Burned out M1 cells  
View related threads: (in this forum | in all forums)

Tower Hobbies
Enter up to 4 keywords or Tower stock numbers
Logged in as Guest



Users viewing this topic: none
  Printable Version
       



All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> A123Racing Support >> Burned out M1 cells
Page: [1]

Login
Message << Older Topic   Newer Topic >>
Burned out M1 cells - 6/19/2008 5:38:45 PM   
dirtybird


 

Posts: 3031
Joined: 1/25/2002
From: Mesa, AZ, USA
Status: offline 		I have recently burned out a number of A123 M1 cells.
I think the cause is overheating due to poor connections.
Has anyone else had this problem?
I have made a couple of pressure type battery holders to avoid soldering to the cells.
       Post #: 1

RE: Burned out M1 cells - 6/19/2008 9:39:43 PM   
everydayflyer



Posts: 932
Joined: 8/21/2005
From: Buchanan, GA, USA
Status: offline 		A123 Racing has always advised against soldering to the cells. They also stated that tabs on DeWalt salvaged cells were to small to solder to without damage to the cells.

Some of us are very skilled at soldering to batteries and most are not . I have soldered to many A123 cells and have purchased and used cells from many DeWalt packs. I have only lost one cell and hat was one of the first four which I purchased from A123 Racing as a developers set long ago. I overdischarged then reversed charged it and it went to zero and stayed there. It cn not be charged past 3 volts and drop like a brick.

You can purchase SPT solderless power tubes from MEC for A123 cells.

Charles



Charles

(in reply to dirtybird)
       Post #: 2

RE: Burned out M1 cells - 6/20/2008 5:30:50 PM   
dirtybird


 

Posts: 3031
Joined: 1/25/2002
From: Mesa, AZ, USA
Status: offline 		SPT solderless power tubes from MEC for A123 cells are a good idea but eight cells make a long tube and its hard to balance the airplane with them.
In my 80" extra I just use the cells as they come after I remove the DeWalt plastic case and the other internal circuitry. I have had no trouble with those cells.
But on the radial engine shown in the other thread I have had to construct the contacts. I have had problems getting a good contact for the current that is required.
I am looking for some kind of a paste to put on the contacts that will enhance the conductivity.
Does anyone know of a compound that will help and where to get it?

(in reply to everydayflyer)
       Post #: 3

RE: Burned out M1 cells - 6/20/2008 9:35:59 PM   
DLS II


 

Posts: 94
Joined: 11/28/2006
From: Rantoul, IL, USA
Status: offline 		Go back to MEC, they sell silver power paste that they use between cells for better conductivity. Have you thought about 2- 4cell spts wired in series? They could be moved around to adjust your cg. Don

(in reply to dirtybird)
       Post #: 4

RE: Burned out M1 cells - 6/21/2008 6:51:26 PM   
dirtybird


 

Posts: 3031
Joined: 1/25/2002
From: Mesa, AZ, USA
Status: offline 		I have now burned out a total of 7 M1 cells.
The last one occured after I had carefully cleaned all contacts and balanced charged all cells to 3.7 volts with a 3 amp Mastic charger.
I ran the pack with a 40 amp load for three minutes. I stopped when the 8s1p pack dropped to 18V.
At the recharge at 7A I heard a pop and saw a puff of smoke from the pack. Scratch 1 more cell.
I guess I just have a bad batch of cells.
I understand there is a strike at the factory in Korea and new cells are currently unavailable. At least that is what MEC told me.

(in reply to DLS II)
       Post #: 5

Page:   [1]
All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> A123Racing Support >> Burned out M1 cells
Page: [1]





Jump to:


Google 



Search | Marketplace | Event Calendar | Local Clubs | Magazine | Product Ratings | New Products | Discussion Forums

Photo Gallery | Member Video Posts | RCU Video Gallery | Instructor Search | Field|Track|Marina Search

Advertisers | Hobby Vendor Resources | Rate Manufacturers | Sign In/Sign Up

SITE MAP!   : :   FORUM RULES

© 2001 - 2007 24-7 RC, LLC, all rights reserved.

Charities we support that also need your help
Yorkie Rescue | Humane Society | ASPCA | Crohn's-Colitis America

Kaango.com Classifieds

0.625RCU1