I tested it with good fully charged cells, i never do tail caps with any thing else. 6.5 amps is still under the 7.5 amp digital regulation. I have not been able to find my fluke since i moved house in last December, so i have brought another DMM it should be here next week.
The tr-1200 is digitally regulated at 2 amps on 2 x 18650,s and the tr-3t6 is digitally regulated at 3 amps on 2 x 18650,s.
So then one could think this about the tr-j12, since the manufacture has claimed it is regulated at 7.5 amps it would be on two cell's as the light does not work well on one cell it run is dim mode and if it was like the other tr lights i have the manufacture claimed regulation would be on 2 x 18650's.
Why would the tr-j12's regulation be one one cell as it has a dimming circuit for low voltage and it is a two cell minimum light.
I mention the regulation because this is what sets the TR lights apart from the skyray lights and so on, with the TR lights as the voltage drops the amps increase but it will not go above the digital regulation. The skyrays did not have this feature and the longer you used the light the higher the amps climbed till the lights driver failed.
Here's a graph that I made when I first got mine. This is with the head hooked up to my bench power supply (which tops out at 5A - resulting in the gaps)
It is slightly brighter on two cells than on three.
$15 eBay DMM -.-
intl-outdoor Panasonic NCR18650A 3100mAh (precharged two days ago; showing ~ 4.14v on DMM)
Brand new Duracell Alkaline C batteries (showing ~ 1.55v on DMM)
Duracell Rechargeable AA batteries (shows 1.2v/2000mAh on the wrapping; showing ~ 1.4v on DMM)*note: AA test done months ago*
Tailcap Readings (on High mode of course!):
2 x 18650 = 4.5A - 5.5A
3 x 18650 = 2.33A
4 x C = 2.50A - 2.75A
4 x AA = 1.8A
My readings shows that drd is correct, in that 4xC batteries is brighter then 3x18650 batteries.
Here are my amateurish pictures using iPhone below. lol
Its a result of two things: a driver that is drawing more current as the voltage drops and a high resistance circuit.
With the 3 cell setup, a drop in voltage (due to the high resistance leads) makes very little difference in the current the driver needs. With 2 cells, the voltage is much more affected by the resistance and the problem is only compounded by the driver wanting more and more amps as the voltage drops.
If you are seeing readings over 5A, then the driver is only getting between ~4.2 and 6 volts.
On 2 trustfire protected 26650's charged to 4.2 volt each, I'm getting 6.83 amps. I does seem easy brighter on 2 cells over 3. I say all yours are just under driven since mine is still with in the manufactures claimed 7.5 max.
The light runs in dim mode only once voltage hits around 6 volt or below and is not that bright at all, but mine still is running in full brightness and you can change modes drawing 6 + amps.
Once the cells run down it will top out at 7.5 amps and will continue to run till it hits low voltage then drops out and dim,s the same as the manufacture claims.
6 volts or under the current draw drops drastically due to the dimming circuit and so does the brightness, the TR-3T6 and TR-1200 work in the same way once they are in dim mode below 6 volt. this is also about when the protected batteries cut out approx 5 to 6 volt depending on the battery.
The skyrays did not do this hence all the fried drivers with there early triples. Useless info 3.7 volt loaded the driver in mine will draw under 1.6 amps and at 2.7 volt it will draw under 0.58 amps.
I wonder why shopbot and benkie are pulling 42-55W at 8.4V, while it seems EVERYONE else is only at 30-35W? Sample to sample variation perhaps? I would think 8.4V is still too high for low voltage protection to be kicking in??
Its pretty weird man. When I test the 2x18650 configuration, the reading fluctuates ALOT. There was like a range of up to 2A. I cannot pinpoint a good average whereas for all other configurations, I can get a nice somewhat consistent reading. Don't really know. Mind you my DMM was a $15 eBay one, so take it for what its worth.
I forget the current measurements, but I calculated the power at about 28 watts for any battery configuration (2 or 3 18650 and 2 26650). I only have 4 26650s, 2 of which are IMR, and two LiFePo4, so I don't want to mix chemistries/voltages to try 3 26650s.
About 4 days after I received the tr-j12, the spring behind the battery contact in the head either broke or dislodged, and now I have to use magnets as spacers for either 18650 or 26650.
Anyone know how to remove the pill from the head with breaking anything? It seems that the head is press-fit into place.
If yours is like mine, there really is no "pill". The driver "engine compartment" comes apart, unscrews and separates the LED+reflector half from the DC-DC driver half. A pair of long wires deliver power from one section to the next. See my pics in the linked thread. The DC-DC board is pressed into the aluminum and a brass collar is threaded over it to lock it into place.
I gently stretched the spring back out and used copper braid to releve the spring of some of the current flow.
The input voltage is not higher than what 5 LEDs need and If the driver is regulated it has to boost the amps to maintain the brightness of all those 5 LEDs the multimeter+ leads will act as a voltage drop, showing high current draws, as it's already boosting the voltage. It doesn't matter matter how good the DMM (reg.Fluke) all have some burden voltage that will affect the reading in series with the flashlight on boosting circuits.
That is extremely helpful Kramer, thank-you very much. I didn't know that the head/heatsink was 2 pieces, though I had my suspicions.
Since I didn't hear anything rattling inside the button, de-tempering of the spring makes perfect sense. Guess I will add a new spring with copper braid (I think I have some old RG-58 floating around - the shield would probably work well for that). I might see if I can retain the button spring cover as well. I will try to post pics and measurements once I get everything all fixed. Once I get repairs done, I may get one of the tr-j10's and see if I can properly drive the led - they look like they could be good throwers.
Anyway, I am really impressed with the output from this light, as well as the seemingly good thermal transfer to the air. I would love to see real measurements of the output using a true integrating sphere. The folks in Asia always pad all their numbers to make their products look better in advertisements.
It also seems, from looking at the performance curves from Cree, that the individual leds in this light are driven nearer the most efficient part of the curves than typical single-led lights. My only real complaint (other than the poorly-chosen spring design) is the fact that this light is very top-heavy - makes it cumbersome to hold and maneuver.
So everyone knows, I am an old-school flashlight modder, back from the days when xenon and halogen were the cutting-edge technology. Since Cree, SSC, Luninus, etc., have gotten the efficiency so high on leds, I can see no purpose for those old tungsten relics, except as museum pieces.
With Kramer5150's help, I figured out how to get everything apart in the head of the TR-J12. Same problem - spring was de-tempered and squashed. I will also use his fix - adding a piece of braided copper to assist current flow. I suspect, however, that the contact between the spring and the button is creating a high impedance failure point (maybe even arcing?), which may be contributing more to heating than anything. Also suspect is the cheap plating on the spring. I will try to dig up some conductive grease or epoxy so that the spring and cap make better contact.
So if anyone else purchases this light, prior to use, some braided wire should be installed at both ends and perhaps this failure may not happen?? Thanks.
Sure np... if you are familiar with incan mods, the wire braid is the same thing. Current is current, wattage is wattage, be it LED or incan.
It should be noted that time duration is also a factor. If you only use it for short burst only, then you may not really need to add the wire braid. Mine only melted after leaving it on for 10-15 minutes to intentionally get it cooking, to let some moisture vent out of the head.
