BM-Helio Review

Discussion in 'BMEBIKES Forum' started by claypigeon, Feb 23, 2015.

  1. claypigeon

    claypigeon New Member

    I watched the review for the shadow, but I am interested in a more powerful drive, can anyone provide feedback on the Helio? I am a heaver rider and would like to know 750w mid drive performs with the larger battery, and it looks like the Helio has some upgraded components like hydraulics. I searched around and could not find any reviews so any feedback would be appreciated.

    Thanks in advance

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  3. Ann M.

    Ann M. Administrator

    Hi @claypigeon , did you look at Court's review of the Bafang BBS02 750 watt system on a Surly? Its the 48V system with the bigger motor, but it may give you a better idea of how the motor performs:

    The Helio does have some good features and their facebook page bmebikes, has some additional info and contact info. Personally, I'd take for a ride before plunking down $2800!;)
    Last edited: Mar 13, 2015
    Kaldeem likes this.
  4. Court

    Court Administrator Staff Member

    I just finished posting the review for the BM-Helio electric bike here. I've embedded the video below as well, it's a powerful bike at a good price but my biggest gripe is lack of motor inhibitors on the brake levers. Since the motor is more powerful and doesn't stop as immediately as one with torque sensing or advance "multi sensor" I found that shifting gears and trying to stop abruptly could challenge the motor and just didn't feel as controlled at some other models.

    The only BME bike I tried that did have motor inhibitors was their entry level BM-Shadow.
    Mike leroy likes this.
  5. JoePah

    JoePah Well-Known Member

    Looks like a lot of 8Fun! btw what town did you film this bit?
  6. Mike leroy

    Mike leroy Active Member

    Is the 8Fun torque sensor is an option? My major reservation for waiting on the 8Fun, until torque sensor becomes standard.
  7. Mike leroy

    Mike leroy Active Member

    Their web site now reads 52V /19 Amps or 1kw peak power. I really like this tradeoff, because it is still Class 1 street legal in Calif. I would like BME to publish a chart like this, so I can better understand the tradeoffs.

    The intersection at RPM and Torque is key, because power is maximized at 80% efficiency.
    160A, 100NM Torque, 700 RPM, 7200W output. That is the ultimate question I believe you are asking.

    Torque is maximized where torque and output power intersect. Efficiency drops like a rock, from this point at 70% efficiency. 140A, 140Nm torque, 450 RPM, 6000W output.

    Notice how highly correlated the lines (RPM inversely) are until 50 seconds, when the motor becomes 70% efficient. Amps and torque are on the same scale, and very closely correlated.

    The motor loves to run between 450 and 700 RPM. You would definitely feel the motor response going up a hill in this range. The motor will start to fade and sound differently.

    My guess is the BBS02 750W might resemble 240 to 600 RPM portion of the following chart, but that is only a very rough approximation for educational purposes. This chart is more similar to a Honda PCX150 10kw gas powered scooter engine, than an eBike motor.

    I believe Amps, Watts and Torque mislead people. The more precise question is: "how does the controller software affect the performance of the motor?".
    Last edited: Mar 20, 2015
  8. Mike leroy

    Mike leroy Active Member

    Equally important is smooth uphill gear shifting across a 400% gear range. The four 5% grade increments below 20% have different speed ranges. Losing momentum when pedaling hard is unpleasant.

    I do not know how the BBS02 performs on a 15% or 20% grade, but that is very important in my situation. Most people hit the brake lever to pause the motor while gear shifting, due to the lack of a torque sensor. I can not imagine myself shifting gears with that technique on my 18% grade. I expect my uphill speed would be between 5 and 10mph. I would reluctantly press the brakes at that slow speed.

    What is the best way to handle steep hill gear shifting? The lack of a torque sensor makes the BBS02 hard enough to accept, that I would rather wait.

    The Rohloff 14 speed hub is the sure bet. However, the Rohloff adds $1400 cost. A better alternative is to drive the bike below 10% grades. But driving defeats the purpose of the bike.
    Last edited: Mar 20, 2015
  9. Dave S

    Dave S New Member

    I just bought a Helio with the 48v bbs02 motor. I absolutely love it! I weight 260 lbs and pull my two kids in a trailer up hills with no problem at all. I don't miss the motor inhibitors on the brakes at all, you adapt to it after 10 minutes. I have no issues shifting gears going up hill either. I just let off of my own strength slightly and shift, no issues. You really don't shift that frequently with this much power either. I really love the bike and I loved dealing with BMEbikes and Tim over there.
  10. Joey Taylor

    Joey Taylor New Member

    I bought the BM Helio for my daily commuter.

    I'm 6'2 185lbs. This had the most power and speed in the BM lineup.

    Will post more once I have more time with it. Right now I'm trying to find a headlight setup that offers a mix of wide flood and long range beam.