Lead Acid Battery Voltage Chart (12V)

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We have two types of Lead Acid batteries. These are:

  • Flooded lead acid
  • Sealed lead acid

The sealed lead-acid batteries can be divided in other groups:

  • GEL
  • AGM (absorbent glass mat)

Here are the voltage charts for 12V batteries:

GEL Lead-acid battery voltage chart

Battery Voltage State of Charge (%)
12.85V 100%
12.70V 90%
12.55V 80%
12.40V 70%
12.25V 60%
12.10V 50%
11.95V 40%
11.80V 30%
11.65V 20%
11.50V 10%
11.35V 0%
GEL
bulk 14,1-14,4
Absorption 14,1-14,4V
Float 13,5-13,8V
Storage 13,2-13,5V
Equalization check manufacturer recommendations

AGM Lead-acid battery voltage chart

Battery Voltage State of Charge (%)
12.90V 100%
12.75V 90%
12.60V 80%
12.45V 70%
12.30V 60%
12.15V 50%
12.00V 40%
11.85V 30%
11.70V 20%
11.55V 10%
11.40V 0%
AGM
Bulk 14,2-14,6
Absorption 14,2-14,6V
Float 13,5-13,8V
Storage 13,2-13,5V
Equalization check manufacturer recommendations

Flooded Lead-acid battery voltage chart

Battery Voltage State of Charge (%)
12.70V 100%
12.55V 90%
12.40V 80%
12.25V 70%
12.10V 60%
11.95V 50%
11.80V 40%
11.65V 30%
11.50V 20%
11.35V 10%
11.20V 0%

How to check the voltage of a battery?

Let the battery rest for at least 30min for the voltage to settle.

After 30 minutes, use a voltmeter and set it to Voltage DC and measure between the positive and negative.

Now you will measure the resting battery voltage. Use the tables provided to estimate the state of charge of your battery.

FAQ

What voltage should a AGM battery be?

An AGM battery should be between 12.9V and 12.15V. If the voltage is lower, then the battery will degrade faster. Try to keep the battery above 50% State of charge (SOC) to maximize lifespan.

What is the charging voltage for a 12 volt AGM battery?

The charging voltage for a 12Volt AGM battery is 14.2V to 14.6V. If you have a temperature lower than 77°F or 20°C, use 14.6V; if the temperature is higher, use 14.2V.

What voltage is too low for a 12 volt AGM battery?

Any voltage under 12.15V for an AGM battery is considered too low. This is 50% of the battery capacity. If you go lower than 12.15V for a 12V AGM battery, you will reduce the lifespan of the battery. You can still go lower to 11.4V, but then the battery will have 0% capacity left. If done repeatedly, the battery will only have a few hundred cycles.

What voltage should a gel battery be?

A GEL battery should read from 12.1V to 12.85Volts. If the value is under 12.1V, the battery is depleted. Long-time depletion of the battery results in a reduced lifespan. Make sure to wait at least 30 minutes before measuring the voltage of the battery. There should be no loads attached.

At what voltage is a 12v gel battery fully charged?

If a gel battery reaches an open circuit voltage of 12.85 volts, then the battery is completely charged. However, you apply a higher voltage to charge the battery. The charging voltage of a GEL battery should be from 14.1 to 14.4Volts depending on the manufacturer. Use 14.1 to stay on the safe side.

What is the voltage of a 12V flooded battery?

A flooded lead acid battery should be between 11.95V and 12.7V. If the voltage is lower, then the capacity is below 50%. If the capacity is below 50%, then the battery will have a reduced lifespan. It is recommended not fully to discharge a lead-acid battery.

What is the full voltage of a flooded battery?

The full voltage reading of a flooded lead acid battery should read 12.7Volts.

What voltage to charge 48v flooded battery?

The open circuit voltage of a 48V flooded battery is 50.8V. The charging voltage is 54V.

What voltages should a lithium battery be at?

Check out my article about lithium battery voltage charts.

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