Planing to use e-bike battery to power head/tail light.

[AF7JA]

I realize this is more headlight related than e-bike; but it is still going on an ebike.


I have a 36V bottle battery for my ebike. I also have a Magic Shine clone and and a 3V (PDW Danger zone) tail light.

Instead of having several batteries on my bike, all with different chargers, I want to power the other two light from the "main" battery.

My plan is to solder leads from the Bottle Battery case, after the main on/off switch, but before the e-bike controller. Those leads would then go to a pair of voltage regulators, one for the headlight and the other to the tail light (I need two of them because they operate at different voltages).

Does this seem sane? Any concerns (I am an Amateur Extra, I know which end of a soldering iron to hold)?


The voltage regulator

Non-synchronous rectification non-isolated Buck (SEPIC) module.
Input Voltage: DC 4.5-55V; Output Voltage: DC 1.25-30V Adjustable.
Output Current: Rated 2A, Max.3A(need heat sink). If output power is more than 15W, please install heat sink.
Short Circuit Protection: current limiting, since the recovery.
Application: DIY Adjustable Power Supply, DIY Universal Charger, Power supply for electronic equipment etc.

 

[flat tire]

Your plan is sane. Consider the efficiency of your regulators and any heat they may need to dissipate as the only issues. A bottle battery sounds like it's pretty small and low-capacity, but even so I wouldn't imagine your range will be much effected unless the regulators get awful efficiency.

 

[Samd]

I don;t like wasting your magic shine, but if you search "80V LED" on ebay you'll find a lot of headlights with regulators built in. You may be able to crimp some connectors and give the sodlering a miss.

 

[ebent]

You are on the right track. You might consider using only 12v accessories. 12v is used on cars and motorcycles so there is a lot of stuff to choose from. I have a 48v pack that sends a lead to a 12v converter. From there I send 12v to a marine grade power bus. That gives me 12v to my head light, tail light, and my motorcycle stereo tiny, with good sound. The lights are led so I do not draw much power. I never need aa and aaa batteries and the lights always work. Charge one battery and all works. I considering a 12v motorcycle horn next.

 

[amberwolf]

Either way works. I actually use both, because I havent' found a (cheap or free) DC-DC powerful enough to properly run the salvaged car headlights and horn I use, so that runs off a 4s NMC 20Ah pack.

Everything else on CrazyBike2 runs off a 15VDC wallwart (from goodwill) that I think used to be a NiCD battery charger, IIRC. The AC-input wall prongs are wired to the main pack via a switch, to turn them off while I charge. All of that stuff is LED, so doesn't take nearly as much power as the halogen headlight.


SB Cruiser presently has everything running off a 4s NMC 20Ah pack, as I haven't gotten another wallwart setup to run them yet, cuz the turn signals are incandescent and take a fair bit of power (still using car headlight, too, so....). The tail/brake light and the downlighting are all LED, at least. All the rear cargo area downlighting, however, does run off the main pack, simply by having the AC wall prongs of the wallwarts of the LED aquarium lights used for the purpose run to the pack.


So, it's easily possible to do what you want, or any combination.