Most efficient board from DX or KD

[wechnivag]

Hi,

Some time ago, recall SKU 7882 (the one with pot for variable current) was the king of efficiency as tested by EEPROM.

I'm building some new lights using the XP-G. Is this still the best board to use, or is there a more efficient board?

Still love the low-med-high group, with a really dim low and 1amp high on this board....

Cheers!

 

[kramer5150]

I have found the 1.0 and 1.4A 7135 boards seem to work very well with the XP-G. But I have no way to measure the actual efficiency. I bypass the protection diodes, and ONLY use them with 1 Lithium ion cell. My understanding is that their efficiency increases as Vbatt drops closer to Vf-led.

I have had long term reliability issues with two of my three 7882 boards.... FWIW.

 

[uk_caver]

For the 7135, the efficiency is basically 100*Vout/Vin, so it does get more efficient as the input voltage drops, up to the point where there isn't enough voltage 'headroom' for the regulator to drive the LED at the desired current.

 

[lolzertank]

There's no reason to bypass the protection diodes! They only drop voltage to the Vdd pin of the regulators (which can go down to 2.7V), not the LED.