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  1. #1
    RC Racer
    Join Date
    Dec 2009
    Posts
    111

    lipo swell/puff question

    I have a couple of older hardcase lipos 2 different brands....I always balance charge and use cuttoff. I race one night per week not bash so they have never come close to running low. I also do not charge a battery more than once a day.

    I have a couple of my oldest lipos starting to puff or swell very slightly. They balance fine and run fine but if I compare it to a new battery the side profile has a slight rounded appearance. Less than an 1/8" but I noticed the new ones are perfectly flat and the older ones have a very slight rounded profile.

    I looked at a few soft lipos fom other guys at the track and they appear to be the same swelling on the older soft pack lipos vs the newer ones.

    Is this normal?
    Emaxx,E-Revo,4x4 Slash,2-Blitz's,Firestorm,Mini T

  2. #2
    RC Qualifier
    Join Date
    Mar 2009
    Posts
    984
    Mine seem to get like that after awhile, but I haven't had any issues with them whatsoever. They aren't puffed to where they're under pressure or 'tight', just the cell 'bags' aren't sucked completely tight against the cells anymore like on a brand new pack.
    Last edited by sfr4x4; 09-03-2010 at 05:06 PM.

  3. #3
    RC Racer
    Join Date
    May 2010
    Location
    Nebraska
    Posts
    148
    Same here. I have experienced that same slight swelling now that my packs are older. They still haul the mail....so I am not too worried.

  4. #4
    RC Champion
    Join Date
    Sep 2008
    Posts
    2,316
    from what i was told by a manufacturer, it just means the battery is reaching the end of its useful life, and should be replaced soon. as time passes the battery will continue to lose voltage. also, when they start to swell, they become more prone to venting or worse.
    Last edited by BashHappy; 09-03-2010 at 11:53 PM.
    Giving the E-Revo long overdue love and affection

  5. #5
    Marshal ksb51rl's Avatar
    Join Date
    Nov 2006
    Location
    Northern NJ
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    20,529
    ...I always balance charge and use cuttoff. I race one night per week not bash so they have never come close to running low. I also do not charge a battery more than once a day...
    That all seems good, even if limiting to one charge a day isn't really necessary. However, there's another cause to the slight puffing, and that is leaving LiPo batteries fully charged for extended periods of time (like more than a couple days.) As the battery capacity and C-rating climb higher, it seems that the batteries are getting more sensitive, much like what happened with NiMH packs. I suggest keeping LiPo packs at a storage-voltage level (about 3.7 volts per cell) whenever they're not to be used immediately. For long-term storage, I'd use a value of 3.5 volts per cell. I'd also never let them discharge past a resting voltage of 3.2 volts per cell.
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