Homemade emergency LED Lantern - looking for ideas

[Frank C.]

Re: Homemade emergency LED Lantern - looking for i

Can anyone recommend a good online source for LED's and such, and what particular ones I should be looking at? Though a banner ad on this site I found BUWLC333BA10 white 10K mcd LED's, do those sound fine for this application?

Thanks,

 

[mvisconte]

Quick and Dirty

[ QUOTE ]
WildRice said:
depending on how much work and how complex you want it. 1 way would use dorcy parts, ie dorcy board and LED. connect this to a single 'C' or 'D' cell and install into something. LONG running and bright.

[/ QUOTE ]
That's a neat quick (and not really dirty) solution. It's been more than two decades since I've done any real circuit development, so it has more than a little beauty for providing a ready-made circuit w/out needing mail-order, soldering, or a ton of research... Is there one or another model that you would recommend? My wife has wanted me to find a LED lantern for emergency use... I found a "Mountain Green" 30-LED model at REI and I popped the case for a look. I was pretty much disgusted. Disappointed at the circuit -- looks like strings of LEDs w/ just a resistor for current-limiting. Disgusted that I paid $50 for the sorry thing. Made up my mind that we need something suitable before we lose power during the next storm or hurricane. I was hoping to find recommendations for commercial models in the forums, but evidently haven't mastered the search yet.

Which, if any, Dorcy models can I scavenge to make my own D-Cell (or multi-D-Cell) lantern?

It's been over a year since I've haunted CPF, so I'm really out of touch w/ the SotA.

 

[KevinL]

Re: Quick and Dirty

Hi Frank,

Hope this isn't inappropriate, since you did ask.. I do sell loose LEDs as well, 26k MCD white (approx. 2x brighter to the eye than the 10Ks) here. The 26Ks get their increased brightness through increased efficiency, so your runtime will be approximately the same as the 10K mcd when both are driven at spec (20-25mA).

 

[WildRice]

Re: Quick and Dirty

If you are going to gut-em for parts, get the 'AAA' the cheapest. And what Kevin said, the 20 and 26Kmcd LED's make a huge difference. some 20k's I asked Craig to test came back something like 9600mcd at 10mA (which is what most standard whites put out at 25mA). If you mod up the dorcy boards, you may want to change the resistor on the board or add a small resistor in the circuit, as the 20-26k's DON'T need/like to be overdriven. (or put 2 LED in parallel). Now the boards from the "AA" model are a bit more robust. They can overdrive 3LEDs, or 6 or so 'nice' ones in parallel. Put one of those circuits, 6 26k mcd LEDs, in a lantern that uses 2'D' batteries (reconfigured from series to parallel (1.5v)), put a toggle switch with a center off position and a resistor (15ohm mabyee) for low mode, and it should chug along in the dark for a LONG LONG time.
Jeff

 

[James S]

Re: Quick and Dirty

I did the taplight mod mentioned earlier. It took 4AA's so I put 2 led's in paralel with a resister to limit current to about 50ma (25 through each LED) my daughter uses this light as a playing or reading in bed when everything thinks I should be asleep light and it gets left on quite often all night long as she falls asleep next to it with a book /ubbthreads/images/graemlins/smile.gif

In the almost 2 years since i've built it, I've just changed the batteries for the 3rd time. Considering the number of nights she has left it on all night it's amazing how long it's lasted.

What would be nice would be a switch to remove the resister when the batteries get low so that it will be bright again after it has faded. But even thats not totally necessary.

For an LED holder I just broke out the glass from the bulb that was in there and soldered my led's and resisters directly into the bulb base so they can even be removed and moved to a different lamp in the future if I choose.

That being said, I also really like the idea of the little booster and a single cell of any size. Around here though. D cells completely dissappear from the store shelves as a hurricane approaches. All those hungry maglights need to be fed /ubbthreads/images/graemlins/smile.gif so an adaptor or a way to run these things from AA's (which were plentiful even as people were boarding up their windows) would be a good idea.

 

[WildRice]

Re: Quick and Dirty

There is a flashlight at wal-mart that has a selector switch for "AA" "C" and "D" batteries, kinda pricy tho.

The main idea at the top of this thread was 10 or so lights. The cheapest way to make ten would be a cheap housing and minimal if no electronics. some kind of pipe (PVC) and 2 cells direct drive a 26kmcd LED would be about the cheapest/simplest way.
Jeff

 

[KevinL]

Re: Quick and Dirty

C-cell lights are nice. In an emergency you can fab an "adapter" by rolling up paper. It so happens they are exactly the same height as AA cells. /ubbthreads/images/graemlins/smile.gif

Remember, there is nothing that duct tape, paper (of any kind.. surely one must have a newspaper around at least), and aluminium foil cannot do in an emergency /ubbthreads/images/graemlins/grin.gif

Round here we used to say, when push comes to shove.. well, put it this way, we've been shoved many times and many interesting things that would otherwise have been deemed impossible have been made possible /ubbthreads/images/graemlins/ooo.gif

 

[NewBie]

[ QUOTE ]
Frank C. said:
Last night we had a good long power outage. Despite numerous flashlights saving the day (night?), I felt what I need now is a bunch of small LED "lanterns" to scatter around the house to provide light during these emergencies. Sure, flashlights work, but it'd be nice to have a stationary light in each bathroom, in the hallway, on the stairs, etc.

I think this would be a nice fun project for me and my boys to work on. What I'd like to end up with is around 10 little lanterns, each with one or more LED's, a switch, and a big enough battery pack to allow them to run for, say, 48+ hours non-stop. Something similar to the Surefire Hurricane lights. I know I can just wire up an LED, a 100 ohm resistor, and a pair of batteries, but I'm looking for any suggestions on what might be better, what specific parts to use, etc.

If this has been covered before, I apologize - I wasn't quite sure what to search on.

Thanks!

[/ QUOTE ]

A set of low cost modified THORs (25 dollars), with a luxeon put in place of the H4 bulb, running at say 100mA, would put out light for a good two days continously. Keep in mind, that you'll at least need a resistor.

If you were to put a buck switcher in there, you could easily have light for 10 days.

Set them up and let them bounce light off the ceiling, and you have a great area light.

 

[Lynx_Arc]

Re: Homemade emergency LED Lantern - looking for i

one cheap way to make a bunch of AA-D adapters is buy a stick of 1/2 inch copper pipe air conditioner insulating, cut to length and slice out a little on the side to make the diameter smaller. It fits very snugly and when you get the right size tape it up on the side to maintain the size. You can get a long 8 foot stick for a little over $1 at Lowes.
I also saw an adapter pack with 4D and 4C to AA adapters with 4 AA batteries (generic cheap brand) at walmart.

 

[mvisconte]

Re: Quick and Dirty

[ QUOTE ]
James S said:
... I also really like the idea of the little booster and a single cell of any size. Around here though. D cells completely dissappear from the store shelves as a hurricane approaches. All those hungry maglights need to be fed /ubbthreads/images/graemlins/smile.gif so an adaptor or a way to run these things from AA's (which were plentiful even as people were boarding up their windows) would be a good idea.

[/ QUOTE ]

I have been eye-ing the LED Supply converter (http://www.ledsupply.com/02009a.html), although I am open to others if somebody offers their favorites... This one is supposed to run down to 0.8v, which is pretty good in itself, but if you use a two-battery (series), you will pretty much drain the suckers period. I hate wasting batteries (wink).

We get our batteries long ahead of time... at Lowe's or other depot-like store, getting 12 or more for $10. It works well w/ the D size, but w/ 3 kids w/ CD players, and no sense of waste, the AA's tend to "disappear". Sigh. Still, having a converter or a muliple-size battery holder, makes it a little more flexible. I'm hoping to rig something to beat the cheap (but expensive) "Mountain Green" PoC(tm)... Some 26k LEDs and some refractive material (a la http://www.niteize.com/productdetail.php?category_id=26&product_id=97 ? ) and I think I'll have some powerful but not blinding lanterns. The only downside w/ the LED Dynamics driver is the 3v upper limit. Limits design use to dual battery designs. Then again, w/ appx 28 watts available in ONE D-cell, a dual-D-Cell lantern would really last a long time. Do they make in-expensive dual D-Cell lanterns commercially? I have only seen the 4 / 8 LED / CFL lanterns or the quad-AA-Cell lanterns (at Walmart!).