.
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Old Mar 21, 2008, 11:00 AM
Go ahead... Build it to crash!
Fuegodeth's Avatar
Conroe, TX
Joined Apr 2007
2,630 Posts
Cool,
You are welcome. It's always nice if I can contribute something useful.
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Old Mar 21, 2008, 11:16 PM
Jay Garcia
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Huntsville, AL
Joined May 2006
305 Posts
I just finished disassemling a Dewalt 36V pack, but 3 of the cells in the pack were below 1.0V. I am attempting to revive these cells but I am not sure it will work. I am charging each cell individualy to see how much capacity they will hold. I assume they should take in 2300ma if all is okay. Has anyone out there had packs with low voltage cells, and if so were you able to pull them back to life? The pack I bought was sealed in the original packaging, so I know it never saw any use.
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