Lead Acid Deep Cycle Battery Voltage Chart - ShopSolar.com
Skip to content
Cart (0 item)

Your cart is empty

Lead Acid Deep Cycle Battery Voltage Chart

Short on Time? Here’s The Article Summary

The article discusses lead-acid batteries, focusing on sealed types commonly used in solar setups. These batteries are sealed and require minimal maintenance compared to flooded types. Two main types are AGM and Gel batteries. AGM batteries have fiberglass mats that absorb electrolytes, while Gel batteries use a gel-like substance.

Both types are durable and require little maintenance. The article includes charts showing voltage levels for different states of charge for 12V, 24V, and 48V AGM and Gel batteries, ranging from 100% charge to 0%. The charts help users understand the relationship between voltage and battery capacity, crucial for managing solar power systems.

Introduction

Lead Acid batteries are affordable and reliable ways to store energy being produced by your solar system. A lead acid deep cycle voltage chart tells you the relationship between the state of charge and the voltage the battery can produce.

Lead acid batteries can be split up into two groups: sealed and flooded types. 

We’re going to be focusing on the former and looking at various lead acid deep cycle battery voltage charts to get a better understanding of the data.

Sealed Lead Acid Battery Voltage Chart

The Sealed Lead Acid battery used falls under the valve-regulated lead acid battery group.

sealed lead acid battery voltage chart

These lead acid batteries are more common in the world of solar compared to their flooded counterparts. A quality deep-cycle solar battery system can run you a good few hundred dollars, but they’re well worth the investment.

Sealed lead acid batteries are rechargeable and the main distinction between them and flooded is that they are sealed with an electrolyte that isn't free-flowing. 

This brings with it several advantages.

The hydrogen gas generated during charging cycles in a sealed battery is reabsorbed into the electrolyte. A safety vent stops the gases from building up too much pressure.

As a result, the sealed battery requires fewer periodic top-ups of distilled water and has less electrolyte loss.

Due to excessive charging resulting in gassing and water depletion, sealed lead acid batteries are made with a minimal over-voltage potential to prevent the battery from reaching its gas-generating potential during charge. 

So when we look at a sealed AGM 12V battery voltage chart and compare it to a wet cell battery of the same capacity, the results favor the sealed battery,

As a result, these batteries are never able to be fully charged. Lead calcium is used in sealed lead-acid batteries rather than lead antimony to lessen dry-out.

Types of Sealed Lead-Acid Batteries

There are 2 types of sealed lead-acid batteries: AGM batteries and Gel-based batteries.

AGM Batteries

Whenever you see an AGM battery’s resting voltage chart and you feel like you don’t know what these batteries are or what affects their values, you should read up on the battery itself. 

battery soc chart

AGM batteries perform better than wet cell batteries in practically every category. Concerning total weight and charge cycles, these lead acid batteries are the best.

The electrolytes can be absorbed by the AGM lead acid batteries, which are mounted between two fiberglass mats.

A unique glass mat separator found in an AGM battery secures the electrolyte solution between the battery plates. 

Due to this, electrolytes can be stored in a dry or suspended condition rather than as a free liquid since the fiberglass can be saturated with it.

Electrolytes are moved from the glass mat to the battery plates as needed during the operation of the battery. 

The battery's electrolyte won't spill if the battery case is destroyed or it is turned on its side since the mat has enough electrolytes to allow the battery to operate at full capacity.

Gel Batteries

A gel battery is a valve-regulated, lead-acid battery that combines silica fumes with an electrolyte in a predetermined amount of sulfuric acid. 

lead acid battery voltage curve

The immobile, gel-like substance produced by this chemical reaction is what gives these batteries their name. 

The one-way valves allow the internal gasses to recombine into the water, therefore eliminating the need to top off distilled water or check the water level. 

As a result, the gel batteries require almost little maintenance. Gel batteries are incredibly durable and adaptable. 

They have extremely low gas output, so they are safe to be installed in locations with restricted ventilation, thus you can even install the batteries inside your home.

We will look at both sealed-type batteries when displaying the battery volt charts and see how they compare to each other.

Battery Charging Lead Acid Battery Voltage Chart

Voltage measurement of charge is straightforward but prone to error due to temperature and cell material effects on voltage. 

Batteries must initially rest in an open circuit state for at least four hours to obtain an accurate reading using the voltage method, while most battery manufacturers advise waiting for 24 hours.

lead acid battery charging curve

As a result, measuring batteries that are actively and continuously in use is not appropriate using the voltage approach.

A hydrometer is used to measure the relative density of liquids based on buoyancy to calculate specific gravity, which is then used to calculate the charge. 

The weight of the battery's active chemicals is monitored by the hydrometer as it discharges.

The specific gravity of a battery reduces proportionally when the amount of sulfuric acid in the active electrolyte decreases as a result of use.

Battery SoC Chart

State of Charge (SoC) refers to the capacity that is now accessible. The state of charge value ranges from 0% to 100%. 

A battery is fully charged if the state of charge is 100%, whereas a rating of 0% means the cell is completely discharged. 

As the value cannot rise above 50% in real-world applications, the cell is recharged once the state of charge hits that level. 

Similar to this, the maximal state of charge starts to drop as the battery ages, meaning a 100% state of charge for an old battery would be similar to a 75%–80% state of charge for a young one.

We’re going to have a look at both types of sealed lead acid batteries and see whether they are the same or vastly different.

12V Lead Acid Battery Voltage Chart

The chart below shows the state of charge voltage of a 12V AGM battery. It ranges from 13.00V at 100% capacity to 10.50V at 0% capacity. 

lead acid battery charge curve

If you measure the 12.30V voltage on your 12V AGM battery, for example, you can determine that this 12V AGM battery still has 70% capacity.

Voltage

Capacity 

13.00V

100% (charging)

12.85V

100% (resting)

12.80V

99%

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%

 

The chart below shows the data for a 12V gel sealed lead acid battery, The values range from 11.80V at 0% to over 12.85 once it reaches 100% state of charge.

Voltage 

Capacity 

12.85V +

100%

12.65V

75%

12.35V

50%

12.00V

25%

11.80

0%

 

24V Lead Acid Battery Voltage Chart

When looking at a 24V battery voltage chart for an AGM sealed lead acid battery, it has a voltage range of 26.00V at 100% charge to 21.00V at 0% charge.

deep cycle lead acid battery voltage chart

A full battery has a voltage differential of 5.00V from an empty battery.

This figure shows that a 24V battery has 20% to 30% charge left if the voltage difference between the cathode and anode of an AGM battery is measured to be 23.50V using a voltage meter.

Voltage

Capacity 

26.00V

100% (charging)

25.85V

100% (resting)

25.75V

99%

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%

 

The data for a 24V gel sealed lead acid battery is displayed in the chart below. Values range from 23.80V at zero charges to over 24.85 at full charge.

Voltage 

Capacity 

24.85V +

100%

24.65V

75%

24.35V

50%

24.00V

25%

23.80V

0%

 

48V Lead-Acid Battery Voltage Chart

The 48V battery voltage chart for a gel-sealed lead-acid battery found below varies from 52.00V at 100% charge to 42.00V at 0% charge.

lead acid battery chart

A full battery has a 10.00V absolute voltage difference from an empty battery.

This chart indicates that this 48V battery still has 20% to 30% charge left if the voltage difference between the cathode and anode of an AGM battery is measured to be 47.00V using a voltage meter.

Voltage

Capacity 

52.00V

100% (charging)

51.70V

100% (resting)

51.45V

99%

51.10V

90%

50.00V

80%

49.20V

70%

48.60V

60%

48.20V

50%

47.80V

40%

47.24V

30%

46.64V

20%

46.04V

10%

42.00V

0%

The data for a 48V gel sealed lead acid battery is displayed in the chart below. Values range from 47.80V at zero charge to over 48.85 at full charge.

Voltage 

Capacity 

48.85V +

100%

48.65V

75%

48.35V

50%

48.00V

25%

47.80V

0%

The Ultimate Solar + Storage Blueprint (Mini Course)

Struggling to understand how solar + storage systems actually work? Looking to build or buy your own solar power system one day but not sure what you need? Just looking to learn more about solar, batteries and electricity?

Join 15,000+ solar enthusiasts breaking free from their energy dependence with this short step-by-step video course that will make you a solar + storage expert. Start your journey to energy independence today.

Learn More Now

Who is ShopSolar.com?

ShopSolar.com is the #1 digital platform that enables consumers & businesses to source and purchase complete solar + storage solutions direct, saving you thousands in time, energy and money! With over 40,000+ happy customers, we’re on a mission to make solar simple, transparent and affordable.

 

Did You Find Our Blog Helpful? Then Consider Checking:

Article by

Cody Oehm

Cody is the Head of Marketing at Shop Solar, and joined the company in spring of 2022. 

He has an entrepreneurial background and has been in the ecommerce industry since 2015. With 4 businesses under his belt and a drive to make a bigger impact, he decided to team up with Shop Solar on their mission to make solar simple and affordable. You can browse best seller's here.

Previous article Solar Powered Generators: 2 Most Common Questions We Get, Answered [Generator Sizing Guide]

Leave a comment

Comments must be approved before appearing

* Required fields

Blog posts

Get a Complimentary Solar Proposal Today!

$150 Value - Free Offer (Limited Time Only!) No Strings Attached. Totally Free. Takes Less than 2 Minutes.

Get Started