Gemini Duo light review

May 27, 2019
Gemini Duo light review

Simon & Garfunkel. Hall & Oates. Antony & Cleopatra. Macaroni & cheese.

History is littered with the achievements of notable duos. The ambitions of the Gemini Duo light are a little more modest – making riding in the dark a bit more bearable. Our staff member Tom McQuillan has been trying out the Duo to see if it makes the grade.

Inside the box

One of the joys of the Duo (and of most lights in the Gemini range) is the extra goodies that come inside the snazzy black box. Most cycling products come with the kind of cardboard one immediately throws in the recycling bin, but all Gemini front lights come in a lovely black case which went straight onto the mantelpiece for safekeeping – and maybe a bit of bragging if anyone asks about it in future.


The main lamp of the Duo is a piece of anodized black aluminium containing two LED lights (hence the name), capable of pumping out 1500 lumens of brightness on full blast. Although the light head only weighs 68g, it definitely feels like a sturdy product, and the test model has already stood up to a few knocks and bumps and come through with flying colours. Aside from the standard fixings such as the light, battery pack, handlebar mount, and charger, there’s an included helmet mount, a head torch mount, multiple stretchy rubber bands to help secure everything in place, and – perhaps best of all – a remote switch for your handlebars.


Crucially, this means that you don’t have to reach all the way up to your head to adjust the brightness of your lights, which is ideal when you need to adjust the level of power on the go. There’s also a dimmer switch on the remote, a very handy feature which will help preserve the eyes of anyone riding the other way.

On the trail

The Duo lights are too powerful for a self-contained battery, and so are available with either a 2-cell or 4-cell hard case battery pack. Each has their pros and cons – the 2-cell is lighter (132g) and ideal for mounting to a helmet, while the heavier 4-cell (234g) doubles the battery life and works best when mounted to the top tube.


The lowest default setting of 300 lumens (one of 10 programmable lumen levels) is a perfect output for commuting in low light conditions – enough brightness to see where you’re going along sealed roads or bike paths, but not so much that you’d be considered antisocial for shining it in the eyes of passing drivers, riders or pedestrians. Gemini’s claimed run time at this output is 6 and a half hours for a 2-cell battery, or 13 hours for the 4-cell version – more than enough for a week’s worth of commuting for most folks.

The medium setting of 900 lumens is better suited to off-road riding, especially on the mostly trustworthy hard-packed dirt trails most common in Australia. The Duo’s maximum output of 1500 lumens is perfectly suited to fast off-road trail riding in the depths of a winter’s night, as it illuminates not only the trail in front of you, but - crucially – obstacles and animals that might jump out as you ride. Of course, with the power to stun possums comes a reduced run time - 90 minutes from full charge with a 2-cell battery, compared with 3 hours for the 4 cell version.

If your battery does start to run low, checking the battery level is very straightforward – all you need to is glance at the battery indicating LEDs behind the translucent main on/off button. Depending on the level of charge, the button will be lit up in one of the following colours:

• Green: more than 50% battery remaining.

• Orange: 20%-50%,

• Solid red: 10%-20%

• Flashing red light: less than 10%.


This is one feature that really separates the Duo from other lights we’ve previously used, as with many other lights there’s no indication that the battery is running low until the light enters a low-power mode at around 20% – not exactly the best if you’re already out on a night time ride when you suddenly can’t see where you’re going. There’s been more than one occasion in the past 12 months when seeing an orange or red battery indicator on the morning of a planned night time ride has given sufficient opportunity to pop the Duo’s battery on the charger and have it fully topped up by the time the ride kicks off.