What do you think of my custom light plan?

[deejayspinz]

Hey all,

First off - I am so glad I found this forum... Over the past months while perusing DX and ordering various bits, I found myself getting more intrigued by all the lights that DX had to offer.. and then the idea hit - my current VistaLight Halogen light is wearing out and I want to build my own custom LED lights..

Soo.. doing some research on DX, I decided to order:

2 x ROMISEN RC-U4

..and power them with a sony battery:
SONY FP90 Compatible Battery (7.2V 2300mAh High Capacity Li-Ion)

I was not aware of this forum before ordering, and hope that I made the right choices. My goal was to have 2 lights that have a nice flood and not too much of a spot. 1 for the helment and 1 for the bars. My biking is all techical MTB'ing.

The plan is to mod the 2 lights, by removing the center section, joining the tailcap to the lense section and then run wires out to the Sony battery with a custom case.

Any suggestions on what to use to join the tailcap to the lense section without it being permanent? One thought I had was to use electrical shrink tubing around the outside of the 2 parts and join them using silcon. That way I could cut it if I need to get back in to mod the emitter etc..

On an aside note, I managed to find some good silcon outer wiring from my local Sayal electronics shop. Im using an RCA-jack stereo cable. I had a look at the wiring inside to ensure it could handle the current draw (approx 1A). The inner wires are 18GA.. one is sealed the other is braided around the rest. I dont envision this having any issues. Thoughts?

Still waiting for the order from DX, but will post pics as I go..

 

[[email protected]]

Well your idea might work. It kind of depends on what kind of driver the flashlight from DX has in it. The range on the driver and the batteries they mention as working makes me a bit skeptical. If the driver is resistor based (or uses an amc7135 driver chip) it will get pretty hot driving a 3.6 volt LED from a 7.2 volt battery. As a general rule of thumb, for a resistive or transistor based driver, power dissipated in the driver will be current thru the LED times difference between battery voltage and LED voltage, in this case about 3.6 volts times 1 amp or about 3.6 watts (conversion efficiency of less than 50%). If the driver uses an inductor and a decent driver chip, the driver will likely dissipate much less power. If they are using the Zetex zxsc300 as a driver chip you'll get much better conversion efficiency (70% to 85%).

Pop open the LED housing if possible and report back what's inside. That may encourage others to follow your lead.

Mark

 

[deejayspinz]

Thanks for the tips... I did not even think about the driver and its abilities... When I get the lights I will pop them open to get a look at the driver. Would the power dissipation translate to more noticeable heat?

 

[Szemhazai]

Would the power dissipation translate to more noticeable heat?

Yes, you will have nice warmer for cold winter rides :devil:

 

[pushy]

For helmet lights I have used 2 of these and modified them by doing this and mounted them on the helmet using velcro tape with hook on one side and loop on the other.

I use 4x18650 protected batteries in parallel for extended runtimes and for the handlebar I use this modified in the same way to accept the same external battery pack.