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Thread: blackjack 29 batteries getting really hot

  1. #1
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    Default blackjack 29 batteries getting really hot

    I have 2 turnigy 2s 5000mah 20c batteries and 2 hobby people 2s 5000mah 35c batteries and they both get extremely hot and a bit puffy when ever I use them. The motor and esc stay fairly cool. I have traxxas connectors and they are barely warm if warm at all. The only things that get hot are the batteries. What could be causing this and what can I do to fix it?
    thanks

  2. #2
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    Is it the stock prop. That's normally caused from batteries that cant supply the current the motor is trying to use. If they are puffed you want to be careful about using them. Especially under the same conditions that caused them to puff in the first place cause after that comes

  3. #3
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    It's 100% stock.

  4. #4
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    how long are you running it?
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  5. #5
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    4-5 min then let it cool off for like 10. It sucks because I want to run it the whole time not wait and they still get hot. I stay on a plane the whole time too.

  6. #6
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    How amany Mah are you putting back into the batteries? Or what is the voltage of the packs
    "Our society strives to avoid any possibility of offending anyone except God.
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  7. #7
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    it depends how low they run. But on average the charger puts about 4700-5200 it really just depends. I normally run them down to about 3.6v per cell. They charge back up to 4.2v. The hobby people batteries are brand new probably 4 runs on them max. I don't even use the turnigy ones anymore they puffed way to much.

  8. #8
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    are you charging in Parallel?
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  9. #9
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    I have no clue I just plug it into the charger and charge it. Are you talking the cells in 1 battery or are you talking about charging 2 batteries at once?

  10. #10
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    Talking about charging tw0 at once. Because you say you are using 5000mah batteries and putting 4700 to 5200mah back in after a run?
    "Our society strives to avoid any possibility of offending anyone except God.
    Billy Graham

  11. #11
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    ya i charge one at a time. I don't know why but on like the first or second charge it put 5190mah in and after that it does high 4000mah now. yesterday it put in 4600 I believe.

  12. #12
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    you are running them down way to far then. Look in the proboat forum for lots of tuning tips
    "Our society strives to avoid any possibility of offending anyone except God.
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  13. #13
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    yesterday they were ran down to 3.6v per cell.

  14. #14
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    Your over discharging the batteries if your going down to 3.6v per cell, at 3.6v their practically empty. You should not go below 20% left in batteries, you need a minimum of around 3.7v.

  15. #15
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    I don't have a voltage reader. When I put the battery on the charger is when I know what is left in them. What is a sign I should stop running the boat on the batteries?

  16. #16
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    Alright I just got back from running the boat and the turnigy batteries got puffy agian. I just checked the voltage of each cell and the lowest was 3.805v. What is going on that was not ran low enough to puff. Also why isn't the low voltage cutoff kicking in? I have it set on high and it isn't coming on.

  17. #17
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    20c lipo's are not up to the job , those are for cars or planes
    they get probably way under that 3.6 volts under load
    when you get them to the charger and read the voltage they already "restored "themselves from the lowest point (chemical proces )
    you should buy something so that you can read the voltage imidiately after using them, not some time later
    honestly ,i think your lipo's are dead already

    and you should stop before there are significant signs of slowing down!!
    these are lipo's not NiMh !

  18. #18
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    why wouldn't the 20c batteries work? Isn't the boat only pulling around 80 amps, the lipos can give 100 amps cont. each. They should be putting out plenty of power for the situation... I am picking up a voltage reader today so I will test that also. I don't think they are bad either because only one puffs and it goes down to almost normal after it cools, and they charge back up perfectly. It's like the plastic wrap expanded and stretched in the heat and didn't shrink back to the original size completely.
    Thanks for the help guys, I've already learned a lot more.

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  20. #20
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    Why didn't you ask this in the other thread you started about this same subject? Yes those lipos should perform better. Get rid of the traxxas connectors and get some of the new castle 6.5mm connectors.

  21. #21
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    I'm gonna keep the traxxas connectors they barely get warm if not at all. If I convert over I can't use the batteries in my cars.

  22. #22
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    I just got back from running agian. I got a voltage reader. The cells did not get below 3.8v. The lowest was 3.84v. There was no puffing and the batteries ran cooler so I had to of been over running them. The run time was clocked att 5ish min. on the stopwatch. Is that normal for these boats? Seems kind of short to me. What batteries would you guys recommend that would last longer?

  23. #23
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    Yea you want to keep it around 5 min run times when running 2 2s lipos in series for 4s. Get a pair of 4s lipos. You might have to mod the tray's a little bit to get them to fit, but you'll have 4s parallel witch will give you 10000 mah. 10min ish run times. If you go this route you need to make sure you have the boat setup perfect all the way around. Longer run times create more heat so tweak it slightly. Have a look in the proboat forum below. This stuff has all been heavily discussed.

  24. #24
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    Alright thanks, I will definitely look into the 4s setup.

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