After you buy a rechargeable desk lamp, do you wonder how long it can last after it is fully charged? Generally, regular products have an instruction manual, and we must read it carefully before using it. The manual must have an introduction to the usage time. If you want to understand how to calculate the lighting time of a desk lamp, I will give you a detailed introduction below.
To calculate how long a desk lamp can be used, we can use the following formula:
Usage time = battery capacity (unit: mAh) * battery voltage (unit: volt) / power (unit: watt)
Next, let's calculate according to the formula: for example, the battery of the desk lamp is 3.7v, 4000mA, and the power of the lamp is 3W, how long can this desk lamp be used when it is fully charged?
First, convert the battery capacity to mAh, since 1mAh = 0.001Ah. So 4000mAh = 4Ah.
We can then calculate the usage time by multiplying the battery capacity by the battery voltage and dividing by the power:
Usage time = 4Ah * 3.7V / 3W = 4 * 3.7 / 3 = 4.89 hours
Therefore, if the battery capacity of the table lamp is 4000mAh, the battery voltage is 3.7V, and the power is 3W, it can be used for about 4.89 hours after being fully charged.
this is a theoretical calculation. Generally speaking, a table lamp cannot keep working at maximum brightness all the time. If it is calculated to be 5 hours, it may actually work for 6 hours. A general battery-powered desk lamp will automatically reduce the brightness to 80% of the original brightness after working at maximum brightness for 4 hours. Of course, it is not easy to detect with the naked eye.
The working time of the desk lamp after it is fully charged is affected by the following factors:
Battery capacity: The larger the battery capacity, the longer the desk lamp will work.
Number of battery charge and discharge cycles: As the number of charge and discharge cycles increases, the performance of the battery will gradually decrease, thus affecting the working time of the desk lamp.
Charger and charging method: Using an inappropriate charger or incorrect charging method may affect the life and performance of the battery, thereby affecting the working time of the desk lamp.
The power and brightness settings of the table lamp: The power and brightness settings of the desk lamp will affect the energy consumption of the battery, thereby affecting the working time.
Ambient temperature: Extremely high or low temperatures may affect the performance of the battery, thereby affecting the working time of the desk lamp.
In general, the working time of a desk lamp after it is fully charged is affected by various factors such as battery capacity, number of charge and discharge cycles, charger and charging method, power and brightness settings of the desk lamp, and ambient temperature.