#12V BATTERY VOLTAGE CHART FULL#

The no-load voltage may take 12 hours or more (!) to reach the proper level after charging or discharging. Make sure that the AGM battery voltage is stabilized before you take a reading. The No-load and Under-load Voltage Charts will give you only a rough indication of the State of Charge: as a rule of thumb, add a +-10% uncertainty to the SoC value you estimate. (UPG actually gives a whopping 0.5V uncertainty to the voltages at all States of Charge.) There are significant differences between AGM brands and some variation due to individual battery use history, wear and temperature. SoC data is not 100% accurate for all AGM units.

6V or 24V AGM batteries?įor 6-volt or 24-volt AGM batteries, respectively, simply divide or multiply the voltage levels given on this page by two. Instead, you should recharge such a battery ASAP. Trying to squeeze out the last 10% damages the battery permanently, and is not worth it outside emergencies. FLAT AGM ( 10% SoC) reads 11.7V to 11.9V without load Advertisements.

#12V BATTERY VOLTAGE CHART FULL#

FULL AGM (100% SoC) – should read 12.7V to 13.0V without load.

The most important AGM battery voltages you should remember are: Not discharging all the way down to FDV extends your battery life considerably. Typical cut-off voltages at moderate load (0.1C, ~5…10A for car/truck battery) would be 11.9V to 12.3V corresponding to 40…60% SoC. In normal cycle use, the cut-off voltage should be set much higher than the final discharge voltage (FDV). AGM Cut-off Voltage?Ĭut-off voltage or low-voltage cut-off refers to the voltage at which the battery discharge is stopped voluntarily. A Victron Super Cycle 100Ah AGM battery drained at around 0.1C rate shows 12.37V under-load voltage, which indicates a State of Charge around 60%. Some data was provided by at least Mastervolt, Mighty Max, Trojan, UPG and Victron. I have found most charts on the Internet inaccurate or confusing (load or no-load?) and had to compile my own.Īdvertisements Manufacturer data is available on no-load voltages are available for many AGM brands under-load voltages are typically limited to the final discharge voltage (FDV).

The voltages in the charts are based on my own measurements and a survey of manufacturer data. Voltage Notes 0.01C 11.7V ~no-load 0.1C 10.7…11.1V 0.3C 10.3…10.8V 0.5C 9.8…10.3V 1C 9.5…10.0V 3C 7.8…9.4V largeįinal discharge voltage is the most important under-load voltage – it is something you (or your load controller) must know, or otherwise your AGM batteries will have a very short life. This voltage is sometimes called the end voltage, and discharge should be stopped at this voltage at latest. AGM Empty VoltageĪdvertisements Final discharge voltage (FDV) is the under-load voltage at which an AGM battery is practically empty it corresponds to 0…10% SoC. The downside is that the under-load voltage depends on the load level. The under-load voltage is advantageous in that it stabilizes fast and allows State of Charge estimation online while the battery is used. The State of Charge of an AGM battery can also be estimated from its under-load voltage, i.e. The no-load voltage takes HALF A DAY to stabilize! AGM SoC vs.

The simplest way to determine the State of Charge of an AGM battery is to measure the battery no-load or open-circuit voltage – this is the voltage across the battery poles when no load is connected. (See end of article for terminology.) AGM SoC vs.

This page gives you charts to estimate SoC from a multimeter voltage reading. When using or charging an AGM battery, you often need to know how full the battery is – or in technical terms, its State of Charge (SoC).

12v battery voltage chart