Two of our three Mistrals recently suffered a power cut, the reason for which took a little while to diagnose, and which may be of interest not only to other Mistral owners but anyone running a similar system (Wuxiing brake levers, Suzhou or Tonxgin motor, multi-wired controller, etc). The symptoms were that, although the battery was fully charged and switched on, and the handlebar indicator was glowing red, the controller was sending no current to the motor. Neither the throttle nor the pedelec would power the motor.
As each of the two bikes had, unusually, been exposed to heavy rain for hours on end before the fault appeared I assumed that the throttle had been contaminated by water, but on opening it up found none, and I also discovered that the arrangement of a magnet moving over a resistor would probably not fail but give erratic results if water did get in.
I then checked the brake cut-out switches, and could discover no water there either: they have a little push button type switch which is shrouded to protect it from water ingress. However when I removed the cover plate from the controller compartment beneath the seat tube, identified the two brake connectors, and disconnected them in turn I found that when the front (right) brake was disconnected, both throttle and pedelec started the motor again.
I assume therefore that water had penetrated the shroud on the front brake push button switch and was keeping the switch permanently closed (by shorting its two contacts). This would give a false signal to the controller that the brake had been applied and the controller would cut the current.
After a couple of days with the bike kept inside, the water seems to have dispersed and I was able to reconnect the front battery lead to the controller and all was well.
I doubt if this problem would arise while using the bike unless one likes cycling in monsoon type conditions, and the intermittent use of the brakes probably expels any water about to penetrate the switches, but some WD40 sprayed around the brake levers, etc should help to protect them. Where the bikes have to be left stationary in rain for hours on end it may be sensible to put a plastic bag over each lever.
And in case the problem does arise far from home carry a crosshead screwdriver to remove the cover from the controller compartment in order to disconnect the brake connections to the controller. And as the controller, as with all these systems, is surrounded by a jumble of wires it is a good idea to practice this first at home, and label the two brake cables for future reference. They consist of two thin wires, blue and red, but there are three like that, and it is necessary therefore to disconnect each in turn to discover which ones relate to the brake switches.
As each of the two bikes had, unusually, been exposed to heavy rain for hours on end before the fault appeared I assumed that the throttle had been contaminated by water, but on opening it up found none, and I also discovered that the arrangement of a magnet moving over a resistor would probably not fail but give erratic results if water did get in.
I then checked the brake cut-out switches, and could discover no water there either: they have a little push button type switch which is shrouded to protect it from water ingress. However when I removed the cover plate from the controller compartment beneath the seat tube, identified the two brake connectors, and disconnected them in turn I found that when the front (right) brake was disconnected, both throttle and pedelec started the motor again.
I assume therefore that water had penetrated the shroud on the front brake push button switch and was keeping the switch permanently closed (by shorting its two contacts). This would give a false signal to the controller that the brake had been applied and the controller would cut the current.
After a couple of days with the bike kept inside, the water seems to have dispersed and I was able to reconnect the front battery lead to the controller and all was well.
I doubt if this problem would arise while using the bike unless one likes cycling in monsoon type conditions, and the intermittent use of the brakes probably expels any water about to penetrate the switches, but some WD40 sprayed around the brake levers, etc should help to protect them. Where the bikes have to be left stationary in rain for hours on end it may be sensible to put a plastic bag over each lever.
And in case the problem does arise far from home carry a crosshead screwdriver to remove the cover from the controller compartment in order to disconnect the brake connections to the controller. And as the controller, as with all these systems, is surrounded by a jumble of wires it is a good idea to practice this first at home, and label the two brake cables for future reference. They consist of two thin wires, blue and red, but there are three like that, and it is necessary therefore to disconnect each in turn to discover which ones relate to the brake switches.
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