NFlex questions

So... I just bought a Mag with an NFlex. So as this depletes the batteries, will it start to 'flashy thing' ala a Wiz2 when the cells are nearly empty?

Is this what all constant current regulators do?

Sorry for the newbie-ish questions... I'm just new to the whole custom regulator side of things.

My Nflex just step down to the dimmer level that the batteries can still sustain as the batteries get weaker. Now it just lights up in the lowest level without flickers of any sort. I dont want to let it run overnight since i am afraid the battery might leak.

cratz2 said:

So... I just bought a Mag with an NFlex. So as this depletes the batteries, will it start to 'flashy thing' ala a Wiz2 when the cells are nearly empty?

Is this what all constant current regulators do?

Sorry for the newbie-ish questions... I'm just new to the whole custom regulator side of things.

Click to expand...

The "flashing" is mainly a boost regulator effect. What happens in a boost regulator is that the current drawn from the battery increases as the battery voltage decreases. This is because the boost current regulator tries to keep constant current at the output (and sort of constant power - depending on LED Vf variations with heat etc). What then happens is that the battery voltage drops pretty quickly when it's nearly flat and the current increases more, this effect 'feeds' on itself and the battery voltage drops to the point the regulator cuts out (goes below the operation input voltage of the regulator) and the LED goes off. The input current then drops and the battery now starts to recover and the voltage increases to the point the regulator starts up again and the LED lights. The cycle then repeats and there you go "flash" "flash" "flash"....

A buck converter works differently since the input current increases as the battery approaches the LED Vf but maxs out around the LED current. Then as the battery voltage goes lower the buck converter transititions to direct drive and as the voltage drops more the current drops and the battery discharges even slower. So, what you typically see on a buck converter (in constant current mode) is constant LED output all the way to ~LED Vf and then it starts to dim down.

nFlex has a buck converter core, so no flashing.

george.

Chris, I am not too sure if mine has a nflex or a uflex, but when the batteries get low, the top brightness just starts getting dimmer. The way I check is I start on the lowest setting and then count the steps up to full brichtness. If less then 7 steps (8 levels total), time to change the batts.

Jeff

Oh, that's fine... I was just planning on using 2 18650s for this light... I will get some protected cells at some point, but I have unprotected ones right now... just wanted to make sure they would be completely safe from unknown over-discharge. I never would leave a light like this on an unattended so sounds like all would be safe.

This will be essentially replacing another 2C that I use with two unprotected 18650s in parallel with a Wiz2 board and it starts flashing at almost exactly 3 hours of continuous use with a U-bin at 937ma.

Anyway, thanks for the answers!

Welp, i just tried using depleted batteries (alkaline) for the nflex, and guess what, it flickers

it is flickers at approximately 10 Hz and then went to the highest level the batteries still able to maintain (prolly the lowest level) for about 1~2 seconds and flickers back.

I record a movie for this but the digicam does not exactly record it right.