Problem with AKM75SX hub kit cutting all power

[LithiumFan]

Hi,
The other day my bike with retrofitted front AKM hub kit decided to show an error message 03. I know that that's a hall sensor error except that from a previous thread I started, this motor doesn't have any. But the throttle still worked. After pulling the controller out of its bag to see if any connectors had come adrift (none were) and rebagging, the throttle still worked but as soon as I started peddling the display and motor turned itself off completely. I have to unplug the battery to get the display to turn back on again.

The current controller is a KT24/36SVPR-HRD01 with jst type connectors. I use Bosch 36v lawn mower batteries. I have also tried with the KT square wave controller and the display and motor just cut out immediately I use the throttle or the pedals.

Any ideas as I'm now stumped.

 

[matthewslack]

When you say 'throttle worked', can you be more specific? Do you mean you can ride on throttle for the full expected full range of the batteries, or just that it gets you going for a short time whilst you start pedalling?

My first suspicion is weak battery, so I am wondering if pedalling settings put more load on the battery than your throttle use?

Are you on speed control or current control with the KT controller? Speed control will use full power as soon as you start pedalling, exposing a weak battery. Current control or gentle throttle use will use lower power and so perhaps be OK.

If you have a conventional ebike battery perhaps see if it makes a difference.

Power tool batteries don't have high number of cycles of life.

 

[saneagle]

Hi,
The other day my bike with retrofitted front AKM hub kit decided to show an error message 03. I know that that's a hall sensor error except that from a previous thread I started, this motor doesn't have any. But the throttle still worked. After pulling the controller out of its bag to see if any connectors had come adrift (none were) and rebagging, the throttle still worked but as soon as I started peddling the display and motor turned itself off completely. I have to unplug the battery to get the display to turn back on again.

The current controller is a KT24/36SVPR-HRD01 with jst type connectors. I use Bosch 36v lawn mower batteries. I have also tried with the KT square wave controller and the display and motor just cut out immediately I use the throttle or the pedals.

Any ideas as I'm now stumped.

When the LCD switches off, it's a battery voltage problem.

It's a while since I looked, but I'm pretty sure that dual mode KT controllers have a setting to force sensorless mode. A sensorless motor will only work with a dual mode version of KT. Any incompatible one will give error 03, then shutdown.

When it's working, set the display to show battery voltage (short press of the power button twice?). Watch what happens to the voltage when you demand power. It'll show whether your battery is too weak.

In summary, knackered battery or incompatible controller or incorrectly set controller.

Generally, it's difficult to find a controller that works well with sensorless AKM motors. Even with a sensorless KT controller, the motor can suddenly lose synchronisation under heavy load, which would be worse with a weak battery.

 

[LithiumFan]

Mathewslack, I can assure you that my Bosch 36v batteries are fabulous. They are designed for strimmers, lawn mowers and hedge trimmers and have ample power. My motors are capable of drawing 450W for short periods.

Saneagle, you got it right. I had made a new adapter for the Bosch battery and needed an XT60 to XT60 waterproof cable. This was the problem: A bad connection somewhere. When I used my original adapter with normal XT60 connectors everything worked fine again.

Thank-you both for your assistance.

I have ended up with the KT24/36SVPR-HRD01 controller which has C13 and C14 parameters although I've no idea what they are for. It's very quiet and back to normal. The other controller didn't have a wire for the internal speedometer as it's included in the hall sensor connector block.

 

[matthewslack]

Glad you got it working.

Two tees in my name...!

 

[LithiumFan]

Sorry Matthew.

 

[saneagle]

When the LCD switches off, it's a battery voltage problem.

It's a while since I looked, but I'm pretty sure that dual mode KT controllers have a setting to force sensorless mode. A sensorless motor will only work with a dual mode version of KT. Any incompatible one will give error 03, then shutdown.

When it's working, set the display to show battery voltage (short press of the power button twice?). Watch what happens to the voltage when you demand power. It'll show whether your battery is too weak.

In summary, knackered battery or incompatible controller or incorrectly set controller.

Generally, it's difficult to find a controller that works well with sensorless AKM motors. Even with a sensorless KT controller, the motor can suddenly lose synchronisation under heavy load, which would be worse with a weak battery.

I'm glad you got it sorted. If it's working OK, you don't need to worry about settings.