What is a Deep Cycle Battery?
The majority of appliances and devices at home or in offices need electricity to make these work while some can be used with the aid of batteries. Over the past decades, different types of batteries were made and introduced to the people and these eventually made everyone’s life easier and convenient in many ways. As batteries are very functional.
Did you ever ask yourself how each type of battery differs from one another? From TV remote’s battery to phones’, cars and even solar batteries?
All batteries store energy but there are significant differences in terms of sizes, features, functions, and applications. Just like Deep cycle batteries, for some instances, these batteries may have a resemblance to car batteries but both of them are quite different from one another.
A deep cycle battery is an energy storage lead battery unit designed for sustaining power over a long period. This battery has thicker plates that can withstand a huge number of discharged cycles, the reason why it is called “deep cycle” battery. The chemical on its battery causes a chemical reaction that can develop voltage and turn in to electricity. With its 80 percent or more discharged, batteries can run reliably and smoothly. However, manufacturers suggest not to discharge it below 45% to extend the battery lifespan.
When to use a Deep Cycle Battery?
Deep cycle batteries are ideal for certain types of applications for it can provide sustained energy that can be used for a long period. Most of its common uses include materials handling, recreational vehicles, marine applications, carts, and even off-grid renewable energy. Aside from this, a deep cycle battery can be also used as a starting battery by considering its CCA. One good thing is you can upsize the battery for about 20 percent to input the same amount of cranking amps of a starting battery.
Deep Cycle Battery for Solar Power Systems
Among the rest of the batteries, the renewable energy industry is using a deep cycle battery for their systems. For it can provide energy storage for solar, wind and other renewable energy group. A deep cycle battery is considered as the key component of every renewable energy system. Whereas, in the solar power system, deep cycle batteries are being used as the system’s batteries for the reason that it is capable of withstanding long and repeated deep discharges which are suitable for the off-grid solar photovoltaic system.
So, If you’re planning to install a solar panel at home, you will be needing deep cycle batteries, particularly if you’re potentially planning to rely on solar panel systems instead of using the electricity provided by the electric utility company. These deep cycle batteries will act as your primary electric power storage at home which is convenient in times of power outage. These batteries are also meant to be discharged and recharged most of the time. To maintain and prolong its lifespan, you need to limit the depth of discharge by 20 percent, as most of the manufacturers suggest. Moreover, It should be charged and discharged by 80 percent or more to reach its full capacity.
Deep Cycle Battery Categories (types)
Compared to an average person a battery consumer must have a deeper and wider scope of understanding about the functional differences of these batteries to purchase the right and effective power storage suited to your needs.
Deep cycle battery is just one of the numerous list of batteries worldwide and it has two main categories, these are the Flooded Deep Cycle battery and Sealed or Valve Regulated Lead Acid battery.
Flooded Lead-acid Battery
The flooded lead-acid battery is the most common category among the conventional deep cycle batteries and it is quite similar to the standard lead-acid battery of a car. This battery is also called “wet cells” which is considered as the oldest yet still in-use rechargeable battery in town for different applications, particularly the marine and automotive industries. This battery type requires regular monitoring and maintenance for it contains a liquid in a covered container with removable caps.
Also, as the electrolyte levels hit its lower point, the owner must refill the liquid container with distilled water to maintain its good performance. As much as possible, the battery should be placed upright in a safe area with good ventilation to make sure that the hydrogen gas coming from the battery during overcharging is safe to disperse in the air. Despite its being a high maintenance battery, still flooded batteries are known for its high surge of current, easy to use and to troubleshoot, and cheaper price compared to other deep cycle batteries. The flooded lead-acid battery has been used for a very long time all over the world for its relatively inexpensive price and quality performance.
Advantages of Flooded Lead-acid Battery:
Among all the deep cycle batteries, flooded lead-acid batteries are the cheapest when it comes to pricing, although it’s starting to phased-out because of modern types of deep cycle batteries. Its design is also undeniably simple and easy to repair and allows quick troubleshooting. Aside from that, it is also known for its high surge of current which is more ideal for different kinds of applications.
Disadvantages of Flooded Lead-acid Battery:
It has an unsealed case, so it needed to be kept upright, always or else the electrolyte will leak. Also, it’s difficult to ship and handed to moving vehicles because it leaks. This requires regular maintenance and monitoring, too. Although it can offer a high surge of current, it has a low energy density. Another thing is, it should be placed in an area with good ventilation because it emits explosive hydrogen when it is charging.
Sealed or Valve Regulated Lead Acid Battery
Valve Regulated Lead Acid (VRLA) battery is sealed and does not need watering requirements, that’s why it was also called as “sealed”. Aside from that, it was also known as the “maintenance-free” batteries for it does not need to be monitored most of the time but still recommended to check once in a while, unlike the flooded deep cycle batteries which need regular inspection and maintenance. This battery has a “recombinant” feature, wherein Hydrogen and Oxygen are being combined inside the battery.
Sealed or valve-regulated lead-acid batteries have a valve that activates every time the battery is recharging at high voltage. The activation of this valve permits the active materials in the battery to exit. As a result, the overall capacity of the battery decreases.
Types of Sealed or Valve Regulated Lead Acid Battery
AGM is the abbreviation of Absorbent Glass Mat battery which is considered as one of the Sealed batteries because of this recombinant characteristic that only sealed or VRLA has. In the gas-phase oxygen is being transferred to the negative plates to recombine both elements back into the water while the battery is recharging. This prevents the loss of water during the electrolysis process. That’s why there is no liquid spill, even under severe overcharging conditions. Besides, AGM’s plates are firmly packed and rigidly mounted so it can handle sudden shock and vibration compared to other standard batteries. Its plates are a flat-like wet cell or can be a tight spiral.
AGM batteries are easy and safe to transport and mount inside a caravan, motorhome or water vehicle. These batteries don’t need to be placed in a sealed box vented when you use outside. Also, AGM battery can be fully charged at a lower voltage and can accept much higher current at the same time, because it has very low internal resistance. Additionally, they can charge in just about 3 hours and can do a deeper discharge without any major damage. With all these features, these can be ideal for military applications and works.
As to charging, voltage is the same as the standard battery with no adjustment in the controls and chargers. Also, it has an extremely low resistance so there will be no battery heating even under heavy current charge and discharge. Unlike the standard batteries, AGM has a low self-discharge typically ranging from 1 percent to 3 percent per month only.
In the early 2930s, a Gel battery was originally produced for a 2,4, and 6V portable valve tube radio LT supply. This is also known as a Gel cell, which contains sulfuric acid mixed with fumed silica, turning it into a mass gel-like solid mass. It also contains less acid compared to other standard batteries. Unlike a flooded lead-acid battery, this battery does not need to keep an upright position because it is also a sealed one.
But in terms of chemical properties, these batteries are almost the same as the wet cells or flooded lead-acid batteries, except with the gas recombination, and it’s lead plates being replaced by calcium. Gel battery can limit the electrolyte evaporation and other subsequent corrosions and just like AGM batteries, it has a great shock and vibration resistance and extreme temperature tolerance.
Gel batteries have numerous advantages for every consumer. It’s a maintenance-free battery so there’s no need to monitor the level of electrolyte. There will be no leak even the container is broken because it has a glass-mat separator that absorbs the top-off water and holds it between its lead plates. It also doesn’t require any special handling precautions and safety gear when being shipped or handled since it’s completely sealed. And since it can tolerate any kind of temperature (high or low) you can operate it without weather interruptions. Although, it requires the right charger (and most of the batteries) to have a better performance.
As to applications, gel batteries are commonly used in aircraft, automobiles, and even marine works.
How to Rate Deep Cycle Batteries?
All kinds of deep cycle batteries are being rated through amp-hour (Ah). An amp-hours means one amp for one hour or can be 10 amps for 1/10 of an hour. Amp-hours is the capacity rating available in batteries’ chemical energy. This chemical energy inside the battery is being converted into electrical energy. It can be also seen as the discharge rate of the battery which measures the time being before the battery needs another recharging.
In terms of the accurate Ah rating period for batteries, deep cycle batteries used in the backup power system and solar power system requires a “20-hour rate” Ah rating. This indicates that it needs to be discharged down to 10.5 volts over 20 hours while the total amp-hours is being measured.
Be guided that the capacity of batteries will reduce if they will be discharged in a shorter period. Its amp-hour capacity can reduce by 50 percent and it can also affect the number of battery cycles.
Whereas, if the battery discharges at a stable rate of its current over its number of hours, it is called the “C” rating. In the larger stand-alone power systems, they rate the batteries at C100 which indicates that these batteries need to discharge over 100 hours. And this makes the battery lasts for about 15 years or more.
Deep Cycle Battery Lifespan
When purchasing a battery, aside from the type, features and functions, the consumer also checks the specifications, particularly the lifespan of the battery. The majority of people consider this before buying for it is one of the indicators that can tell how long does a battery can last and be useful to them. Also, By checking this, the consumer can provide maintenance (if ever needed) to prolong its lifespan even more.
However, some manufacturers measure the lifespan of a battery not only by years but more on the number of its cycle. Their interpretation is that you cannot guarantee that the number of years is the best indicator that a battery will last longer, because there are more important factors to be considered such as the temperature, weather and purpose. So, it’s more accurate to rely on the cycle of the battery, instead of the number of years it claims. Or it can be both. Because these two are correlated to one another, for example, a battery acclaims that it can last for twenty-five years but you’ll see in the product description that it can only last for that given years if you will discharge it by about 5 percent. So, if you did not follow the recommended cycle, don’t expect that the battery will last for 25 years or so.
A cycle is the process of the complete charge and discharge of a battery. When a battery claims a lifespan of 1000 cycles, it only means that the battery can undergo up to 1000 times the discharge and recharge process before it reaches its life-end. That is the simplest way to interpret it. Just be guided that, cyle is not always about a discharged battery is reaching its zero percent and its recharged percent is 100 percent again.
Not all batteries have the same cycle, the cycle can differ from one type of battery to another, but commonly all batteries depth of discharge (DOD) level can be 10 percent, 20 percent and 50 percent. So, the cycle of battery plays a vital role in determining its actual lifespan.
Take note also that discharging the battery to 100 percent is not advisable to do as it can decrease the life expectancy of your deep cycle battery.
The lifespan of deep cycle batteries vary, it depends on how it is being used, maintained and charged. Sometimes you need to consider other factors such as depth of discharge (DOD) temperature resistance, shock tolerance, how often it needs to be cycled, etc.
However, Flooded Lead-acid deep cycle battery and AGM deep cycle lifespans are about 4 to 8 years, while Gel deep cycle can last up to 2-5 years only.
Selecting the right battery is quite hard and confusing since everyone claims to have high-quality materials, best performance and features and very well suited to be your energy storage. Since investing in a deep cycle battery is quite expensive, it’s a must to consider all the factors as much as possible to make sure that you will get the best battery you need for your work and you can use it for a longer time.
If you want to ensure a long lifespan for your deep cycle batteries is to provide maintenance. Watering the batteries (if it is a flooded lead-acid battery type) to the appropriate level, avoid discharging the battery more than the recommended 50 percent of its total capacity. Monitor them even once in a while (for sealed deep cycle battery) and for the flooded lead-acid battery, it requires regular monitoring. Also, have an appropriate charging system, do not over-charge or under-charge the battery because it can affect its performance including its lifespan.
Deep Cycle Battery Price
Absorbent glass mat battery (AGM) can range anywhere from $80 to $1,000. The price varies, depending on the type, volt and amp-hour. While you can buy a gel battery with a price of $100 to $500, still depends on the quality, machine and types. On the other hand, the price of the flooded lead-acid battery is three times lower than the sealed or valve-regulated lead-acid battery.
Deep Cycle Battery Maintenance
These kinds of battery are the typical batteries that off-grid power system are using because it has much thicker lead plates. So, if you’re using this for your solar panel system you should not discharge it below 20 percent of its full capacity because its internal resistance can cause heat and damage to the battery when it’s recharging.
Usually, the solar energy system uses a low voltage warning light and cut-off switch when using these batteries to avoid battery damage.
Although, most of the deep cycle batteries can withstand high temperatures it is still advisable to store them at lower temperatures, due to the slow reactions of the chemicals inside the battery. And as a rule of thumb, it’s a must to return it the batteries to its room temperature to reach its maximum voltage.
Some deep cycle batteries do not require regular monitoring and maintenance like the AGM battery and Gel battery, but manufacturers recommend to make a check-up once in a while and for wet cells like Flooded lead-acid batteries, regular maintenance and monitoring are high-recommended.
When it comes to charging the lead-acid batteries, it should not be charged quickly or in a long time because it can cause acid leakage, hydrogen fire, severe damage to the battery or worst scenario, battery explosions. It is also recommended to use the automatic current and temperature regulator device to monitor and regulate the right amount of current.
Safety Hazards of Deep Cycle Battery
Batteries have a high tendency to explode since they carry large amounts of currents and it’s possible to have a short circuit especially if there’s a malfunction happening. It can be the result of misuse like attempting to recharge non-rechargeable batteries and short-circuiting the batteries.
Explosions may happen if the batteries are experiencing overcharging because they release hydrogen in the air. Particularly those deep cycle batteries that electrolyte. This released gas can ignite even by a simple spark in the cables. Although this gas is not a problem when you’re using a lithium-ion battery.
Moreover, charging deep cycle batteries beyond their electrical capacity can also lead to battery components damage and worse is battery explosion. Including conventional batteries, if they recharge excessively, the hydrogen and oxygen can create an explosive gas mixture even in seconds. Therefore, producing big pressure inside the battery that can surely lead to an explosion.
Take note that even the maintenance-free batteries like sealed or VRLA are not excluded from an explosion, it can also happen when the valves of the battery fail or there’s a blockage in the valve. This valve failure can also cause pressure within the cells until short-circuit occur and ignites the explosive gas mixture. Proper handling and utilization of batteries must not be neglected for it can cause severe injury and danger.
Deep Cycle Battery Reviews
Offgrid Deep Cycle Battery Review – Motomaster Nautilus UltraXD AGM
EverythingNewUnderTheSon YouTube channel made a review of their Nautilus Ultra XD Absorbed glass matt (AGM) battery and the standard Nautilus Flooded Lead Acid deep cycle battery.
Battery Bank Options + Wiring Solar Batteries from 6v to 12v vs 24v
Duet Justus discussed on their content the different types of deep cycle batteries that can be used to Solar panel system. (flooded lead-acid, absorbed glass mat (AGM), and lithium-ion)
Deep cycle battery AGM vs standard which battery is better?
Deep Cycle Battery San Diego explained the different types of deep cycle batteries, its features, functions and differences. (AGM, Gel battery and flooded lead-acid battery).
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