AGM deep cycle batteries have a specific voltage at a specific charge. That means that you can figure out what charge the AGM battery has if you measure its voltage and compare it with the AGM battery voltage charge. To help you out, we have prepared these 2 AGM deep cycle battery voltage charts:
- 12V AGM Deep Cycle Battery Voltage Chart (1st Chart). The 12V AGM battery state of charge voltage ranges from 13.00V (100% capacity) to 10.50V (0% capacity). If you, for example, measure the 12.30V voltage on your 12V AGM battery, you can figure out (with the help of the 1st chart) that this 12V AGM battery still has 70% capacity.
- 24V AGM Deep Cycle Battery Voltage Chart (2nd Chart). The 24V AGM battery state of charge voltage ranges from 26.00V (100% capacity) to 21.00V (0% capacity). If you, for example, measure the 23.90V voltage on your 24V AGM battery, you can figure out (with the help of the 2nd chart) that this 24V AGM battery still has 40% capacity.
Because all AGM batteries have the same voltage discharge curve. That’s why we can use the voltage state of charge (SOC) charts to determine how much juice is left in the AGM battery just be measuring the voltage, and consulting the voltage discharge chart.
Here are the 12V AGM battery voltage chart (1st chart) and 24V AGM battery voltage chart (2nd chart):
12V AGM Battery Voltage Chart
| 12V AGM Battery Charge Voltage: | Battery Capacity (Percentage): |
| 13.00V | 100% |
| 12.75V | 90% |
| 12.50V | 80% |
| 12.30V | 70% |
| 12.15V | 60% |
| 12.05V | 50% |
| 11.95V | 40% |
| 11.81V | 30% |
| 11.66V | 20% |
| 11.51V | 10% |
| 10.50V | 0% |
As you can see, the voltage of a 12V AGM deep cycle battery ranges from 13.00V to 10.50V.
Example of how to use this chart: Let’s say that you measure the voltage on the 12V AGM battery; it reads 12.10V. That means that the battery still has between 50% and 60% charge (55%, to be exact).
This is true for all 12V AGM deep cycle batteries.
Here is the 24V AGM battery voltage chart as well:
24V AGM Battery Voltage Chart
| 24V AGM Battery Charge Voltage: | Battery Capacity (Percentage): |
| 26.00V | 100% |
| 25.55V | 90% |
| 25.00V | 80% |
| 24.60V | 70% |
| 24.30V | 60% |
| 24.10V | 50% |
| 23.90V | 40% |
| 23.62V | 30% |
| 23.32V | 20% |
| 23.02V | 10% |
| 21.00V | 0% |
With this higher voltage 24V deep cycle battery, the voltage ranges from 26.00V at 100% charge to 21.00V at 0% charge; the absolute voltage difference between a full and an empty battery is 5.00V.
Example how to use this chart: If you use a voltage meter and measure the difference between AGM battery cathode and anode to be 23.50V, you can read of this chart that this 24V battery still has between 20% and 30% charge left.
With these two AGM deep cycle battery voltage charts, you are now fully equipped to determine the state of charge of your AGM batteries.