Custom Headlamps, Lighting Systems & Battery Packs

[UnderUtah]

Yes it's me designing the components and another member, Derek, who completed the electrical engineering. The emitters are essentially drop-in replacements - it was easier to work with them than design from the diode out. We use a single mode and a multi mode in each unit, purchased from DealExtreme; while I dont remember the exact model, the 3W 5 mode and the 3W single mode units you can view on their site are the same overall design and output. A PVC housing mounted at the rear of the helmet holding two clicky switches, paired with a remotely mounted battery complete the units. The housings were milled from billet aluminum with a polycarbonate lens and aluminum retainer.
These really began as a personal experiment and grew to be a decent and reliable light source that blows all but the most insane commercially available lights out of the water.
The issue to watch out for, depending on your resources, is the cost of development. If I kept track of the money and time expended on these little lights it would reach beyond 2K. But I can't help but tinker and attempt to improve and adapt things to my needs.
Thermal dissipation was the reason we used aluminum. Derek is developing another system for our cameras, a high-powered LED panel that will mount to the hot shoe. Tons of fun. Derek is an invaluable resource for the electrical engineering - I am just a design / build monkey. The devil is in the details!
Have fun and feel free to discuss any of the details!

[Therrin]

Awesome, so you guys used dropins also!

They're very convenient like that. I intend to end up making a few prototype units that are built parts-up... but for several of the designs I didn't see a need to re-invent the wheel.

My machinist and I discussed development and such. He'd like to eventually get to the point that we have a few versions we like, then he makes them and I market them.
For the prototype stuff since we're working together on it, we're splitting the cost of materials, and he's not charging me for build time. But his company uses LOTS of billet aluminum stock, in several different shapes/sizes. So most of the stuff he's already got on-hand. When we get to actually building prototypes, I want to drive out there and watch how he goes about it. The CNC stuff takes care of the brunt of the work, and he's going to teach me how to start using a mill and lathe, and how to do most of the other stuff; which I'm really looking forward to.

My EE buddy lives in... North Carolina, I think. I took a couple years of electronics in college though, so I can form the basics, and he helps me smooth out the finished circuits.

Thankfully, my machinist is a lifelong friend and kind of a "second dad", and with our development agreement it really should keep our overall costs quite low throughout.

[Joanne]

I volunteer to perform in-field product evaluations!! I realize that it will be a huge burden to have to use your lights while exploring some great mines, but no effort is too great for a compadre on MojaveUnderground!!

Seriously, this is a very interesting project you have undertaken and it will be interesting to watch as your lights are designed, tested, and come to market. I for one will be watching with interest. I don't know how many photos of the machining process you'll get, but they would be interesting too.

Good luck on your project!!

Joanne

[Therrin]

Right on Joanne

I'll um, keep that in mind! You're right though, having to test the darned things would really be a pain; I'm thrilled that you've offered to take that problem off my hands! hehe.

Drawing up a new quick plan for a handheld light. Uses a p60 style XML dropin with two 18650's. Shouldn't cost much. I wanna see what the heat output is like on the xml's, and how much light they put out. I figure this will be a nice, simple, quick project to see how efficiently we can go from design, to CNC, through to prototype use.

Working on it now.... only problem is my Solidworks version is 2004, so I have to have my friend try to import it into 2008/2009/2010 version, then re-save it.
I had looked at buying a new copy of solidworks to get a fresh version, then when I found out how much it was going to cost, I decided to stick with my 2004 one. =P

[Therrin]

Pretty much got the body design finished up in SolidWorks.
Just dithering between two ideas I had for the head of it...

Now I'm stuck, trying to figure out if I want to go with a P7, SST50, or XML for the dropin on it. This is the handheld light, btw. Doing a test run on a handheld to see how smoothly our prototyping system will work out. And I wanna experiment a little with the output & heat of whichever dropin I end up getting.

I've been drooling over the sst50's for a while, but I still really want to see how well I like the xml's. Ack... decisions decisions...

**EDIT**
I almost forgot... the XML's will last quite a bit longer than the sst50's on two 18650's. And since it's a mining light and I want a good duration off of it, that'll prolly end up being my deciding factor. I can always play with the SST's later. Hopefully the XML are as efficient as everyone claims.

[offroadcmpr]

My brother created his own headlamp. One thing I thought that was interesting is that he used the little battery connectors used for RC cars for the light. That way he could just use a RC car battery, and easily switch out for a new battery. Plus it made it easy to charge sine we already had a rc battery charger.

I know that surefire p60 dropins are popular, especially the malkoff ones. It would make it easy to change and install. All you would need is the case and headstrap with battery. The module will take care of most input voltages and such, so no drivers.

[Joanne]

One of the folks over at www.mine-explorers.co.uk posted about this controller www.taskled.com/techh6flex.html. It handles a lot of current and is user programmable. Read through the spec sheet (downloadable from the web page) to see all of the features and programmable options. It's expensive, but might be just the ticket for a high-end light.

Joanne

[Therrin]

Joanne, I'll have to look that over some more, it looks pretty interesting so far, thanks for the link!!

(Sorry I realize this is long, but it explains a lot, in simple terms, so I think it's worth reading :P)
OffRoadCmpr, that sounds pretty niffy! Do you have any pictures of his finished headlmap rig??
I like where your thinking is at with that... but it's actually a little more involved than that. The dropins are rated differently. Some of them handle large spreads of voltage range, others are very picky.
For instance, my current R2 dropin on my L2 platform is designed for voltages only between .8 to 4.2 volts. There are other dropins which handle like 3 to 18v, or more commonly 3 to 9v... But running an lithium ion battery on my .8-4.2v dropin runs very *efficiently*.
The dropins basically either buck or boost voltage to get the specific level they need, and the more of one or the other, like, the less efficient they run. It's a bit complicated for me to explain here, unless someone has a very simple way of putting it.

The "RC car battery packs" are NiMH constructed. Since NiMH runs about 1.2V per cell, and Li-Ion run about 3.7, you need 3x as many NiMH cells to get the voltage up, as what Li-Ions already start with.
Li-Ion's have a higher energy density by both weight and volume (Watt hours per kilogram & watt hours per liter), have roughly 300 more times of cycle life per cell, average considerably less self-discharge per month (NiMH is about 30-35%/month vs LiIon is about 6 to 9%/month), as a result they cost a little bit more. But inside a mine you want your battery packs as small and light as possible, and the Li-Ions achieve that very well over NiMH. Also, RC car battery packs are just plastic tubes of battery cells which someone else has configured together. Unless you're fond of the shape/size of those packs, it's more convenient to create your own packs for your specific application. It's very easy.
(Polymer Li-Ion batteries are better in all respects mentioned than normal Li-Ion cells, but they're more expensive as well).

Personally, I think battery packs built using 18650 size cells would be a good setup, for a decent mix between weight, mA/h rating, rechargeability, and the voltages you need to run your dropins efficiently.
That way with 3.7V nominal (4.2v fresh), I can get around 2200mAh to 2400mAh per cell, at a weight of only 1.66oz each.
I had looked at using some larger 26650's, which have up to 10Ah capacity, but they require special charging circuits and their discharge rates are quite beyond what I want to deal with in the circuit.
The Li-Ion 18650's give me "the most bang for the buck" and allow the circuit to remain relatively simple.

But now I'm also looking at possibly using pre-made Polymer Li-Ion packs too. At 7.4V, you can get packs that have 3, 4.8, and 5.3 A/h ratings! They're $25, $39, & $42, respectively; and only weight 10oz per pack which is 5.5" x 1.9" x 1". That's fantastic!!!

I'm designing my headlamp models to IPX-8 specs for waterproofness.
I'm currently looking at using either these "waterproof" connectors, or something similar to them.
They basically fit together snugly, then a fitting slides over the connection and screws them tight against eachother and seals them against the environment.
The works to both make them waterproof, and to make them very unlikely to come undone or come loose.

http://www.batteryspace.com/connectoradaptoronepairtwopinslockableconnectorwith8coilcord.aspx

[offroadcmpr]

The 18650 size definitely makes sense. I think my brother just used the NiMh battery packs because we already had them around so there was no extra cost of buying batteries and chargers. Those waterproof connectors do look much better than what he is using.
Have you ever heard of plastidip? What you can do is wire up the batteries together, wrap some tape around them to keep them in place, and then dip it with a couple coats of plastidip. I know that people have had success waterproofing their battery packs with it in the past. Try searching for google for it. Of course it won't work if you have the charge the batteries by individually.

Another thing that my brother swears by is a good flood light. He took out the 4 5mm LED's in his PT Apex and replaced them with two bare LEDs. It gives a very smooth output, similar to the zebralight headlamps. It is very nice for when you are just sitting around in a cave, or for just simple walking through a passage. He likes it especially in tight passages where having a strong beam doesn't help at all. Plus it means you don't have to move your head much to see stuff around you.

[Therrin]

I have heard of people using the plastidip on the battery packs. I posted back on a thread in CPF about it and I'm not sure a response has come back down the pipe yet. I was worried about heat buildup while recharging Li-Ion packs when they're totally covered in plastidip.

The floods are a great idea. =D Getting a high degree of surround flood and still protecting the LED can be a bit of a pain though.

I just got my Thrunite XML dropin, the 18650 tube extender, and the two RCR123's in the mail today. Charging up my two 18650's right now.

Unfortunately, the RCR123's have a good 2.6mm play inside the battery tube, so if the tube shakes at all, they slide around and the dropin starts flickering and mode-swapping.

I just called my machinist to verify the details, and sent him an email with the dimensions I need. He's gonna make me an aluminum body sleeve to use with the RCR123's to eliminate the diameter slop. Simple sleeve, no big deal. He's gonna mail it over to me when it's done.

[Joanne]

Therrin,

Your discussion about flashlight modifications and custom headlamps got me thinking (and that's often a dangerous thing...) So anyway, I was reading through the lighting threads over on www.mine-explorer.co.uk and seeing how they are modifying the obsolete Oldham mining lamps to utilize new high power LEDs and driver boards. I am impressed with their creativity in reusing the housings.

That got me thinking about whether it would be practical to use the head off of a Maglite "C" or "D" cell flashlight as a basis for a helmet light. Some options for the lamp would be to use the existing reflector, then add an emitter and driver board similar to the Maglite mods we often see on Candlepower. One advantage to this is the availability of parts that would fit the head. Another option is to remove the existing reflector and replace it with multiple emitters. The aluminum head would be good for dissipating heat. In order to use the head, a "body" would need to be machined from aluminum that would screw into the back of the light head. The body could have heat fins machined in it and the inside would hold the switch and the driver board.



I realize that you planning on designing a high-end lighting system, but your initial discussion about modding some hand held lights or using drop-ins as the basis of a headlamp got me thinking along the line of using the Maglite. I'm not sure how many different types of lamps you are planning on developing, but even if you just offer the "body" and allow people to do their own custom lamps it might be a fun project.

Anyway, I just thought I would throw this out there because I enjoy playing with different ideas.

Also, in my reading I have found several references to folks who dip their battery packs in liquid plastic, then use a large piece of shrink tubing to make their battery packs. They did not indicate any heat problem during recharging.

Joanne

[Kiel]

tenergy's packs are plasti dipped also except for small spots on one end where the wires and board are.

[Therrin]

Huh, that's actually an interesting concept Joanne.

Overall I was going for a much smaller/lighter system, but you've got a good point about creating parts that other people could use to build systems out of other existing platforms that they have.

When I finish some of these other designs in SolidWorks I'll see about creating something like that. Maybe you could collaborate with me on it =D
Nice picture btw... =P

Oh! so I came across these battery packs, check it out! Li-ion, 6Ah, and relatively small too!

http://www.sparkfun.com/products/8484

Thanks for the info on the plasti-dipping too guys. I was on Plastidip's site last night looking at some of their niffty polymers. Thinking about maybe using some of it for different things.

[Derek]

Oh! so I came across these battery packs, check it out! Li-ion, 6Ah, and relatively small too!

http://www.sparkfun.com/products/8484

Other than the fact that you'll have to add overcharge/discharge circuitry to it, that looks like a good deal. I have ordered stuff from these guys before with good success.

[Joanne]

Huh, that's actually an interesting concept Joanne.

Overall I was going for a much smaller/lighter system, but you've got a good point about creating parts that other people could use to build systems out of other existing platforms that they have.

When I finish some of these other designs in SolidWorks I'll see about creating something like that. Maybe you could collaborate with me on it =D
Nice picture btw... =P

Oh! so I came across these battery packs, check it out! Li-ion, 6Ah, and relatively small too!

http://www.sparkfun.com/products/8484

Thanks for the info on the plasti-dipping too guys. I was on Plastidip's site last night looking at some of their niffty polymers. Thinking about maybe using some of it for different things.

I almost didn't post the idea because of the overall size, but I figured I would and see if it would prompt some discussion about different lamp designs. I'm a software developer and we brainstorm a lot when we are faced with tricky requirements. Sometimes "dumb" ideas are the catalyst for good solutions. For me the next question would be, "Are there any other hand held lights whose head unit would be a good basis for a headlamp?" The whole concept may not have legs, but it's worth a few minutes to consider. Again, just thinking out loud.

I like the battery pack! 6ah is a beast, even if it is a bit pricey initially. So do you double two of those for a 7.4v 6Ah pack and really drive some emitters? The same company offers a fast charger that runs off of 5v, so you could build a simple 12v charger for overnight charging right at the campsite.

Anyway, it's fun stuff to talk about when we can't be out exploring....

Joanne