I own a two 18650 battery “1200 lumens” zoomable headlamp with an XML-T6 emitter. I like that it’s bright, but it lasts me about an hour and a half then goes dim.
I was looking through amazon and found a headlamp that uses a Q5 emitter with about “160 lumens”.
My 2 battery XM-L T6 headlamp can be used with one battery or two. What I am wondering is,
1) between a 1 battery xml-t6 headlamp, and a 1 battery Q5 headlamp, can I expect more battery use out of a Q5 emitter than an xml-t6, considering the fact that the Q5 is less lumens? In my mind I’m thinking less battery draw from a Q5 LED than a higher lumen xml-t6 LED using 18650 batteries, would I get longer battery use from a Q5 than an XML-T6, while sacrificing a couple hundred lumens?
2) which of these two would be more efficient, a) to use my 1200 lumens xml-t6 headlamp with one battery, then switch to a new battery once it goes dim or b) use it with both batteries (would I get longer use of an xml-t6 emitter using 2 batteries at the same time, or separated one after the other)
It sounds like your head light is wired parrallel - it runs on one cell or two, using matched cells, two cells should double your run time. What cells are you using? A single 3000mah cell should do 3a for one hour, I’d expect a headlamp doing that to get uncomfortably hot to be honest.
The simple answer is it all depends on your cells and the run current on your light - 3000 milliamps is 3 amps so you get roughly 3a of use to an hour from a 3000 milliamp/hour cell (losses mean it’ll be shorter than that but you get the idea). A well common drive current for a q5 is 1.5a, that would mean roughly two hours from one cell of 3000mah rating.
You can see there’s some questions to answer, how’s the light driven? how good are your cells?
I would expect to find your head lamps driven at 2.5a max, so two decent (as in real tested capacity) cells (panasonic/xtar/sennybor/sanyo) cells rated at 3100mah would give you more than two hours run time. The other thing is, it may be dimming due to over heating, rather than the batteries going flat….
So what’s the light doing? What are your cells and can you even test cell voltage to give an idea what’s going on?
Then you can get some meaningful advice on where, if at all to spend your money.
Welcome to the forum, and don’t worry, we’ll see you right, or spend lots of your cash in a meaningful way…… 8)
I’m using 3000mah batteries. Judging by the estimates you put at 2 to 3 hours, it seems just about right for my xml-t6 zoomable headlamp.
What I was wondering though, what would I get more runtime on one battery with, xml-t6 running on high, or q5 running on high. Or it doesn’t matter? I figured since the q5 throws less lumens, an 18650 battery would last me longer on q5 throwing less lumens than one running on xml-t6 throwing higher lumens. I’m not that versed in voltage, amps, mah, but I’m learning by reading threads on the forum.
First question is whether a specific LED is measured in real lumens or something more generous.
The link above says that the energy needed is likely much lower, needing only ~2W for those Q5 lumens. If the XML is running ~10W it is drawing 5 times as much energy as the theoretical Q5 at 160.
In real life, the battery, driver, and LED all affect the draw, along with run time and output.
thank you. this is the answer i was looking for. i will be purchasing a couple of q5 headlamps to keep around in my toolbox. my question wasn’t really about the lumens, but i can sacrifice a bit of brightness for longer operational use of a headlamp. thank you once again.
i am using ultrafire 3000 mah batteries from amazon. but honestly one does not really know the true capacity of ultrafire 18650 batteries coming from china unless they have the tools to test them so it’s only a guess.
Before buying any more head lamps, try some Panasonic or Sanyo 3100 protected cells. You may find you don’t need to sacrifice the lumens, besides, if your xm-l light has medium and low, you can always switch to them, this will drop your drive current and prolong your run time.
I do feel though, that your money would be better spent on good cells from a trusted supplier, I have a couple of the ultrafire cells, and whilst they work, I have since bought quite a few more better quality cells, the difference in run time is remarkable.
If the new headlamp uses lower capacity batteries and a high draw, you won’t necessarily get longer run time. Try to ask for others to measure and share draw rates on any you are interested in so you can estimate run times along with their experiences.
Suggest you buy an inexpensive digital multi meter if you don’t have one. With that and a little math, you can also measure your battery capacity.
My UF 3000 is the worst of my UF batteries. Though it works fine as a spare in some lights, the protection circuit was too sensitive for the light it came with and it shut down after only a couple minutes on high.