12V batteries are commonly used to power a variety of electrical devices, such as lamps, car radios, and more. However, how long a 12V battery can light up a lamp depends on the capacity of the battery, the type of battery, the depth of discharge, the type of lamp, and so on, all of which will affect how long a 12V battery can light up a lamp. In this article, we will explain to you how long 12V battery can light up the lights, the specific factors are as follows:
1. Battery capacity
Battery capacity is simply how much power can be stored, just like how much water we can put in the cup. We measure battery capacity in Ampere hours (Ah) or milliampere hours (mAh). If there is a battery with a capacity of 100ah, this means that it can deliver 100 amps of current in one hour or 10 amps of current in 10 hours. Specific examples are as follows:
1.1 Assuming you have a 12 volt 100ah battery and you are using the light at 5 amps, you can calculate how long your light will stay on with a 12V 100ah battery by calculating the run time as follows:
100Ah/5Ah = 20 hours.
1.2 Assuming you have a 10Ah battery and you are using the lamp at 2 amps, it is possible to calculate how long your lamp will be able to stay on, calculating the run time as follows:
10Ah/2Ah = 5 hours
1.3 Summary: When we understand the Ampere hours, we will be able to calculate the use of time under different load conditions, this knowledge is very important for our daily life in the use of batteries or calculating the load runtime, we can better choose the battery, select the battery capacity and load power needs to match, to ensure that the load has enough power.
2. Lighting Power Consumption
The power consumption of lights is usually measured in watts, we need to convert the battery capacity from Ampere hours (Ah) to Watt hours (Wh), Watt hours is a better unit of measurement and can directly show the energy consumption. Usually the more watts a light consumes, the shorter the battery life will be, of course this is also related to the type and life of the battery, specific examples of calculating how long a light can stay on are as follows: (Watt = Ampere x Voltage)
2.1 For example if we have a 12 volt 100 amp battery and we are using a 40 watt light, calculate how long the light can stay on and calculate the run time as follows:
Battery watt hours = 12 x 100 = 1200 watt hours
The lamp run time is: 1200 watt hours / 40 watt hours = 30 hours
2.1 For example, if we have a 12 volt 100 amp battery and we are using a 60 watt lamp, calculate how long the lamp will stay on and calculate the run time as follows:
Battery watt hours = 12 x 100 = 1200 watt hours
The lamp run time is: 1200 watt hours / 60 watt hours = 20 hours
3. Battery discharge depth
The depth of discharge of the battery will also affect the running time of the load, and the depth of discharge of different batteries is different, the depth of discharge of lead-acid batteries is about 30%, and the depth of discharge of lithium-ion batteries can reach 100%. Examples of how long a specific 12V battery can keep a light on are as follows:
3.1 For example, if we have a 12 volt 100 amp lead acid battery with a depth of discharge of 30% and we are using a 30 watt lamp, calculate how long the lamp can stay on and calculate the run time as follows:
Battery watt hours = 12 x 100 x 30% = 360 watt hours
The lamp run time is: 360 watt hours / 30 watt hours = 12 hours
3.2 For example, if we have a 12 volt 100 amp lithium ion battery with a depth of discharge of 80% and we are using a 60 watt lamp, calculate how long the lamp will stay on and calculate the run time as follows:
Battery watt hours = 12 x 100 x 80% = 960 watt hours
Lamp running time is: 960 watt-hours / 60 watt-hours = 16 hours
4. The effect of battery efficiency on loads (e.g. lights)
Battery efficiency will be due to temperature, age, the quality of the battery itself, etc., will have an impact on the capacity of the battery, the voltage required to convert from 12V output to lamps will also lose energy, which will have an impact on the load use time. Specific impact on battery capacity leads to load use time as follows:
1. Battery condition: Batteries of different degrees of old and new, will affect the capacity of the battery, only use a good condition of the 100-amp lithium-ion batteries may provide close to 100 amps of power, the old batteries can not reach such energy, will affect the use of the load time.
2. Temperature: Extreme temperatures affect the performance of the battery, at very low temperatures the operating time of the battery will be shortened, i.e. the operating time of the load will be reduced, at very high temperatures the self-discharge rate of the battery will be increased, which will lead to a loss of capacity, accelerating the aging process of the battery, and reducing the battery’s lifespan, which means that the battery will not be able to run the load for a very long period of time.
3. Self-discharge: when we do not use the battery, the battery will also lose power, lithium-ion batteries have a low self-discharge rate. Lead-acid batteries have a much higher self-discharge rate, which also affects the usage time of the load.
4. Load characteristics: the different characteristics of the load will also affect the use of time, the lights on the battery power consumption is more stable, but pay attention to some special circumstances, the load will also consume more battery power, such as intermittent devices.
Conclusion
How long a 12V battery can light up a lamp depends on a variety of factors, such as the type of battery, the depth of discharge of the battery, the efficiency of the battery, etc. We can make a rough estimate in our daily life to calculate how long the lamp can run.
