electronics help...spoke lite modification

[cityevader]

So I have Niteyez spoke lites that run off two 3v coin cells. They last a few hours and die. The repalcement batteries cost as much as the lites themselves!!! So I had the "brilliant" idea to solder some leads to the circuit board where the batteries connect, then touched them to an 18650 to see how it worked. It glowed fine, and started to switch to another color (fades in/out between 7 or so colors) and then dies. The resistor in the second picture gets really hot and melts the hot glue.
Any rocket scientists out there with an idea to allow the 18650 power source to work?

 

[MikeAusC]

Two coin cells will theoretically put out 6 volts but being so small they have a high internal resistance so when connected to a load the voltage drops.

I suggest dropping the 18650 output by connecting a diode in series. Any 1 amp diode will do.

 

[HKJ]

I suggest dropping the 18650 output by connecting a diode in series. Any 1 amp diode will do.

A resistor is probably a better idea.

 

[bshanahan14rulz]

Yep, I think it wasn't meant to limit input current, that is the batteries' job.

Found this: http://www.azoteq.com/images/stories/pdf/iqs904_datasheet.pdf
here: http://www.azoteq.com/proximity-switches-design/proximity-sensor-switch-datasheets.html

 

[Lynx_Arc]

A resistor is probably a better idea.

+1 on this, the power loss at that current drain coupled with the huge capacity of an 18650 should make for runtime that is mind blowing in comparison. The diode would have an advantage if you were to keep adding more lights to the circuit but for a one time thing a resistor will allow you to choose what level of light you want and change it more easily up/down.

 

[cityevader]

Quick replies, wow!

I'm planning on running two lites in each wheel, if that matters.
As for that capacitive dimming deally-bob...a bit complicated for me. A resistor or capacitor added would be easy.

Approximate value of resistor?

 

[HKJ]

Approximate value of resistor?

100 ohm is probably a good value. If the light is to week, try 47 ohm. In both cases a old fashion 0.25W leaded resistor can be used.
Use a separate resistor for each circuit.

The relative brightness of the different colors will probably not be the same with a LiIon battery as with the coin cells.

 

[cityevader]

Sweet! Had a diode laying around, and sure enough, it works!
Thank you all.