I’m quoting myself because I believe my question was misconstrued. I did not mean to reignite the short vs long tube debate. I like the idea of 8 cell capacity.
I am honestly wondering about the above scenario and the chances of thermal runaway.
It’s a valid point Caleb, most of us are well versed in proper use of Lithium ion cells, but a light like this will certainly bring new people in and a scenario like you describe could get ugly. That’s why some are concerned about having to have a “matched set” and using an 8 bay charger to charge all simultaneously and with the same algorythm’s. For most flashaholics, the charger and cells isnt’ that big of an issue. I have 3 8 bay chargers, many many cells, and imrbatteries.com with their 15% discount for BLF users is a couple of hours away from me.
I realize not all will be in this situation, and I realize this light won’t be for everyone. It’s really a specialized set-up and anyone considering it just for the WOW factor might need to reconsider.
Edit: To clarify, it might be prudent also for those looking at this light to think about where and how they’d put it to use. Some municipalities might take exception to someone randomly shining a powerful spotlight around, it could result in fines and/or confiscation of the light. So it might pay to look at all aspects.
Obviously you should not do that on purposes. That said I charge all my cells on a parallel charging bank (posted in another thread). I regularly put cells with a .5V difference and just let them sit for a little while to “balance out” before I start charging. No issues here at all, they don’t even get warm.
I have done as much as a 1V difference and it still handles it fine, although they can get a tad warm, basically the same as a high current charger.
So the cells can handle this kind of thing quite well actually. The voltage sag in both directions means that there is a lot of wiggle room.
You really want to ensure that the cells are at an equal charge in both carriers though, although the cells themselves do not have the match between the carriers, just inside the carrier.
The TK75 does things this way and they don’t have any issues, I think it will be fine.
I think some still don’t realize how big this light is going to be.
Is going to be huge! And awesome of course.
I think you are right, it is basically 3 L6’s side by side by side at the head.
Sounds about right…… :+1:
Ahh, think Dale has some good points. With a FET based driver, there's techniques to limit voltage/amps but have other side effects. If we limit it to the max amps for the hottest setup, then you will only achieve the max performance from having the best cells, etc.
Not sure if we can use, possibly, a current limiting resistor. We could employ thinner/longer LED wires, or even long traces can be added on the driver PCB, as I've seen done in SRK clone drivers. Buck drivers will have better control over amps.
Can I assume no one has done a 4S FET based driver build for a XHP35? If not, and we want to go that route, we need to get goin on some testing/experimenting now. All this can be done way ahead of having a GT proto. I would ask DEL if he could help out - he'd probably would have some great ideas.
For those drawings, the short version really doesn't look that bad, compared to the MT07. Balance wise, might be a big issue...
How about a linear/7135 driver?
I bought this one from mtn electronics and it does a great job regulating current even if voltage is higher than the LED can take, but it is not a buck driver.
It’s only for 2s though, and it’s driving a XHP70. Maybe there is something similar for 12v LEDs and 4s?
Already working on that 
Worst case the Texas buck would work but at a hefty price premium, I doubt we could keep it in the budget with it.
I have seen some talk by VOB and some others that they ran XHP35’s with FET drivers but they had to limit max duty in order to keep them alive, I plan to be testing this shortly. I just had my L6 drivers show up today, if I have enough parts I will use one of them to test an FET driver with and XHP35. With some firmware tweaks it could have “regulation” by raising the duty cycle as voltage drops to keep the current the same.
I also have a totally new possibility I am working on with DEL at the moment. It is not the best option but for our budget it looks like it might be the best we can get. Should hopefully have something worth showing in the next week or 2.
I’d say: this light was supposed to be an affordable MEGA thrower.
So yes, it’s going to be really big. And heavy. So what? I like that!
An expectional light needs exceptional specs.
Just go for the 8 cell batt tube and design the driver for use with one (1) specific led.
Keep the cost and development time as low as possible, not loosing quality.
If we can run the light with either 4 or 8 cells that would be great.
If we need dummies - IF - no problem, let the manufacturer sell them with the light, if so desired.
4 Dummy cells should not cost a whole lot of money, right?
According to my calculations, a 2,5A driven XHP35 HI should come well abov e the 1Mcd mark (depending on quality of the reflector, quality of the lens, optimal focus and centering….).
Grtz
Nico
Maybe sketch a 3D Maglite on the side for size reference…
It gets ESPECIALLY cheap for 4 cells because the amperes drained will be very low. That means that laptop pulls, or other low quality cells will provide the same output performance as the most expensive Sony/Samsung. That is very important with this kind of battery guzzlers. That brings the price of the light right down, and brings the battery cost down close to 0$. Which is a good thing.
Correct, with all 8 cells each cell would only need to prove about 1.5A max, so basically any cell will handle it just fine. Although obviously runtime will not be as good.
I have been watching this one from the outset and like what I see.
The OP says this:
A new project
Aim:
BIG thrower that surpasses the latest super throwers like the TN42
I say IF that is what the intent was and still is… then let’s make it a good one.
Don’t worry about “bells & whistles”. Use whatever ‘parts’ (driver, LED, Reflector) are needed to make it exactly what the stated aim is.
“BIG thrower that surpasses the latest super throwers like the TN42”
Most likely that will narrow the choices drastically of what LED & Driver to use.
In other words, ‘form’ should follow ‘function’ on this one.
My .o2, ymmv. :+1:
Sadly it is not always so simple lol. For example with the LED, the XP-L Will technically throw further but be less useful everywhere else.
With the battery tube, going with fixed cells like the Q8 would work but drastically limit modding ability due to not being able to use 3V LED’s, which would throw further for those that wanted to do that. Although honestly with the cell setup, besides the ability to run 3V LED’s it is really more about cosmetics and flexibility.
Going with a solid tube with no carriers would save a little cost, it really depends on how close the pricing is on weather the savings is worth it.
Teacher you forget the price. It can’t be astronomical like the TN42 which is the main problem of that flashlight.
I think we are over complicating this light. Mostly with exactly what you have just said - using 2 types of led (being able to). I for one don’t and won’t.
Ok, a quick look at the results of the poll so far, it would seem to me that virtually no one wants ‘One particular LED’ anyway, in fact it’s such a small percentage that it surely cannot even warrant ANY say in the manufacture of this light - the extra machining, time, planning, etc etc of being able to fit a different led that -
- no one seems to want anyway
- that many of the buyers will never fit
seems to be a big waste of funds and time.
Basically from what I can see, it’s causing over complication of the whole thing for no real valid reason, other that a few of the buyers may change the led to the other type (but likely it will go back to the other anyway) - that is if the poll is to be believed.
My personal opinion would be to concentrate on the chosen emitter (when voting ends) and design the light soley around that. No moving head parts/locks etc.
The old adage - ‘Jack of all trades, master of none’
I’m sure people have their own opinions - but this is mine, sorry if it upsets anyone in advance :+1:
carriers offer security, one sees the cell placed correctly and then puts the whole carrier in the tube.
Also when using 4 cells, all the cell weight can be put away from head.
that a carrier could be modded is nice but not the main reason i think
Alright, alright, those renderings convinced me. :sunglasses: Sign me up Scotty!
No one upset here. It is a legitimate opinion.
I guess it is easier to convert down to 1S then up to 2S. All they would need is 4 dummy cells to convert. They would not be able to run 8 cells with an XP-L.
The conversion would actually not be as bad as I was thinking (used to the SRK that is a pain to convert to 2s or 4s).