The terms “min” & “typ” are commonly found on rechargeable batteries. Due to the slight inaccuracy in battery capacity, manufacturers cannot specify the exact capacity and instead write two, one being the minimum (min) capacity and the other being the nominal capacity (typ). If you’re interested in learning more about battery indicators, let’s get started.
In the context of a mobile phone, the phrases “minimum” and “typical” refer to the charge at 95% and 100%, respectively. According to the BMS/charging-safety of a mobile phone, it first reaches minimal, then typical, which takes a long time when it is charged. The capacity written on the smartphone batteries is typical, indicating the nominal capacity.
For example, if a phone’s battery capacity is 4000mAh, this is the typical capacity. However, due to the slight inaccuracy associated with battery capacities, no manufacturer can confidently state the capacity of their batteries. Consequently, manufacturers specify a minimum capacity, such as 3900mAh, to guarantee that the battery capacity does not go below this value.
The safest voltage level to discharge a battery is the min voltage value. Remember, there is a risk of the battery being damaged if the voltage drops below the recommended minimum voltage.
A lower voltage than the minimum value can cause damage to the battery.
Rated/ typical voltage
Rated voltage is the voltage that the manufacturer specifies is necessary for a battery or device to function properly. For example, when using a mobile phone charger, you may have noticed the words “Input: 100–250 VAC” printed on the label. That is the voltage at which the phone charger is designed to operate.
This is the highest voltage to which a battery may be charged.
Rated capacity vs. Real capacity. What is the cause behind this?
Lithium-ion batteries, which are used in devices such as power banks, operate at a voltage of 3.7V. On the other hand, USB output ports provide 5V, as indicated on the package or on the power bank itself. Changes in voltage result in changes in capacity; for example, if you have a 15000mAh power bank, converting it to 5V reduces its capacity to 11100mAh; and vice versa. Besides, voltage conversion generates heat and consumes energy, which reduces the capacity of the battery. Conversion efficiency varies, based on the product and brand. Certain brands mention the conversion efficiency of a product, but others do not mention it at all. The percentage could range between 2% and 10%, depending on the product.
Here is the formula for calculating real capacity:
Actual capacity = 3.7V x Advertised capacity x efficiency (in decimal) / 5V
To learn more about this subject, see Why is there a difference between real and rated battery capacity? article.
Why don’t manufacturers simply state power bank’s real output?
As a result of the highly competitive nature of this market, manufacturers are striving to attract customers by labeling their products with bigger capacities. The second reason is that they do not provide information regarding conversion efficiency rates and other data, which makes it easier for them to compete with brands that have higher conversion efficiency.