What is Maglite 3D LED conversion runtime & output?
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TigerhawkT3
Flashlight Enthusiast
Go to www.flashlightreviews.com/index1.html. They're great lights.
Extending the runtime on these Mag LED upgrades
For what its worth on the 3D cell light, I have two Mag 2-D cell flashlights. I bought them at Homedepot a few weeks back. They are a great improvement to the light. But I have also taken it a bit further and modified the current sense resistor in them to greatly extend the life of the batteries at the expense of marginal light output.
As was posted, http://www.flashlightreviews.com/ has a good write-up on these LED upgrades. But even better is a CPF poster by the name of NewBie that took it apart and analyzed it.
http://candlepowerforums.com/vb/sho...ghlight=mag-led
There's a lot of reading here but in short this is the scoop:
There is a heat problem when driving a 3 W LED without proper heat sinking. I suppose this is just the problem of doing an upgrade to a flashlight that originally wasn't designed for an LED in the first place. However Mag did a great job in controlling this by limiting the heat to say 70 deg C. The regulation circuit limits the current so as to not exceed this temperature.
The drawback is if you keep the light on continuously, then the output drops as the heat/current regulation comes into play. You see it in these guy's long term output charts. But this isn't necessarily a negative because the batteries will last a lot longer. It's a tradeoff. But its still way better than the stock bulb. At least Mag is protecting the life of the LED.
Now this brings me to my final point. Since you can't get the full brightness and capibility out of the 3W LED, then what about a mod to make this really long lasting light on a set of batteries. NewBie did a great write-up to modify the current sense resistor so that it even draws less current than stock but amazingly it doesn't drop the light output much. That's because brightness is not linear with current. Most of the brightness occurs up front at lower current.
http://candlepowerforums.com/vb/showthread.php?t=130861
The current draw on the 2D cell initially is about 1.12 amps at 3.00 volts. If the stock current sense resistor is 0.1ohms then the current regulation circuit comparator is tripping at 0.12volts. So if the 0.1 ohm current sense resistor is changed out for a 0.47 ohm resistor then the current draw will be 0.12v / 0.47 = 255mA. It's about a forth of the power draw on the cells but only about 30% loss of brightness. I ususally only use the light for just a few minutes at a time if even that. Now every time I turn the light on initially it only draws the 255mA of current instead of 1.12A.
After modding the first light I decided to do it to the 2nd. Runtime is phenomenal on a set of 2 D cells. Now I know you have the 3D but I would imagine that the same scenario would apply for them....just take the existing current sense resistor and multiply it by 4 or 5 depending on how low you want to take the current to the LED.
For what its worth on the 3D cell light, I have two Mag 2-D cell flashlights. I bought them at Homedepot a few weeks back. They are a great improvement to the light. But I have also taken it a bit further and modified the current sense resistor in them to greatly extend the life of the batteries at the expense of marginal light output.
As was posted, http://www.flashlightreviews.com/ has a good write-up on these LED upgrades. But even better is a CPF poster by the name of NewBie that took it apart and analyzed it.
http://candlepowerforums.com/vb/sho...ghlight=mag-led
There's a lot of reading here but in short this is the scoop:
There is a heat problem when driving a 3 W LED without proper heat sinking. I suppose this is just the problem of doing an upgrade to a flashlight that originally wasn't designed for an LED in the first place. However Mag did a great job in controlling this by limiting the heat to say 70 deg C. The regulation circuit limits the current so as to not exceed this temperature.
The drawback is if you keep the light on continuously, then the output drops as the heat/current regulation comes into play. You see it in these guy's long term output charts. But this isn't necessarily a negative because the batteries will last a lot longer. It's a tradeoff. But its still way better than the stock bulb. At least Mag is protecting the life of the LED.
Now this brings me to my final point. Since you can't get the full brightness and capibility out of the 3W LED, then what about a mod to make this really long lasting light on a set of batteries. NewBie did a great write-up to modify the current sense resistor so that it even draws less current than stock but amazingly it doesn't drop the light output much. That's because brightness is not linear with current. Most of the brightness occurs up front at lower current.
http://candlepowerforums.com/vb/showthread.php?t=130861
The current draw on the 2D cell initially is about 1.12 amps at 3.00 volts. If the stock current sense resistor is 0.1ohms then the current regulation circuit comparator is tripping at 0.12volts. So if the 0.1 ohm current sense resistor is changed out for a 0.47 ohm resistor then the current draw will be 0.12v / 0.47 = 255mA. It's about a forth of the power draw on the cells but only about 30% loss of brightness. I ususally only use the light for just a few minutes at a time if even that. Now every time I turn the light on initially it only draws the 255mA of current instead of 1.12A.
After modding the first light I decided to do it to the 2nd. Runtime is phenomenal on a set of 2 D cells. Now I know you have the 3D but I would imagine that the same scenario would apply for them....just take the existing current sense resistor and multiply it by 4 or 5 depending on how low you want to take the current to the LED.
