Do notice that in the 2nd schematic of the PDF version of the article the circuit is equipped with an push button switch. This is probably there for more reasons that stated in the article.

As stated the LEDs can be very bright and one would press the switch for just a short period of time.

I suspect that another reason for the switch was that the quoited "10mA margin at 13V" was really not quite enough to save the LEDs in all cases.

Lastly it is almost for sure that the switch helps keep the LED monitor circuit from seriously loading the battery and leading to its discharge. If the LED_var current is indeed 100 times higher than the current in the LED _ref as you said then a continuously applied monitoring circuit would subject even a rather beefy battery to some excess load.

All in all I would not use this circuit.

Michael Karas