Tinkerer54
Newly Enlightened
- Joined
- Mar 28, 2013
- Messages
- 16
I sure could use some help on selecting an efficient driver board. I just recently purchased 2 LED lanterns as mod projects. One is a clone of the original 4AA River Rock lantern, the other is
clone of the Osram Golden Dragon (also 4xAA). Both have had the original high power LEDs replaced by 5MM leds.
As a starting point, I'm looking at using the Cree XR-E Q5, although I do have a XP-G2 R5 coming in from KD. I'm shooting for approximately 6-8 hours runtime on high, so it looks like I'm talking a Buck driver. Batteries would be 4xAA either Alkalines or LSD NiMh. Currently, I have Tenergy Centura LSD AAs @ 2100Mah; though I'm eyeing the new Eneloop LSD 2500 Mah AAs.
I've studied this post on Drivers: Flashlights>Flashlight Electronics - Batteries Included>Flashlight Electronics - Batteries Included - Threads of Interest
"Drivers, how leds are adapted for different battery voltages" by HKJ November 2009
(sorry, but I don't know how to link to another post on this forum)
A single 7135 driver board seems an obvious initial choice. However, studying the graphs HKJ's post, it seems that when using battery voltage above about 3.6V, any excess voltage is just burned off as heat. Not too efficient; it seems like I'm just wasting the 4th AA battery as so might as well just short across the 4th battery contacts and use only 3AA. Also, I've read that KD recommends not going about 4.5V with these drivers, in spite of the 2.7 - 6 Volt rating due to heat issues. Am I correct on this?
Other buck drivers I see on KD, DX, and Fastech with higher voltage ranges like 3V - 8.4V put out far too much current and use unknown type and number of driver chips. If It's possible to reduce the current, I haven't found out how.
Can anyone give me some pointers on this?
You can safely assume I'm familiar with Ohm's Law and Kirkoff loop equations, and have read most of the CPF posts about the River Rock and Osram Golden Dragon lanterns, including mods. But drivers are still somewhat of a mystery. I'm an ex PC overclocker, so I'm familar with heatsinks and heat issues and have a good stock of heatsinks in sizes down to those fitting motherboard voltage regulators and ram chips. The Modding posts I've read were retaining the original River Rock or Osram driver boards, and so are not much help.
Any comments or suggestions would be greatly appreciated.
clone of the Osram Golden Dragon (also 4xAA). Both have had the original high power LEDs replaced by 5MM leds.
As a starting point, I'm looking at using the Cree XR-E Q5, although I do have a XP-G2 R5 coming in from KD. I'm shooting for approximately 6-8 hours runtime on high, so it looks like I'm talking a Buck driver. Batteries would be 4xAA either Alkalines or LSD NiMh. Currently, I have Tenergy Centura LSD AAs @ 2100Mah; though I'm eyeing the new Eneloop LSD 2500 Mah AAs.
I've studied this post on Drivers: Flashlights>Flashlight Electronics - Batteries Included>Flashlight Electronics - Batteries Included - Threads of Interest
"Drivers, how leds are adapted for different battery voltages" by HKJ November 2009
(sorry, but I don't know how to link to another post on this forum)
A single 7135 driver board seems an obvious initial choice. However, studying the graphs HKJ's post, it seems that when using battery voltage above about 3.6V, any excess voltage is just burned off as heat. Not too efficient; it seems like I'm just wasting the 4th AA battery as so might as well just short across the 4th battery contacts and use only 3AA. Also, I've read that KD recommends not going about 4.5V with these drivers, in spite of the 2.7 - 6 Volt rating due to heat issues. Am I correct on this?
Other buck drivers I see on KD, DX, and Fastech with higher voltage ranges like 3V - 8.4V put out far too much current and use unknown type and number of driver chips. If It's possible to reduce the current, I haven't found out how.
Can anyone give me some pointers on this?
You can safely assume I'm familiar with Ohm's Law and Kirkoff loop equations, and have read most of the CPF posts about the River Rock and Osram Golden Dragon lanterns, including mods. But drivers are still somewhat of a mystery. I'm an ex PC overclocker, so I'm familar with heatsinks and heat issues and have a good stock of heatsinks in sizes down to those fitting motherboard voltage regulators and ram chips. The Modding posts I've read were retaining the original River Rock or Osram driver boards, and so are not much help.
Any comments or suggestions would be greatly appreciated.