Running Tail and Front Lights From Controller Help!

I’ve been thinking about running tail LED and front LED from my controller. They are both USB, and up until now I just bring a power bank along with me and plug them in there. I’d like to make a USB hub using my controller, but I’m not sure if it would be able to handle the 2 amps required to run the lamps.








We have a 13003 transistor which goes into a big coil thing (don’t know what this is), which somewhere along the line delivers 14v to the AS78L05. Now obviously I would need to upgrade this 7805, and I plan to use a bigger and more efficient buck converter to do this. But I’m not sure how much current I can draw from it, because I don’t know what that coil is doing and what current these other parts can take.

So maybe my other option is to get a step down converter, though this is challenging because I couldn’t find a good one for above 72v for cheap.

420b said:

I’ve been thinking about running tail LED and front LED from my controller. They are both USB, and up until now I just bring a power bank along with me and plug them in there. I’d like to make a USB hub using my controller, but I’m not sure if it would be able to handle the 2 amps required to run the lamps.








We have a 13003 transistor which goes into a big coil thing (don’t know what this is), which somewhere along the line delivers 14v to the AS78L05. Now obviously I would need to upgrade this 7805, and I plan to use a bigger and more efficient buck converter to do this. But I’m not sure how much current I can draw from it, because I don’t know what that coil is doing and what current these other parts can take.

So maybe my other option is to get a step down converter, though this is challenging because I couldn’t find a good one for above 72v for cheap.

Click to expand...

Seems complex. I run a small lead acid battery that is used just for lights and horn. Wire it directly to the battery, even have turn signals. I put a switch on the positive side of the Lead acid battery, and I switch on and off as needed and of course use the turn signal switch. Very simple, no messing with the expensive controller and the LAB charges easily in a short period of time. I have used a 6ah battery for hours with several high powered lights on my bike. Quick and easy set up.

$10 Plug and play
https://www.amazon.com/ZOOMPOWER-el...537891409&sr=8-4-fkmr1&keywords=72v+to+5v+usb

$4 DIY (can probably fit inside existing controller or use a small project box)
https://www.ebay.com/itm/5V-2A-Dual...-Buck-Step-down-Power-Converter-/173487748733

2WheelsMovesTheSoul said:

$10 Plug and play
https://www.amazon.com/ZOOMPOWER-el...537891409&sr=8-4-fkmr1&keywords=72v+to+5v+usb

$4 DIY (can probably fit inside existing controller or use a small project box)
https://www.ebay.com/itm/5V-2A-Dual...-Buck-Step-down-Power-Converter-/173487748733

Click to expand...

Wow, great finds! I obviously wasn’t looking hard enough. I think I’ll go for the second one because it has two USB and it’s cheaper. I’d maybe fit it in some plastic case or find one for sale with an acrylic case. My only worry is that at full charge my battery would damage it at 84V but it might work... Anyways, you’ve set me on the right track. Thank you.

changeissimple said:

420b said:

I’ve been thinking about running tail LED and front LED from my controller. They are both USB, and up until now I just bring a power bank along with me and plug them in there. I’d like to make a USB hub using my controller, but I’m not sure if it would be able to handle the 2 amps required to run the lamps.








We have a 13003 transistor which goes into a big coil thing (don’t know what this is), which somewhere along the line delivers 14v to the AS78L05. Now obviously I would need to upgrade this 7805, and I plan to use a bigger and more efficient buck converter to do this. But I’m not sure how much current I can draw from it, because I don’t know what that coil is doing and what current these other parts can take.

So maybe my other option is to get a step down converter, though this is challenging because I couldn’t find a good one for above 72v for cheap.

Click to expand...

Seems complex. I run a small lead acid battery that is used just for lights and horn. Wire it directly to the battery, even have turn signals. I put a switch on the positive side of the Lead acid battery, and I switch on and off as needed and of course use the turn signal switch. Very simple, no messing with the expensive controller and the LAB charges easily in a short period of time. I have used a 6ah battery for hours with several high powered lights on my bike. Quick and easy set up.

Click to expand...

I currently have something like that set up. I made a DIY power bank with USB output from some old laptop Sanyo 18650 cells. I’d just like to consolidate the power sources into one battery so there is less to worry about in terms of charging and organisation.

420b said:

Wow, great finds! I obviously wasn’t looking hard enough. I think I’ll go for the second one because it has two USB and it’s cheaper. I’d maybe fit it in some plastic case or find one for sale with an acrylic case. My only worry is that at full charge my battery would damage it at 84V but it might work... Anyways, you’ve set me on the right track. Thank you.

Click to expand...

Pretty sure it would work at 84v.

It's cheap enough to take a shot. Sometimes these cheap parts work very well and last, as long as you "finish" the job.

Personally if I were going this route, I'd also buy an on/off switch, a fuse and a $1 5v mini fan.
https://www.ebay.com/itm/Cooling-Br...256105&hash=item48b1f0e3fc:g:~LUAAOSwqo5bfxVw
Tap 5v power off the board and mount the fan on there to make sure it never fails from overheating.

ProTip: adding a layer of silicone conformal coating would make sure it lasts

I don’t see why you want to run the lights from the controller. Though I have seen some controllers that have a running and brake light circuit, and some are now pretty common with USB charging circuit. I still find the simple way is to run them from the battery, either using a DC-DC converter or using lights (or lights combination) that can be powered with full battery voltage. I prefer leaving the controller with its basic function and avoid crowding it with multiple add-ons, because I ride them high power and they get hot, but even building conservative I would like them minimalist for simple repair or replacement.

At 72v, most 120vac phone chargers will work directly. Just attach wires to the prongs. You might have one lying around.

fechter said:

At 72v, most 120vac phone chargers will work directly. Just attach wires to the prongs. You might have one lying around.

Click to expand...

That’s insane! I’ll try it on a Chinese cheap one.

well i run a small 5 amp buck converter spliced into the battery connector on the controller side with a inline mini blad fuse on the hot side and a on off switch on the negative side.. you could always solder the usb connector on the output of the buck converter. in a usb the last pin on either side is the power pins. if it was me i would cut the usb off and use desired connection or solder because then you can parallel both of your lights on the same power source and you will be able to see the hot and negative side wire colors in the wire jacket housing. but also it's worth mentioning that LEDs have a wide range of voltage acceptance and you will be surprised how high a voltage LED lights can run on without destroying themselves. my other bikes controller has a auxiliary power connector it still is battery voltage but I did not have to splice anything I just had to make a connector to meet up with it