Crossfire front light - wiring take-off point?

Electrically assisted bikes, trikes, etc.
james01
Posts: 2057
Joined: 6 Aug 2007, 4:48am

Crossfire front light - wiring take-off point?

Postby james01 » 5 Dec 2020, 12:03pm

I'm hoping to install a decent ebike front light onto a Carrera Crossfire e-bike. Does anyone know if there is a point in the wiring harness to tap into? Can't see any thing in the manual. I'm aware of the USB socket under the speedo, but this is only 5 volts, which severely limits the choice of suitable lamps.

hemo
Posts: 886
Joined: 16 Nov 2017, 5:40pm
Location: West Sussex

Re: Crossfire front light - wiring take-off point?

Postby hemo » 6 Dec 2020, 11:32am

Most of my controllers utilise a specific lighting cable, on one controller without this I spliced in to the v+/v- wiring between controller and battery and used the 6 - 80v lighting with internal buck converter via a switch with an inline mini fuse. Wiring the front and back one in parallel.

hemo
Posts: 886
Joined: 16 Nov 2017, 5:40pm
Location: West Sussex

Re: Crossfire front light - wiring take-off point?

Postby hemo » 6 Dec 2020, 11:34am

The usb even if it could take the voltage are only suitable for small current draw < 1a.

james01
Posts: 2057
Joined: 6 Aug 2007, 4:48am

Re: Crossfire front light - wiring take-off point?

Postby james01 » 7 Dec 2020, 9:47am

hemo wrote:The usb even if it could take the voltage are only suitable for small current draw < 1a.


Yes. In fact the manual states that the output from this accessory socket is only 0.5 amps. The resulting 2.5 watts would be insufficient for the type of headlamp which I was hoping to fit, even if I could find a 5 volt lamp.

hemo
Posts: 886
Joined: 16 Nov 2017, 5:40pm
Location: West Sussex

Re: Crossfire front light - wiring take-off point?

Postby hemo » 7 Dec 2020, 11:53am

Adding lights is fairly simple if you can solder, wiring only needs to be thin 22/24awg capable of min 4a current load. Either splice the v+/v- wiring between battery/controller or if brave enough add tails inside the controller on the same two power wires.

james01
Posts: 2057
Joined: 6 Aug 2007, 4:48am

Re: Crossfire front light - wiring take-off point?

Postby james01 » 7 Dec 2020, 1:26pm

hemo wrote:Adding lights is fairly simple if you can solder, wiring only needs to be thin 22/24awg capable of min 4a current load. Either splice the v+/v- wiring between battery/controller or if brave enough add tails inside the controller on the same two power wires.


I'm OK about the actual wiring job, but I feel unsure about any knock-on effect on the electronics of an Ebike of interfering with the wiring & adding an accessory. I'm probably over-thinking it!

hemo
Posts: 886
Joined: 16 Nov 2017, 5:40pm
Location: West Sussex

Re: Crossfire front light - wiring take-off point?

Postby hemo » 7 Dec 2020, 7:39pm

Adding lights won't affect how the power is supplied or how the kit is used as long as shorting of the wiring is prevented.
If adding lights add an inline fuse 3 or 5a close to the controller or battery on the v+ line, mini blade fuse holders with tails are ideal.
If the battery BMS hits lvc then the bike won't have enough power to power the bike but will have plenty left to power the lights to get home.