… and went for the torch in question, after a long while of deliberation (and waiting for the credit card’s best date ). I needed a thrower that isn’t Tony Mag’s stock artifact-riddled trash, wanted a light in Neutral White (currently I’ve only got two NW lights [a Thrunite Ti3 and an Archer 2A v2 with a broken lens, the replacement glass for which I’m waiting for the mail to deliver already] and I’m in love with the tint), and since it was on a good discount on Banggood, I felt it was high time I got a quality reverse-clicky and stop being prejudiced.
The sample I got was an AK47 8*7135, with an XM-L2 T6-4C emitter. Should be arriving to my hands late July, and then the party begins! :partying_face:
And now for a question: would anyone be a peach and tell me what should I expect in terms of range, power and especially battery life? I can’t for the life of me find any info on runtimes around teh interwebz.
I don’t have hard numbers, but I will reassure you that you will be pleasantly surprised.
They’re one of those things that ‘punch above their weight’, so to speak. That probably explains why, like the ubiquitous P60, they are such a successful and enduring design. Your money was well spent.
Run times depend on the modes and cell used as well as which species of 7135(350mA or 380mA). Also, run time in regulation is how long the cell can supply the current while the cell remains above the Vf of the led at that current. Spring resistance doesn’t affect max output of a regulated light as it does with one of the Fet DD varieties but the voltage drop incurred comes into play when battery voltage nears Led Vf shortening time in regulation. Also, Led Vf varies with current and temperature so guesses based on current/Vf graphs are only rough estimates. Best place to learn is the Cree website where you can see those graphs along with the performance characteristics of each type of led and output bin. Just click the link for the led of interest and then on the data sheet link.
I have the same 4C and would estimate 100-120m as usable throw beyond which I can’t differentiate small branches and foliage on trees. Haven’t run it longer than 45 mins on high with a 2600 mAh battery.
If you want more throw I’d suggest the XPL HI version. Gonna give up on the mind control and pull the trigger on one myself one of these days.
Appreciate it, man :innocent: I got an OP reflector myself for a smoother beam, since I don’t need TOO much throw. I guess 125-150m is plausible in this case?
Convoy’s 7135’s seem to be 350mA each. So with 8 7135’s the light will draw 2800mA from a freshly charged battery. If your battery has 2800mAh capacity, you will get 1 hour on the highest mode. Sort of. Actually as the voltage of the battery falls with use, the LED won’t want as much current (it falls out of regulation) and the demand will be less than 2800mA, so you will get more than one hour, but with less output. An hour is an okay estimate, but it depends on the true capacity of the battery.
Excellent! This is the throw mark I was hoping for: a good deal above the Thrunite TN12 2014, but not a laser beam. I’m not intending to employ it in situations where I have to use binoculars.
I only have 3400mAh cells, so I should be good for an hour or more on max. Any idea on the 40% and 5% modes (in flat regulation)? I feel I’m gonna use those more often than turbo.
(if anyone has measured the current drains on the more taxing 7135’s, that’d be of great help already!)
So in that math, a 3400 would last 1.21h on High, some 3h on Medium, and a bit over 24h on Low. That’s assuming it runs full throttle until the very end, which is underestimating the runtime since we’re not considering the dimming at the tail end, something I’m fine with. If so, excellent, absolutely excellent!
… though now I kinda sorta wish I’d gotten the 7135*6 for even longer runtimes. But that’s me being a stinker.
Thank you so much for the clarification, now I have my questions answered :student:
4C is a NW tint and is rated at 280 lumens at 85C and 320 lumens at 25C so a direct thermal path cooper mcpcb will help keep the die cool and maintain output as current rises. To the right on the same line it lists an output of 679 lumens for 85C @ 2 Amps and if you scroll down the page there is a graph showing relative flux vs current which shows that at 2.8 A you get 310% and at 3 A 325% . 280 times 3.1 = 874.2, times 3.25 = 910. Out the front (OTF) lumens are never as great as calculated lumens because of losses in the reflector and lens so many use calibrated devices to measure actual lumens to get a more accurate number.
Just above that graph is another showing Vf vs current and it’s here you need to look for approximating run time in regulation. At 2.8-3A it shows a Vf of ~3.3V and when battery voltage gets close to this value the light will begin to dim. There’s not much capacity left at this point and drivers with LVP will soon blink their warning. Taking this value and comparing it to the discharge curve for your particular cell will allow you to read off the time it takes to deplete your cell to that voltage attention that current. This is why you can’t find a quick answer to your search. Too many variables. To add another, with age and use cell capacity diminishes unevenly due to the charging, use, and storage of the cell.
Cell capacity is measured from a fully charged state of 4.2V down to empty at 2.75V but some chargers stop a bit low and good practice is to not discharge completely as well(swap cells when it dims or LVP kicks in) so a cell rated at 3000MAhr (3 amps for one hour) will likely dim before an hour is up. Cell capacity also degrades as current goes up getting dramatically worse as the maximum discharge current is approached.
Jack you are likely closer than I am. I do not have one built with an XM-L2 4C, and there are some lumens lost going up in the tint bin and with the dome on some throw will be lost.
For sure! At least after I find the time to go to an open field, what with the home stretch of university leeching off the little free time I have, heh.
The C8 has likely arrived at my house right now in this (beautiful but very dry) afternoon, if the tracking app is correct and my mailman’s habits are still the same. Currently I’m tangled up in a university assignment for Monday, but Tuesday at most I’ll be taking some beamshot photos.
Who here wants to know how an XM-L2 in 4C tint behaves with an wide and deep OP reflector?
They do quite well if you replace the stock LED with an XHP50 and switch the reflector to an OP version. Not quite the same throw but they will illuminate everything in front of you for about 100m.
). I needed a thrower that isn’t Tony Mag’s stock artifact-riddled trash, wanted a light in Neutral White (currently I’ve only got two NW lights [a Thrunite Ti3 and an Archer 2A v2 with a broken lens, the replacement glass for which I’m waiting for the mail to deliver already] and I’m in love with the tint), and since it was on a good discount on Banggood, I felt it was high time I got a quality reverse-clicky and stop being prejudiced.
