# Help trying to build a LED lantern



## daguy80 (May 9, 2010)

I always wanted a bright LED lantern but there doesn't seem to be a lot of choices on the market. I think that the coleman with 580 lumen is the brightest one yet. Can I just go and buy a cheap led lantern with 8 D cell batteries and change the drive and LED? I was hoping to get around 750 to 1000 lumens with either a sst 50 or sst 90 led. How hard would it be to mod?


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## Lynx_Arc (May 9, 2010)

could be harder to mod than you think. first to get that many lumens you would probably be using close to 2 amps off D cells which will greatly reduce runtime, second you may have to replace everything but the battery holder to handle the higher current load. third you would have to design and fit a heatsink for the LED as it most likely puts out a lot more heat. fourth you may need to redesign the light delivery system as many diffusers are designed to the LED in them and an LED with a different light pattern may not work as well which means losing some of the gain you have. At the end you could have a lot of money and effort in a lantern and then as it was cheap to begin with you damage the lantern and your $20 with $40 parts and $200 labor goes up in smoke. On top of this instead of it running on high at 200-500 lumens for a day your upgraded version runs for 4-5 hours on high eating up expensive D cell batteries or you end up investing in nimh D and a charger adding up to another $80+.
Here is my advice, get a lantern that at least uses an SLA in it, as an SLA can deliver a lot more current that D cells and also with the greatly decreased runtime (on high) after a few recharges you start saving lots of money about $10 or so a set of D cells adds up very fast while an SLA costs about ~$20.


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## AlexLED (May 10, 2010)

Hi, 
I have bought the Coleman 580 lumen and replaced about all but the LEDs: 12V SLA, new wires, decent driver. I'll post some pictures in the next days. 
I'm very pleased with the outcome and with the SLA you it should actually reach 580 lumens, which I think is a bit stretchy with D-cells because they can't really deliver more than about 1.5 Amps. 

If you improve the cooling you should even be able to get more than 580 lumens. 

Taking any other lantern and exchanging the LED could be possible, although the cooling within a plastic lantern should be challenging. And as said above, with D-cells you will have a hard time getting the current you need for a SST-xx. *Although* they sometimes use a 4s2p configuration, like in the coleman mentioned above. If you use NiMH D-cells you might have more luck. 

Anyway, considering you will probably use the lantern in remote areas, a 12V SLA would be much easier to recharge !! 


Whatever you do, keep us posted !! :wave:


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