You Need to Know 12V AGM Deep Cycle Battery for Solar

A deep cycle battery for solar is providing sustained power over an extended period of time, rather than short bursts of energy like a starter battery. Deep cycle batteries can commonly use in applications that require continuous power, such as RVs, boats, solar power systems, and golf carts.

A deep cycle battery is a type of rechargeable battery that can provide sustained power over an extended period of time. Unlike a regular car battery, which is designed to provide a burst of energy to start the engine and then be recharged by the alternator, a deep cycle battery can discharge slowly and then be recharged by an external power source.

FG200-12 maintenance free agm 12v 200ah deep cycle battery

What is meant by a deep cycle battery full discharge?

A deep cycle battery can discharge at a slow rate over a long period of time and then recharge. Full discharge of a deep cycle battery refers to completely using up the stored energy in the battery until the voltage drops to a specified level. This is different from a partial discharge where only a portion of the energy in the battery before recharging.

In order to achieve maximum battery life and performance, it is important to follow the manufacturer’s guidelines for charging and discharging the battery. For deep cycle batteries, fully discharging the battery on a regular basis can help prevent “memory effect,” a phenomenon in which the battery gradually loses capacity over time due to repeated partial discharges.

However, it is important to note that fully discharging a deep cycle battery for solar too often or too deeply can shorten its lifespan and damage the battery. It is best to consult the manufacturer’s guidelines for proper charging and discharging procedures for your specific battery.

DoD is inversely related to state of charge (SoC), which is how much charge remains in the battery. 100% DoD = 0% SoC.

With this understanding of DoD and a battery’s cycle, you may be left wondering what truly classifies as a deep discharge. A deep discharge is classified as 80% to 100% of capacity discharged from the battery.

Application of deep cycle battery

Deep cycle batteries can use in various applications where a reliable and consistent source of power over an extended period. Some of the common uses of deep cycle batteries include:

Renewable energy systems: Deep cycle batteries are widely in off-grid and grid-tied renewable energy systems, such as deep cycle battery for solar, wind turbines, and hydroelectric generators, to store excess energy for later use. This energy can power homes, cabins, and other off-grid locations.
Marine and RV applications: Deep cycle batteries can use in boats and RVs to power onboard electronics, lighting, and appliances when the engine is not running. These batteries would provide a steady source of power over an extended period of time.
Electric vehicles: Deep cycle batteries are in electric vehicles, such as golf carts, electric bicycles, and electric cars, to provide the power needed for propulsion.
Backup power systems: Deep cycle batteries can work as backup power systems for critical applications, such as hospitals, data centers, and communication towers, in case of a power outage.
Industrial and commercial applications: Deep cycle batteries can use in various industrial and commercial applications, such as forklifts, floor scrubbers, and ups backup power systems for critical equipment.

When to charge deep cycle battery for solar

It is important to charge a deep cycle battery for solar when its charge level drops below a certain point to prevent damage and extend its lifespan. The exact charge level at which you should charge your deep cycle battery will depend on the type of battery and the manufacturer’s recommendations, but typically it is recommended to recharge the battery when its charge level drops to around 50-80% of its capacity.

If the battery is allowed to discharge too much, it can lead to sulfation, which occurs when lead sulfate crystals form on the battery plates and reduce the battery’s capacity and performance. Therefore, it is important to recharge the battery before it gets too low to prevent sulfation and damage to the battery.

You can monitor the charge level of your deep cycle battery using a voltmeter or a battery monitor, which can give you an accurate reading of the battery’s charge level. If you notice that the battery’s charge level has dropped significantly, it is time to recharge it. It is also important to follow the manufacturer’s recommendations for charging the battery, such as using the correct charging voltage and current, to ensure optimal performance and lifespan of the battery.

Deep cycle battery voltage chart

Here’s a general deep cycle battery voltage chart that shows the battery voltage at different states of charge:

100% charged: 12.7 – 12.8 volts
75% charged: 12.4 volts
50% charged: 12.2 volts
25% charged: 12.0 volts
Discharged: less than 11.9 volts

Please note that this is a general guideline and the specific voltage readings may vary depending on the type, age, and condition of the battery. It’s important to consult the manufacturer’s specifications for the specific battery you are using. Also, keep in mind that a battery’s voltage can fluctuate based on temperature, load, and other factors.

Deep cycle battery for solar amp hours chart

You can also can learn a general deep cycle battery amp hours chart that shows the estimated capacity at different discharge rates:

20-hour rate: This is the most common rating for deep cycle batteries, which is the number of amp hours (Ah) a battery can deliver over a 20-hour period. For example, a 100Ah battery at a 20-hour rate can deliver 5 amps for 20 hours (5A x 20h = 100Ah).
6-hour rate: At a higher discharge rate of 6 hours, the capacity of the battery will decrease. Typically, a battery rated at a 20-hour rate will have a capacity of around 85-90% at a 6-hour rate.
1-hour rate: At a very high discharge rate of 1 hour, the capacity of the battery will decrease even further. Typically, a battery rated at a 20-hour rate will have a capacity of around 50-60% at a 1-hour rate.

It’s important to note that these are general guidelines, and the specific capacity of a deep cycle battery will depend on its type, age, and condition, as well as the discharge rate and other factors. It’s always best to consult the manufacturer’s specifications for the specific battery you are using.

How deep cycle battery to inverter

A deep cycle battery can connect to an inverter to convert the DC (direct current) power stored in the battery into AC (alternating current) power. It can use to power household appliances and other electronic devices.

Here are the general steps to connect a deep cycle battery to an inverter:

Determine the power requirements of your appliances and electronic devices. This will help you select the right size of inverter and deep cycle battery.
Choose an inverter that matches the power requirements of your appliances and electronic devices. Make sure to select an inverter that is compatible with the voltage and frequency of your electrical system.
Connect the positive (+) and negative (-) terminals of the deep cycle battery to the corresponding terminals on the inverter. The connection is using heavy-duty cables and connectors that are for high-current applications.
Turn on the inverter and monitor the voltage and current output to make sure that it is operating within safe limits. You may need to adjust the inverter settings or add additional batteries to meet the power requirements of your system.
Make sure to charge the deep cycle battery regularly to maintain its performance and extend its lifespan. A battery charger or solar panel can charge the battery.

Can you leave a deep cycle battery charging overnight?

It is generally safe to leave a deep cycle battery charging overnight, as long as the battery charger can automatically switch to a maintenance or float charge mode once the battery fully charging.

However, it’s important to make sure the battery charger you are good for deep cycle batteries and has an automatic charging feature. Overcharging a deep cycle battery can cause damage to the battery and reduce its lifespan.

To be on the safe side, it’s also a good idea to periodically check the battery while it is charging to make sure it is not getting too hot or producing any unusual smells. If you notice any signs of overheating or other issues, it’s best to stop the charging process and investigate the problem before continuing.

Overall, while it is generally safe to leave a deep cycle battery charging overnight, it’s important to use a quality battery charger and to follow the manufacturer’s recommendations for charging and maintenance.

Why deep cycle battery for solar

Deep cycle batteries are commonly for solar energy systems as several reasons:

Energy storage: Solar panels generate electricity during the day when the sun is shining. However, this energy cannot use at night or during periods of low sunlight. Deep cycle batteries allow this excess energy to store for later use, providing a reliable source of power even when the sun is not shining.
Deep discharge capability: Unlike other types of batteries, deep cycle batteries can discharge to a low level, typically 50% or more of their capacity. This makes them well-suited for solar energy systems, which often require frequent deep discharges.
Long lifespan: Deep cycle batteries can last for many cycles of charging and discharging, typically thousands of cycles. This makes them a cost-effective choice for solar energy systems, which require a long-lasting and reliable source of power.
Environmentally friendly: Solar energy systems can work as a renewable and environmentally friendly alternative to traditional power sources. Deep cycle batteries can store this renewable energy, making the overall system even more eco-friendly.

Overall, deep cycle batteries are an important component of solar energy systems, providing reliable energy storage and helping to make solar power a practical and cost-effective choice for many applications.