esaj Posted June 28, 2015 Share Posted June 28, 2015 Now, we probably pretty much all know that Firewheel and most other wheels have the dreaded BMS-cutout problem. This can be solved by shunting the BMS, as mentioned in numerous places, and the instructions are, once again, here:BUT, this topic isn't about the BMS-problem, but about the mainboard ("overspeed") cutout in Firewheel. Hobby16 thinks it's tied to the RPM of the motor, and so did I, until I noticed that I was sometimes getting the overspeed-warnings at lower speeds when the battery had less charge left. Today, I've had the "last" warning that says "Take care" at 26.5km/h (somewhere after 10km on the trip) and at 24.5km/h (about 18km on trip). Once I got home after riding little over 19km, I didn't put the wheel on charger and instead waited a while, added the kilometers to my signature, and zeroed the values on the bike computer. Then I took the wheel outside, and turned it on, the battery indicator was showing 25-26% stationary.What followed was a series of "lift-tests", meaning I turn the wheel on and lift it off the ground so it can run free. I've done this test before, but with full battery, and was getting constant values around 39-40km/h before the wheel would shutdown the motor and start saying "Please restart the unicycle" (I think the variation depended on what point the the sensor-magnet was when the shutdown occurred, ie. higher speed if the magnet just had passed the sensor before shut down, otherwise the last "fastest" round of the wheel would seem slower to the computer).This time however, I was getting low values at first (around 29km/h and once 19km/h), as the wheel would shutdown the motor very fast, if tilted more, it could even shutdown so fast that the bike computer didn't get a full turn to record any value (0km/h). After more tries, I got the wheel to run a bit longer at a time before the mainboard would shut the motor off, by tilting it very, very slightly forwards, so the acceleration wasn't as fast. I was constantly getting values around 35km/h.So this leads me to believe that the Firewheel mainboard cutout is NOT (only) tied to the motor RPM, but (also) to voltage and/or current. I'd like to ask @hobby16 to perform similar tests with his FW F260 (lift-test with full battery and lift-test with battery much less full), if he could confirm this. Link to comment Share on other sites More sharing options...
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