Newbie needs advice on 3x XM-L build

[Diving Gecko]

hmm, interested... any info?

Well, since I live in China, I am sourcing a bit from Taobao which is kinda like Ebay & Amazon all rolled into one.
Lots of crap there, but also real Ferraris and Mercedes, as all businesses now feel like they have to be there.

Anyways, the holders don't look like high quality at all, but they are cheap and cheap is great for making it easier to prove concepts. For now, these will likely suffice.
(Divide the prices by 6, and you'll have it in USD)

http://item.taobao.com/item.htm?spm=a1z0d.1.1000638.41.SMqo4E&id=15199789351
http://item.taobao.com/item.htm?spm=a1z0d.1.1000638.46.SMqo4E&id=14186771223
http://item.taobao.com/item.htm?spm=a1z0d.1.1000638.46.SMqo4E&id=14186771223
http://item.taobao.com/item.htm?spm=a230r.1.14.280.VSmvZr&id=19343569343&_u=tm9b7uq2ebc

Jspeybro, if you don't mind me asking a favor in return and digging into your knowledge:
Given the above notion that capacity is not super important, how would you rig cells to drive triple XMLs (prolly through a Taskled driver)?
3s, 2s2P, 4s?

 

[arek98]

If you get lFlex than 3 Li-Ion, for b3Flex 4 Li-Ion, nothing from TaskLed that will work with 3 XM-L in serries and 2 Li-Ion (HBFlex needs more voltage input and maxFlex is only 1.2A output).

b3Flex with 4 Li-Ion should stay in regulation pretty much thru whole batteries discharge.

lFlex with 3 Li-Ion will at some point drop out of regulation and will give you long runtime with lower output.

 

[Codiak]

Well, since I live in China, I am sourcing a bit from Taobao which is kinda like Ebay & Amazon all rolled into one.
Lots of crap there, but also real Ferraris and Mercedes, as all businesses now feel like they have to be there.

Anyways, the holders don't look like high quality at all, but they are cheap and cheap is great for making it easier to prove concepts. For now, these will likely suffice.
(Divide the prices by 6, and you'll have it in USD)

http://item.taobao.com/item.htm?spm=a1z0d.1.1000638.41.SMqo4E&id=15199789351
http://item.taobao.com/item.htm?spm=a1z0d.1.1000638.46.SMqo4E&id=14186771223
http://item.taobao.com/item.htm?spm=a1z0d.1.1000638.46.SMqo4E&id=14186771223
http://item.taobao.com/item.htm?spm=a230r.1.14.280.VSmvZr&id=19343569343&_u=tm9b7uq2ebc

Jspeybro, if you don't mind me asking a favor in return and digging into your knowledge:
Given the above notion that capacity is not super important, how would you rig cells to drive triple XMLs (prolly through a Taskled driver)?
3s, 2s2P, 4s?

Now why is it we can't seem to find those thing on Ebay or Amazon... or for that matter anywhere in english ;-)

 

[Diving Gecko]

Now why is it we can't seem to find those thing on Ebay or Amazon... or for that matter anywhere in english ;-)

I think you just answered your own question. I suspect the vendor does not speak English, so Ebaying would just be too much of a hassle.

Also, a year or two ago, the Chinese import-export regulations were changed and you need to do a whole lot more paper work now to send out packages.
Now, in order to do it with less hassle, you need to obtain an import-export license but that takes forever and is expensive.

 

[Diving Gecko]

If you get lFlex than 3 Li-Ion, for b3Flex 4 Li-Ion, nothing from TaskLed that will work with 3 XM-L in serries and 2 Li-Ion (HBFlex needs more voltage input and maxFlex is only 1.2A output).

b3Flex with 4 Li-Ion should stay in regulation pretty much thru whole batteries discharge.

lFlex with 3 Li-Ion will at some point drop out of regulation and will give you long runtime with lower output.

Thanks Arek,
Very helpful.
I am gettting close to putting down the Taskled order.

 

[arek98]

Maybe here http://www.taobaobuying.com/

 

[Codiak]

Maybe here http://www.taobaobuying.com/

Thanks for the hassle I did find a 18650 holder PCB... it's 15$ but quick to get

Or I may just cut some PCBs and put a couple together

 

[Diving Gecko]

Hey Codiak,
Can you share where you found it. Turns out the Chinese vendor doesn't have a 4s1p but only 2s2p holder.

 

[Codiak]

Hey Codiak,
Can you share where you found it. Turns out the Chinese vendor doesn't have a 4s1p but only 2s2p holder.

On ebay, just search for "18650 holder pcb"
It's only a 3P holder though...

 

[alpg88]

you can wire 2 of thses http://www.batteryjunction.com/olight-sr50-18650-magazine.html

 

[Diving Gecko]

Yeah, I think I have even seen these on the Chinese site. I may get a few. I am thinking of rewiring the 2s2p one I am getting also.
Thanks

 

[Diving Gecko]

BATTERIES - PROTECTED OR NOT, INDIVIDUALLY OR AS A PACK?
A small update.
I will get both an b3flex and an h6flex. Just had a small Paypal setback, but they should be on their way soon (happens when you try to change the country to China on your Paypal...).

In the meanwhile, I ran a simple test with 3 x XM-L and 4 x Panasonics 3100mah and a local board that promised to output 3A but it doesn't.
Eg. when the driver is hooked up to the LEDs and powered by my voltage regulator, the regulator says about 2.4A @ 14.8V. Can I use that amp measurement at all?
The output V at the board is 9V. Would it be possible to take an amp reading with a multimeter on the board or the LEDs? If so, where exactly?

Anyways, back to the batts. I also hooked driver and LEDs up to 4 x Pana 3100mah cells and it ran at full brightness for 1H 25Min! So, that means, either the LEDs are at less than 3A or there is more juice in the cells than 3100mah;-).
I had the LEDs on a heatsink lowered in a small bowl of water. I changed the water out 3-4 times when it got hot.

I bought these cells with individual protection boards and they seem like good quality and I can get them from the same vendor without protection boards.
So now, I am wondering.
I plan on using a balanced charger to charge the batts and I would like to make them into packs for simplified use (I have just soldered up a few balancing harnesses for 4S).
Should I use unprotected cells and let the Taskled handle low voltage cut-off and the charger handle balanced charging?
Should I make the pack with just one protection board handling the cells? And still wire the balancing cable in?
Or should I make the pack with individually protected cells?

What do you guys do?

 

[Diving Gecko]

AMP READINGS AND BATTERY LIFE (TEST)

In the meanwhile, I ran a simple test with 3 x XM-L and 4 x Panasonics 3100mah and a local board that promised to output 3A but it doesn't.
Eg. when the driver is hooked up to the LEDs and powered by my voltage regulator, the regulator says about 2.4A @ 14.8V. Can I use that amp measurement at all?
The output V at the board is 9V. Would it be possible to take an amp reading with a multimeter on the board or the LEDs? If so, where exactly?

Anyways, back to the batts. I also hooked driver and LEDs up to 4 x Pana 3100mah cells and it ran at full brightness for 1H 25Min! So, that means, either the LEDs are at less than 3A or there is more juice in the cells than 3100mah;-).

So, I am a noob, I hadn't "spliced" in the multimeter for amp reading which is why I had no readings.
But I just went back and hooked it up to the 4 x Panas again and this time with multimeter in series in between the driver and LEDs.

The driver has three brightness levels and these were the readings of within first five mins of a fully charged pack:

Brightness Level I: 2.95A @ 9.6V (This was the level I got 1H:25Min on the other day)
Brightness Level II: 1.46A @ 7.7V
Brightness Level III: 0.29A @ 6.1V

I am not sure if this is the right way to do it. But if it is, then it seems like the driver does indeed output app. 3A and it seems like it is quite efficient and that my 3100mah batts are pretty much packing what they promise.

If my math and understanding of these things are up to scratch and the above readings are OK, then these are my conclusions:
To run at the 100% brightness level for 1H 25min would take:
(2.95A x 9.6V) x 1h 25min = 40.1 watt-hours.
So, that means the Pana 3100mah cells pack 10 watt-hours each of their theoretical 11.5 watt-hours. (They were discharged to 3.17 - 3.21V at cutoff).
Probably more as the discrepancy could be lost in the driver and not so much the cells.

Now, I am still wondering about how to pack them. For now, I am just happy that my Chinese-sourced Pana cells seem to be genuine;-)
Would love to hear your thoughts on the protection board options as per the above post.

 

[Diving Gecko]

HEAT SINK SIZE?
So, here is a screen shot of my simple drawing. Pretty self-explanatory but as you can see, the heat sink is minimal.
This whole head will be lathed (and milled) in one piece of alu.
Remember, I don't need this to work out of the water. I'd much rather have a lightweight torch than one with wings and a massive heatsink.
The diameter is 50mm and the part that the Taskled and the LEDs sit on is app. 4.5mm.

Would you say, bearing in mind this is for in-water use only, that there is enough heatsink?

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As you can tell, I am hoping for a Piezo switch in there as well.
(Also, I know there is a flat face "missing" on the round barrel from where the switch will be. Early days...)

 

[DIWdiver]

Just offhand, I'd say that's enough heatsink. To be safe though, I'd not remove any more alu from the area of the LEDs than necessary. You've shown nice smooth curves, which are not only hard to do but also remove material that could help provide better heat conduction. Especially on the inner bore, where the LEDs are, I'd leave as much material there as possible. And on the outside, I'd definitely leave enough material that the screws don't poke out!

 

[Diving Gecko]

Hey,
Thanks for your input, much appreciated.
Screws can be shortened
Also, this will hopefully be done on a CNCed lathe, hence the pretty curves. But I'll add a few mm of wall. Well, I could even resort to wings if need be...

BTW, just wondering if you had any thoughts on a 4 x 18650 pack...?