Duneit

Hello all. I have a Trek Allant commuter that came factory with a headlight and taillight. I tow a trailer and want to wire trailer lights off my taillight. I want them to come on and off with the built in bicycle lights. Will this mess with the computer? Does anyone know what the voltage is to the taillight? Thanks for any help. I ride alot of streets and the trailer completely blocks the bicycle taillight

wesmamyke

If I recall the dealer can actually set the voltage with the Bosch software. It has some limits to how high/low it can be set. I think we actually had trouble with one bike that had an updated motor and software, it seemed like it was over driving the lights.

Pretty sure you could swap out the tail light wire for one running to the trailer. Not sure about running them both at the same time. Someone who actually knows how to wire things could do the math on what both lights would require, and maybe the resistance of all the extra wire length if that matters.

Unfortunately the Bosch software is on a USB dongle thing and is dealer only. So you probably need to visit the bike shop. You can get the long wire with connector pretty easily: https://www.ebay.com/itm/11371168379...3ABFBMtp7Z-cpf

BobbyG

Duneit I'm ashamed to say, my first reflex was to think, "how hard is it to turn an LED tail-light on and off?" After all that's what I do.

But then my "adult" inner voice said, "It's 2022...surely some company makes a motion-activated led tail-lamp for bicycles..."

So I Google "motion activated bicycle tail light"...and I'm glad I did!

Not only are there rear lights that turn on when they sense motion, but there are others that light-up brighter when they sense deceleration so they can function as "stop lamps", and they seem affordable.

For some one like me who's first foray into bike lighting was a tire-driven "bottle" generator in 1971, these moton-activated LEDs are like science fiction.

So my suggestion to you is to look into motion activated tail-lights. You may have to recharge them, but if there are any that take batteries, lithium batteries will last for scores of hours in flashing mode.

Anyway, I, myself am going to look into this, so thanks Duneit for posting!

Duneit

This is what I'm doing. Just ordered one to see how I'm going to be able to mount it. They're designed to be installed on a seat post, not a trailer

Sardines

Those Chinese motion sensored lights are screw in attached and USB charged. So order the seat rail mount and unscrew the mounting kit, then screw the mount on your trailer end. I did that with my racks, but felt it wasn't bright enough for riding at night, AND it's a throwaway once the battery is dead, which mine did after 1.5 years. I went with a Cygolite 350 as a replacement, which my battery guy has told me he can definitely replace the liPo battery vs those little motion lights (I bought Meroca, but they have OEM for many different brands).

Duneit

hopefully I bought a good one. It wasn't cheap

Sardines

Huh? They are less than $12 + shipping?

Duneit

I try to avoid cheap Chinese products if possible. They don't last and you have to constantly replace them. I'll try to remember to post a long term review on the ones I purchased. My Grandson is in the trailer I pull. The most valuable cargo ever!

Sardines

That's my point. The "cheap" products are the same OEM of many of the expensive products, just unknown brands.