Discussions

LIPO EXPANSION

Posted by John Spencer on July 9, 2014 at 7:44am

Well, My 8000 MAH lipo has blown up like a balloon...

Put it on the charger, Came back and the charger was flashing and the lipo was blown up like a football..

Can anybody give me a reason this happened or is it just the nature of the beast...

No fire but I'm glad I had it in the bag just the same...

Thanks

JOHN

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Replies

Nico D July 13, 2014 at 10:41am

Probably overcharged. I had a Imax B6AC 50W charger that notriously overcharged my cells to 4.25-4.28. Replaced it with a new charger (same but 80W and not a clone) and it seems to be better (now around 4.18-4.20 per cell). I also recommend using a Hobbyking HK-010 to double check the battery and also to balance it after the fact. Also, always use balance mode and a lower charge rate than the battery suggests. Some batteries might degrade in the capacity and you don't want to overcharge (so a 2200mah i charge at 2A instead of 2.2, and 5000mah at 4.5A). Takes a bit longer but is safer.

Oh and yes, always charge in a bag or somewhere away from combustibles.
Quadzimodo July 9, 2014 at 9:14pm

John - what voltage did you discharge the battery to prior to expansion? I have puffed two cells, both by over-discharge (drawing 3S turnigy lipo down to ~9.9VDC). I make sure I am out of the air before any of the cells (I monitor each cell, not just the series total) reach 3.3VDC (under load). I have had no issues, but countless cycles since.
Dave July 9, 2014 at 9:53am

I have the same charger and charge mode is different then balance mode. Charge mode does not monitor the cells only the total. You should always charge in balance mode. Only use charge mode for a single cell lipo.
- nickthecook > Dave July 9, 2014 at 9:56am
  
  Thanks Dave. Good to know.
Admin

Thomas J Coyle III July 9, 2014 at 7:51am

@John,

What brand of LiPo and what brand is the charger?

Sounds like either the charger overcharged the LiPo or the LiPo has one or more defective cells in it.

Regards,

TCIII ArduRover2 Developer
- John Spencer > Thomas J Coyle III July 9, 2014 at 8:00am
  
  It's a Zippy Flightmax...
  
  Guess I'll be buying a new charger..Too...Isn't the charger supposed to shut down once the battery is charged ?
  
  Damn...Can't trust anything these days..
  
  John
  - Admin
    
    Thomas J Coyle III > John Spencer July 9, 2014 at 8:08am
    
    @John,
    
    Was the charger being used in the balance mode or just the charge mode?
    
    Regards,
    
    TCIII ArduRover2 Developer
    - nickthecook > Thomas J Coyle III July 9, 2014 at 9:30am
      
      Just out of curiosity, Thomas, what would be the difference here? Both modes should stop charging when the battery voltage reaches the max you've configured it to charge, right?
      
      For example, I charge my 3300mah 3S batteries at 3.3A, and the charger stops when it gets to 12.6V or so.
      - Admin
        
        Thomas J Coyle III > nickthecook July 9, 2014 at 10:51am
        
        @nickthecook,
        
        I prefer to have balanced cells when charging and it takes longer than just a non-balanced charge. The balanced charge is supposed to put the same voltage on each cell at the end of the charge cycle.
        
        My four port charger will allow me to do an unbalanced or balanced charge on my LiPos. I always use the balanced charge.
        
        Regards,
        
        TCIII ArduRover2 Developer
      - Rob Dunbar > nickthecook July 9, 2014 at 9:44am
        
        With non balanced charge If you have one go bad the charger will still try to put 12.6 volts into your battery. If the a cell shorted then 12.6 volts will go to the remaining two cells with 6.3 volts each. Better chargers even though not using balance charge do monitor each cell if you use the balance charge port. I know my cheap Turnigy chargers don't let me charge a lipo unless the balance charger and main connector are both connected.