Converting a Florecent Camp light to LEDs

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Converting a Florecent Camp light to LEDs

Postby donavan » September 26th, 2012, 9:22 am

I have an older Coleman Camp Lantern with works fine enough but it eats batteries and could use some new bulds becuase the old ones or a bit burnt on the ends. The lantern currently is powered by 6 D cell batteries wired in series. The bulbs are also wired in series and what I am able to read off of them indicate they are 4.? volt florecent tubes. So my question is this... is there an easy way to hack this sucker to cheaply allow me to use LED's or would I be better off just tossing this one in the closet as a back up and buying a new one. The cost of replacing the bulbs is about $20. and for about $10 more I could buy a new LED version, so hackaday what do you think ... hack it or just use it till the bulbs finally give out.
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Re: Converting a Florecent Camp light to LEDs

Postby UAirLtd » September 26th, 2012, 11:35 am

Hmm...difficult question to ask.

Firstly one thing you should note is that florescent lamps need high voltages (often AC), so almost definitely there is going to be a small circuit somewhere that is boosting the low DC battery voltage to a high AC voltage.

The question is: where is this circuit? If it's in the bulb (usually inside the plastic plug housing), then the lantern need only supply the bulb with the DC battery voltage, and let the bulb do the converting. This would mean you could remove the bulb and replace it with some LEDs without too many problems.

However if the circuit is inside the lantern, supplying the bulb with high voltage AC, then you're going to need to bypass this circuit inside the lantern in order to plug your LEDs in. OR an interesting option comes to mind: if the voltage output by the converter is relatively stable in the range of 85-265Vac at the right power output, then you could wire that to one or more of these things: http://www.ebay.com/itm/GU10-LED-Light- ... 1c2b999538 and suddenly you have a pretty cool hack that turns a boring old lantern into an LED lantern with color controls.
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Re: Converting a Florecent Camp light to LEDs

Postby donavan » September 28th, 2012, 3:19 am

Although I like the idea of the color control, that would be a pretty big hack for this lantern to make it physically fit. If you check the link http://tinyurl.com/czvvygo you can see what I'm talking about. I will take a volt meter to the connectors the bulb sits on and see what I'm getting voltage wise. I don't really want to have to convert form DC to AC and then back again as this will surely cut into my batter life thus the desire for going LED in the first place. I think hacking out the AC driver circuit (if it exists) is my best shot. So that leads me to my next question of how do I go about wiring up the LED's to get the maximum juice out of each battery and also which type I should use. One thought I had was getting a couple of the Maglite LED upgrade bulbs sticking a bulb socket in the base and making some sort of reflector to angle the light out of the lantern rather than straight up at the cover. Opinions?
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Re: Converting a Florecent Camp light to LEDs

Postby UAirLtd » September 28th, 2012, 4:16 am

yes, bypassing that circuit would be ideal, if it exists inside the lamp. I would actually advise you open it up to check if it's relatively easy before probing around.

As for LEDs, I'd suggest you go with some high intensity power LEDs like 3W LEDs.

Now to connect up your LEDs, you've got many many options of circuits to safely drive your LEDs, two of them are worthy of note. Firstly the simplest, is to add a small resistor in there to limit the current of the LED. In some instances you can actually get away with not using a resistor if your battery voltage matches your LED's nominal forward voltage well. If you use Alkaline D cells, then your battery voltage ranges between 6V and 9V depending on charge, in which case you should use two 3W LEDs in series, and a 2W rated 2.7 ohm resistor. If you use ONLY NiMH cells, then you can in theory get away without a resistor when using two 3W LEDs in series, though to be on the safe side, you might want to add a <1 ohm resistor in there, you can use 1/4W rated resistors in this case since you won't be expecting to dissipate much power in the resistor.

Note: you could also double up the circuit if you wanted more light output, simply by adding in a second chain of two LEDs (plus the resistor) in parallel with the first.

The problem with using a resistor is two-fold, firstly you're loosing power in the resistor, and secondly because there's not actual regulation of current (the resistor is there just to limit the current), it means that the lamp dims as your battery runs down. This may be a good thing - it'll remind you when to change the battery, and maybe you might even get sufficient light on nearly empty batteries.

The other choices involve more complex LED driver circuits, though you may be able to buy a driver module off the shelf.

My suggestion however, is to go with the resistor option, and try it out with nearly-flat batteries, and see if the light intensity is still adequate, if not then go with the regulator.
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Re: Converting a Florecent Camp light to LEDs

Postby donavan » September 28th, 2012, 4:53 am

Thanks for the info I know about the resistors and the LEDs in series and also the downfall of going that way. I will be using just disposable D cell batteries with this lamp... not worth building a charging circuit and getting the batteries for it when I can ebay a whole lamp for about 20$ with a crank charger. What is your take on the LED replacements for the Maglite's I have used a few on my mini maglites and they are great and I know they make some for the larger cell units that will handle 2-6 cell units, which tells me they have all the voltage limiting hardware built in. I know the one mini-mag replacement bulb I use you can see 3 LEDs and some small IC and some resistors. Im only guessing the same is the case with the rest of them just plastic covered. If I can implement them then all the leg work is already done and were only talking about 15$ to make the switch.

Here is a link to what I am refering to.
http://flashlightreviews.com/reviews/ma ... ag-led.htm
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Re: Converting a Florecent Camp light to LEDs

Postby UAirLtd » September 28th, 2012, 3:29 pm

replacement LED bulbs for flashlights that take 6 D cell batteries would work very well. I would not recommend using LED bulbs that are supposed to work with smaller flashlights.
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Re: Converting a Florecent Camp light to LEDs

Postby roseawebs » February 20th, 2017, 3:46 am

donavan wrote:I have an older Coleman Camp Lantern with works fine enough but it eats batteries and could use some new bulds becuase the old ones or a bit burnt on the ends. The lantern currently is powered by 6 D cell batteries wired in series. The bulbs are also wired in series and what I am able to read off of them indicate they are 4.? volt florecent tubes. So my question is this... is there an easy way to hack this sucker to cheaply allow me to use LED's or would I be better off just tossing this one in the closet as a back up and buying a new one. The cost of replacing the bulbs is about $20. and for about $10 more I could buy a new LED version, so hackaday what do you think ... hack it or just use it till the bulbs finally give out.

Ohh my bad! Last year I bought a florecent flashlight. This was my wrong selection and I successfully wasted my $65! Now, I know I should buy only led flashlight not any other junk florecent flashlight! Then, I have read this Best Tactical Flashlight Reviews – Top Bright Best flashlight guide and select the fenix led flashlight!
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