How I power the lights

[GreenMantis]

I thought I would share this, I thought it was a pretty good idea. I used a 4 cell 18650 holder, and attached the charging/balancing board right to the back of it, so it's like a protected pack, but that I can take the cells out of if I want to. I can charge them right where they are with any appropriate power supply, it doesn't have to be a charger, as the circuitry is on the pack. I can take them out and charge them in the special charger, too. I went with a 4S setup, but 3S would work, and is closer to 12vdc.

 

[machanic]

Nice little package, and 4s is right for 12v which run at 13.8-14.2v, does that circuit balance the discharge also?

 

[GreenMantis]

I think it does. And it's rated for 30A.
https://www.ebay.com/itm/4S-14-8V-3...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

It doesn't really matter all that much, those are IMR 18650 cells, high discharge capacity. Those can make 25A. But it was still a good idea.

 

[GreenMantis]

And at full charge, a 4s stack makes 16.8V, a 3s stack peaks at 12.6V. Either will pass as a 12v system, for the most part, but you have to be careful, since capacitors generally come in certain voltages, and most 12v electronics use 16v caps, and they won't like 16.8v at all. This seems to be the event horizon for most lithium powered electronics, like laptops, which come in either category, 3s or 4s, and they won't interchange.

 

[machanic]

My understanding of lithium batteries is that they do not take being discharged below a certain voltage, I have some that have a over charge over discharge circuit built on the individual cells. As for the voltage I was playing with the lighting coil with its wide range of output voltage and found most of the led lights (I bought about ten in all) work between 6 and 36v with their internal power regulators. With that said I have been looking for a small battery setup to go between the lighting coil and lights to keep the lights bright at idle and in case of a maintenance stop.

 

[GreenMantis]

This setup could do that for you, easily. I think what you would probably want to do is wire in a diode between the charging coil, and the battery pack, with the negative to the pack's positive, and the positive to the coil's positive (or the rectifiers, if you have one). That way the batteries won't dump any current into the coil, the coil will only dump into the battery pack when it's voltage is higher than the pack's is. Did that make sense? The circuit board on the pack will protect the batteries no matter what. At this point, you are running your lights off the battery pack, and your charging system is just charging the pack whenever the voltage (or your rpm) gets high enough.

 

[machanic]

Yes I am running a full bridge rectifier and filter cap off the coil so it won't back feed, the next decision is if I use the USB powered lights or a 12v system.

 

[GreenMantis]

Well as you know, I went with 12v, usb charging sounds bogus to me. The other thing about my little pack setup I like is I can carry an extra set of batteries in my pocket, in case I need them. There are some great led lights out there, now, I have a couple of them, they are great. In addition, I put a lot of lights on mine.

 

[Frankenstein]

No kidding, I went to harbor freight and picked up one of those little led bar lamps, has high medium and an led on the tip as a low. It's just amazingly bright and recharges on a micro USB (the android phone standard) the battery is another one of them 18650 which I already have plenty of. On a work site I can light up everything I need and since the end screws off and the battery can be removed I can and already do carry spare charged cells for it, though it can be used while charging lol. It's also magnetic

Anyway, you're right how amazing these leds are, I'm tempted to throw a s**t ton of these led strip lights on my bike but then I run into not having enough juice, certainly I can power them but having lights for only half a trip is kinda not good... I also don't like the idea of charging a battery every time I ride or even more often than once a week, I get enough of that with my roller skate lights..

 

[GreenMantis]

I used one of these to make the turn signals flash:

https://www.ebay.com/itm/10x-12V-Wi...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649