When watt-hour is used for a lithium battery it means that the capacity of the battery to provide energy in watts that will continue for one hour. Lithium-ion batteries are used nowadays in almost every device. The lithium-ion watt-hour rating decides the shipping for the battery. The mode of the shipment depends on the energy providing capacity of the battery. The battery of the battery in watt-hours depends on the amount of current in amperes drawn from the battery and the voltage provided by it. A watt is the product of volt and ampere. It means that a battery providing 5 Volts and having a 20 watt-hour rating will draw 2 amperes of current. In other words, we can say that the battery will last for two hours. So, the watt-hour rating of a battery provides information about the battery life.?
The watt decides the power provided by the battery. A lithium battery has some internal resistance that can use some of the power generated by the battery. The power generated overcomes the internal resistance of the battery. The watts generated by the battery depends on the number of cells placed in a battery. The internal resistance is due to the lithium, lead-acid, and alkaline used in the battery. The power in the watts is the measure of the energy provided by the battery in watt-hours. The voltage generated is mostly fixed for the battery. Every battery has a different power.
The watts of the battery can be calculated from the Ampere or milliamp reading provided on the battery. The watt is the product of volt and ampere. If we have the ampere value of current and the fixed value of the voltage provided by the battery, then we can calculate the watts provided by the battery.
Watt = Volt * Ampere
Power = Voltage * Current
How do you calculate lithium battery watt-hour?
The energy provided by the battery is measured in watt-hour. The watt-hour capacity of the battery depends on the number of cells. The single cell is mostly 10 watt-hours. It means that this cell will provide 10 watts of power for one hour. If 12 such cells are present in a battery, then it means that the battery will have an energy of 120 watt-hours. This is also the measure of battery life. The formula used to calculate the watt-hours of a battery commonly is:
Watt-hours = Watt * Hours
Watt-hours = Volt * Ampere * Hours
In some of the batteries, the value of the current is given in milliamperes so in that case, you need to divide the value with 1000 and the formula comes out to be:
Energy = Voltage * (Current / 1000) * Time in hours
So, a 100 watt-hour battery can deliver 100 watts for one hour or 20 watts power for a time of 5 hours. You can also use another way to calculate the watt-hours of the lithium battery. If the voltage rating is given for a battery you need to divide it by 1000 and multiply the value with the value of ampere-hour reading of the battery. The formula comes to be
Watt-hour = ampere-hour * voltage/1000
So, if we define one watt for a battery then it is the product of one ampere-hour and one volt. It is a great unit that can be used for commercial purposes. The commercial unit used for energy capacity is kilo watt-hour. The batteries are compared by their watt-hours capacity. A 300 watt-hours battery may provide 100 watts output. There are many extra circuits in a lithium battery that can prevent the battery from over-charging and over-discharging. These safety circuits absorb some amount of energy produced by the battery. So, remember that the output of the battery mentioned in watt-hours on it will not be the actual output provided by it. The actual output will be less than the reading provided.
How do you prolong the lithium battery watt-hours?
After knowing completely about the energy capacity of the battery you should know how to prolong the watt-hours provided by the battery. Simply, you should know some techniques to increase the battery life of your lithium battery. Battery life is very important for your device. Some of the lithium batteries are very expensive so you should take care of the batteries so that they must deplete slowly. You only need to preserve the current charge on the batteries. There are many different ways. Some of them are mentioned here:
Always keep the batteries between the temperature range of 20 to 25 degrees Celsius. It is the room temperature range. Keep your batteries away from heat. It is the largest affecting factor to reduce the watt-hours provided by the battery. Never keep lithium-ion batteries at high temperatures.
You should keep an extra battery with you. The battery depletes with time. if the battery is not used for a long time then it will start discharging. You should always purchase a battery with a recent manufacturing date.
Try to allow your battery to complete discharge. Experts have advised that full discharge after some charging cycles will increase the battery life. Avoid partial discharging.
The batteries must not be completely discharged frequently. It means that the batteries must not go below 2.5 volts per cell. Remember not to recharge the lithium-ion batteries if they have remained discharge for a long time duration.
If you want to extend the life of a lithium-ion battery you should first discharge it 40 % and then store it at room temperature. If you will store a full charge of the battery, then the oxidation of the lithium-ion will increase and it will result in discharge. It will surely decrease the watt-hours of the battery.
The above-mentioned tips will help you a lot to improve the energy capacity of lithium-ion batteries.