@brjones
Little dissertation. Impressive but to much words.
Can you please give a short summary? Four or five sentences?
If you were referring to my post, note that I was talking about a quad XHP35 TM16 style light. Based on a test or 2 I have seen floating around plus general results from cree emitters when you overdrive them I think that 2500 lumens from an XHP35 is well within reason. That is only a ~35% increase over the rated lumens afterall. Particularly with the new higher bin XHP-35’s being released now.
Here is the best way I have found to describe this subject to people over the years, I copy/pasted it from here due to the fact I could not say it much better.
Voltage is like the pressure in a garden hose with a hand operated spray nozzle at the end.
Even when the nozzle is turned off there’s still pressure in the garden hose. Even when a light is switched off there’s still voltage in the energized portion of the circuit.
Current is like the rate of flow of water in the garden hose, say how many gallons per minute (or in our case mAh) are moving in the hose. When the nozzle is turned off, there’s still pressurized water in the hose, but there’s no flow.
When a light is turned off the electrons are still in the wire, but they aren’t flowing — there’s no current.
Power / Wattage is the product of pressure and flow rate. If you were spraying the water into a bucket, it’s like a measure of how quickly the bucket is filling up.
If you have a big hose with lower pressure, or a small hose with high pressure, you may have the bucket filling at the same rate (if the numbers are right).
Electrical power is the product of voltage and current, and it’s measured in watts
You could have a light bulb operating at 50 volts and 2 amps of current…
50 volts x 2 amps = 100 watts
You could have another light bulb operating at 25 volts and 4 amps of current.
25 volts x 4 amps = 100 watts
Even though the light bulbs have slightly different construction and are hooked to different energy supplies, both would be burning 100 watts of power, and both would have the same brightness.
Thank you.
I got it.
As far as I am concerned no further electrical discussion here required.
“…and both would have the same brightness.”
Um, not necessarily so.
The Luminus SBT-70 is a good example of that, at 17Amps and 3.7V, it’s still only making 1500 lumens. A Cree XM-L2 U4 3C at 3.6V and 4.9A can do 1800 lumens. Equal Wattage is not necessarily equal output.
Again, 2 lights built in the last few days. Same host, same Samsung 20R cells. Both utilize 6V emitters. One pulls 10.45A for 5451 lumens, one pulls 9.4A for 4126 lumens. It’s not all about V*A=W.
All the talk is well and good guys, now go build some flashlights and lets see what you come up with. There will almost certainly be some surprises in store.
I personally have only taken the XHP-35 to 2.89A at 2200 lumens. Other’s have tried higher amperage and have thrown fried emitters in the can. YMMV
As amusing/educational/thought provoking as this all is I have to agree at this point that even by BLF standards 
we have spent too much time off-topic regarding the electrical engineering side of all this.
The topic is very much worth discussing and I’d subscribe to a thread about it. Perhaps this aspect could be moved to another thread?
It’s hard enough for people trying to find out about the L6 to sift through nearly 70 pages of info… :zipper_mouth_face:
Sorry, but I have to correct this [no disrespect, it’s good overall… love your sig]. Current is not how many gallons per minute. In your analogy, voltage would be the speed of the water, and current would be the width of the hose. Current is not the total amount of water. The TOTAL amount of water coming out (gallons per minute) is WATTS. “Speed” of the water is caused by pressure (or drop of gravity, which is like pressure), so yes, voltage can be viewed like water pressure. It is easier for a beginner to visualize “speed of water flowing” than “pressure of water”. That’s why I state it this way. In reality, when things are moving, they are essentially the same thing. But yeah, that pressure is there when the water is not flowing, too. Current is the “width” of the flow, which doesn’t say how fast it’s flowing. Both the pipe width and the speed or pressure of the water together determine how much actual water comes out.
Like, literally you could have a gigantic, single 1.5V alkaline battery, just like one AA cell, but the size of a car. It would be literally a “wide” battery. That gigantic, one-cell alkaline 1.5V would be able to put out a HUGE amount of amps, but they would still only go at 1.5V. So, like a very wide stream that doesn’t have a lot of pressure behind it (or is flowing slowly, but still can deliver a lot of water). So you can have a big car 12V battery, or a small spotlight 12V battery. The “wider” battery just has more “stuff” in it, it can just do more chemical reaction to make electricity. A smaller battery can’t keep up, the chemical reaction is happening as fast as it can. The wider car battery can put out more watts, because it can do more chemical reaction (current). But both lead-acid batteries will always be producing their current at 12V, because of their lead-acid chemistry. So: same volts, but more amps (wider stream/wider battery/more chemical reaction—but same chemistry), equals more watts (more power). Just more chemical reaction going on at that 12V chemistry.
In reality, it’s about the balance. You don’t want anything too extreme, or not making sense. You want the voltage to be high enough to do the job (get the water flowing, or make that circuit work), then you want enough current to do the amount of work you need to do. The voltage should be ideally at or just slightly over what the LED needs to operate. That means the electricity will flow. Then you decide how much current you want to pump into it. If the voltage is too high, the voltage will need to be adjusted down with circuitry—but that circuitry is simple. It is easier to dam up water, than to pump it uphill. But ideally, your battery chemistry (voltage) and motor (or LED or whatever), will be good matches for each other.
Everyone knows that “volts * amps = watts” is oversimplified, and that there are variations in the real world. You have to walk before you crawl. Trying to explain the nuances of Power Factor to people who don’t know what an Amp is—-is why this (manifestly necessary) diversion went on so long to begin with… The original answers were too technical/detailed. Not overly-simplified enough. So people weren’t understanding. I wouldn’t have understood either; I read those earlier posts. All indications are that the confusion is probably cleared up now, so complaints are belated. I doubt many beginners would read a thread on “Whatts a Watt?”, so this info is perfect where it is. I have found often the most valuable info I’ve ever picked up in forums (not just this one) has been supposedly “off topic”.
Just a suggestion… How about a wiki section that explains this stuff ? Many of you are qualified to write and explain topics. It would certainly help noobs like myself. As it is now we’re just flotsam on the waves picking up what we can here and there and most of it gets lost in jargon and minutia.
A really good start is found here: LEDs & Other Stuff - (Reference Guide) I found the basic flashlight and battery information to be priceless. I’d also bet that it kept me out of future harm, along with BRJ’s advice about adding cells and potential problems there.
It could be organized into a wiki with a sort of Index up front to lead folks to the info that they want. If there was a wiki section off topic stuff like this could be (maybe) referred to it and topics could be there for noobs and the folks at “phd” level. One could delve into it at whatever level they can use and the info is there as they want to access it. Just pick a topic… it could include mod’ing; fixing a light, and an explanation of how to match components, troubleshooting, just think about what you experienced folks do, and don’t think that anything is too small to include in the wiki. Too, a wiki isn’t carved in stone, it could be modified and added to by folks in the know. Maybe a peer review?
It’s just a thought that has had possibly a minute of thought behind it. Yeah, I can see folks getting perturbed at this off topic stuff being here in a review, but for us noobs it was priceless, at least it was for me; hence my suggestion. I doubt that I’m unique; I just speak up. How many noobs don’t have an L6, have no desire to have one, and completely passed over this information that could help them? I know it’s good of me to make the suggestion since there’s no way that I can write any of it and I just put it on the shoulders of other folks. Anyway, it’s just an idea. Do with it as you will.
Unsubscribed
Could you explain which resistor you did replace/bridge? Maybe a photo?
Seriously people… :person_facepalming:
PLEASE move the technical electrical discussion to another thread. I enjoyed it for a few posts but now it really has gone on too long IMHO.
I have respect for all of this discussion but I don’t think Glen is the only one who will walk away if this goes too far off course which it already has.
I started this thread for the L6.
It should be about the L6 and discussion about it, not a discussion of electrical fact and theory.
I respectfully request that a new thread be started to continue this discussion.
Edit: Even if it’s been covered, a return to talking about the resistor mod as requested in the post above would be most welcome. 
Since you began this thread, I will respect your request.
What do I need to do to add a cell to the L6? Meaning, if I want it to be 3 series instead of 2, how can I best achieve that?
Edit: Ok, looking at making a threaded coupler to join an L2 single cell tube to the end of the L6 double cell tube for that one more cell. If I can make this work smoothly I’ll swap out the XHP-70 for a 9V MT-G2. (just kind of hooked on the fat MT-G2)
Edit II: Since I know it will be asked, a 6V MT-G2 would go in the light easily but would drop lumens in the switch, down from 4500-4600 to 4100-4300. With the 9V variant on the MT-G2 I can probably count on 4900-5100 lumens. That’s what would make it worth it, the better tint and more lumens. Not sure of course, so I’ll be looking into it.
I rigged the L2 similarly to the L6 and used it tonight for chores. Short story, my fav’ so far is the L6. The L2 just has too much throw, too tight a hotspot, and not enough spill; it doesn’t have enough floodlight for good close in work and that includes walking. I was almost constantly readjusting the over the neck sling to reposition the light. Who needs a sling when the light is almost always in the hand anyway because of the beam? No need to do that with the L6. My previous fav’ was the Trustfire TR-3T6 which has a very floody beam, but it has no holes for even a wrist lanyard. It also lacks a low beam, or maybe the low beam is just too high? Just semantics.
As previously discussed, the L6 has a few minor problems that on my light are mostly fixed with kludges until cold weather comes when I might need to wear gloves (I try not to). Maybe at that time I’ll swap to a C8, S2+, or S3 which I don’t have yet, to keep the light in a pocket and warm when that time comes. But right now I’m happy with the L6 as I have it rigged.
Is nobody gonna make a topic of this watt/volt/amp stuff?
It is really nice explained but bor in the right topic.
OK I will quote/copy/paste some gems in a topic as suggested give me half an hour.p
Done
copy pasted 3 explaining posts (edited some not relevant stuff out of some and think it is clear now.)
Here is my Convoy L6
Another picture: L6 with my old friend FandyFire:
I am very impressed from this flashlight. You can light up huge amount of area with it. It is also a good thrower. Much better than my Nitecore EC4S.
Where can I find more information about FX-30 driver?
Is there also some graphics about run time in different level output and stuff like this?
Thank you.
Welcome to BLF
Used the L6 to see some squirrels yesterday, our guest was very impressed with the light.
I haven’t been this excited about a flashlight in damn near 10 years, but I’m having a hard time locating the shorter 69.5mm keeppower protected cells. The link in the original post seems to be out of stock or a preorder at the moment. Is there anywhere else that sells them?