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Thread: Hoverboard Battery issues with 18650 cells

              
   
   
  1. #1
    Senior Member DRZ400's Avatar
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    Hoverboard Battery issues with 18650 cells

    Probably all seen the news of the "hover boards" catching fire. They use (20) 18650 cells in a 10S2P configuration. I bought (2) last August, advertised as SAMSUNG batteries. Most fires seem to occur during charging (leaving charger on over night) although there have been several during riding fresh off charge. Ebay and Amazon have been selling 100's a minute for Xmas gifts. I can see the danger in running the charge down and letting it sit for several weeks....quite possibly a few cells could dip below 2 volts due to the BMS loading. Next charge the remaining cells could over charge. Also you se kids going off curbs and stairs and jumping on them. they have solid tires and do suspension with no shock mounting. Recipe for failure which could lead to shorting the battery especially if the BMS fails. Hopefully a source will appear with high quality batteries and an improved BMS.
    Last edited by DRZ400; 17 December 2015 at 1317.
    2003 Ninja 250EX, Agni #95R, 6:1 Gearing, 11 Leaf Modules.
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    Have you torn one down?
    Is there actually a BMS in there?
    Reckon cell mismatch at EoC is the culprit personally.

    I reckon there are three likely mechanisms leading to the mismatch (in order of likelyhood):
    - Absence of load limiting hardware leading to over-discharge of the pack.
    - Poor quality, mismatched, cell performance leading to voltage deviations which leaves both the weaker cells getting over-discharged, and the stronger cells subsequently getting overcharged.
    - Cell mismatch is arising on account of uneven BMS loading.

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    Senior Member DRZ400's Avatar
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    Yes, there is a 3"x3" square board. Its shrink wrapped but has wires going to each cell. I played around with 18650 cells 6 months ago...the Chinese Ultrafires (ably named?) were really bad. Rated at 4000 mah but barely did 1000. Self discharged to 0 after 2 months.
    Last edited by DRZ400; 16 December 2015 at 1059.
    2003 Ninja 250EX, Agni #95R, 6:1 Gearing, 11 Leaf Modules.
    Alltrax SPM72400, 400 amp Controller, all LED lighting
    2014 CRF450X Supermoto
    http://www.evalbum.com/1955
    http://www.evalbum.com/3337

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    That issue made the front page headline of my local newspaper today. It seems like these hoverboards are lighting up every day and causing house fires and scorching little kids. To say nothing of Li batteries getting a real PR hit. Many of the safety talking heads are really jumping on the bandwagon, implying that Li batteries should be banned for the public's safety. The newspaper notes that many of the cheaper Chinese hoverboards are not UL listed, I might add. My thought is that some of the boards do not have a BMS, or if they do have one it is likely fake or doesn't work properly. (Reminds me of the two different BMS boards in my two EMS GPR-S bikes. My first GPR-S caught on fire when the BMS failed.)

    I might add that I just found a relatively expensive remote-controlled, gyro-stabilized, 1/6 scale electric motorcycle in my closet. It has been sitting there for 15 years without being used or recharged. The rechargeable battery is a NiCad. I charged it up and the voltage looked good, the bike ran like new when I tried it out. So I would say that good quality components and proper design make all the difference. When the Chinese decide to bring out a product in a hurry, mass-produce them (as only they can) and sell them as cheap as possible - watch out!
    Richard - Current bikes: 2014 14.2 kWh Zero S, 2016 BMW R1200RS, 2011 Royal Enfield 500, 2009 BMW F650GS, 2005 Triumph T-100 Bonneville, 2002 Yamaha FZ1 (FZS1000N) and a 1978 Honda Kick 'N Go Senior.

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    It's all over the place here (Ireland) as well.

    Yeah DRZ, those ultrafires are mostly repurposed second life cells, they're a frikkin' disaster - that would also definitely do it alright.

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    Member mistercrash's Avatar
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    Quote Originally Posted by Richard230 View Post
    Many of the safety talking heads are really jumping on the bandwagon, implying that Li batteries should be banned for the public's safety. The newspaper notes that many of the cheaper Chinese hoverboards are not UL listed, I might add.
    Maybe it's the cheap Chinese crap that should be banned.

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    ROFL - I would LOVE to see an attempt at a ban on Li batteries!!
    Society would fall apart!

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    Quote Originally Posted by Spoonman View Post
    ROFL - I would LOVE to see an attempt at a ban on Li batteries!!
    Society would fall apart!
    But "They" have apparently managed to put lithium batteries (of all types) on the "no fly" list. Perhaps "They" should realize that not all lithium-chemistry batteries tend to explode when flying. It is amazing what "They" will do with a little knowledge - but not enough knowledge.

    I am still hearing people talk about "chem-trails", claiming that the government is dropping chemicals from high flying airplanes trying to sterilize the world's population. And how well is that working? I have a neighbor who actually runs out in the street to take photos of aircraft contrails and post them on the internet to prove that they are a government conspiracy. When I try to tell him that contrails are similar to steam coming out of his pickup's exhaust on a cold morning he doesn't believe me and says I should stay out of the street when airplanes fly over (and I live near three major airports). I then tell him that I will go get my tin foil hat and that will protect me from government mind control. This country really needs to have a better education system that requires children to take and pass a couple of science courses before they become adults.

    (I might add that this neighbor has two semi-automatic pistols and an assault rifle - along with a couple of very large dogs.)
    Last edited by Richard230; 17 December 2015 at 0801.
    Richard - Current bikes: 2014 14.2 kWh Zero S, 2016 BMW R1200RS, 2011 Royal Enfield 500, 2009 BMW F650GS, 2005 Triumph T-100 Bonneville, 2002 Yamaha FZ1 (FZS1000N) and a 1978 Honda Kick 'N Go Senior.

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    ROFL! That definitely one of the better ones I've heard lately.

    ..and don't even get me started on the lithium no fly thing

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    Senior Member DRZ400's Avatar
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    Just wait till Xmas morning when 100,000 + Hoverboards are put to use.....

    "My nuts roasting by my hoverboard fire, Jack Frost trying to put it out....and so its been said, many times many ways, say no to Chinese batteries allways".

    I have 2 SWAGWAYS, when not in use I store them in my Weber grill.

    This guys takes a SWAGWAY apart. Shows Samsung cells and a BMS board.

    http://mashable.com/2015/12/15/apart-swagway-hoverboard
    Last edited by DRZ400; 17 December 2015 at 1456.

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