Need a comparison please

[Eric_M]

Hi,

I ordered my first "sandwich" yesterday, a BB500.

I'll be running it off a 3.7v Lithium 14500 cell.

Does anybody know how this will compare in brightness to a Longbow Micra?

I did the reflector/lens mod to the Micra to give you an idea of the type beam I'm used to.

Thanks for any help,

Eric

 

[Shanghaied]

It would help to know what kind of LED you are thinking about using.

 

[Eric_M]

Sorry, that might help.

It's a Lux3TX1J.

It's the BB500 drop in module from the shoppe.

Thanks,

Eric

 

[modamag]

It would be extremely bright but would not be wise to run a Lux3T TX1J on 14500 Li-Ion.
When using 14500 Li-Ion with any sandwich, it's virtually identical to direct drive.
And what you're doing is direct driving a Lux with Vf=3.5V with a battery that put out 3.7V-4.2V.

In short
If you only want to do it for fun for a short time, no prob.
If you want to keep your "expensive" sammie for a long time, get a K or higher Vf LuxIII.

 

[knifebright]

I've done the 14500 thing with a madmax and a j-vf lux 3. Note these are just what i've found. There is an underload drop of .30 volts off my li-ion cells. The converter board seems to suck up another .2 volts. That's .5 off the top bringing the max voltage to 3.2-3.8 in. Giving an average overdrive of .2volts which is pretty tollerable. Just my observation though
jimmy

 

[TrueBlue]

knifebright has it right the way I've seen it. With a 14500 cell after the maintanence power of the Sammy has been factored in the emitter is working with just over 3 volts. The emitter can handle the load.

 

[wintermute]

So knifevright and haveblue...can I use a J Vf rated lux3 with a nexgen and a pila Li-ion battery? I read that the nexgens have a Vin overdrive voltage of the Vf of lux + 0.7V, so with a J Vf Lux that would be a 3.97V-4.21V. Since a Li-ion battery comes off the charger at 4.2V, I figured that if the Vf of my Lux3 was in the lower range, I would be overdriving it. So I just traded one of my TWOJs for a TWOK, since with the Vin overdrive of the Nexgen the operating voltages would be 4.21V-4.45V...so there wouldn't be any chance of overdriving the lux on a newly charged Pila (or other Li-ion cell like the 14500).

Was this a mistake, could I have stayed with the J Vf luxeon for a Nexgen 750mA?

 

[TrueBlue]

My lowly homebrew Li-ion charger stops charging at 4.11 to 4.13 volts. I haven't had any problems with the combination of Sandwiches and charger.

Wayne at the Sandwich Shoppe has had two of my homebrew chargers for over two months now and he hasn't had a single complaint about the charger/14500/Sandwich combinations.

I use Lux III emitters with J, K and L voltage series in my Sandwiches and haven't had any problems with the bunch of Sandwiches I have. Of course...YMMV.

 

[dat2zip]

I've used a R123 in my FF1 with Nexgen sandwich combo for many months now. I know of others who are using Li-ion sandwich combos.

As far as I can tell these are pretty safe configurations. Some will go into overdrive, but, not self destruct.

Wayne

 

[Eric_M]

Thanks everyone. This is my first sandwich mod and I'm really excited to see what everyone has been talking about.

Take Care,

Eric