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How to open a soft pack to access the BMS and to to put it back like it was.

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    How to open a soft pack to access the BMS and to to put it back like it was.

    Ok so you need to open your soft pack to test or replace the BMS.

    It's easier when you have a hard case, just need to remove a couple bolts and voila you have the BMS right there.


    Opening a soft pack is pretty easy, but be sure you have what it takes to put it back together.

    You will need a blade (Xacto)
    Heat shrink You can have some here
    Kapton tape (Amazon or eBay) or good high temp insulation tape (no cheap electric tape)
    Heat, so either a good heat gun or take your hair dryer or small hobby torch.

    First before cutting it, you need to find out what size of heat shrink you need. so measure 2 sides and add the numbers, That will give you the size you need, heat shrink is sold folded so if you buy a 7.5inch wide piece it will cover a circumference of 15 inch max.

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    Mine was about 3.5 and 3.25, so a 7.5inch wide was perfect has the shrink ratio is close to 2:1.

    Now Order that heat shrink, but be sure that you order more than what you need, good chances are that you won't get it the first time, the second time you will!

    PS: if you are really in the rush, you can always reuse the heat shrink that you cut and tape it back till you get your new heat shrink in the mail...


    Now you will have to open you pack... but were? I fist start by removing the silicone around the opening and cut from there to the other end, just slide you knife like I do do not try to pierce the pack, yours may not have fibreglass sheet under it like mine and you can slice a cell or a wire.

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    #2
    Now be careful and slide your knife on the edges to cut the tape... there are many wires under this tape so be really gentle:

    And you have this... Wow this mini cube 30Q is well made!

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    Now do what you have to do, test it, reset it, change it.....

    Once done you will need to cut the right length of heat shrink, I leave about 7/8inch on both sides.

    center it and start on the corners just a little... there are plenty of video on how to do a good heat shrink job:

    Micah at ebike school has a video on it here
    Hes using a thinner heat shrink with 3:1 ratio so he needs bigger ends, if you are using Luna super think heat shrink you don't need that much on the ends...it won't look good at all.

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    After the fist try it looks like this: just needs to seal up the grommets and around the heat shrink and you are done:

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