Good, compact off-road light - but we weren't impressed by the mounting bracket

Putting its cards on the table from the outset, the Electron Terra 3 front light is described as an off-road light. The previous range-topper, the Terra 2, is still available and - confusingly - is a rather different beast with a separate battery pack and two individual light units. On test here, the Terra 3, an all-in-one light with three Cree XP-G R5 LEDs giving a claimed 800 lumens on high-power.

As any fool knows, or at least road.cc readers, light manufacturers have been known to use lumens somewhat hyperbolically, and you can go to ebay and find some pretty outlandish claimed outputs (such as a 5000 lumen light for £32!) Our comparative testing gives rather more useful information - see the beam-o-tron comparatorator at the bottom of this review.

On full power, the Terra 3 kicks out a more-than-useful 1340 Lux at 2 metres, with a particularly widely-spread beam. Off-road, this wide beam is superb, giving a wide field of vision that enables you to make rapid progress without fear of overhanging branches or other obstacles lurking in the gloom.

For road use it provides plenty of illumination but the wide beam makes it awkward to find a position that doesn't dazzle other road-users while still lighting far enough down the road. We ended up using it a bit like full-beam on a car: switching to full power for fast sections of road and then hastily dropping to a lower setting when someone came around the corner. Here a narrower beam would probably be better.

Electron note that, like all of their lights, the Terra 3 is not BS-approved (for cost reasons they say, but we couldn't imagine a helmet-manufacturer applying the same logic). It lacks any side-illumination which is a requirement for bicycle lights intended for road use. It's a shame that the slight recesses on each side of the bezel (see picture) weren't a bit deeper so they could let some useful side illumination out - they appear to be merely cosmetic.

So far so good then. It's a neat package and kicks out plenty of light, albeit with a beam width better suited to off-roading (not unreasonably, given it's marketed as such.)

However, we found that there is rather a weak-point to the Terra 3 - the mounting bracket. Our first impressions of this were good too - it has a neat clamp with an easy quick-release function (you partially unscrew the screw and then it pivots out of the way allowing removal of the light). On our first test ride, an over-the-bars incident on some wet rocks at Afan saw it snap clean off. But even that, we liked. It's a big ask to make a bracket that can stand up getting smashed against some rocks, but it snapped in a way that allowed the light to be slotted back onto the bracket and zip-tied in place - a limp-home mode if you like.

The part that broke is a plastic piece that fixes between the light body and the bar-clamp (see picture). "Clever," we thought, "a cheap bit breaks and you don't damage the expensive bits". The distributor sent us a replacement bracket, but when that failed again a few rides later, this time with no crashes, we began to have some doubts about how clever it really was. The second time around, the little screw that holds the plastic bracket to the bar clamp stripped out the threads in the plastic, leading to a wobbly light and then no light.

Quite simply, the plastic part needs to be made of something tougher than plastic. A 250g lamp-unit held in place with a tiny self-tapping screw into an awfully slender piece of soft plastic is no recipe for durability. When we asked Electron about this, they said they'd had only one unit fail in a similar way, despite extensive testing and racing with these lights.

Maybe we were unlucky, but the fact is that this is a high-stress part. With no pivot between the clamp and the light, if you decide mid-ride that you want to adjust the angle of the light and can't be bothered to loosen the clamp (likely, as the screw gets really fiddly with gloves or cold hands), you'll break it sooner or later.

It is far from the first time we've seen a really decent light where money has clearly been spent optimising beam output, battery life and so on, but where the clamp appears to be an afterthought. In this instance, replacing a small plastic part with an aluminium one costing a couple of quid more would solve the problem.

One of the brackets that broke was apparently a pre-production part, and Electron tell us they are planning a better CNC'd metal clamp, but that this is still a few months off.

Another minor niggle (again, common to plenty of lights) is the lack of peak on the lamp unit. As the Terra 3 is set a bit further forward relative to the handlebar than many lights, this is a bit less of a problem here, but it would prevent you getting blinded when you're out of the saddle and hunched over the bars.

User operation of the light is dead simple, and - for those who don't read instructions - Electron include a simple key on the back of the light. Two clicks to turn on, one click to toggle through the 3 modes, one looooong press to turn off. Really long. We timed it at three seconds, and this seemed unnecessary. We're talking minor details here, but surely one second is enough? If you're an irritable sort of person, this kind of thing can bug you every time you use something.

The three available modes are high power, medium and low power. There are no flashing modes (flashing lights are not much use off-road). We were very pleased to discover that unlike some other lights, we could install the Terra right next to a (Cateye) wireless cycle computer without any interference.

The power button changes colour to show you how much juice is left, starting at green and then going amber and finally red. On high power, with a claimed life of 3 hours, we were surprised to see that the indicator had turned red at 1h40, but the light was still going strong at 3h15. When the battery is nearly gone, the light drops to low power so as to give you the best chance of getting home.

You might well be able to justify owning a mountain bike and a road bike, but if you're investing in a good light you probably want it to be able to handle off-roading and on-road use.

This is an excellent off-road light - you can see enough to ride unfamiliar trails at a decent pace. The wide beam-angle shows up what's coming up even if you're not yet pointing at it, and even lights up overhead obstacles (good for avoiding low branches).

As a road light it is a bit less well-suited. The beam is so wide that it's hard to choose an angle and power-setting that lights far enough ahead for speeds above 25mph without dazzling everyone in sight. We'd want better visibility from the side to use this on road, too.

The Electron Terra 3 has an enviable combination of compactness, low weight, decent battery life and a blazing output. A tougher bracket would put this near the top of the list if you're looking for an off-road light.

If you want a light that can do everything on-road and off-road, you may find better options elsewhere - but you may also have to pay more for them.


Good, compact off-road light - but we weren't impressed by the mounting bracket.

If you're thinking of buying this product using a cashback deal why not use the road.cc Top Cashback page and get some top cashback while helping to support your favourite independent cycling website

road.cc test report

Make and model: Electron Terra 3 front light

Size tested: n/a

Tell us what the light is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

The flagship electron light, boasting an 800 lumen output and a runtime of up to 9 hours.

The perfect light for the serious off-road cyclist

Three high power Cree XP-G R5 LEDs in a handlebar mounted unit

Huge 800 lumen light output, with tiny power consumption for great power to runtime ratio

Engineered reflector for a great light beam pattern

Compact, light-weight and water resistant headlight design

3 modes - high (800 lumens), medium (500 lumens) and low (250 lumens)

Advanced Sanyo Li-Ion battery with a guaranteed runtime of at least 3 hours on full power

Li-Ion batteries are lighter, more reliable and more compact than lead-acid or Ni-Cad alternatives

Built in USB smart-charge and protection circuit, maximising battery life

Low battery indicator provides warning to make sure you're not caught out in the dark

Fully integrated design, no batteries or wires

Quick release designed bracket

UK mains USB fast charger included

Average system weight 287g

Only quibble would be the reference to a USB charger. The charger was very small and neat, but didn't have a USB connection and appears to charge at 12v, which is definitely not USB voltage either.

Tell us some more about the technical aspects of the light?

Weight: 288g (including clamp)

Length: 105mm

Diameter of light: 48mm

Output (claimed): 800 / 500 / 250 lumens (high, med, low power)

Run time (claimed): 3 hours on full power, 9 hours on low power.

Charging time (claimed): 8 hours from empty

Our tests backed up the run-time claims, and charging time was faster than claimed.

Rate the light for quality of construction:

The body of the light is nicely made out of solid-feeling aluminium. Lens cover is plastic but feels pretty tough. The bracket which attaches the bar clamp to the light is the real weak point - made of plastic and with quite small screws, it is vulnerable. Not unreasonably broken during a crash, but a second failure while on-road suggests a flawed design.

Rate the light for design and ease of use. How simple was the light to use?

Smart-looking lamp unit.

Simple to use: two clicks to switch on, then one click to cycle through high/med/low power. Switching off requires you to hold the button for 3 seconds - this seemed unnecessarily long (and a bit annoying).

Rate the light for the design and usability of the clamping system/s

Plastic clamp with rubber pads for grip. Additional removeable rubber shim to fit to 26mm bars. Uses a screw to clamp up - when the screw is loosened it can hinge out of the way (so screw doesn't need to be fully removed) - this is good. Screw-head is a bit fiddly, especially with cold hands or gloves on.

Plastic part between bar clamp and (metal) light body is a weak point. If this does break, you can probably "limp home" with it slotted into place especially if you had a zip-tie on you. Would be hugely improved if this part was made of aluminium.

Rate the light for waterproofing. How did it stand up to the elements?

Survived downpours without any issues.

Rate the light for battery life. How long did it last? How long did it take to recharge?

Exceeded claimed battery life, charging time also better than claimed. Very good indeed, given output, size and weight.

Rate the light for performance:

Superb illumination for off-road riding - one of the best. Less well suited for road-cyclists: you need the high-power setting if you're going fast on a twisty road in the dark, but other road-users likely to be dazzled.

Rate the light for durability:

Hard to come up with one rating here. Lamp unit very well made and should last for ages. Clamp attachment probably won't.

Rate the light for weight, if applicable:

Impressive, given the battery life and light output. Advances in battery and LED technology really showing here.

Rate the light for value:

This is a fairly expensive light, but for the performance it's reasonably priced. When matched up against the Exposure Strada (with similar form-factor and comparable full-power beam) it looks almost like a bargain. The Exposure has a nice metal bracket and some other features which may justify the higher price, however.

Tell us how the light performed overall when used for its designed purpose

Super-bright beam makes light of dark trails - mtb night-riding is a lot of fun with this light.

Tell us what you particularly liked about the light

Very well packaged, neat light with stonking output. Seems like only yesterday that you'd need a weighty bottle-battery to get this sort of brightness.

Tell us what you particularly disliked about the light

Might have mentioned this already, but the bracket is rubbish. For on-road use, flashing modes would be nice, as would the ability to switch to "dipped beam".

Did you enjoy using the light? Yes, but it was not without its frustrations.

Would you consider buying the light? Yes, but not until they improve the bracket.

Would you recommend the light to a friend? Ditto.

Overall rating: 7/10

About the tester

Age: 35  Height: 6"3  Weight: 81kg

I usually ride: Boardman CX team for the daily commute  My best bike is: Fixed-conversion Eddy Merckx MX-Leader

I've been riding for: Over 20 years  I ride: Most days  I would class myself as: Expert

I regularly do the following types of riding: road racing, commuting, touring, club rides, sportives, general fitness riding, fixed/singlespeed, mtb,


Jez spends his days making robots that drive cars but is happiest when on two wheels.  His roots are in mountain biking but he spends more time nowadays on the road, occasionally racing but more often just riding. 


FMOAB [289 posts] 6 years ago

My experience of Electron's customer service is that they are excellent. I have the terra 2 mentioned in the review and I recently contacted them about the lens steaming up, asking if it was possible to open the unit to clean it. I was told that that shouldn't happen, asked for my address and had a new head unit delivered to me within a couple of days. Most impressive.

jezzzer [329 posts] 6 years ago

Well they were certainly pretty responsive when I broke the bracket, so it's good to know your experience (as a non-reviewer!) backs this up.