Forums Forums Enthusiast Forums A - Z Gadgets & Tech Torch home build help wanted

Hi there,i have a technical question regarding bulbs leds volts amps etc that i don't understand.

So here goes, i have a twin set mountain bike bulb setup


http://www.blt-lights.com/manuals/blt_explorer.pdf

And i want to take out the old mr11 bulbs and fit a cree led kit like this

http://www.cutter.com.au/proddetail.php?prod=cut947

The system is 6 volts, 4.3 amp/hour, sealed lead acid bottle battery
Low beam 6v 6w MR-11 Halogen (avg.run time per full charge: 3.25 hrs.)

How long would i get now on a 370 lumen, and more to the point would this all work together or do i need something else and how easy would it be to solder together.

All the blt system works fine now it just doesn't work for very long and the bulbs are a bit dim compared to the white crees running on my mining caplamp right now.

Ta
pace

I have made many torch contraptions over the years for both my bike and hand held but I have no experience of crees. It you could find out the currant draw of the crees you are planning to use you could work out the run time.

Have you looked here?. Everything you need to know about all things that glow are here.

*****WARNING! MAJOR GEEK WEBSITE URL ALERT!!!*****

http://candlepowerforums.com/vb/index.php?

Have a look in the bicycles sub forum in the transportation lighting section.
Yes I am a member.

Does that mean it only draws 700ma?

Currently the 6v 6w in your low beam draws 1 amp and the 15w in the high beam draws 2.5 amps. So if thats the case the crees would be a significant improvement. Someone who can remember what they where taught in collage better than I can could work out the actual runtime for you.

wd40 informs me that 1 watt at one amp will be 4.3 hours based on my duffish bottle battery

watts = volts * amps - is all you need to know.


A 6 watt bulb at 6 volts, uses 1 amp (ie 6 watts divided by 6 volts - derived from: "watts=volts*amps", therefore "amps=watts/volts").

Therefore a 4.3 amp/hour battery will provide 1 amp for 4.3 hours (you are actually getting 3.25 hours, therefore battery must be a bit dud).

The lumen is a measure of light, and has nothing to do with the electrical power used, it depends more upon the efficiency of the light source (led or bulb). But - a 1 watt cree will still last for the 4.3 hours, but give out a lot more light.

The amp-hour rate for rechargable batteries is based on 20 degrees C and 10 hour discharge current. Higher currents will have a lower amp-hour, likewise temperature at charge and discharge can affect capacity.

What CREEs are you using? The 6V might be a bit too low voltage to drive them after the current regulator.

its this one
http://www.cutter.com.au/proddetail.php?prod=cut947

http://uk.farnell.com/cree/mce4wt-a2-0000-000je5/led-smd-white/dp/1649027

http://www.cree.com/products/pdf/XLampMC-E.pdf