Is it possible to boost LED current to one emitter. Example XPL HI direct driven from 26650 gets about 5 amps. Is there some driver or some way using a capacitor or something that it can be boosted to like 7 without going up in pack voltage?
I have a friend I am trying to assist. He makes coon hunting lights that use a 6 position rotary switch. Power source is a 26650. He gets modes by using resistors in various places and says that switch is a very key piece of marketing for his industry. He wants to get more power to the emitter on high, but I just can think of a way without going up in pack voltage. The one advantage this setup has over most of our own is space. We’ve got about a 2” square of extra space to add components if needed.
It sounds like you want a boost driver, which boosts the battery voltage to some higher value. But I understand that high power, small boost drivers hard to make because the small components cannot handle high current. But if you have a relatively larger space to fit a boost driver, you might look at boost voltage regulators to see if you can find a suitable one.
You can boost the current very temporarily using supercapacitors because of their lower internal resistance. A good 26650 has an internal resistance of around 35milliOhms. A D-size supercapacitor has an internal resistance of about 2.5milliOhms. These supercapacitors can only be charged up to 2.7V, so you would need two of them in series. Using the two supercapacitors charged to 4.2V might send 7A through the LED, very temporarily. This is of course not very useful.
You’re already running the light in direct drive. I don’t think any circuit will boost performance over direct drive as that is pretty much as high as you can get.
There are boost circuits which can increase the voltage. However, when the voltage goes up the amps go down. Total amount of watts doesn’t increase. It actually decreases due to inefficiencies in the circuit. Net result is less power to the LED than with direct drive. Boost circuits are typically only used when the voltage from your cell(s) isn’t high enough to drive the particular LED you’re using. If you want to run an LED with a forward voltage of 6V (meaning it needs 6V to light up) on a single 3.7V cell, then you need a circuit to “boost” the voltage.
Since you’re already running direct drive, you can improve output in the following ways:
Add more cells
Use a cell with lower internal resistance such as a Samsung 30Q, 18650; or just use a larger cell.
Upgrade the LED to a more powerful one that can take advantage of higher current or voltage (can be used with a boost circuit)
Upgrade the wiring to thicker gauge to reduce resistance.
Solder braid the battery tube springs to reduce resistance.
An ideal boost driver would indeed increase the current to the LED. If the boost driver applies 4V to the LED, a high current will flow, say 7A. An even higher current then must flow from the battery, say 8A at 3.5V to conserve power. But as I said, I don’t think the high power boost drivers we want exist.
Practically, reducing circuit resistance is the best way to maximize current.