Bike lights come in all different shapes and sizes but one thing’s for sure – they’re essential if you’re riding in dark or dull conditions.
With so many options on offer, you may wonder how long your light will last. This article explores how long you can expect a bike light to last before it needs replacing, as well as how long it works after a full charge.
How Long do Bike Lights Last?
Most rechargeable bike lights on the market today use lithium-ion batteries that typically last between 300 – 500 full charges, or 3 – 5 years, whichever comes first. This estimate assumes no defects with the product. Damage or faults from the manufacturer would likely reduce the light’s lifetime.
As most modern bike lights rely on the same technology, we can assume they’ll last as long as the expected lifetime of the component that typically degrades the fastest.
If you’re looking for info on how long a bike light will last on a single charge, skip to the next section.
In most cases, the batteries will degrade fastest as the LED lights themselves can last many years, with a number of manufacturers rating their LED lights to 50,000 hours or more.
As for whether or not you’ll hit 300 – 500 charge cycles or 3 – 5 years first depends on a number of factors, including how often you use your lights, how large the battery is, and how powerful the lights themselves are.
The larger the battery, the further you’ll be able to ride on a single charge and therefore the fewer charge cycles you’ll go through versus using a light with a smaller battery. Battery size also affects how long your light will take to recharge. I’ve discussed what else affects recharging times in this article.
Bike light batteries, as is the case with many other batteries, are specified by their capacity in ‘Milliampere Hours’ (mAh). This is effectively a rating of how much charge a battery can hold. For bike lights, the typical range is from 1,000 mAh to 10,000 mAh.
Things get a tad more complicated as the amount of charge a battery can hold is not the only factor affecting how long a charge will last and therefore how quickly you get through your estimated 300 – 500 charge cycles.
For example, if you have a 1,000 mAh battery powering an LED that draws 1,000 mA (i.e. has an operating current of 1,000 Milliamps), then it will last 1 hour.
The same battery would power a weaker LED light that draws a 500 mA current for 2 hours. In this simplified example the more powerful LED would provide 1 hour of light per full charge, whereas the weaker light would provide 2 hours of light per full charge.
Therefore we can say that the light with the higher-powered LED will reach 300 – 500 charge cycles twice as fast as the less powerful LED, despite the two lights having the same battery.
Everything we’ve discussed so far assumes no failure of the part or water ingress into the light housing itself, but of course, a defect from the manufacturer or simply a poor-quality part will increase the chances of your bike light breaking before the battery fails.
That’s why it’s really important to buy your lights from reputable bike light manufacturers, or if you’re looking for a cheaper option, say in the $15 – $25 range, at least make sure there are a decent number of positive reviews from people who have used the product for a reasonable length of time.
How Long do Bike Lights Last on a Single Charge?
As a general rule, a bike light set to high power will last from 2 – 6 hours, whilst in low power modes anywhere from 4 – 15 hours. Most modern bike lights have at least two power settings, with the time taken to fully drain the battery varying between models and the power setting selected.
It’s important for you to consider what sort of light best suits your riding style, as opposed to simply looking for the light with the longest charge life. Further in the article I share a table with info on a number of bike lights along with a battery life comparison.
For example, if you’re into trail riding at night you’re probably going to benefit much more from a high-lumen, high-powered light with an extra wide beam with a charge life of 4 hours vs. a weak light with a narrow beam that can last 12 hours.
Of course, usage time on a single charge varies substantially across the range of bike lights available. To account for this, we’ve considered a number of bike lights across different price points in order to compare their performance, as well as to give you a range that should provide a reasonable battery life estimate for most bike lights.
Bike Light Battery Life Comparison
| Light Make/Model | Price ($ – $$$$) | Battery Capacity (mAh) | Battery Life in Low Power Mode |
| Ascher | $ | 2,000 | 10 Hours |
| Victagen | $$ | 5,000 | 15 Hours |
| REI Cygolite | $$$ | N/A | 10 Hours |
| Trail EVO | $$$$ | 10,000 | 8.5 Hours |
The battery lives stated in the table are based on the constantly lit low-power mode for each light, as the battery life in the flashing modes of all of these lights varies greatly as a result of the different flashing patterns of the products.
As you can see from the table, the highest battery life is around 15 hours, whereas the lowest is 8.5 hours. As I mentioned earlier, battery life isn’t the only factor you should consider.
The Trail EVO has the lowest battery life stated (still an ample 8.5 hours), but it’s also got the largest battery and will undoubtedly be brighter and have a wider beam providing greater visibility than the other options listed.
Whilst more powerful and definitely more suited to nighttime trail riding, the EVO’s price tag is more than double that of the second most expensive option at the time I’m writing this. So my point is this – there are a number of factors you need to consider when finding the bike light for you, with battery life being just one of a handful of important considerations.