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Deep Cycle Batteries

Guide to Deep Cycle Batteries from RVs to Solar

If you want to store electricity from your solar systems or if you need to power your motor propellers, then a deep-cycle battery is your best option. These are made to recharge themselves several times in their lifecycle, providing backup power for devices and equipment for years.

Batteries for deep cycles come in different sizes, shapes, and capacities. They vary in performance characteristics, and some are better suited than others for certain applications. 

Points to Remember

  • Deep cycle battery packs are designed to be used frequently and deliver a consistent energy supply.
  • Deep cycle batteries come in three main varieties: flooded, sealed, and Li-Ion.
  • Lithium batteries generally cost more than lead-based batteries, but they last longer.
  • Most batteries can store solar power in moving homes or immobile buildings.

What Do Deep Cycle Batteries Mean?

Deep cycle batteries are designed for regular charging and discharge cycles. They can provide a steady flow of energy when they're fully depleted.

They usually have features like a normal 12-volt automobile battery, but they're often packaged in hefty containers having positive and nega­tive terminals at the top.

Deep cycle battery types include lead-based technologies, which contain lead plates attached to the terminals and immersed in an electrolyte mixture that contains sulfuric acids. However, lithium-ion (Li-ion) battery types are becoming increasingly common.

Car Battery vs Deep Cycle Battery

Deep Cycle Batteries

Cars that run on gasoline use a battery of 12 volts to supply electricity for the ignition system, start mechanism, and headlights. Car batteries are sometimes called SLI (starter, light, and ignition) batteries.

To produce a powerful surge of electricity, the SLI battery must pull many electrons from the electrolytic fluid. It has several thin metal sheets attached to its terminal posts to achieve this. This charges the battery at a faster speed by increasing the contact area of the electrolyte.

Lead acid batteries have thick metal electrodes. The batteries cannot deliver a large current at once, but they can supply a constant flow of electricity, and their thicker plates prevent them from corroding even after discharging.

Deep cycle batteries are available in many different shapes and dimensions because they don't need to fit into the standard automotive battery package.

Lithium Battery

A lithium battery can be identified as a deep-cycle battery because of its complete charging and discharging. They're not built quite the same way.

They use cylinder-shaped cells with two electrodes in an electrolyte solution which controls the movement of electric charges.

Most of these batteries are connected to form a battery pack, then packed with plus and minus terminal points. Batteries usually include built-in battery management systems (BMS) unless made from raw cells.

Deep Cycle Battery Categories

Deep Cycle Batteries

Lead acid and lithium batteries are the most common types of batteries with deep-cycle that people use these days.

Flooded lead acids (FLAs) can be divided into two types: the first one is flooded lead acids, which need frequent watering and should be maintained regularly. The second one is called sealed lead acids; they need zero maintenance and usually do not need watering.

Two types of batteries in the SLA category are absorbent glasses mats (AGMs) and gels.

Read our article to learn more about various lead acid batteries.

Deep-cycle lithium-IoT batteries have similar features; however, they use different materials to make the positive terminal.

One category includes nickel, magnesium, and cobalt, known as NMC batteries, and another uses LiFePO4, known as LFP batteries. On average, they perform pretty similarly.

Lithium polymer (LFP) batteries are safer, less harmful, and more durable than nickel metal hydride batteries and are hefty and more costly.

Concepts to Keep in Mind While Purchasing Deep-Cycle Batteries

There are several key concepts to know when choosing between various kinds of batteries. 

  • Amp-hours
  • Voltage
  • Depth of discharge
  • Life of Battery

The voltage affects how powerful the battery pack is. Common voltages range from 6 volts to 24 volts. A 12v battery is usually suitable for portable applications, whereas battery bank systems for homes use multiple cells connected to provide greater voltages (e.g., 24 V or 48 V).

Battery capacity gives you an indication of how long you can use a battery before it needs recharging. In deep-cycle batteries, this rate of discharger is calculated over 20 hours. A battery with 100Ah can deliver up to 5A for continuous 20 hours before it stops supplying more power.

DoD refers to the charge that can be safely removed from a battery before it becomes damaged. Some batteries promise a large battery life but deliver less power than they say.

For maximum battery life, discharge batteries to less than half their capacity. Discharging very deeply can cause mutilate the plates inside an FLA battery. Don't let them get too low; keep them to at least 20%.

Most experts recommend discharging AGM and gel batteries to no more than 50 percent of their full capacity. Lithium batteries can be fully charged and drained (100 percent DoD). However, most manufacturers recommend using them at 80 percent DoD to ensure they last longer.

It's time for battery life, which is usually expressed in terms of the charge cycle. This is related to DOD because the total discharge cycles a battery can withstand decrease when DOD increases.

For instance, gel batteries survive for up to 1,000 charges at 50 percent DOD and no longer than 450 charges at a full 100 percent DOD. AGM batteries can usually handle up to 500 charge/discharge cycles at 50 percent DOD but only 200 at full DOD.

Remember that the battery life doesn't necessarily indicate that the battery will be completely useless after using it for some time. A battery's life doesn't end until it goes down to 80 percent of its initial battery charge.

Below is a list of various battery types, their average life cycle, and DoD recommendations:


DoD (in percent)








Lithium LFP



Lithium NMC






Deep Cycle Battery Applications

Deep Cycle Batteries

Deep cycle battery types vary widely in terms of which applications they're best for.

Static applications require FLA batteries. They're relatively less costly and easily connected to batteries for off-grid solar electricity backup and storage requirements.

Some drawbacks of these devices are that they require regular cleaning and the fact that the battery may leak if the device is not kept motionless.

AGM batteries are safe for use in applications where spills may occur, and they're resistant to vibrations, so they may be suitable for devices such as golf cart motors and vibrating power tools.

They're also generally used in UPS battery packs for backup power purposes in solar panels. They cost more than FLA batteries, require special charging care, and don't work well at low temperatures.

As its literal meaning suggests, gel batteries contain their electrolytes within a gel matrix, giving them resistance to shock and allowing them to be used in motorbikes and propellers.

Since the electrolyte is as thick as a solid mass, it is less likely to freeze even when exposed to cold temperatures. Low charging rates and high prices are some of the major drawbacks of gel battery packs.

Lithium-ion batteries are widely adopted by electronics manufacturers because they're reliable, safe, and efficient.

They've become the preferred battery technology for bigger applications like electric vehicles, home energy storage systems, and portable power sources.

They can be discharged without mutilation, can not handle vibration shock, and last longer.

The high starting cost is the drawback of lithium-ion batteries. Another drawback is that nickel metal hydride cells may catch fire if damaged. They're among the top choices regarding cost, battery life, and usability.

Leading Brands for Deep Cycle Battery

There is no single best deep-cycled battery. There are great deep-cycling batteries suited for various applications.

If you want the cheapest solution and can deal with the upkeep, go for FLA batteries. For a simple and shock-proof battery with lower upfront costs, an AGM or gel battery would be best suited for you.

If cost is not an issue and you are looking for the simplest, most effective solution, then choose Lithium.

Here's a list of the leading battery types available today:

AGM Batteries

  • Choice 1: Sun Xtender
  • Choice 2: Weize

Concorde Sun batteries are among the leading ones for static solar energy storage. They're not always easy to carry around but last for a long time. If you want a battery system that you can install inside an RV, then the Weize 12V 100 AH battery available at Amazon is a good option.

Concorde AGM batteries can be bought from the AltE Store

FLA Batteries

  • Choice 1: Trojan
  • Choice 2: Rolls Trojan

For years, Trojan has been the number-one brand in flooded lead-based deep cycle batteries for solar power storage. They're so much in demand that they currently have a four-five month waiting period.

If you don't want to wait longer than necessary, you can get good quality batteries from brands such as Rolls and Crown, currently available in the market.

Trojan and Crown batteries are available at the altE Store, and Rolls batteries at

Lithium Batteries

  • Choice 1: SimpliPhi
  • Choice 2: Battle Born batteries
  • Choice 3: Bluetti solar battery

For reliable, long-lasting home power storage, there's no battery better than SimpliPhi. With lithium iron phosphate (LiFePO4) chemistries and lifespans of around 10, 000 cycles at 80 percent depth of discharge, these batteries deliver long-life performance.

They're relatively expensive initially, but their long life cycle and DoD mean they ultimately deliver energy for less than most other batteries available today.

Portable power options for camping trips, off-the-grinders, and RVs include small rechargeable battery packs like the ones made by Battleborn Batteries.

For the most parts, these batteries are simply replacements for existing battery packs. If you want something simple and easy to use, use portable solar batteries from Bluetti.

All Bluetti's solar panels come with a MPPT solar charger, a smart BMS, a pure sine wave inverters, AC and DC charging ports, and multiple methods for charging.

Gel Batteries

  • Choice 1: Mighty Max
  • Choice 2: Weize

Solar panels are not well suited for household applications. These batteries from MightyMax and Weizi are good for small applications where quick recharging isn't necessary, such as a power source for a mobility scooter or troller.

You can purchase Mighty Max and Weize batteries from Amazon

Is a Deep-Cycle Battery a Perfect Match for Your Needs?

If you're living a nomadic lifestyle or prefer to be at home, batteries with deep cycles can be quite important.

These panels are well suited for a home solar installation or a small portable power source. With devices increasingly dependent on electrical power, knowing battery technology has become ever more important.

Calculate the amount you can save by combining solar power with battery backup systems.

About the Author David Roberts

I'm a Mechanical Engineer who's obsessed with solar energy and sustainable living.

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