EM Battery Details

Discussion in 'Electric Motorcycles' started by Kyler, Aug 12, 2019.

  1. Kyler

    Kyler Geezer

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    I've started this thread to record details about the EM battery as a reference. My goal is to provide enough information so that someone can repair, rebuild or build a battery; with that in mind I hope other EM owners will add details too. I'll add those details to this post.

    I have a 2016 EM Sport+ with a 16ah battery. I left the bike on recently and ran it down to the point where it wouldn't charge. My friend, smdub took it apart and nursed it back to health. The battery is just a pouch lipo, simple BMS, hall sensor, and a pair of contactors. Much of what you see below comes from smdub. The rest is from my research and from other EM owners.

    My SmugMug gallery of my EM battery internals is here

    [​IMG]

    If you drill out the rivets, be sure to avoid pushing them into the case. They can be hard to get and you don't want anything metal bouncing around inside. All connections are covered in RTV as you can see below. Rivets holes are 0.165-0.170" diameter. Since these were built in France, that is a 4mm rivet; a 5/32" aluminum rivet works. I bought these. Sheets are ~0.065" thick each so the grip range will be >1/8" w/ the sealant between. Qty 16 are needed each side = 32 total. Clear RTV works to seal the case sides.

    [​IMG]

    The battery has 14 4-volt cells for 56 volts with one cell also powering the relay. If the battery is very low, the relay won't engage and the battery won't charge. Charge that cell and then the charger will work.

    More to come ...
    #1
    rediRrakaD, catfish, smdub and 2 others like this.
  2. dentvet

    dentvet Long timer

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    Can you tell who makes the cells? They are 16 Ah cells?
    #2
  3. Kyler

    Kyler Geezer

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    No, but as I continue my research I'll add the manufacturer. Mine are 16ah cells.
    #3
  4. rediRrakaD

    rediRrakaD Whoopdie do Supporter

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    @Kyler can you post any additional instructions/thoughts about this? My 16yo left my bike on and it won't charge...
    #4
  5. dentvet

    dentvet Long timer

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    Make your kid push it around the yard with the regen button pushed in. Only half joking... theres a video of a guy using the motor to recharge his EM bike far enough to get the charger on line
    #5
  6. rediRrakaD

    rediRrakaD Whoopdie do Supporter

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    Saw that video and we read all the comments. Trying to figure out if we can save this and may try his method. Problem is I'm seeing only .07v on the battery currently. Not good according to my research.
    Thought about a 2am run down from the top of the Santa Cruz mountains with the clutch pulled in! We don't have the regeneration button he has on his unit.
    #6
  7. ctromley

    ctromley Long timer

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    Not familiar with EM's products. You should have a situation where, at worst, you have a reading of near-zero volts because of a low-voltage system shutoff (probably built into or activated by the BMS, maybe the controller) that tripped to protect the battery pack. If this bike actually allowed a user to inadvertently leave the system on, and allowed the drain to pull the pack voltage down to zero, then shame on EM. That's far too high-stakes a problem, far too easy to predict, and far too easy to prevent. What the [bleep] were they thinking? Or were they thinking at all?

    Or hopefully, in a sane world, they did think of it, something simply needs to be reset and your pack is fine. Let's hope for the latter. If the former, all EM owners should revolt, demand a fix, and if that's not forthcoming abandon the brand. Because if that's really what happened, Electric Motion is too stupid to live.

    Where are you taking your voltage measurement? Put a meter right on the pack with no intervening devices to make sure.
    #7
  8. rediRrakaD

    rediRrakaD Whoopdie do Supporter

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    T
    Thanks for the reply. I'm in the process of educating myself... going to open the pack up today and start measuring (reading above taken off the electrical leads coming out of the battery). Electrical is not my forte, but not afraid to dig in and learn. The OP had his fixed by another inmate and I was hoping for some guidance.
    #8
  9. ctromley

    ctromley Long timer

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    If you're going in uneducated, please know that anything over 36 VDC is considered high voltage and a lethal hazard. Rubber gloves, eye protection and insulated tools (even with tape and shrink-wrap) are your friends. (And still be aware of the consequences of a dropped tool.) Keep the proper kind of fire extinguisher nearby. Look for disconnects that break the pack into lower-voltage modules that allow you to work safely. (Or break connections where needed to do it on your own.)
    #9
  10. smdub

    smdub Been here awhile

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    Sorry, just saw this since I wasn't tagged in this thread. I'm the fellow that helped Ken out. Memory is a little fuzzy but AFTER taking it apart and charging it manually, EM got back to Ken and told us a secret. One of the pins in the charging connector goes right to the battery. One of the pins in the power connector goes to the other side of the battery. So you can jump start the BMS by charging enough using a power supply and not have to crack the case open.

    I found some of the email chain between Ken and I. PM me your email and I'll send you what little info I have on the XLR charge connector pinout. Looking at the pics I took, I'm fairly certain that the positive power lead on the power connector goes through the contactor. That means the negative power is directly connected. Use a voltmeter to measure from the negative power connector and the + in the charging connector. The charging connector has three pins. For no better way of describing the orientation, lets call them a face w/ two 'eyes' and a 'nose'. Its left 'eye' (the one on your right when looking at the battery connector with the face upright (nose lower than the eyes)) should be the + charge terminal on both the 13S and 14S pack variations. IIRC, the BMS interrupts the negative of the charging connector when full (or dead). So w/ one pin disconnected in each connector when the BMS shuts down you can't measure any voltage differences in either connector. But using a pin of one and a pin of the other connector is the backdoor to measure the voltage and charge it far enough to get the BMS started again and use the EM charger to finish it off.
    #10
  11. rediRrakaD

    rediRrakaD Whoopdie do Supporter

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    AWESO
    AWESOME!!! Pm sent. Very appreciative.

    @ctromley Your warning was appreciated as well!
    I work with/around 6700v breakers on a daily basis (when not SIP). Massive power, but these itty bitty things might as well be alien. Hahaha
    Yes our facility can draw HUGE power to operate. ( 160 Megawatts +)
    #11
  12. dentvet

    dentvet Long timer

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    #12
  13. Kyler

    Kyler Geezer

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    @smdub is the man with all the answers. He's a battery genius. Not to mention a great rider.
    #13