Can anyone suggest where is a good place to buy a spare speed sensor to have on hand in the event of failure?Error 21 can bring a total shutdown. Not common. I can't confirm which models but I have seen cases where that has happened. The speed sensor is an inexpensive part I have had failures with. I always keep one, if not for reolacement, then for tending and process of elimination. Cheap backup part. And in a spot that makes it vulnerable, IME.
I just had a very similar issue with a Shark Pack. The bike would power up but as soon as I put any load on the battery the LCD would shut down. Bought another pack and the bike works fine.I should also mention every time when it shuts down I check voltage at battery connectors and it reads very low then I disconnect the battery by itself and it reads full charge at 54 volts.
I would suggest this is confirmation you have a battery problem.Even if I just let it sit in about 10 or 15 seconds it shuts down then it is dead
There's a rash of bad BMS with some suppliers. I ordered my last packs from China and had them include backup BMS. Of course I never needed it until another USA vendors BMS went bad. It was pretty much plug and play with just minimal soldering. Expect higher rates of failure with budget priced batteries. Nothing insurmountable, but I'm going back to some slightly higher priced suppliers with longer warranties. Shipping batteries back is a PIA. And NO sorry, I'm not naming sources. Just remember price isn't everything.Thanks for that info I was suspecting the same. I am thinking a BMS problem really since the batt holds a charge. I should know more later this week thanks again.
Metal Oxide Field Affect Transistor. This is the power regulating device. BMS, Battery Management Sytsem. This is the circuit that manages battery function.mosfet
Thanks for the response... I should have been more clear. I have been downshifting the bike as well as taking the mode down to 1 before coming to a stop.. so it *is* in lower gear/mode when starting out. I've tried to make sure it's not "lugging out" (my words for it) as if it were a motorcycle in too high of a gear for the rpm's/load.Metal Oxide Field Affect Transistor. This is the power regulating device. BMS, Battery Management Sytsem. This is the circuit that manages battery function.
Without going into detail I would say you are overloading the motor and or the BMS. Drawing to much amperage. If you are running on 5 all the time you are asking for maximum power in all riding conditions. Starting from a stop with a high power setting puts maximum stress on the system particularly if you are starting in a high gear. When you add passengers you are increasing weight which puts even more stress on the motor.
General recommendation pedal cadence of at least 40-45 60 and above is better. Start in 1-3 increase power to 4 and 5 when the bike is moving above 10 MPH.
That would happen if the battery shut down. If the supplier is sending you a new battery that would be the right start at finding the problem. If that fixes the issue great, if it doesn't the motor controller would be the most likely culprit.where the display went blank, too.
The number underneath is encoded to tell us the date the motor was made. That would allow us to know what version controller it has. If it's an older model controller that might be an issue. The newer controller has MOSFETs that handle more amperage, less prone to problems.BBS02 48V 750W