The lead acid battery uses the constant current constant voltage (CCCV) charge method. A regulated current raises the terminal voltage until the upper charge voltage limit is reached, at which point the current drops due to saturation. The charge time is 12&#;16 hours and up to 36&#;48 hours for large stationary batteries. With higher charge currents and multi-stage charge methods, the charge time can be reduced to 8&#;10 hours; however, without full topping charge. Lead acid is sluggish and cannot be charged as quickly as other battery systems. (See BU-202: New Lead Acid Systems)
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With the CCCV method, lead acid batteries are charged in three stages, which are [1] constant-current charge, [2] topping charge and [3] float charge. The constant-current charge applies the bulk of the charge and takes up roughly half of the required charge time; the topping charge continues at a lower charge current and provides saturation, and the float charge compensates for the loss caused by self-discharge.
During the constant-current charge, the battery charges to about 70 percent in 5&#;8 hours; the remaining 30 percent is filled with the slower topping charge that lasts another 7&#;10 hours. The topping charge is essential for the well-being of the battery and can be compared to a little rest after a good meal. If continually deprived, the battery will eventually lose the ability to accept a full charge and the performance will decrease due to sulfation. The float charge in the third stage maintains the battery at full charge. Figure 1 illustrates these three stages.
The battery is fully charged when the current drops to a set low level. The float voltage is reduced. Float charge compensates for self-discharge that all batteries exhibit.
The switch from Stage 1 to 2 occurs seamlessly and happens when the battery reaches the set voltage limit. The current begins to drop as the battery starts to saturate; full charge is reached when the current decreases to 3&#;5 percent of the Ah rating. A battery with high leakage may never attain this low saturation current, and a plateau timer takes over to end the charge.
The correct setting of the charge voltage limit is critical and ranges from 2.30V to 2.45V per cell. Setting the voltage threshold is a compromise and battery experts refer to this as &#;dancing on the head of a pin.&#; On one hand, the battery wants to be fully charged to get maximum capacity and avoid sulfation on the negative plate; on the other hand, over-saturation by not switching to float charge causes grid corrosion on the positive plate. This also leads to gassing and water-loss.
Temperature changes the voltage and this makes &#;dancing on the head of a pin&#; more difficult. A warmer ambient requires a slightly lower voltage threshold and a colder temperature prefers a higher setting. Chargers exposed to temperature fluctuations include temperature sensors to adjust the charge voltage for optimum charge efficiency. (See BU-410: Charging at High and Low Temperatures )
The charge temperature coefficient of a lead acid cell is &#;3mV/°C. Establishing 25°C (77°F) as the midpoint, the charge voltage should be reduced by 3mV per cell for every degree above 25°C and increased by 3mV per cell for every degree below 25°C. If this is not possible, it is better to choose a lower voltage for safety reasons. Table 2 compares the advantages and limitations of various peak voltage settings.
2.30V to 2.35V/cell
2.40V to 2.45V/cell
AdvantagesMaximum service life; battery stays cool; charge temperature can exceed 30°C (86°F).Higher and more consistent capacity readings; less sulfation.LimitationsSlow charge time; capacity readings may be inconsistent and declining with each cycle. Sulfation may occur without equalizing charge.Subject to corrosion and gassing. Needs water refill. Not suitable for charging at high room temperatures, causing severe overcharge. Table 2: Effects of charge voltage on a small lead acid battery.Once fully charged through saturation, the battery should not dwell at the topping voltage for more than 48 hours and must be reduced to the float voltage level. This is especially critical for sealed systems because they are less tolerant to overcharge than the flooded type. Charging beyond the specified limits turns redundant energy into heat and the battery begins to gas.
The recommended float voltage of most flooded lead acid batteries is 2.25V to 2.27V/cell. Large stationary batteries at 25°C (77°F) typically float at 2.25V/cell. Manufacturers recommend lowering the float charge when the ambient temperature rises above 29°C (85°F).
Figure 3 illustrate the life of a lead acid battery that is kept at a float voltage of 2.25V to 2.30V/cell and at a temperature of 20°C to 25°C (60°F to 77°F). After 4 years of operation permanent capacity losses become visible, crossing the 80 percent line. This loss is larger if the battery requires periodic deep discharges. Elevated heat also reduces battery life. (See also BU-806a: How Heat and Loading affect Battery Life)
Not all chargers feature float charge and very few road vehicles have this provision. If your charger stays on topping charge and does not drop below 2.30V/cell, remove the charge after 48 hours of charging. Recharge every 6 months while in storage; AGM every 6&#;12 months.
These described voltage settings apply to flooded cells and batteries with a pressure relief valve of about 34kPa (5psi). Cylindrical sealed lead acid, such as the Hawker Cyclon cell, requires higher voltage settings and the limits should be set to manufacturer&#;s specifications. Failing to apply the recommended voltage will cause a gradual decrease in capacity due to sulfation. The Hawker Cyclon cell has a pressure relief setting of 345kPa (50psi). This allows some recombination of the gases generated during charge.
Aging batteries pose a challenge when setting the float charge voltage because each cell has its own unique condition. Connected in a string, all cells receive the same charge current and controlling individual cell voltages as each reaches full capacity is almost impossible. Weak cells may go into overcharge while strong cells remain in a starved state. A float current that is too high for the faded cell might sulfate the strong neighbor due to undercharge. Cell-balancing devices are available compensate for the differences in voltages caused by cell imbalance.
Ripple voltage also causes a problem with large stationary batteries. A voltage peak constitutes an overcharge, causing hydrogen evolution, while the valley induces a brief discharge that creates a starved state resulting in electrolyte depletion. Manufacturers limit the ripple on the charge voltage to 5 percent.
Much has been said about pulse charging of lead acid batteries to reduce sulfation. The results are inconclusive and manufacturers as well as service technicians are divided on the benefit. If sulfation could be measured and the right amount of pulsing applied, then the remedy could be beneficial; however giving a cure without knowing the underlying side effects can be harmful to the battery.
Most stationary batteries are kept on float charge and this works reasonably well. Another method is the hysteresis charge that disconnects the float current when the battery goes to standby mode. The battery is essentially put in storage and is only &#;borrowed&#; from time to time to apply a topping-charge to replenish lost energy due to self-discharge, or when a load is applied. This mode works well for installations that do not draw a load when on standby.
Lead acid batteries must always be stored in a charged state. A topping charge should be applied every 6 months to prevent the voltage from dropping below 2.05V/cell and causing the battery to sulfate. With AGM, these requirements can be relaxed.
Measuring the open circuit voltage (OCV) while in storage provides a reliable indication as to the state-of-charge of the battery. A cell voltage of 2.10V at room temperature reveals a charge of about 90 percent. Such a battery is in good condition and needs only a brief full charge prior to use. (See also BU-903: How to Measure State-of-charge)
Observe the storage temperature when measuring the open circuit voltage. A cool battery lowers the voltage slightly and a warm one increases it. Using OCV to estimate state-of-charge works best when the battery has rested for a few hours, because a charge or discharge agitates the battery and distorts the voltage.
Some buyers do not accept shipments of new batteries if the OCV at incoming inspection is below 2.10V per cell. A low voltage suggests a partial charge due to long storage or a high self-discharge caused by a micro-short. Battery users have found that a pack arriving at a lower than specified voltage has a higher failure rate than those with higher voltages. Although in-house service can often bring such batteries to full performance, the time and equipment required adds to operational costs. (Note that the 2.10V/cell acceptance threshold does not apply to all lead acid types equally.)
Under the right temperature and with sufficient charge current, lead acid provides high charge efficiently. The exception is charging at 40°C (104°F) and low current, as Figure 4 demonstrates. In respect of high efficiency, lead acid shares this fine attribute with Li-ion that is closer to 99%. See BU-409: Charging Lithium-ion and BU-808b: What Causes Li-ion to Die?
Figure 4: Charge efficiency of the lead acid battery [2]Manufacturers recommend a charge C-rate of 0.3C, but lead acid can be charged at a higher rate up to 80% state-of-charge (SoC) without creating oxygen and water depletion. Oxygen is only generated when the battery is overcharged. The 3-stage CCCV charger prevents this from happening by limiting the charge voltage to 2.40V/cell (14.40V with 6 cells) and then lowering to a float charge about 2.30V/cell (13.8V with 6 cells) at full-charge. These are voltages below the gassing stage.
Test show that a heathy lead acid battery can be charged at up to 1.5C as long as the current is moderated towards a full charge when the battery reaches about 2.3V/cell (14.0V with 6 cells). Charge acceptance is highest when SoC is low and diminishes as the battery fills. Battery state-of-health and temperature also play an important role when fast-charging. Make certain that the battery does not &#;boil&#; or heat up during charge. Put an eye on the battery when charging above the manufacturer&#;s recommended C-rate.
Watering is the single most important step in maintaining a flooded lead acid battery; a requirement that is all too often neglected. The frequency of watering depends on usage, charge method and operating temperature. Over-charging also leads to water consumption.
A new battery should be checked every few weeks to estimate the watering requirement. This assures that the top of the plates are never exposed. A naked plate will sustain irreversible damage through oxidation, leading to reduced capacity and lower performance.
If low on electrolyte, immediately fill the battery with distilled or de-ionized water. Tap water may be acceptable in some regions. Do not fill to the correct level before charging as this could cause an overflow during charging. Always top up to the desired level after charging. Never add electrolyte as this would upset the specific gravity and promote corrosion. Watering systems eliminate low electrolyte levels by automatically adding the right amount of water.
[1] Courtesy of Cadex
[2] Source: Power-Sonic
Understanding batteries has never been easier, but the battery voltage charts can help you learn about the relationship between a battery's voltage and its charge state. These charts act as an important tool to understand how a battery's components work, so you can optimize the battery's performance and extend its lifespan. However, the battery voltage chart varies depending on the type of batteries you are using.
Jackery Portable Power Stations are ideal charging solutions for your household or outdoor appliances. They feature efficient and reliable batteries, such as NMC and LiFePO4. The upgraded BMS technology helps you safely charge appliances without equipment damage due to voltage or circuit fluctuations. In this guide, we will reveal the battery voltage charts of different popular batteries, including lead-acid, deep cycle, LiFePO4, and AGM.
The term "battery voltage" represents the electrical potential difference between any battery's positive and negative terminals. The battery voltage is crucial because it determines the power or energy your battery can supply, its charge state, and the voltage required for certain electronics.
Battery voltage charts describe the relation between the battery's charge state and the voltage at which the battery runs. These battery charging voltages can range from 2.15V per cell to 2.35V per cell, depending on the battery type. You can check or read a battery's voltage using a multimeter.
Here's a 12V battery chart that reveals the relationship between the charging state, voltage, and specific gravity hydrometer.
Percentage of Charge
12V Battery Voltage
Specific Gravity using Hydrometer
100%
12.70
1.265
95%
12.64
1.257
90%
12.58
1.249
85%
12.52
1.241
80%
12.46
1.233
75%
12.40
1.225
70%
12.36
1.218
65%
12.28
1.204
55%
12.24
1.197
50%
12.20
1.190
45%
12.16
1.183
40%
12.12
1.176
35%
12.08
1.169
30%
12.04
1.162
25%
12.00
1.155
20%
11.98
1.148
15%
11.96
1.141
10%
11.94
1.134
5%
11.92
1.127
0% (Discharged)
11.90
1.120
The battery voltage chart differs depending on the type of battery. Below we'll reveal five different types of batteries.
Lead-Acid: These battery types are economical and extremely popular choices. The heavy and bulkier batteries sometimes leak, making the device unusable.
Lithium-ion: These commonly used battery types have a superior energy density and can store more energy than others. These lightweight batteries are designed for portable devices.
Deep Cycle: A deep-cycle battery is designed to be regularly deeply discharged using its maximum capacity. It has thicker active plates, thicker separators, and higher-density active paste material.
LiFePO4: Also known as lithium iron phosphate or LFP battery, it offers increased power output, reduced weight, longer lifetime, and faster recharging.
AGM: AGM (Absorbent Glass Mat) is an advanced lead-acid battery type. The battery contains positive and negative lead and lead oxide plates that release electrons.
State of charge (SoC), usually represented in percentage, is the charge level of an electric battery relative to its capacity. Battery's SoC can be quickly determined by reading either specific electrolyte gravity or terminal voltage.
State of Charge
Sealed or Flooded Lead Acid battery voltage
Gel battery voltage
AGM battery voltage
100%
12.70+
12.85+
12.80+
75%
12.40
12.65
12.60
50%
12.20
12.35
12.30
25%
12.00
12.00
12.00
0%
11.80
11.80
11.80
A battery's depth of discharge (DoD) indicates the percentage of discharged battery relative to overall battery capacity. The depth of discharge (DoD) complements the state of charge (SoC). That means if DoD increases, SoC decreases.
Battery or Battery Pack Ah Rating
30-Minute Maximum Discharge Current
5Ah
10A
7Ah
14A
8Ah
16A
9Ah
18A
10Ah
21A
12Ah
24A
14Ah
31A
15Ah
32A
18Ah
40A
22Ah
46A
35Ah
84A
The battery voltage charts track the battery's voltage and maintain the battery. The primary role of voltage monitoring is to extend the battery's lifespan.
Lead-acid battery voltage varies depending on the temperature, discharge rate, and battery type (sealed or flooded).
Flooded lead-acid batteries are cheaper but require proper ventilation and more maintenance. Alternatively, sealed lead-acid batteries need less maintenance and ventilation.
Lead-Acid Battery Voltage Chart
Capacity
6V Sealed Lead Acid Battery
6V Flooded Lead Acid Battery
100%
6.44V
6.32V
90%
6.39V
6.26V
80%
6.33V
6.20V
70%
6.26V
6.15V
60%
6.20V
6.09V
50%
6.11V
6.03V
40%
6.05V
5.98V
30%
5.98V
5.94V
20%
5.90V
5.88V
10%
5.85V
5.82V
0%
5.81V
5.79V
Lithium-ion batteries are most used in power stations and solar systems, all thanks to the built-in additional layer of security. The popular voltage sizes of lithium-ion batteries include 12V, 24V, and 48V. Let's understand the discharge rate of a 1-cell lithium battery at different voltages.
Lithium-ion Battery Voltage Chart:
Capacity (%)
1 Cell
12 Volt
24 Volt
48 Volt
100
3.40
13.6
27.2
54.4
90
3.35
13.4
26.8
53.6
80
3.32
13.3
26.6
53.1
70
3.30
13.2
26.4
52.8
60
3.27
13.1
26.1
52.6
50
3.26
13.0
26.0
52.5
40
3.25
13.0
26.0
52.4
30
3.22
12.9
25.8
52.0
20
3.20
12.8
25.6
51.6
10
3.00
12.0
24.0
48.0
0
2.50
10.0
20.0
40.0
LiFePO4 battery voltage charts reveal the SoC (state of charge) based on different voltages, such as 12V, 24V, and 48V.
LiFePO4 Battery Voltage Chart:
Capacity
12V
24V
48V
100% (charging)
14.6V
29.2V
58.4V
100% (resting)
13.6V
27.2V
54.4V
99%
13.4V
26.8V
53.6V
90%
13.3V
26.6V
53.2V
70%
13.2V
26.4V
52.8V
40%
13.1V
26.2V
52.4V
30%
13.0V
26.0V
52.0V
20%
12.9V
25.8V
51.6V
17%
12.8V
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25.6V
51.2V
14%
12.5V
25.0V
50.0V
9%
12.0V
24.0V
48.0V
0%
10.0V
20.0V
40.0V
Deep cycle batteries are among the most used batteries that discharge slowly to a low SoC and recharge again. Here are the deep cycle battery charts for 12V, 24V, and 48V.
Deep Cycle Battery Voltage Chart:
Capacity
12V
24V
48V
100% (charging)
13.00V
26.00V
52.00V
99%
12.80V
25.75V
51.45V
90%
12.75V
25.55V
51.10V
80%
12.50V
25.00V
50.00V
70%
12.30V
24.60V
49.20V
60%
12.15V
24.30V
48.60V
50%
12.05V
24.10V
48.20V
40%
11.95V
23.90V
47.80V
30%
11.81V
23.62V
47.24V
20%
11.66V
23.32V
46.64V
10%
11.51V
23.02V
46.04V
0%
10.50V
21.00V
42.00V
An AGM battery voltage chart describes the relationship between the state of charge, current, and voltage. Let's see how different charging or discharging currents affect battery voltages in this deep cycle AGM battery charge voltage chart.
Deep Cycle AGM Battery Charge Voltage Chart:
Capacity
12V
24V
48V
100% (charging)
13.00V
26.00V
52.00V
100% (resting)
12.85V
25.85V
51.70V
99%
12.80V
25.75V
51.45V
90%
12.75V
25.55V
51.10V
80%
12.50V
25.00V
50.00V
70%
12.30V
24.60V
49.20V
60%
12.15V
24.30V
48.60V
50%
12.05V
24.10V
48.20V
40%
11.95V
23.90V
47.80V
30%
11.81V
23.62V
47.24V
20%
11.66V
23.32V
46.64V
10%
11.51V
23.02V
46.04V
0%
10.50V
21.00V
42.00V
Jackery is the leading manufacturer of portable power stations and solar solutions. These battery backups for homes or outdoors are designed to provide reliable power to various applications, including emergency power, camping, RVing, etc.
Jackery portable power stations use lithium-ion batteries, best known for their high efficiency and long lifespan. However, the Jackery Explorer Plus is equipped with a LiFePO4 battery. Some popular charging solutions offered by Jackery include:
Jackery Explorer 300 is a compact and portable power station for outdoor activities like hiking, camping, or other one-day trips. It has a capacity of 293Wh and can be recharged using a car charger, solar panels, or wall outlet. The lithium-ion battery can supply stable electricity to small sensitive devices like laptops, smartphones, etc.
Customer Review
"Great lifesaver during Hurricane Ian; we used this portable power station to charge our phones, radio, flashlights, etc. We ordered with a next day delivery, came next day, on time when we left without power. This portable power is a must-have, easy to charge in the car." &#; M Costas
Jackery Explorer 500 features a high-quality lithium-ion battery with a high capacity of 518Wh. It is extremely easy to carry and features multiple AC outlets, carports, and USB-A ports to charge low-to-high power-consuming appliances. You can recharge the power station using car outlets, solar panels, or electric generators.
Customer Review
"This product is awesome. I cannot recommend it enough. Just got through the power outages in Texas, and the Jackery500 came in so clutch. We were able to power some heating pads, our cell phones, and LED lights for 3 days so that our house was lit, and we stayed (sort of) warm." &#; Nick Athey.
Equipped with a LiFePO4 battery, the Jackery Explorer Plus can easily expand from 2kWh to 24kWh. It can power heavy-duty devices up to watts. The power station has advanced IBC technology and ultra-fast solar charging in only 2 hours.
The portable power station features a lithium-ion battery with a capacity of Wh. It can power 99% of your home or outdoor appliances. Thanks to ultra-fast charging technology, the power station can be fully solar charged in 3-4 hours and wall charged in 2.4 hours
Customer Review
"The pro is one of the best-designed & highest-wattage units available on the market today & provides the peace of mind that I need to ensure efficient functionality in my home during short or long-duration power outages." &#; Ya.
Power Station
Capacity
Recharging Time
Ports
Appliances
Explorer 300
Lithium-ion
20.4Ah/14.4V
(293.8Wh)
AC Adapter: 4.5H
Car Adapter(12V): 5H
1 x SolarSaga 100W Solar Panel: 5H
USB-C PD: 5.5H
AC Output (x2): 110V, 60Hz, 300W (500W Peak)
USB-A Output (x1):
5V&#;2.4A
Quick Charge 3.0 (x1), 18W Max
USB-C Output (x1): 60W Max, (5V, 9V, 12V up to 3A)
Car Port (x1): 12V&#;10A
DC Input: 24V&#;3.75A
USB-C PD: 19V&#;3.42A
Light (5W): 49H
Camera (8.4W): 13 Charges
CPAP (28W): 8.8H
Electric blanket (55W): 4.5H
Explorer 500
Lithium-ion
24Ah/21.6V
(518.4Wh)
AC Adapter: 7.5H
Car Adapter (12V): 7.5H
1 x SolarSaga 100W Solar Panel: 9.5H
AC Output (x1):
110V, 60Hz, 500W (W Peak)
DC Output (x2): 12V&#;7A
USB-A Output (x3): 5V&#;2.4A
Car Port (x1): 12V&#;10A
AC Input:
doesn't support direct AC charging - use external AC charger provided
DC Input: 24V&#;3.75A
Light (5W): 88H
CPAP (28W): 15H
Electric blanket (55W): 8H
Blender (300W): 1.4H
Space Heater (350W): 1.2H
Explorer Plus
LiFePO4
45.6Ah/ 44.8V DC
(.8Wh)
AC Adapter: 2H
Car Adapter (12V): 25H
6 × SolarSaga 200W: 2H
4 × SolarSaga 200W: 3.8H
3 × SolarSaga 200W: 4.8H
2 × SolarSaga 200W: 7H
1 × SolarSaga 200W: 14H
AC Output (×4) 120V~ 60Hz, 20A Max
AC Output (×1) 120V~ 60Hz, 25A Max
USB-A Output (x2): Quick Charge 3.0, 18W Max
USB-C Output (x2): 100W Max, (5V, 9V, 12V, 15V, 20V up to 5A)
Car Port (x1): 12V&#;10A
AC Input: 120V, 60Hz, 15A Max
DC Input: 11V-17.5V, 8A Max, Double to 8A Max 17.5V-60V, 12A Max, Double to 24A/W Max
Blender (300W): 5.7H
Space Heater (350W): 4.9H
Microwave (700W): 2.4H
Kettle (850W): 2H
Explorer Pro
Lithium-ion 70Ah/43.2V (Wh)
AC Adapter: 2.4H
Car Adapter (12V): 35H
6 x SolarSaga 200W Solar Panel: 2.8H
6 x SolarSaga 100W Solar Panel: 9H
AC Output (x1): 120V~ 60Hz 25A Max
AC Output (x3): 120V~ 60Hz 20A Max
USB-C Output (x2): 100W Max, 5V&#;3A, 9V&#;3A, 12V&#;3A, 15V&#;3A, 20V&#;5A
Car Port (x1): 12V,10A Max
AC Input: 120V, 60Hz, 15A Max
DC Input: 2x DC 8mm Ports: 11-17.5V (Working Voltage)&#;8A Max, Double to 8A Max; 17.5-60V (Working Voltage)&#;12A, Double to 24A/W Max
Blender (300W): 8.5H
Space Heater (350W): 7.3H
Microwave (700W): 3.6H
Kettle (850W): 3H
When the battery voltage drops to 12.2V, it is considered a bad battery. That means the battery is no longer capable of holding a charge. In such a case, you'll need to replace the battery with a new one.
At 50% state of charge, a 12V battery has a voltage of 12.20. The below 12V battery chart table reveals the voltage at different percentages of charge of a 12V battery voltage.
Percentage of Charge
12V Battery Voltage
Specific Gravity
100
12.70
1.265
95
12.64
1.257
90
12.58
1.249
85
12.52
1.241
80
12.46
1.233
75
12.40
1.225
70
12.36
1.218
65
12.32
1.211
60
12.28
1.204
55
12.24
1.197
50
12.20
1.190
45
12.16
1.183
40
12.12
1.176
35
12.08
1.169
30
12.04
1.162
25
12.00
1.155
20
11.98
1.148
15
11.96
1.141
10
11.94
1.134
5
11.92
1.127
Discharged
11.90
1.120
When selecting a new battery, check its Ah (amp-hour) rating. The physical size and terminal type are other crucial factors to remember. The popular types of batteries include lithium-ion and LiFePO4. They generally have a longer lifespan and can hold a charge for more time.
The battery voltage is a critical component that determines how much energy the battery can supply, its charge state, and the voltage needed for certain electronics. Understanding the battery voltage charts will help you maintain the battery's performance, energy storage, and lifespan.
Different types of batteries require different voltage charts. For example, a 12V AGM battery's state of charge voltage ranges from 13.00V at 100% capacity to 10.50V at 0% capacity. A 12V battery with a voltage below 10.5V under load is usually a sign that it has reached the end of its cycle life.
If you are looking for a safe charging solution that can power most of your home or outdoor appliances, you may trust the Jackery Solar Generators. They feature NMC or LiFePO4 batteries along with an all-round safety mechanism to protect the equipment being charged.
For more 12 volt deep cycle agm batteryinformation, please contact us. We will provide professional answers.