Rear Bike Light Buying Guide

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Rear Bike Light Buying Guide

It is important for cyclists to be visible when out at night or on a darkened winter day. This means placing reflective gear, and lights on the bicycle. Most important of all are the rear bike lights that let automobile drivers know that there is a cyclist on the road. Without these lights, the cyclist is in great danger of being hit by cars, other cyclists, and even of running into pedestrians. There are lots of different types of lights including LEDs, krypton, and halogen lights. Each of these offers plenty of features for the cyclist.

Various power sources are also available for these lights including batteries, magnets, and even dynamos. Most lights do use the widely available AA and AAA batteries, although, there are a few different options in these for cyclists too. Rear bike lights are sold in retail stores, cycling and sports stores, cycling websites, and on auction sites like eBay.

Types of Rear Bike Lights

Cyclists have a few different types of rear bike lights to choose from. Light styles vary in design and purpose, including those intended for urban travel or lighting the night on a nature trip. Cyclists may prefer to choose their bike lights by the method of illumination which varies from noble gases to light emitting diodes (LEDs).


The LED is a modern type of light, first developed for use on computer boards. LED lights are very small, so several rows of them are needed to make up one complete bike light. Many prefer using LEDs because they provide long-lasting light without requiring a lot of power. LEDs are also bright and easy for passersby to see. LED lights are available in steady or flashing modes. The flashing mode lights have been legal to use in the UK since 2005 as long as they conform to Road Vehicles Lighting regulations. LED lights are bright, affordable, long-lasting, and small in size. In fact, some experts say that an LED light never burns out because they are solid-state technology.

The only drawback to using LED lights is that they tend to shut off quickly when they run out of battery power. For this reason, it is suggested that the cyclists use two LED lights on the rear of the bike with one serving as a back up.


The krypton light uses a filament inside a glass bulb filled with krypton gas to create light. This is an older style of light, but still effective. Krypton lights are not as long-lived as LED lights. However, they do provide bright, well focused light that is easy to see by. The light produced by the krypton gas is warmer and yellow in colour. While these bulbs do not last as long as some other types of rear bike lights, they are much cheaper on average, especially compared to LED lights.


The halogen light provides light through the same method of illumination as the krypton light, except that the bulb is filled with halogen gas. Halogen issues a very bright, white light compared to the krypton light. This light creates a strong, focused beam of light. In fact, the halogen light produces the same intensity of light during its entire lifespan, and dies slowly when battery power begins to run out. Cyclists should be aware that the light does produce a lot of heat while on.

Cyclists may also come across rear bike lights made by using other forms of illumination. Very old bike lights were actually filament lamps, a type of incandescent bulb. These bulbs are no longer used in modern lights because they burn out quickly and produce a lot of heat. Xenon strobe lights are another style of light cyclists may come across. These lights are relatively common, but were only recently used in bike lights. Xenon is a gas like halogen or krypton, which produces a bright light, but has a short lifespan.

Power Supplies Used in Rear Bike Lights

Rear bike lights are powered in a few different ways. Most lights use batteries, but there are some emerging technologies cyclists seem to like for their long-lived power supply. When using different kinds of light power supply, a cyclist needs to get a light that is setup to use that source of power.


Most rear bike lights use standard double AA or AAA batteries, usually one or two batteries per light. These batteries are typically Nickel-cadmium (NiCad) or Nickel-metal hydride (NiMH). Alternatively, cyclists may want to use the rechargeable NiMH to save money and reduce waste. Another type of rechargeable battery growing popular in usage is the Lithium-ion (Li-ion) and Lithium polymer (LiPo) batteries.

Furthermore, certain kinds of bicycle lights produce such a high powered light that they require an external 12 volt VRLA battery. The VRLA battery straps to one of the bike's horizontal bars, mounts to the water bottle holder, or rests in a basket attached to the bike. This battery can be used to power other lights or even small electrical devices that use 12 volt power sources.

Dynamo Systems

Dynamo systems are a power supply that do not need replacing or recharging. These systems are powered by the cyclist when using the bicycle. The energy is stored or used immediately for powering the light. The dynamo is a small electric generator attached to the bicycle that produces an alternating current through rotation. There are three basic types of dynamos.

Hub dynamos

Hub dynamos are built into the wheel hub of the bicycle. These are the most efficient type. However, they have to be specially built into the wheel of a bike, which takes time and money.

Bottle dynamos

Bottle dynamos are shaped somewhat like a bottle and are attached to the fork of the bike while the neck of the bottle is in direct contact with the bike wheel. The turning of the wheel turns the dynamo. This system is less efficient, but can be disconnected as desired.

Bottom bracket dynamos

These types of dynamos connect between the chainstays and behind the bottom bracket. A small roller pressed against the tyre turns it. There are complete light kits available with both the bicycle light and the dynamo to power it. However, most bike lights set up to use dynamo power are sold separately.

Electromagnetic Induction

Lights powered by electromagnetic induction are sometimes called "magnetic lights". These lights create power by exposing a conductor to a varying magnetic field. Magnetic lights are usually attached to the bicycle wheel. Small magnets are attached to the spokes of the bike. When the cyclist begins pedalling, the movement of the magnets pass the conductor to create power for the light. The light may also contain a battery, so that it stays charged for a short time after the rider stops pedalling. Lights powered this way may not be as bright as a battery powered light. This is also a less commonly used method of powering a bicycle light.

Buying Rear Bike Lights on eBay

You can buy rear bike lights on eBay in any type using many power sources. To find these lights you may want to use the eBay search engine. The search engine is available from any page on the site. Just enter the search term, such as "waterproof bike lights" or even a brand name like "Torch" into the search engine bar and hit the search button. The website searches through the entire site within seconds and returns matching results in a search results page. These results can be narrowed down using the refinements menu available on the same page.

Seller History

Before purchasing rear bike lights from a seller on eBay, take the time to research the seller history. You can access the seller's history by clicking on any seller name within a listing. This takes you to a new section of the website with all of the previous customer comments and a star rating from each customer. The star ratings are all averaged together to create the seller's overall rating. When you complete a sale with the seller you can also leave customer feedback and a star rating of your own.


Rear bike lights are excellent ways to alert traffic of one's position. These lights are available in a surprisingly wide array of types and use varying kinds of power supply. LED lights are long lasting and provide consistently strong light. Halogen lights produce a focused beam of white light. Krypton lights produce a warm yellow light and are inexpensive. The power sources for these lights include batteries, dynamos, and electromagnetic induction. However, batteries are the most commonly used power source for rear bike lights. Electromagnetic induction is less common, but provides an unlimited source of power. There are a few different types of dynamos that cyclists can use.

When looking at rear bike lights cyclists should be certain to select a power supply that is compatible with the light. Sometimes complete kits with lights and the power supply are sold together, and more often the lights are sold by themselves. Rear bike lights of all types are sold on eBay.

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