Maintenance Free Deep Cycle Battery

maintenance free deep cycle battery

Maintenance Free Deep Cycle Battery

Deep cycle batteries are engineered to drain down and recharge on a repeated basis. These types of batteries can usually handle several hundred cycles.

They are available in various group sizes, voltages and chemistries. These batteries are typically used for solar electric power systems, golf carts and backup power.

Maintenance free deep cycle batteries are sealed and do not require the regular watering and checking that flooded lead acid batteries must have. They also have vents that do not open during charging to prevent excessive pressure build up.


Deep cycle batteries are also known as lead-acid batteries and they are available in both flooded and sealed types. The main difference is that flooded (or unsealed) batteries require regular additions of distilled water, whereas sealed batteries don’t need the extra maintenance. The electrolyte inside the flooded battery is in liquid form, while the electrolyte inside a sealed battery is either in gel form [GEL BATTERY] or replaced by an acid-soaked glass mat that’s sealed between the battery electrodes (AGM BATTERY).

We offer several types of sealed and gel deep cycle batteries here at altE. You can find the perfect battery for your solar energy system, backup sump pump, RV, boat, mobility scooter or other application in our selection of deep cycle batteries.

These batteries are a good choice for your backup power needs and will provide long term service as long as you maintain them properly. That means keeping them well-watered, not discharging them more than 50% of their capacity and ensuring that they have a proper charging system in place. Both over and undercharging can severely reduce the lifespan of these batteries, so it’s important to check them regularly and charge them if they go unused for a prolonged time. Most deep cycle batteries are rated in amp-hours, which is an indicator of how long you can use the battery before it’ll need to be recharged.


The most common type of battery is a standard flooded deep cycle battery. These have thick plates that are submerged in electrolyte fluid, they charge and discharge very efficiently. They also hold a very good rate of charge for their price. Since they vent gases internally, they need to be topped off with distilled water when the cells get low (usually every 2-4 weeks) to maintain their performance.

They will self-discharge more maintenance free deep cycle battery rapidly at higher temperatures, but this is normal. The Gel battery lifespan of a flooded battery can be significantly reduced if the manufacturer’s guidelines are not followed, such as maintaining a proper cell temperature and not charging with too high a current.

Flooded batteries that are properly charged and maintained will have a long life. It is important to use a smart charger when charging these types of batteries as they can sulfate quickly if not charged properly. To maintain the condition of a flooded battery, clean the top and terminals with a non-metal brush or cloth soaked in baking soda and distilled water, adding the solution to one-eighth inch above the maximum fill line. Also, check the vent cap for corrosion and add distilled water to the battery if needed. These are the same type of battery found in golf carts, marine batteries and other applications that require a deeper-discharge lead-acid battery.


AGM batteries are a great choice for deep cycle and backup power applications. They have lower internal resistance than flooded lead-acid batteries, which increases their output voltage and decreases the time it takes to charge them, as well as reducing losses to heat as power flows through them. They are also leak proof, meaning that they will not contain any dangerous acid if the battery is damaged during transport or use.

Unlike traditional flooded lead-acid batteries, most AGM and gel batteries are “valve regulated”, which means that a tiny valve keeps a slight positive pressure in the battery. This prevents overcharging and maintains their lifespan, while still allowing them to vent during charging so that the gases produced can be recombined into liquid.

While all deep cycle batteries will eventually die, their lifespan can be maximized through proper maintenance. For flooded batteries, this includes checking water levels on a regular basis to ensure that the electrolyte level does not fall below the plates. It is also important to keep the battery clean, especially around the terminals, and to regularly perform a load test.

For AGM and gel batteries, a battery health check is typically sufficient to extend their lifespan. However, it is always recommended to use a quality charger that follows a multi-stage charging process. This includes a bulk charge (fast charging until about 80% capacity), an absorption charge, and a float charge to maintain full capacity.


Deep Cycle Gel Batteries use a silica gel to hold their electrolyte which is not prone to spillage. They are more resistant to damage than other battery types and operate well in harsh environments. They can be mounted in any position, are safe for limited ventilation areas and are also transportable via air or ground without special handling. They also have a lower density of electrolytes meaning that they are less sensitive to water loss and have a longer lifespan than other battery types.

Gel batteries do have some limitations; they take a longer time to charge, have a higher energy cost per kWh and are less responsive to high load applications. They are also more prone to damage from things like quick charging or high discharge which can cause the formation of voids within the gel, reducing their life and performance.

However, they are still the preferred maintenance free deep cycle battery for a variety of uses. For example, they are the best choice for off-grid holiday cabins where you need backup power but only intermittently. They can also be stored in a shallow draw where they won’t go flat for months at a time. They are still susceptible to self discharge death but it is far less than a flooded or AGM battery. Nevertheless, we recommend testing and charging them regularly to avoid them going completely flat.

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