Max Draw For 14500 batteries?

Hey guys, i have some host kits on sale, and someone asked to buy a "JAD" kit from me. First off, what's a JAD kit (not the main question here )

Also, he wanted to know if he could pair the host with a 9mm diode. I am just wondering, what would be the highest driver setting i could use with a single 14500 battery (ultrafire 3.7v 1200mah)

Thanks guys!
-Matt
:beer:

For cheap li-ions I found out that value (safety and batt life concerned) is around 1.6C to 1.8C. For better branded ones I'd stick with 2C.

C = capacity of the cell. If the 14500 is 1200mAh, I'd not draw more than 2.4A for long life.

So if i were to set a boost driver at 2.1 amps to draw from this 14500, would it be OK?

No.

And quite honestly, 2C from a no-name battery can be kinda iffy.

Also, 14500s are generally 800mAh, so even at 2C, you'd be limited to 1.6A INPUT.

To do basic conversion of input to output, convert both sides of the equation to watts. This ignores any inefficiencies and assumes that your driver is 100% efficient at all voltages.
Pin=Pout
Iin*Vin=Iout*Vout
Iin*2.8V=2.1A*Vf of load <(2.6V is the lowest voltage that most protection circuits will allow)
Iin=(2.1A*5.1V)/2.8V <(estimating Vf of 5.1V for a 445nm 9mm @2.1A)
Iin at that point would be 3.8A, much higher than the 1.6A limit obtained by using the very generous 2C rule of thumb. And that is for a theoretically perfectly efficient driver.

Unless the battery is a brand name one and has high capacity drain on it i would as above stick to the 2C rule as a ball park ,The better batteries actually have high drain capacity on the battery if it is a high drain one, which by the spec on the last lot of batteries i got was almost 4C on 18650 so i would day it would apply to smaller capacity batteries as well

Smaller cells have smaller electrode-insulator-electrode surface area. This means they have lower current capability. Also lower capacity. 2C is rule of thumb for 18650s, mainly name brand 18650s. (___fire is not a name brand). If you have name brand smaller cells, you may could get away with using that same rule of thumb. But real cells will have datasheets that you can reference.

The old Sanyo had some old 16650s floating around, and I don't remember who, but I think it is Panasonic that has some 14500s around too, though I can't remember why I think this.

If you want a high current draw from a 14500 you could look into the AW IMR cells. They have a max current of 7C and can handle a 4 A constant draw.

Here's a review: Test / Review: AW IMR 14500 600mAh (Red) | BudgetLightForum.com


The problem however, will be the capacity and you'll have very short run times before recharging with one cell and a boost.

I actually run my Saik on 2 x AW IMR 14500's in series and it works flawlessly and the run times are not problematic. In fact I rarely charge the batteries but my on-times are limited to a few seconds to admire the beam, or max 1 -1.5 mins for some photos / LPM reading... Im using a moh linear @ 1.8 A though and not a boost. :beer:

KRNAZNBOY said:

Hey guys, i have some host kits on sale, and someone asked to buy a "JAD" kit from me. First off, what's a JAD kit (not the main question here )

Also, he wanted to know if he could pair the host with a 9mm diode. I am just wondering, what would be the highest driver setting i could use with a single 14500 battery (ultrafire 3.7v 1200mah)

Thanks guys!
-Matt
:beer:

Click to expand...

A "JAD" kit is a just add diode kit, can also be called a "no-diode host bundle" in other words all the parts to assemble a complete laser except the diode/module. As one example take a look at the ones SL sells here:
No-Diode Host Bundles

Guys do you think i could get an output of 1.5 amps with a boost driver off of one 14500?

I taught a man to fish. Try going through the math in my post above, if you want proof, but the answer to your second question is no. But, have a look at Grainde's post, where he links you to some 14500 that are of a special chemistry. They don't have as much capacity, but should be able to handle higher currents. 2.1A is pushing it, though. By the time the IMR14500 reaches the end of its cycle, the driver would be drawing >4A from it.