Wisper 705 se

coggsi

Finding my (electric) wheels
Aug 19, 2025
10
0
Hi I have a problem with the above bike the battery is fully charged and checked with multi meter yesterday when switched on the head unit is showing 1 battery icon and current isshowing all icons but there is no power at all see photo
 
Last edited:

saneagle

Esteemed Pedelecer
Oct 10, 2010
9,195
4,104
Telford
Hi I have a problem with the above bike the battery is fully charged and checked with multi meter yesterday when switched on the head unit is showing 1 battery icon and voltage is showing all icons but there is no power at all
If you checked it with a meter, what was the exact voltage?
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
9,195
4,104
Telford
If you had a dead short, it would show that.

Switch everything off, lift the motor wheel off the ground and turn it BACKWARDS. if it's difficult to turn, you probably have the most common type of short - a blown MOSFET. You can confirm that by disconnecting the motor connector then trying again. If it frees up, it's a MOSFET.
 

coggsi

Finding my (electric) wheels
Aug 19, 2025
10
0
If you had a dead short, it would show that.

Switch everything off, lift the motor wheel off the ground and turn it BACKWARDS. if it's difficult to turn, you probably have the most common type of short - a blown MOSFET. You can confirm that by disconnecting the motor connector then trying again. If it frees up, it's a MOSFET.
How dow I disconnect the motor connector
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
9,195
4,104
Telford
Not a blown MOSFET then. It took a long time to get there.

The display is showing that there is a large amount of current going through the controller, but not enough to trip the battery. There are two possibilities: 1. The display is faulty because water got in it or a wire has been pulled. 2. There really is high current and a reason for it. The reason could be faulty controller or a damaged wire somewhere between the controller and the display.

If you can't find a damaged wire, there are some more complicated tests you can do to confirm whether or not the high current is really happening. That involves removing and dismantling the controller, and measuring with a meter. Are you up for that?