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    Couple of Questions before buying kit

    Hey all,

    On the conversion of my 2014 Specialize Sirrus Elite Disc, I have a few questions before making the kit purchase. BOM below

    - 750 vs 500 W motor? I'm 250 lbs 5'9" with a single long hill at the origin side of my 10 mile (each way) commute. The rest is flat. Seems like 750W is commonly available, almost de facto standard. No reason to choose 500W, right?

    - Should I bother with weight saving by choosing a 10Ah battery over a 15Ah one or am I just limiting myself for future use or over straining parts?

    - Am I right thinking I can use a 52V battery pack with a BBS02 48V motor? Is this a controller/programming issue?

    - Gear change sensors are recommended, yes? To save wear on cassette?

    - Any reccos on using the phone as the display? Is that a thing? I'd love to just mount my phone and see and control the bike assist, speed, etc.

    Thanks in advance,
    Moe

    BOM:
    • BBS02 750W 48V
    • 48v 13Ah 30Amp
    • Chainring 46T
    • SW102 Display
    • Brake sensor (hydraulic)
    • Speed Sensor
    • Shift Sensor

    #2
    It depends on the firmware on the unit and the display model and its firmware which as far as I know can't be changed buy users on how well the 48 vs 52 works. Most cases the worst issue you would have is the battery meter not being accurate but they are not that accurate to begin with so usually not a huge deal. Some of the displays allow you to choose and some of the motor firmware allow you to choose also. I would not worry too much about it. If you found what you believe to be a reputable vendor that has something close to what you think you want in stock go for it. The difference isn't worth waiting several months for a slightly different one to come into stock.

    Size wise I don't think I would worry about weight at all especially for commute type of riding unless you are going to have to carry the bike up stairs a lot. If you do have to do stairs just tanking the battery off and making a 2nd trip may be better than skimping just due to weight. If you were a 90 lb person putting the kit on a 20 pound bike maybe battery weight would be a concern but I don't think it is here. For range for these middle of the road power motors I like to use 2 miles per hour as a ballpark number assuming you are doing some pedaling and not trying to maintain 20+ mph. So a 10ah pack should be good for around 20 miles with some reserve so for your 10 mile commute if you can charge at work should be no problem. If you can't charge at work it could be close or if you want to do throttle only 20 mph, could be close there too.

    I would for sure not mess with the 500w versions, you mention hills and are like many of us not in the lightweight class so that motor will have a lot of work to do getting us up hills. Going up those hills even with the 750w version is going to require shifting to the lowest gear and putting in some pedal effort. Its not going to be anywhere near as much work as not having a motor but its going to need the help. Its a little more weight and money but maybe even consider a BBSHD?

    Speed sensor is a required part of the kits, should not be listed as an option. Hydraulic sensors are a reasonable choice, you can glue them onto any brake lever, I use hot glue especially for the trial fitting since its easy to remove. Gear sensor is nice because you don't have to worry/think as hard about shifting. Its not perfect there still will be times you make some horrible noises but I think they help.

    For the display I don't think there are any that are 100% phone only but the Eggrider2 is a very small unit that is still usable on its own but then has Bluetooth and an app that lets you do stuff with your phone. I haven't actually seen one in person but they have been around a couple years now and people seem to like them. I think it works with the 02 but you should confirm that.

    Comment


      #3
      Originally posted by moejurray View Post
      Hey all,

      On the conversion of my 2014 Specialize Sirrus Elite Disc, I have a few questions before making the kit purchase. BOM below

      - 750 vs 500 W motor? I'm 250 lbs 5'9" with a single long hill at the origin side of my 10 mile (each way) commute. The rest is flat. Seems like 750W is commonly available, almost de facto standard. No reason to choose 500W, right?

      - Should I bother with weight saving by choosing a 10Ah battery over a 15Ah one or am I just limiting myself for future use or over straining parts?

      - Am I right thinking I can use a 52V battery pack with a BBS02 48V motor? Is this a controller/programming issue?

      - Gear change sensors are recommended, yes? To save wear on cassette?

      - Any reccos on using the phone as the display? Is that a thing? I'd love to just mount my phone and see and control the bike assist, speed, etc.

      Thanks in advance,
      Moe

      BOM:
      • BBS02 750W 48V
      • 48v 13Ah 30Amp
      • Chainring 46T
      • SW102 Display
      • Brake sensor (hydraulic)
      • Speed Sensor
      • Shift Sensor
      Definitely the bigger battery!! If you want to keep it simple you can skip the shift sensor. The slightest back pedal will kill the motor and then you can shift. You can always add it later. I never found the need for one. I have both the BBS02 and the BBSHD and I would always opt for more power. You might not use it very often but when you need it it is nice to have.

      Comment

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