LED
The number of individual light emitting diodes (LED) in the bike light (see "Type").
A larger number of LEDs, on the one hand, makes it possible to achieve greater brightness of the headlight and reduces the likelihood of its complete failure (the failure of one LED does not lead to a loss of lamp operation). On the other hand, the technical features of modern LEDs are such that manufacturers prefer to put one bright single-chip LED instead of several case ones into powerful “long-range” bicycle lights. On the third, there can also be several single-chip LEDs, to increase reliability and provide additional adjustments (for example, changing the brightness by turning on / off individual LEDs). Therefore, only lamps of the same price category should be compared by this parameter. At the same time, “multiple-charged” models, in addition to the described advantages, also have disadvantages — they are, usually, more complicated, more expensive and larger.
Illumination range
The greatest range at which a bicycle headlight (see "Type") provides effective illumination. The criteria for what is considered effective lighting are very arbitrary and may be different for different manufacturers; therefore this figure is approximate. Nevertheless, it allows you to fairly accurately assess the effectiveness of the flashlight and is more visual than the value of the luminous flux (see above). It is also worth choosing a bicycle headlight according to the range, taking into account the intended application; here note that in some (especially inexpensive) models, “range” can be achieved by narrowing the beam and, accordingly, reducing the light spot.
Max. operating time
The longest time of continuous operation without replacing or recharging the power source, provided by a bicycle headlight (see "Type") in constant light mode (if there is a flashing mode, the operation time is usually longer, but it cannot be called the main one). This item indicates the value for the most economical format of operation, at minimum brightness; therefore, the actual headlight run time will generally be lower than advertised. It is also worth considering that many replaceable batteries (see "Power") are available in different capacities and have different durability — which means that battery life will also depend on the quality of the batteries. At the same time, this indicator is quite suitable for evaluating bicycle headlights and for comparing them with each other.
Max. brightness operation time
Bicycle headlight battery life at maximum brightness (see "Type"). This indicator is closer to reality than the maximum operating time (see above): in fact, it indicates the time that the flashlight is guaranteed to be able to work without replacing or recharging the battery. However note that some batteries (see "Power") can be produced in different capacities, and the manufacturer usually indicates the operating time for the most capacious (and expensive) batteries.
