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  1. #1
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    3s lipo not charging or working right

    Okay guys, I'll try to make this quick and to the point. I tend to be wordy so I'm going to do my best. I have a 3s LiPo SMC battery. I'm not sure how long I've had it. I would say probably at least a year. It's the premium tru-spec. It has a 90c rating. Anyway, this battery used to be pretty good for me, but for a while now it will not charge correctly. If I charge it on normal, it takes a very long time and then after that very long time, it shows a red light that something went wrong. It will charge on the fast option, but the charge does not hold long at all. I would guess that it would last around 10 minutes ish
    I use the Traxxas EZ charger with it. Someone told me to charge it on the 4 amp option, I'm not sure if that's right or not. I think I tried it at the 1 amp charging rate as well, and neither one of them will work They both end up with the red light at the end

    I have left it fully charged before more than a couple of days, but I'm not sure if that would ruin it to this extent or not. With a multimeter, what should be the reading at full charge, and what should be the reading at when it's drained? What's the best way to troubleshoot this issue with this battery?

    Thanks so much

  2. #2
    RC Turnbuckle Jr. Greatscott's Avatar
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    Do you have a lipo checker? If so, what are your cell voltages?
    Submarine Qualified, Chief Inducted, Navy Retired

  3. #3
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    Quote Originally Posted by Greatscott View Post
    Do you have a lipo checker? If so, what are your cell voltages?
    I'm not sure what a lipo Checker is. What I've checked lipos before was with a regular multimeter to see what the voltages were.

  4. #4
    RC Qualifier Myrustlervxl's Avatar
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    what Mah is that battery? I have a 3 s s m c 7200 mah, and I charge it at 1 C which is 7.2 amps. if your battery is more than 4000mah then your charger is not adequate enough.

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  5. #5
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    Quote Originally Posted by Myrustlervxl View Post
    what Mah is that battery? I have a 3 s s m c 7200 mah, and I charge it at 1 C which is 7.2 amps. if your battery is more than 4000mah then your charger is not adequate enough.

    Sent from my SM-G930P using Tapatalk
    The Mah is 5000.

  6. #6
    RC Turnbuckle Jr. Greatscott's Avatar
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    A lipo checker is just a device you plug into the balance port that tells you the overall pack voltage and the voltage of each cell.

    https://www.google.com/search?q=lipo...w=1920&bih=935

    Most chargers will display this data when you plug in a battery, but Traxxas EZ charger is not one of them.
    Submarine Qualified, Chief Inducted, Navy Retired

  7. #7
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    Quote Originally Posted by Greatscott View Post
    A lipo checker is just a device you plug into the balance port that tells you the overall pack voltage and the voltage of each cell.

    https://www.google.com/search?q=lipo...w=1920&bih=935

    Most chargers will display this data when you plug in a battery, but Traxxas EZ charger is not one of them.
    Could you recommend a good charger?

  8. #8
    RC Qualifier Myrustlervxl's Avatar
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    I use the hitec X2

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  9. #9
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    Quote Originally Posted by stilllearning7 View Post
    The Mah is 5000.
    I apologize I thought it was 5000 mah but when I looked later I noticed it has 5200 MAH I'm going to try and run the car this evening and drain the battery then check the voltage. I'll charge it back up and then check the voltage again. I just have a multimeter so it won't be as detailed as a lipo checker.

    I appreciate all the feedback thus far. Hopefully the information I gain from the multimeter this evening will be beneficial

  10. #10
    RC Champion MaXXL's Avatar
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    You can use your multimeter in place of a lipo checker.

    Just check the voltages of each cell on the balance plug.

    I cant remember exactly how the harness is wired but i believe the right-most wire is common ground and all the other wires are cell 1 positive, cell 2 positive, and cell 3 positive.

    Each of the cells should be between 3.2v and 4.2v. So if your getting anything higher than 4.2v your probably probing the harness wrong and your accidently reading the voltage of more than one cell.

    So connect one probe from your multimeter to the common ground wire. Then use the other probe to read each of the other individual cell voltages. All of the cells should be nearly the same voltage. Like within 0.15 volts. If 1 of the cells is very different from the other 2, you have a bad cell and you should replace your battery pack.
    Last edited by MaXXL; 06-20-2018 at 03:38 PM.
    10 RCs and counting 😅

  11. #11
    RC Turnbuckle Jr. olds97_lss's Avatar
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    Your pack probably dropped a cell. I had that recently on one of my SMC 2S packs I've been running for 15 months. One of the cell voltages dropped to less than 2V. I tried coaxing it back to life to see if it was something I did, or if it was the pack, but I kept a very close eye on it and the charger after I forced the cell back up to a level that my Lipo charger would try and charge it. Then I left it off the charger for a few hours, rechecked the cell voltage and the bad cell was dropping fast while not being plugged into anything. By the next morning, it was back down to less than 2V. I won't tell you how to force it, because you really shouldn't do that if that is what your issue is.

    This was a SMC 9000mah 2S2P packs. Before this happened, it had been taking forever to balance charge. While my other 9000mah packs were taking 60-70 minutes, this one was taking 100+ minutes.

    I was using a charger that did 10A per port, so they are all starting to get a bit worn since they are no longer charging in under an hour at 10A like they should be.

    If it's doing that, you should stop using it. Run it dead dead on a light bulb, then cut and twist the battery leads together so it doesn't recover any voltage. Keep an eye on it though as you run it clear dead. I went so far as to solder my leads together. Not sure what to do with it now. lol
    https://www.youtube.com/c/olds97lss

  12. #12
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    Okay, I apologize that it has taken me so long to post the results from testing my battery. Hopefully from my memory and notes, this will be as accurate as possible:

    Results from multi meter: Fully charged at 13.00. Bashed for appx 1 minute and 40 seconds before it shutdown while the red light flashing on the ESC. I had to disconnect the lipo because while the red light was blinking I couldn't get it to shut off.
    Voltage at that time was around 12.8 volts.

    I reconnected the battery and ran it for about 5 minutes and 15 seconds. Since the ESC was hot, I let it rest, about 2 minutes later, the voltage was appx. 11.84. Took about a 30 minute break before testing the battery again at 11.73, ran the car again. It ran about 20 seconds then the green lipo light began to blink red. I reset the ESC and it ran again for about 10 seconds before it shut down. The battery voltage at that time was 10.90 .

    Does this seem like a lipo issue or an ESC issue?

    Thanks so much

    FYI (typically when the car shuts off from the red light blinking, the steering still works)

  13. #13
    RC Turnbuckle Jr. Squeegie's Avatar
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    You need to read individual cell voltages, not the total voltage.

    Read post #10 above.

    Good luck!
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  14. #14
    RC Qualifier Myrustlervxl's Avatar
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    This is how you check individual cells. this is a 2s. It will be the same thing for 3s and 4S and so on from left to right.

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  15. #15
    RC Champion MaXXL's Avatar
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    Your pack should never read higher than 12.6v. If your seeing 13v, one or more of the cells in your pack is being overcharged.
    Last edited by MaXXL; 06-27-2018 at 01:59 PM.
    10 RCs and counting 😅

  16. #16
    RC Turnbuckle Jr. olds97_lss's Avatar
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    Or you get one of these things:
    https://www.horizonhobby.com/lipo-vo...alarm-dynf0002

    I got a 5 on ebay for $10:
    https://www.ebay.com/itm/5X-RC-Lipo-...D/222259485961

    Not sure how well they stay connected when bashing though. They cycle through and show you the voltage of each cell and I think it also shows you the total as it cycles. You can adjust the low limit and it will beep very loudly if one of your cells gets that low.
    https://www.youtube.com/c/olds97lss

  17. #17
    RC Champion MaXXL's Avatar
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    You need to address the overcharging situation ASAP. An overcharged lipo is a FIRE HAZARD and people have lost ENTIRE HOUSES due to charging malfunctions.

    Try a different lipo pack or charger (do this outside and away from anything flammable) and moniter it very closely.
    10 RCs and counting 😅

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