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Thread: Connecticut guy upgrading an E Boom Vader, E Grom.

  1. #1
    Junior Member
    Join Date
    Jun 2020
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    Connecticut guy upgrading an E Boom Vader, E Grom.

    Hey all-

    Been lurking here for awhile. Great group! I got a Razor RSF 650w midrive for my kid and have been upgrading it. Started thinking about finding a donor bike to covert to electric and discovered the Grom Clones with 72v of SLA and 2000w hub motor.

    I have a short wife who wanted a motorcycle or scooter and she likes this little electric bike. I have had a blast running around the neighborhood on it but also bought it as a platform to mess with upgrades. My hope is to mod it with a new QS hub motor, controller and battery pack, and with luck, it will get lighter and faster but I can still put it in "low mode" for my wife to ride. I am more interested in real zip than top speed but have registered it as a motorcycle so i can do short stints on faster roads.

    So far I installed the fender delete, added one more SLA to go to 84 volts and have an upgraded shock to install.

    I am hoping to get some up-to-date info on what controllers and battery packs people are running. I like the idea of Nissan Leaf Gen2 but can't see how i could fit the pack I want without fabricating new bodywork. This bike is small!

    Looking forward to learning more about electric bikes. I spent many years wrenching ICE bikes but now am excited by doing the same with electrics.


  2. #2
    Join Date
    Jun 2020
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    I looked into these a lot. I tried to buy one even with the intent of upgrading it, but the seller canceled my order.
    I wasn't happy about that.
    I ended up starting an XS750 conversion with a 12kw QS hub motor instead.

    I can give you some of the information I gathered though.
    Can you post a photo of the motor controller yours is using?
    Some of them have it mounted on the side where the exhaust would go and others mount it under the fairings.
    It would also be helpful to get some pictures of the text on the hub motor. I've seen a couple different ones used.

    The leaf cells will have a hard time fitting.
    I did measurements before, and they just won't fit well.

    Any upgraded pack is going to need some fabrication done to make a metal box to hold the cells securely, or at least some sort of frame.
    If you used LG chem cells you might be able to fit enough into the stock battery bay if you got creative.

    You're going to need to get a BMS though. I would not skimp either. The ANT bms is a decent budget option. I would use the Orion 2 if money was not an object, but it cost more than the battery cells I used in my project.

    "Zip" as you call it, is going to directly correlate to amps that your controller can provide/motor can handle.

    The stock motor is okay, but if you upgrade to the 13" 3kw or 8kw hub from QS, you can push some serious power. Just make sure you get the "v3" or "v2" motor. The "v1" is their "economy" motor. AKA cheap, and not in the good way.

    If you get it with a thermocouple inside and a controller with thermocouple input (like a Kelly KLS) you can also have the controller push out way more power than you could otherwise, and have it automatically dial back the power if the motor overheats so you don't cook it.

    Kelly controllers have a bad reputation for burning up at random. I'm sure that they do indeed do this more than something like a sevcon controller, but I suspect that part of that is people pushing them right up to or beyond their rated power. Also keep in mind that the amp rating on kelly controllers is phase amps (or amps going to the motor) and not how many amps are being drawn from the battery. For example, my 600A rated kelly should only actually draw a max of 240-300A from my battery.
    I haven't actually tested peak draw yet, but that's what the specs say.

    I was not able to confirm if the 13" hub motor would just drop in, but if it had any issues they could probably be easily modified to make things fit. It's not a huge size difference.

    Sent from my GM1915 using Tapatalk


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