Build Thread: An absurdly bright tent-light.

[Toke]

Entertaining project.
The closest I have been were putting a 250W halogen work light in a 2-man tent.
It looks really cool from the outside, but does not work outside e.g. a festival employee camp, electricians corner.

 

[rhd]

About 5 minutes after taking that photo, I was disconnecting battery packs, an let one of the loose clips short against another (in my carelessness).

The insulation on the wires instantly vaporized, strands of wire glowed bright orange, and all of this in the under 5 seconds that it took me to grab the nearest wire cutters and snip the main power trunk.

So, tomorrow it's back over to The Source to buy some more wire clips

 

[Somedude]

Very nice, can you make something lighter for backpacking?
Im not gonna carry anything i dont have to. :can:

 

[Things]

If you wanna make it as light as possible, then consider using LiPo battery packs instead. You can get them fairly cheaply. The only issue is you have to be fairly careful about charging and discharging them, as they'll find any excuse they can to catch fire.

 

[Somedude]

If you wanna make it as light as possible, then consider using LiPo battery packs instead. You can get them fairly cheaply. The only issue is you have to be fairly careful about charging and discharging them, as they'll find any excuse they can to catch fire.

Some of the places ive backpacked i would have begged for some fire :crackup:
Im to the point now at my age i just fall down, so on second thought i wont need a light,

 

[Things]

You can rely on LiPo batteries to give you fire if needed. All you gotta do is look at them wrong and you'll have fire

 

[Benm]

Somehow i think they dont want to do that... sure, they catch fire if abused, but when you actually need them too splitting cells in half with an axe will probably fail to produce fire.

 

[benmwv]

^^ I have punctured li-po before... No fire. It got warm and stayed warm for two or three days and that's all.

@rhd
Does it get hot quickly? That heatsink looks kinda small for 58 watts of LED.

I have been thinking of making my dad a dusk to dawn light to mount on the garage out of one or two 100W LED's to replace the current one which is two fluorescent 20W or something. For a heatsink I was gonna use a piece of big channel aluminum about 6in wide and 2-3 feet long and half an inch thick then mount fans on the back.

I read some where that when comparing brightness of these generic high power LEDs and incandescent bulbs that roughly one watt of led is equal to six watts of incandescent. And a 100W led is equivalent to a street lamp.

I guess that makes your light equivalent to ~350W incandescent.

 

[HIMNL9]

Careful with the wires sections ..... in that pic of the 10 packs in parallel, i don't see wires thick enough, at the end (for the supposed current of 10 packs, at least )

Those leds you posted, are 11V 1A each, if i recall correctly ..... so, 6A in parallel, more if used at full 12V ..... but also the 4.2A you mentioned are a bit too high, for that what appear AWG24 wire ..... better you use at least 2 x 1.5mm section wire (common cheap red/black wire for loudspeakers ), if you don't plan to get some melted wires for a long time usage

 

[rhd]

Ben:
The LED assembly doesn't get hot at all, but i'm using four fans to keep the lamp cool.

HIMNL9:
The current isn't 6A. As mentioned above, it is 4.2A. I am regulating the current, not just letting the LEDs eat whatever they want.

So each pack would provide 420mA at 16.8 V. Those wires are about the gauge of Flaminpyro wire. Then two sets of five packs are each paralleled using two 22 gauge wires. Those two 22 gauge wires would be carrying 2.1 A at 16.8 V. Then the control unit's output to the LEDs carries 4.2 A at 13 V max, again over 22 gauge wire.

I think all of the above is fine. I ran the setup for 3 hours yesterday, and nothing got hot.

 

[HIMNL9]

^ then it's ok ..... i'm always a bit paranoid, about wires sections, from when an old phon i was using, took fire for that reason ..... from that time, in each thing i build, i tend to always use the double of the needed ones

 

[rhd]

^ then it's ok ..... i'm always a bit paranoid, about wires sections, from when an old phon i was using, took fire for that reason ..... from that time, in each thing i build, i tend to always use the double of the needed ones

The real lack of safety in my build comes from the use of 9V battery clips to attach each battery pack together. 9V clips are too easy to short, especially when you have 10x of them dangling about.

I really need to swap out the 9V clips. I think I will use SAE connectors, unless anyone has a better alternative. The only challenge with these is that I need 20 of them, and there surprisingly doesn't seem to be a cheap source of them online. Lowest I could find was $1.50 each, which is $30 plus shipping just for some damn connectors.

 

[benmwv]

I saw those 9v battery connectors lol.

I don't know exactly what they are called, but have you seen those connectors that have a wire crimp on one side and on the other side the male is just a flat tab and the female is shaped like [ and the edges curl more. I have crap loads of them.

Here is the female one:
ImageShack® - Online Photo and Video Hosting
http://thumbs.dreamstime.com/thumblarge_357/1232606397AbwfiO.jpg

This pic has about every kind there is:
http://www.fabian.com.mt/PAGESgifs/crimpl_64.jpg

 

[rhd]

I decided to go with 10x of these cables:

DC Power Extension Cable (90CM) - Free Shipping - DealExtreme

 

[BShanahan14rulz]

Worst-case, you can short one of the packs and use it as a fire-starter or charcoal lighter. :wave:

 

[rhd]

Just a bit of a teaser. Still some work left, but it's getting there

The 12x DC couplers are required so that I can easily detach each 4S1P 18650 pack from the 4S12P array for charging. It would be pretty darn unwise to trying parallel charging 48 18650s

EDIT: And while it may look like I'm just plugging 4S1P 18650 packs into a regular old laptop AC/DC brick, I'm not. That's a 16.8V lithium ion charger with all the bells and whistles of a typical charger, but at a higher voltage, and in a brick form factor.