Beginner DIY headlamp idea / possible project

Parallel LEDs is ok(not recommended but many do it) but max output would then be 1.75A/led. If you want 3A to each Led from Lflex you need 2s LEDs to 2s li-ion. I use Judco normally open momentary (only makes contact while pressed) switches from Digikey. If you are only using high for brief periods you might decide to do without the thermal monitoring of a Taskled driver. Then you could do the master/slave mod and run the LEDs in parallel from parallel batteries. Ordinary switches would then work(see how he bypasses the master with the led current). This is a much better way to run LEDs in parallel as the current is controlled to each led. Try not to be in too much of a rush at this point while you are still learning about options and how they work. What you learn now will pay big dividends shortly.

Would it be simpler, if it’s possible, to connect two masters to the battery pack, each driving its own LED?
I could have two switches (if they can fit) to independently regulate each LED, e.g. if I want full flood without a hotspot.

(edit: fix mistypes)

Sure, you can power each led with its own driver and switch from the same pack. Hotspot or flood depends on the optic chosen for each. The master/slave just let’s you control both with one switch. Another way to go is with a 2-position switch to control additional 7135 chips for high. This would be beneficial as 2 LEDs at 1/2 power are more efficient than one at full power. 1/4 or less might be even better as countless times I have read that the human eye sees light magnitude more on a logarithmic scale than a linear one. That means that 100 lumens seems 1/2 as bright as 1000 lumens rather than 1/10.

well, theres’s a noticeable difference between XinTD C8 and Spark NW460, so it would be cool if I could get the output to be near the xintd’s.

I was thinking go ahead and make high HIGH but it’s more efficient to run 2 LEDs on low than one on medium and even a low power an XML puts out a lot of light. For mountain biking low is fine for going slowly uphill on dirt roads, medium is nice for slow technical stuff and high is for balling the jack. I’m just thinking that you can get a lot more run time by keeping the low mode around 300mA/led and high at 3000mA/led and still have plenty of light to walk/crawl by. Experience will tell you how much you need.By the way, even with the poor efficiency, low and medium will extend you’re runtime over just using high, just not as much as a more costly driver.

Than you. I think I’m going to go with two AMC7135s for now. If this goes well I might decide to build a better quality light with machined housing and a tasked later on. Which one of these would give a good medium light, that would not overheat but give a good enough light?

8xAMC7135 (3.04A)

8xAMC7135 (2.8A) (selectable) Mode Driver

4xAMC7135 (1.4A) 3 Mode Driver

(edit: I’m reading Results: Testing XM-L, MC-E, SST-50, and XP-G emitters **Updated**)

Here is a link to a thread that has links to many other threads on 7135 drivers. If you want to learn about the drivers and chips I would suggest you subscribe to the thread so you can readily access it. Since you are asking I personally would get an 8 x 7135 driver with modes(I prefer the 105C which allows the modes to be solder fixed) and slave to it another 8 x7135 without modes in order to run 2 leds from 1s?p battery pack. That is the master/slave mod and it has been very popular. It really isn’t hard to do and you will get all the help you need/can stand if you try it. I recommend modes to allow you to conserve battery power and only use the light you need. You could also get 1 board with modes and 1 without and run separate switch wires as you mentioned above to switch the leds independently but the m/s mod is power wise a more efficient way to do the same thing. Also listed in the thread above is are 2 methods for using a single 7135 driver to run multiple leds in series. The second (shameless plug)was developed by me earlier this summer and while its been tested up to 3 series leds - 3 series li-ions, it has not yet been used in a light. Keep reading and asking questions! :slight_smile:

The idea was that I could change each LED level independently. I think it would be useful in caving, when I’m in tight passages or on the rope I could have only the LED with flood optics on, so that the hotspot from the other one doesn’t distract me. When walking through halls I could have both on at mid, and if I want to throw a beam up to the ceiling I’d switch the narrow optics LED to high. Can I do that with master/slave?

No, that doesn't work with master slave set up. It sounds like you are doing something similar to yobailey so you may want to look through this thread.

Whay don’t you do simple setup:

  • one source of power (1-3 18650 in parallel)
  • two drivers - each for one led
  • two switches - each for one pair of driver/led

This way you can control each led indepedently. Simple as pasulj (bean soup):wink:

You can run any single one or both at same time at any mode. For ex. led1 at low and led2 at high or whatever combination you choose. I would also recomend using two different optics - wide/dispersion for closeups (pasages/small caves) and narrow for throw (big rooms/high ceiling). Trust me, I know…… We have more than 10k registered caves in our country :wink:

I’m a bit worried about heatsinking, so not sure if I should get the 1.4A or 2.8A boards.

Edit: I ordered the 2.8A, we’ll see how it goes :bigsmile:

You can also remove 1 or 2 chips(save ’em) from each board if high is too hot. Even at 2A they will still be very bright but the lower modes will be lowered as well. It sounds like you are closing in on your design.

The LEDs and the optics are here, but I’m still waiting for the other parts. I did find something interesting, there’s a store in the vicinity that sells aluminium rods, pipes and profiles ( I haven’t contacted them yet, and I don’t know the prices, but the selection listed on the site looks promising. So, I thought I could make a better housing than the one I had been planning. For example, there’s a round aluminium tube 50 x 4,0 I could use ( I suspect that this means it is a 50mm diameter with a 4mm thick wall. There are also rods from 4mm up to 300mm diameter. If I bought an aluminium rod, would I be able to hollow out the necessary compartments for the LEDs and drivers using just a drill? If not then I guess I should get the tube. I hope they have scraps laying around, it could be really cheap that way :smiley:

Unless you have access to a mill or lathe your original plan is better. A hand drill is not a safe way to do it and the chuck on a drill press can come loose with side loading.

Well, yeah, I guess I would have to drill holes side by side or something. But I see your point, it would be a bit of trouble. I could try to find someone to do it for me.

Less than ten bucks just seemed like such a reasonable price to get so close to what you need. You would still need an extra cover plate for the battery pack though. If you can find somebody with a lathe or mill that would be great and fun besides so I’m not reccommending against it just didn’t want you to hurt yourself trying to cobble it up with the wrong power tool. Something already hollow like tubing round or square could work but that oval piece you linked was nice since it was already tapped for screws and has two of the plates already done. There’s no “wrong” here as this is your project.

Well, I’m still waiting for the drivers. I’m sure it will be delivered….

Wow, that’s some serious hang time. Shipper should try out as an NFL punter. Can you check with your postal service. If there was a delivery notice, it may have slipped away. Happened to me. Item was sitting there 4 blocks away for 5 weeks!

Well, found an email with a tracking number I had totally forgotten about. It’s USPS, this is the last entry:

First-Class Mail International
October 11, 2012, 8:25 am

The drivers are here, finally :slight_smile: