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Why Deep Cycle Batteries Are Best for RV

Table of Contents

How do deep cycle batteries work?

Deep cycle batteries work by using a chemical reaction to produce electrical energy. Inside the battery, there are two electrodes – a positive electrode and a negative electrode – that are immersed in an electrolyte solution. The electrolyte solution is typically made up of sulfuric acid and water.

When the battery is connected to a load, such as a motor or an appliance, an electrical current flows from the positive electrode to the negative electrode, providing power to the load. As the battery discharges, the chemical reaction that produces the electrical energy also causes the electrolyte solution to weaken. When the battery is fully discharged, the electrolyte solution is at its weakest point.

To recharge the battery, a charger is used to reverse the chemical reaction and restore the strength of the electrolyte solution. This process is called recharging, typically taking several hours to complete. Once the battery is fully charged, it can be disconnected from the charger and used again to power a load.

Deep cycle batteries are designed to be discharged and recharged repeatedly without damaging the battery. This is because the electrodes and the electrolyte solution are made to withstand the stresses of the charging and discharging process.

Additionally, deep cycle batteries are designed to discharge more slowly than other types of batteries, which means they can provide power for longer periods of time.

In Australia, deep cycle batteries are commonly used in various applications. One of the most common applications is in solar power systems. In a solar power system, deep cycle batteries are used to store energy generated by solar panels during the day for use at night or during periods of low sunlight.

Deep cycle batteries are also commonly used in marine applications, such as for powering electric trolling motors or providing power to lights and appliances on board a boat. In addition, deep cycle batteries are used in RVs to provide power for appliances and other electrical equipment.

What Causes Lead Acid Battery Failure in an RV?

Before we can get into why a deep cycle battery is the best battery to use in an RV, you need to know why a lead battery fails in the first place. There is nothing worse than travelling around and your battery dies and leaves you without power for your whole trip. Below are a couple of common causes of lead battery failure.

deep-cycle battery inside
deep-cycle battery inside

Frequent Undercharging

Battery failure is typically the result of constantly draining the batteries without fully recharging them in between cycles. Long-term discharge of the battery puts it at risk as well.

Many different battery types cannot withstand this treatment and will eventually stop functioning correctly. Without a full recharge, the sulphate in the battery will harden and crystallise.

Frequent Overcharging

Various problems may arise when batteries are charged for too long or with too much power. Batteries lose water when they are overcharged, and a significant enough water loss can prevent a battery from operating. If the battery is overcharged, the plates may also corrode and cause your battery to be unreliable.

What Deep Cycle Battery Has More Capacity?

Capacity differs greatly between lead-acid and lithium batteries due to their inherently different chemistry. The major difference is their capacity in relation to their rate of discharge. Lithium batteries can provide up to 100% of their rated capacity regardless of their rate of discharge. Lead-acid batteries provide significantly less usable energy with higher rates of discharge. Although both battery types may lose capacity in colder weather the changes in performance are far less drastic with lithium. At 0°C, for example, a lead-acid battery’s capacity is reduced by up to 50%, while a lithium iron phosphate battery suffers only a 10% loss at the same temperature.

How Long Do Deep Cycle Batteries Last?

The lifespan of a deep cycle battery is affected by a few factors. More factors impact the life of a lead-acid battery than lithium. In other words, lead-acid batteries are easier to abuse. Proper maintenance can extend the life, as well as discharge and charge it correctly. Improper watering, over-discharging, over-charging, and under-charging a lead-acid battery regularly can greatly reduce its lifespan.

Lithium batteries don’t require watering, so the issue of improper watering is eliminated. Lithium batteries are not damaged by a partial state of charge, or under-charging, so that issue is also eliminated. Lithium batteries can be damaged if they are severely over-discharge or if they are charged at a high current below freezing temperatures, thereby reducing lifespan.

Heat affects the battery as well. Higher temperatures degrade the battery much quicker.

Because of these factors, plus the fact that different types of batteries have different lifespans, it’s hard to state a specific time frame. Check the manufacturer’s specifications for your battery to get an idea of the capabilities of your battery.

BPG12-18 deep cycle gel battery
BPG12-18 deep cycle gel battery

How to Properly Maintain Your Battery for an RV

A battery, like every other component in your RV, needs to be maintained so that you get the longest life possible out of it. An important factor to consider in battery life is how deep it will cycle between each use.

A single cycle consists of a full discharge of energy from 100% to 50% and a full recharge back to 100%. The following below can be done to maintain your batteries life:

  • Recharge your batteries after use to prevent malfunction
  • Always use your built-in charger on the RV
  • Don’t overstrain the battery
  • Do routine inspections and maintenance of the battery
  • Use the appropriate charger for the battery type

Advantages of Deep Cycle Batteries

Battery technology has grown exponentially over the past few years. However, deep cycle batteries have been in existence for quite some time. For example, navy submarines make use of deep cycle batteries since the inception of submarine building.

What sets a deep cycle battery apart from other types of batteries is the ability to continuously discharge energy and be recharged without the battery failing. In other words, it is the perfect battery to use in an RV.

The following are a few advantages to deep cycle batteries:

Tough and Durable

Deep cycle batteries have a longer lifespan than other batteries, which is one of their main advantages. A deep cycle battery, for example, can last up to two or three times longer than a normal battery.

In other words, because they have a very low self-discharge rate, they can maintain a charge for longer and stay charged for 6 to 8 months without being used.

Safety Aspect

In your RV, you will need a battery setup that is safe. A deep cycle battery won’t leak or explode like a normal lead acid battery can. When a lead acid battery gets overcharged, a negative reaction can take place within the battery and explode.

Should anyone be within the vicinity, the explosion can cause severe bodily harm. Furthermore, if you have young children and your battery is leaking, the acid can get on their skin and cause severe burns.

Outstanding Efficiency

Deep cycle batteries have the distinct benefit of charging up to five times faster than normal batteries. In contrast to lead acid batteries, which require a 50% depth of discharge to maintain the same cycle duration, deep cycle batteries need a depth of discharge of 80%.

Where Do We Use Deep Cycle Batteries?

Deep cycle batteries are used in many different areas of life but are extremely popular for recreational and all-terrain vehicles.

Other areas that deep cycle batteries are used:

  • Cars
  • Motorized wheelchairs
  • Electric bikes
  • Golf Carts
  • Boats, Water Vehicles
  • Energy storage systems (solar and wind)
  • Traffic lights
  • Audio equipment
  • Electric floor cleaning machines
  • Electric scissor lifts
  • Electric forklifts

Going Off the Grid

Most people who choose to go off the grid are only able to do so because of deep cycle batteries. They allow for solar, wind and other reusable energy to be their power source for lights, electricity, etc.

Nomads, doomsday preppers, RVers, and survivalists all use deep cycle batteries to run generators, lights, power, and other life necessities.

Many essential services such as health care prisons, schools, stores, and other organizations use deep cycle batteries to run their generators so if there is an emergency or loss of power they do not lose power totally.

Things like respirators, oxygen supplies, power lifts, etc are able to still be used in patient and client care because of deep cycle batteries being used as a backup.

Deep cycle batteries are different to SLI or ISS batteries used in cars as they have:

  • Thicker grids and corresponding plates, which gives them longer life.
  • High density active material to increase capacity.
  • High percentage antimony in the positive grid alloy which improves cycling ability.
  • Separators made of rubber with a glass mat designed to retain active material and control water loss.

How Do Deep Cycle Batteries Compare?

The following table shows a simple comparison of four of the major types of deep cycle batteries and their features.

Flooded Lead Acid Battery AGM Battery Gel Cell Battery Lithium Ion Battery
Depth of discharge 30–50% 80% 75% 80–100%
Charge efficiency 70–85% 95% 85–90% 85%
Sensitive to overcharge Tolerant Yes Highly Yes
Position sensitive Yes No No No
Lifespan Up to 6 years 6 years 10 years Up to 5000 charge cycles, 3–10 years
Charging time 8 to 16 hours 5 hours 5 to 10 hours 2 to 3 hours

What do the deep cycle battery specs mean?

The specifications mainly denote the battery capacity, discharge cycle, and depth of discharge. For example, you can get something like 100 Ah at 20 hours raised 1100 full cycles at 70% DoD.

  • Most deep cycle batteries come with a 20-hour discharge rate. Therefore, 100 Ah at 20 hours battery capacity means that the battery can produce 5 Amps (100/20) for 20 hours. If you have more appliances that will be depending on the battery, it is best to get one with a higher capacity.
  • 1100 full cycles mean that the battery can be discharged and recharged 1100 times without a decrease in capacity or performance. A high number of cycles means that the battery will last longer.
  • 70% DoD refers to how much of the battery capacity you should use before a recharge is needed. A 70% DoD means that you can safely discharge the battery up to 30% of its capacity.


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