new Lipo - WattFlyer RC Electric Flight Forums - Discuss radio control eflight

Batteries & Chargers Discuss Li-P, Li-Ion, NiMh, Nicad battery technology and the chargers that juice 'em up!

new Lipo

Old 04-11-2010, 04:44 AM
  #1  
Gofer303
Member
Thread Starter
 
Gofer303's Avatar
 
Join Date: Aug 2008
Location: Glenwood IA
Posts: 282
Question new Lipo

Today I purchased a Thunder Power Pro Lite V2 Lipo 1350 mAh 2S 7.4v 20c continuous and 40 c burst for my brushless J3 Cub from Park Zone. I have a Eflite 2 to 3 cell lipo charger (eflc3110) and had to get an adapter cable they come in a set of 4 (EFla229).
My question is which adapter cable do I use? there are 4 in the pack only one plugs into the 7.4 volt part of the charger the other 3 are for higher voltage batteries. The one which plugs into the 7.4 port has 3 wires on it and the wires have only 3 terminals hooked up 2 black and 1 red the battery has red blue white and black wires the adapter has 3 wires but it omits the red wire from the battery.That pin is empty. I hook it up to the charger and get the proper led indications and the digital multimeter says it has 7.75 volts on the battery connection. does this seem right i cant find any info on their web sites which explain what cable is the correct one.
thanks for any info in advance
Larry
Gofer303 is offline  
Old 04-11-2010, 12:39 PM
  #2  
mesh
Member
 
Join Date: Mar 2010
Posts: 158
Default

A 2-cell (7.4v) battery needs a balancing lead with three wires. You can visualize it like if two normal AA batteries are placed end to end, + to -. The three cables then connect to the front, middle and back. This is so you can measure and charge each battery individually. A 3-cell battery would then need front-middle-middle-back connections, so 4 wires and so on.

So back to your problem. I see that the Thunder Power batteries weirdly use four wires even on a 2-cell battery. I don't know what the extra wire would be used for, but it should be no problem to leave it unconnected, like the adapter cable does.
Is the last wire even connected to anything in the battery? With your multimeter, check the voltage against the other three leads, just make sure not to short it while measuring.

Oh, and each cell in a lipo has a working voltage of 4.2 to about 3.3 volt, so a 2s battery would be from 8.4 to 6.6 volt, so your battery is about half charged, which is normal.
mesh is offline  
Old 04-11-2010, 01:36 PM
  #3  
Gofer303
Member
Thread Starter
 
Gofer303's Avatar
 
Join Date: Aug 2008
Location: Glenwood IA
Posts: 282
Default

Mesh
that was the info I needed Thanks ! The red wire apparently does nothing as there is no voltage indicated between it and either other contact. There is no voltage when using the red lead on the battery but between the blue, black or white, there is 4.22 volts on each cell when you ignore the red. Strange that the red wire is not used, that is not the way any of my other lipos is wired! must be a system that is their own color coding? Again thanks !!!
Gofer303 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
psychorevo
Batteries & Chargers
86
06-08-2009 12:30 AM
night_life
Batteries and Chargers Forsale/WTB
0
05-11-2009 01:19 AM
d&mrc
Batteries and Chargers Forsale/WTB
7
01-18-2009 06:37 PM
Sam_K
Batteries & Chargers
7
05-02-2008 11:34 PM
admin
Batteries & Chargers
8
01-18-2006 03:00 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Quick Reply: new Lipo


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.

Page generated in 0.05376 seconds with 15 queries