building my own bike light budget $50

I attempting to build my own trail head light (not for street use as it would be way to bright.) I ride early in the morning on these trails, like 4am so there is only wildlife on the trail ( dear, raccoon, fox, rabbits ) no people.

Does this look like it might work?



36V 15AH PING

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Anderson connection (this is how I would turn on the power to the unit, as I think 36 volts would blow any Chinese on/off switch.)

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Converter DC 36V Step Down to 12V 3A Power Module
Input Voltage: 15-50V DC
Suggested Input Voltage: Below 40V DC
Output Voltage: 12V DC
Output Current: 3A

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DC-DC 100W Constant Current Boost Step-up Module Mobile Power Supply LED Driver
Input voltage :11-35V
Output voltage: 11-35V (adjustable)
Output Current: 10A (MAX)
Input Current: 10A (MAX) (Please enhance heat dissipation if more than 10A)
Output power: natural cooling 100W (MAX), enhance heat dissipation 150W (MAX)

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(two of these guys, yes I know I’ll look like an aeroplane landing )
50W White 4600~4900LM COB LED SMD Lamp Light Bulb
DC Forward Voltage (VF): 30~34Vdc
DC Forward Current (IF): 1500mA
Viewing Angle: 140 Degree
Color Temperature: 6000~6500K
Intensity Luminous (Iv): 4600~4900LM
Single COB LED Chip Size:45?m
LifeSpan Time:>50.000 hours

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(two of these as well)
LED 44mm Lens Reflector Collimator with Base for 10-100W LED Lamp Blub
Angle: 30-130 degree
Diameter: 44mm
Material: optical glass
Light transmittance: 99%
Compatible for 10W-100W LED spot light, automobile lights, DIY projecting lamp etc.
Service temperature range up to more than 400 degree Celsius
Dimensions: 44mm x 19mm

No way. Those LEDs will be a puddle of molten slag within seconds. You need massive heatinking on those things (like 10 square inches of surface area per watt) unless you use forced air cooling..

Also those Chinese LED arrays are crap. Search Digikey for arrays made by Bridgelux. Here is my 15,000+ lumen light: http://budgetlightforum.com/node/15483

Your 36V to 12V converter is good for 36W total. Each one of the arrays you want burns almost 1.5 times that much, and that's before the step-up converter takes its bite.

the 36V lifepo4 will not work since he has a 40V max on the converter anyway. i think he believes a 36V battery is 36V DC. it is 44V charged.

dnmun said:

the 36V lifepo4 will not work since he has a 40V max on the converter anyway. i think he believes a 36V battery is 36V DC. it is 44V charged.

Click to expand...

Dnmun - you are right i'm an idiot, 44v is what I have. I think I found a good upgrade.

Chalo said:

Your 36V to 12V converter is good for 36W total. Each one of the arrays you want burns almost 1.5 times that much, and that's before the step-up converter takes its bite.

Click to expand...

Chalo - thanks for pointing out the lack of watts, took me awhile but I found a different converter, it should be go!

texaspyro said:

No way. Those LEDs will be a puddle of molten slag within seconds. You need massive heatinking on those things (like 10 square inches of surface area per watt) unless you use forced air cooling..

Also those Chinese LED arrays are crap. Search Digikey for arrays made by Bridgelux. Here is my 15,000+ lumen light: http://budgetlightforum.com/node/15483

Click to expand...

Texaspyro-Thanks, I took a look at some of the arrays by Bridelux, unfortunately there a little out of my price range....

-Do you think if I run the crappy Chinese arrays in these conditions, they would be ok?

+Constant 20mph speed
+Max run time of only ten minutes
+50% power to bring down the heat
+Massive aluminum backplate heat sink. (Exposed in the cool morning air)
+also I found a new converter below.

Thanks for all the input!
Found this guy after some searching.

600W DC-DC 10-60V to 12-80V Boost Converter Step-up Module Power Supply

http://www.ebay.ca/itm/DC-DC-600W-10-60V-to-12-80V-Boost-Converter-Step-up-Module-Power-Supply-/171018322225?pt=LH_DefaultDomain_0&hash=item27d17c8131

Input voltage : 10V -60V
Input Current: Maximum input current of 15A
-Output voltage : 12V -80V continuously adjustable
-Output current: maximum output current of 10A ( adjustable )
-Output power: the effective power P = input voltage V * 10A
-Conversion efficiency: up to 95% ( input voltage, current; output voltage and current impact of conversion efficiency )
-Short circuit protection : Fuse

its_me_jason said:

I took a look at some of the arrays by Bridelux, unfortunately there a little out of my price range....

-Do you think if I run the crappy Chinese arrays in these conditions, they would be ok?

+Constant 20mph speed
+Max run time of only ten minutes
+50% power to bring down the heat
+Massive aluminum backplate heat sink. (Exposed in the cool morning air)
+also I found a new converter below.

Click to expand...

You get what you pay for... the best Chinese 100 watt array puts out less light than a Bridgelux array at 60 watts.

Surface area is everything when it comes to passive cooling of LEDs.

I would just swing for the 100W LED arrays at that point. They're about $15 and are capable of reasonable light output. You absolutely need a big heatsink with airflow, but they don't put off all that much heat if you drive them at something like 50W. Straight passive will end poorly unless the heatsink is gigantic. You can put one of those snazzy Airpax TO-220 thermal switches on the heatsink if you want a bit more protection, but its probably fine if you avoid stopping much.

It's hard to beat those 100W chinese arrays at this price.

http://www.ebay.com/itm/100w-White-led-Free-US-shipping-US-seller-DIY-8000-9000LM-/251253195781?pt=LH_DefaultDomain_0&hash=item3a7fdb8405

http://www.ebay.com/itm/100W-White-High-Power-LED-Panel-9000LM-100-Watt-Lamp-Light-/380471977704?pt=LH_DefaultDomain_0&hash=item5895e5a6e8

Never mind, after lots of reading this 600W DC-DC 10-60V to 12-80V BOOST Converter Step-up Module Power Supply will not work...

-BOOST is for when you have a battery pack that is less then the required voltage.
-BUCK is for when you have a battery pack that is greater then the required voltage.
-BUCK/BOOST converter is for when your not sure. but these cost more and use a-lot more juice.

I have a 36 volt battery, and charged it is 42V i think, and 100W led requires a forward voltage of 30V-34V so i need a "DC-DC buck converter that can handle an input of more than 42V"....

So the search on E-bay continues!

ZOMGVTEK said:

I would just swing for the 100W LED arrays at that point. They're about $15 and are capable of reasonable light output. You absolutely need a big heatsink with airflow, but they don't put off all that much heat if you drive them at something like 50W. Straight passive will end poorly unless the heatsink is gigantic. You can put one of those snazzy Airpax TO-220 thermal switches on the heatsink if you want a bit more protection, but its probably fine if you avoid stopping much.

It's hard to beat those 100W chinese arrays at this price.

http://www.ebay.com/itm/100w-White-led-Free-US-shipping-US-seller-DIY-8000-9000LM-/251253195781?pt=LH_DefaultDomain_0&hash=item3a7fdb8405

http://www.ebay.com/itm/100W-White-High-Power-LED-Panel-9000LM-100-Watt-Lamp-Light-/380471977704?pt=LH_DefaultDomain_0&hash=item5895e5a6e8

Click to expand...

done and done. 100W array it is.

Ok my new setup with Start with My Ping 36V 15A battery

I need to find a switch that can handle 36+Vs for now I will use these guys.

then I have a DC to DC 3-60V 12 24 48V step down buck power converter
current: Max current=3/(input voltage-output voltage)
D-value of voltage: at least 3V between input and output voltage
input: 4.5-63V
output: 3-60V

Next is a massive heat sink, I'm not sure which one to pick yet. one of these two.
this

or this

then the 100W White High Power LED Panel 9000LM
View attachment 1
then the 44mm Lens Reflector Collimator & 50mm Base

I loved my Ping and Ping too. Just don't turn the amp's up to high on your controller. My 48v20ah worked great below 25 amps. It didn't like my 40amp controller and hills combo.

I need to find a switch that can handle up to 42V to turn the buck on and off so its not draining the battery all the time.

Hi Jason , if this buck converter u pasted is based on lm317 ...it wont work dont bother with it .U need a led driver with that + step down .
Best of luck

Indeed.

You can modify the 150W buck converters available cheaply (someone else did this here) with a little effort.

100W is rather a lot of light for a bike - I was running 3 cree XM-L lights for night-time singletrack (some of the most fun you can have) and rarely was short of light.

What are you planning to be doing that you need that much light? Riding with sunglasses at night?

ev tocak said:

Hi Jason , if this buck converter u pasted is based on lm317 ...it wont work dont bother with it .U need a led driver with that + step down .
Best of luck

Click to expand...

Not sure what you mean by based on lm317?

I know the 100W led I bought needs Forward Voltage between 30-35Vdc and a current 3000 - 32000mA

Here are the specs on the buck converter

-input: 4.5-63V ( I'm going to have 36V ping, 41V charged )
-output: 3-60V ( I would tune this down to 30V )
-D-value of voltage: at least 3V between input and output voltage ( In the morning with a fully charged battery this should not be an issue )
-current: Max current=3/(input voltage-output voltage)
-load regulation: ±1%
-voltage regulation:±0.5%
-Dynamic response speed:5% 200uS
-temperature: industry class （-40℃ to +85℃）

from what I saw on one site (ill see if i can find it again) it said all i would need is a buck converter with low ripple as the led driver.

heathyoung said:

Indeed.

You can modify the 150W buck converters available cheaply (someone else did this here) with a little effort.

100W is rather a lot of light for a bike - I was running 3 cree XM-L lights for night-time singletrack (some of the most fun you can have) and rarely was short of light.

What are you planning to be doing that you need that much light? Riding with sunglasses at night?

Click to expand...

I just bought a 5 cree xm-l its still in the mail somewhere can't wait to get it. I'm just building this 100w light for fun. Why..... because i can, I mean.... I think I can lol. Ill let you know.

By the way, what is night-time single track?

Oh, this is just great (the fact I found this thread)!
I was also thinking of buying the $14 "100 watt" LED arrays off of ebay.

Related: http://tesladownunder.com/WorldsBrightestBike.htm#BikeLights

3 LED arrays in series and I get a voltage range for the LEDS of 96 to 108v
My 24s pack outputs within this range, so it would be pretty much plug-n-play with the bike.

I also came across these as an alternative but don't have much experience with the types of car headlights so I'm unsure if they're any good.
http://www.ebay.com/itm/2-X-H1-XENON-HID-SUPER-WHITE-HEADLIGHT-Bulbs-Bulb-Car-/130803138108?pt=US_Car_Lighting&hash=item1e74797e3c
Multiple bulbs in series would land total required voltage around what we're running our bikes at. Any comments? How do these compare to the $14 "100W" LED arrays?

Cool article... wow he spent $500 dollars per led??? now there $15 lol

When your using your ebike the voltage of the battery goes up and down. This is not good for those Leds, they need a constant voltage from what ive read.

There is 3 basic topologies, buck, boost, and buck-boost, if your going to drive a 100W led, it is normally 33V forward voltage type. if you put two of these converters in a row one will blow!

its_me_jason said:

When your using your ebike the voltage of the battery goes up and down. This is not good for those Leds, they need a constant voltage from what ive read.

Click to expand...

Do you have a source on variable voltage being bad for LEDs? I know that there is an exponential relationship between voltage and current when powering an LED, but because I would always remain several volts below the maximum voltage of 3 arrays, I don't think the varrying voltage would do any damage to the LEDs because the current wouldn't reach dangerous levels to burn the LED junction (assuming adequate cooling is used to keep the overall array cool). The only effect as a result of directly running it off my bike's battery that I can see would just be a varrying level of brightness as voltage drops (and even more-so current) when the bike's controller/motor uses current.

I double checked, you are right! no constant voltage required, but I found this bit of info.....

If the maximum voltage rating is exceeded by a small amount, the current rating may be exceeded by a large amount, potentially damaging or destroying the LED. The typical solution is to use constant-current power supplies, or driving the LED at a voltage much below the maximum rating. Since most common power sources (batteries, mains) are constant-voltage sources, most LED fixtures must include a power converter, at least a current-limiting resistor

Electrical polarity
As with all diodes, current flows easily from p-type to n-type material.[100] However, no current flows and no light is emitted if a small voltage is applied in the reverse direction. If the reverse voltage grows large enough to exceed the breakdown voltage, a large current flows and the LED may be damaged. If the reverse current is sufficiently limited to avoid damage, the reverse-conducting LED is a useful noise diode.

I thought it would be fun and inspirational to post these home made lights ive seen, thanks for the link to the last two!! lol




View attachment 3

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its_me_jason said:

ev tocak said:

Hi Jason , if this buck converter u pasted is based on lm317 ...it wont work dont bother with it .U need a led driver with that + step down .
Best of luck

Click to expand...

Not sure what you mean by based on lm317?

I know the 100W led I bought needs Forward Voltage between 30-35Vdc and a current 3000 - 32000mA

Here are the specs on the buck converter

-input: 4.5-63V ( I'm going to have 36V ping, 41V charged )
-output: 3-60V ( I would tune this down to 30V )
-D-value of voltage: at least 3V between input and output voltage ( In the morning with a fully charged battery this should not be an issue )
-current: Max current=3/(input voltage-output voltage)
-load regulation: ±1%
-voltage regulation:±0.5%
-Dynamic response speed:5% 200uS
-temperature: industry class （-40℃ to +85℃）

from what I saw on one site (ill see if i can find it again) it said all i would need is a buck converter with low ripple as the led driver.

Click to expand...

Lm 317 linear volt.reg ..from the photo it sure looks like it ,u are going to power 100w led with it correct '?
If so it wont work ,Also from the specs it doesnt say max wattage ...i suggest u to ask seller bout it.
here is what could work for u ,check da specs
http://www.ebay.com/itm/DC-DC-48V-t...0838854788?pt=US_Adapters&hash=item43b758bc84