No matter where we are, we need batteries, which provide electrical support to many electronic devices. All of this is based on knowing the voltage of the battery, which is similar to the fuel gauge in a car. The battery’s voltmeter indirectly tells us how much energy is left in the battery and also measures the performance of the battery. In this article, we will tell you all about battery voltmeter.
1. What is a battery voltmeter?
Battery voltage is the potential difference between the positive and negative terminals of a battery. Then a battery voltmeter can accurately see the change in voltage of a battery under normal operation. The voltmeter of these batteries are different, specifically also with the rated voltage and type of battery. But you can measure it directly with a multimeter. This means that the voltage of the battery is very important, because the voltage of the battery can provide enough output power and output voltage for the battery, in addition to the battery voltmeter is also related to the performance and service life of the battery.
2. State of Charge (SOC)
State of Charge (SOC) is the percentage of different power content of a battery. It represents the ratio of the power contained in the battery to its full state power. The state of charge of a battery is usually expressed as a percentage, with 100% indicating that the battery is fully charged and 50% indicating that the battery is still half-charged.
Once you know the state of charge of your battery, you will know when it is time to charge your battery so that your electrical system can work properly. When the battery’s charge level falls below a certain value, the battery may be irreversibly damaged, and the battery’s service life will be reduced. If you regularly check the state of charge of your batteries and estimate the remaining operating time of your batteries, you can plan accordingly to minimize losses.
3. State of Discharge (SOD)
The state of discharge is a complement to the state of charge, which indicates the percentage of original power that has been consumed by the battery. Battery emissions status is the same as the battery’s state of charge, they are expressed as a percentage, 100% means that the battery’s power has been depleted, 0% means that the battery is still in a full state.
When you know the discharge state of a battery, you can avoid draining the battery beyond the minimum range. If the battery’s charge falls below a certain value, the battery’s performance as well as its service life will be reduced. If you can keep your battery’s discharge state in a normal state, your battery will last longer.
Below we will take a 12V battery as an example, where the types of batteries are lead-acid, AGM, and deep-cycle. Below is the voltage table of each battery in time
| battery capacity（%） | Lead acid battery | AGM battery | Deep cycle battery |
| 100% | 12.9V | 13V | 13.1V |
| 90% | 12.79V | 12.76V | 12.77V |
| 80% | 12.66V | 12.51V | 12.5V |
| 70% | 12.52V | 12.31V | 12.32V |
| 60% | 12.42V | 12.15V | 12.18V |
| 50% | 12.24V | 12.06V | 12.06V |
| 40% | 12.1V | 11.94V | 11.94V |
| 30% | 11.95V | 11.80V | 11.80V |
| 20% | 11.82V | 11,68V | 11.67V |
| 10% | 11.72V | 11.50V | 11.51V |
| 0 | 11.64V | 11.48V | 11.49V |
For all the above batteries, we don’t use them a lot, but in daily use, lithium iron phosphate battery will be more widely used. And the voltmeter of lithium iron phosphate battery can let us judge the state of lithium iron phosphate battery more easily. Below is the voltage table of 12V,24V,36V,48V,96V lithium iron phosphate battery.
| battery capacity（%） | 1 battery cell | 12V | 24V | 36V | 48V | 96V |
| 100% | 3.40 | 13.60 | 27.20 | 40.80 | 54.40 | 108.80 |
| 90% | 3.36 | 13.41 | 26.84 | 40.24 | 53.64 | 108.68 |
| 80% | 3.33 | 13.32 | 26.65 | 39.68 | 53.15 | 108.42 |
| 70% | 3.31 | 13.24 | 26.48 | 39.15 | 52.81 | 107.98 |
| 60% | 3.26 | 13.14 | 26.19 | 38.85 | 52.64 | 107.75 |
| 50% | 3.25 | 13.05 | 26.08 | 38.22 | 52.58 | 107.64 |
| 40% | 3.24 | 13.03 | 26.04 | 37.91 | 52.41 | 107.21 |
| 30% | 3.22 | 12.96 | 25.86 | 37.11 | 52.02 | 106.97 |
| 20% | 3.21 | 12.84 | 25.62 | 36.54 | 51.64 | 104.76 |
| 10% | 3.01 | 12.05 | 24.08 | 35.68 | 48.06 | 100.35 |
| 0 | 2.52 | 10.06 | 20.05 | 30.26 | 40.02 | 90.98 |
CONCLUSION:
Battery voltage is an important indicator of the battery in the process of use, which has a great impact on the performance of the battery, service life and so on. When you fully understand the battery voltmeter, you can improve the efficiency of the battery, prolong the service life of the battery as well as the safety during use.
