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Bike light interferes with computer


JCooper

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Hi guys, I have a sigma BC9.16 wireless computer and recently purchased a bike light due to the winter days coming up.

 

The light is a 1000lumens led light wired to a battery pack and for some reason the computer stops working whenever I switch on the light, while riding with the light constantly on or flashing the speed on the computer will either stay on a specific speed or it'll go to 0km and stay there and then return to the correct speed once the light is switched off.

 

Can anyone please help in this regard or point me in the right direction to fix the problem

 

Thanx

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Contrary to what you eye sees, the light is flashing at a very high duty cycle (on-off). The electronics doing this is probably causing RF interference with the wireless comms between speed sensor and bikeputer.  It's likely the light unit doesn't have EMI suppression.

 

You can confirm by wrapping the light in foil (just a temporary means of confirming). it will help suppress the EMI, and your bikeputer should work normally or close enough.

 

Successful resolution can require some invasive soldering to the electronics controlling the light, suppression coils around the power leads, or replacement with a unit that complies with FCC/CE/ICASA  EMI regulations.

 

Brand of light?

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Contrary to what you eye sees, the light is flashing at a very high duty cycle (on-off). The electronics doing this is probably causing RF interference with the wireless comms between speed sensor and bikeputer. It's likely the light unit doesn't have EMI suppression.

 

You can confirm by wrapping the light in foil (just a temporary means of confirming). it will help suppress the EMI, and your bikeputer should work normally or close enough.

 

Successful resolution can require some invasive soldering to the electronics controlling the light, suppression coils around the power leads, or replacement with a unit that complies with FCC/CE/ICASA EMI regulations.

 

Brand of light?

Wow, what an explanation! ????

 

Electrical engineer perhaps?

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Hi guys, I have a sigma BC9.16 wireless computer and recently purchased a bike light due to the winter days coming up.

 

The light is a 1000lumens led light wired to a battery pack and for some reason the computer stops working whenever I switch on the light, while riding with the light constantly on or flashing the speed on the computer will either stay on a specific speed or it'll go to 0km and stay there and then return to the correct speed once the light is switched off.

 

Can anyone please help in this regard or point me in the right direction to fix the problem

 

Thanx

I had the exact same thing happen with my Sigma BC-2209.  The problem was the battery pack being too close to the computer.  When I moved the battery pack to the join of the toptube and seat tube, the computer worked fine.  I then used insulation tape to attach the cable to the top tube so it wouldn't flap around

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Contrary to what you eye sees, the light is flashing at a very high duty cycle (on-off). The electronics doing this is probably causing RF interference with the wireless comms between speed sensor and bikeputer. It's likely the light unit doesn't have EMI suppression.

 

You can confirm by wrapping the light in foil (just a temporary means of confirming). it will help suppress the EMI, and your bikeputer should work normally or close enough.

 

Successful resolution can require some invasive soldering to the electronics controlling the light, suppression coils around the power leads, or replacement with a unit that complies with FCC/CE/ICASA EMI regulations.

 

Brand of light?

The light output is probably controlled by PWM, aka pulse width modulation and that causes the high frequency flashing you mentioned. Only the better and often expensive lights manage to use alternative methods of output control to avoid using PWM. PWM is the cheapest and most efficient way to control light output.

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The light power box is to close to the Computer . I had a similar incident with a Citi Golf that had a a Hazard light bar / siren and the control box was too close to the cars ECU and many functions were compromised on the dash . We moved it with a firewall protector next to it and problem was solved . .

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Had a similar problem with a Blackburn computer and an extreme lights 1000 lm light. Solved it by getting a garmin!

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Had a similar problem with a Blackburn computer and an extreme lights 1000 lm light. Solved it by getting a garmin!

Best way to sort it out!

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Contrary to what you eye sees, the light is flashing at a very high duty cycle (on-off). The electronics doing this is probably causing RF interference with the wireless comms between speed sensor and bikeputer.  It's likely the light unit doesn't have EMI suppression.

 

You can confirm by wrapping the light in foil (just a temporary means of confirming). it will help suppress the EMI, and your bikeputer should work normally or close enough.

 

Successful resolution can require some invasive soldering to the electronics controlling the light, suppression coils around the power leads, or replacement with a unit that complies with FCC/CE/ICASA  EMI regulations.

 

Brand of light?

 

Such a detailed answer and the solution is a tinfoil hat?

 

No man.

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As Savage said.  Get a Garmin  :whistling:

 

Had the same problem with my old Polar S720 HRM.  My led light had three settings.  Low, Med, High.  Riding on low or high would interfere with the Polar.  Med was fine.  But the battery would not last my 80 minute commute on Med.  I am not experiencing the problem on Garmin.

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