How to Remove the Speed Limit on Sundiro K9?
3 Answers
Whether the electric vehicle is in full speed or speed limit state, under the condition of power off, hold the left brake lever without releasing, and turn the speed control handle to the end. Turn on the key switch of the electric vehicle, turn the right throttle to the end, and wait for 3 to 5 seconds. Release the brake lever, turn off the key switch, and then turn on the key switch again to complete the decoding. It should be noted that in summer, high ground temperature, coupled with factors such as tire aging, high-speed rolling, over-inflation, excessive load, and poor road conditions, can easily lead to tire blowouts.
I previously modified a Sundiro K9 electric scooter, and to remove the speed limit, I had to open the controller cover to locate the speed-limiting wire. This model usually has a wire labeled SPD connected to the controller, which enforces the speed limit—cutting it removes the restriction. However, it's crucial to disconnect the battery's positive and negative terminals before operating to avoid short circuits and circuit board damage. In practice, use a multimeter to confirm the wire's function to prevent cutting the wrong wire and causing malfunctions. After removal, the top speed can increase to around 45 km/h, but power consumption doubles, and battery temperature rises noticeably. Prolonged use under these conditions shortens motor life, and the factory cooling system can't handle it. Last time I modified it and took it on mountain roads, the motor coils burned out, and I had to spend a lot on a new motor replacement.
The safest way to remove the speed limit on the Xindazhou K9 is to contact the manufacturer's after-sales service for a firmware flash. They have specialized computer debugging software that can reset the controller parameters. Last year, my scooter was stuck at 25 km/h and couldn't go faster. Through the dealer, I contacted the manufacturer's technician, who plugged in a diagnostic tool and entered the engineering password to unlock it. This method doesn't damage the original wiring and retains the response speed of the electronic brake after completion. Regular repair shops often use the wire-cutting method, but it can easily trigger the temperature sensor and cause false alarms. The worst part is that after unlocking, the front wheel tends to slip, and even crossing a zebra crossing on a sunny day can cause the scooter to skid. Once the speed is increased, you'll need to switch to tires with better grip, as the original tread pattern is simply not up to the task.
