Anyone know what thos cable is for .

Carlyzf250

Member
Feb 16, 2021
11
3
Swadlincote, Derbyshire
Hi all I can't get my bike to turn on . Does anyone know what this yellow cable is for ? It says batt v on it? Thank you

20250212_105146.jpg
 

Stihldog

Handheld Power Tool
Subscriber
Jun 10, 2020
3,973
5,656
Coquitlam, BC
I’m not exactly sure on this brand/model of bike but it does look like an auxiliary power feed for accessories like lights. Activating this circuit may require programming by your LBS.

I found a similar cable in Bosch motor equipped bikes. In several of those bikes I removed the cable entirely and added a small neoprene plug in the motor connection area. This cleaned up the motor compartment area and head tube. IMO this cable was hastily installed during the manufacturing or assembly process…very little attention to care was given.

I eventually continued my quest and added AXS systems (dropper/shifter) which freed up more areas. Dropping the motor is not a complicated matter anymore.…and keeping things clean and dirt-free is easier.

I add this cable (4) to my spare parts bin for future use.
 

HeathenRides

Official Title
Jan 26, 2025
14
10
Norway
Hi all I can't get my bike to turn on . Does anyone know what this yellow cable is for ? It says batt v on it? Thank you

View attachment 154476
V is most likely not volt it probably means it's split of from the battery it's handy to have one of those measure devices with two pen like handles so you can measure the output if it's no output at all it's grounding if it's really thin and not black or red it's either for display or for lights. You could try to Google and see if there is a owners manual with a drawing of the circuit. But I guess you already fund out what it is by now
 

Stihldog

Handheld Power Tool
Subscriber
Jun 10, 2020
3,973
5,656
Coquitlam, BC
Our ebikes at subject constant vibrations …regardless of the terrain. I would start with the main power supply connection. It’s been my experience that even a moment of power loss can cause a number of issues.

The mechanics at our LBS are not electronic technicians … they usually know how to diagnose an issue and replace the suspect part or module until the problem goes away. Sometimes that works.

Electrical connections can be a mystery sometimes …especially when you can’t replicate the conditions. I don’t know what to say? …start with a good power connection. It might look good …but it might not be good.
 

Sergey K

New Member
Feb 24, 2025
4
1
R
This wire comes from the battery, and there is a second one next to the motor. Outputs a range of 30-42 V, depending on the battery charge level. I use it to connect MagicShine 906s via step-down DC/DC to 12v. If the DC/DC is connected with the wrong polarity, the bike will not turn on. If you switch between + and - , the bike will not turn on.

Sorry, I'm using Google Translate.
 
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