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How You Should Choose Your Best Deep-Cycle Battery for Your RV

This article is part of a recent series of posts related to charging and maintaining a deep-cycle battery for RV. In this case, I am going to focus on the most common question when we talk about camper batteries. What is the best deep-cycle RV battery? But more important, it is to understand What is best for you and the use you will give to this battery. How should you choose it? This article is not the typical post just encouraging you to buy some commercial brand, as we do not review commercial brands of batteries. This post is all about teaching you and explaining to you why some chemicals may be better, depending on the conditions. Let’s see some of the best deep cycle batteries for RVs and small campers, understanding How You Should Choose Your Best Deep Cycle Battery for Your RV.

Throughout this article, we will review the deep-cycle batteries that better suit you and your RV. We should choose based on their chemistry, the life expectancy of a deep-cycle RV battery, and other technological features (such as Bluetooth) that currently allow us to monitor the state of charge and useful cycles.

Why is it Important to Choose the Best Deep Cycle RV Battery?

The RV Deep Cycle Battery is a critical element for functionality and also for the quality of life when we are enjoying our camper. Not to mention that it is fundamental when we are living in a camper or boondocking.

In my case, the deep cycle RV batteries I use allow me to save fuel and adjust my generator usage, especially during the winter when I want to winterize my pop-up camper and visit my brother in Nebraska. That’s why having the best deep-cycle RV battery is a must and key to staying within budget and even making a difference.

In a starter battery, 300 to 600 amperes are drawn in about 3 to 5 seconds. Starting from a 100% charged starter battery, the energy consumption we have made does not exceed 5%. Why do we use deep cycle batteries instead of starter batteries in the RV? Because we are looking to have power for a longer period, not just for a few seconds. So, for example, with a 65-amp battery to light the camper, we take 3 amps over 10 hours. To do something like this, we use batteries for RV that are denominated of the deep cycle since they admit to being discharged in 90 %.

Rated Capacity of a Deep Cycle RV Battery

With a deep cycle battery, we are looking for a battery to store as much energy as possible to be used for as long as possible. That is called the Rated Capacity of a Deep Cycle RV Battery.

These measurements are expressed as the number of amperes that can be delivered over a long period of time, measured in hours before the battery is discharged. Two grades of capacity are commonly used: ampere-hours and reserve minutes.

Ampere-hours measure the total amount of energy a battery can deliver at the end of a 20-hour cycle at a constant rate of discharge before the battery reaches 10.5 volts.

This 20-hour cycle measurement is key to understanding the usage, the number of batteries we need, and seeing that the “20-hour” measurement is a standard, which allows us to easily compare deep cycle VR batteries to find and determine which one is the best.

What does it mean for a deep cycle battery to be 200 amp-hours? This means that a 200 amp-hour battery on a standard 20-hour cycle can run at an Amp-hour/20-hour draw, so a 10 amp draw for 20 hours. If I start with a 100% charged battery and consume 10 amperes per 20 hours, the battery will be completely discharged after 20 hours.

The reserve minutes of a deep-cycle battery is the number of minutes a battery can run at a 25-amp draw until it drops to 10.5 volts. For example, a group 27 deep-cycle battery may have a reserve minute rating of 160, meaning it will run at a 25-amp draw for 2 hours and 40 minutes. This measurement comes from the automotive world, where the combined load of lights, fan or heater, and other accessories could easily reach 25 amps.

What Is The Life Expectancy of an RV Deep Cycle Battery

When we talk about what is the life expectancy of a deep-cycle battery for an RV we are talking about a measure in “cycles”. This is a measure of how many cycles a battery can withstand, i.e., how many times a deep-cycle battery for RV can be discharged and charged. This is 1 cycle. One charge and discharge cycle can represent one day in the case of a solar panel.

The battery will cycle more or less depending on the depth of discharge (DoD) of each cycle. The number of cycles indicates how long a battery will last and is an indicator of quality. The number of cycles of a battery is one of the factors we will consider when choosing the right deep-cycle battery for an RV.

It is the ability to complete a cycle multiple times that distinguishes deep cycle batteries from automotive starting batteries, which can only withstand so many deep discharges before their life is over.

How Long Will My Battery Last?

For this general question, how long will my battery last? Now you know how manufacturers calculate and usually communicate this feature for the product. The number of cycles indicates the lifetime of the battery.

By general rule, lead-acid batteries typically last 3-5 years, depending on how they are charged and discharged.

Thus, in the curve that we see in the graph with the number of life cycles (n) for the depth of discharge (DoD %):

how to choose number of life cycles for the depth of discharge
Representation of the number of life cycles (n) for the depth of discharge (DoD %) for a specific deep cycle RV battery
  • 8,000 cycles with discharge depths of 20%; about 21.9 years of life.
  • 3,000 cycles with discharge depths of 50%; about 8.2 years of life.
  • 1,500 cycles with depths of discharge of 80%. About 4.1 years of service life.

In a camper, during daily use, there are rainy days, cloudy days, winters, and large consumption peaks due to simultaneously used appliances and, therefore, discharges closer to 30%. Therefore, a real battery life closer to 15 years can be expected for our example.

Using a deep-cycle battery at a discharge of about 40-50% greatly reduces its lifetime. How to Prevent this? You may have more deep-cycle batteries in your camper because you need to use more energy. So, you will use them without discharging more than 20-30% and that will considerably extend the life span of your deep cycle batteries for RV in years!!

Which Deep-Cycle Battery Offers the Best Cost-Benefit Ratio?

Which Deep-Cycle Battery Offers the Best Cost-Benefit Ratio? What you want is the highest number of amp-hours delivered at the end of the battery’s life for the lowest possible price.

For example, we buy a new $80.00 battery. We discharge and recharge the 100 amp-hour battery daily, and that battery will run for 200 “cycles” before it has to be discarded. How much does it cost for each day (100 amp-hours) of use? At the end of the battery’s life, you will get 20,000 amp-hours (200 cycles x 100 amp-hours). So, if I paid $80.00 and got 20,000 amp-hours (80,000 / 20,000), each amp-hour cost me $0.004.

Comparative Chart: Advantages and Disadvantages of Different Deep-Cycle Batteries Based on Capacity, Chemicals, and Amperes per Hour

Product NameRenogy 12V 200Ah Lithium LiFePO4 Deep Cycle Battery with Bluetooth,2000+Deep Cycles,Backup Power Perfect for RV,Off-Road,Cabin,Marine,Off-Grid Home Energy StorageLiTime 12V 200Ah PLUS Lithium LiFePO4 Battery, Built-in 200A BMS, 4000+ Deep Cycles, Max 2560W Power Output, FCC&UL Certificates, 10-Year Lifetime, Perfect for RV, Solar, Marine, Off-Grid, etc.Renogy Smart Lithium-Iron Phosphate Battery 12V 100Ah w/ Self-Heating Function for RV, Solar, Marine, and Off-grid ApplicationsDeep Cycle Agm Battery 12 Volt 200AH for RV, Solar, Marine, and Off-Grid Applications
ManufacturerRenogyAmpere TimeRenogyExpertPower
Nominal Voltage (V)12V12V12V12V
Rated Capacity (Amp/h)200 Amp/h200 Amp/h100 Amp/h200 Amp/h
ChemicalLiFePO4 Lithium-Iron PhosphateLiFePO4 Lithium-Iron PhosphateLiFePO4 Lithium-Iron PhosphateAGM
Life Cycles2,000 cycles4,000 cycles4,000 cyclesNo Information
App & BluetoothYesNoNoNo
Amperes per hour achieved over the entire service life200,000 amp-hours800,000 amp-hour400,000 amp-hourNot possible to calculate – Don’t trust
Ampere/Hour Cost$ 0.0052 amp-hour$ 0.0010 amp-hour$ 0.0019 amp-hourNot possible to calculate
How many years may last for boondocking? *5-7 years7-9 years2-3 yearsNot possible to calculate – Manufacturer does not declare the number of cycles
AdvantagesGood value for money. Monitoring through an application. Long life (2000 cycles) with good amperage per hour.Excellent value for money. Best ratio cost-benefitN/ANo advantages
DisadvantagesN/AN/ABeing only 100 Ah, although the life span is long, the cost-benefit ratio is almost twice as expensive as other similar batteries on the market. It is not the best cost benefit foundManufacturer does not declare the number of cycles
(*) We believe that when boondocking, we will face situations where we will discharge the battery by more than 50%, which drastically reduces the battery life. We consider the worst-case scenario, with a 30% shortening of the battery life due to misuse.

While options 2 and 3 have a very similar cost per battery ($ 790-820), the amperes per hour achieved over the entire life of the battery are so different (800,000 vs. 400,000 amp-hour). Therefore, the cost per amp/hour in option 3 (Renogy, 12V 100 Amp/h) almost doubles the cost per amp in option 2 (Ampere Time, 12V 200 Amp/h).

This is how we realize when we are really paying for quality and this is how we decide between one battery and another to know which one is the best deep cycle RV battery.

Do I need to Charge a New Deep-Cycle Battery Before Using it?

Do I need to charge a new deep-cycle battery before using it? When you are buying a deep cycle battery, most of them are at least 75 percent charged when they arrive. I would recommend discharging the battery to no less than 50% and then charging it. You’ll have a longer battery life if you are discharging the battery no less than 50% in each cycle.

Current Comparison of the Best Pure Sine Wave Inverter for RV

How to Charge or Recharge a Deep-Cycle Battery?

I encourage you to read my article explaining “How to charge or recharge a Deep Cycle RV Battery”.

In summary, you can determine the kind of charger you’ll need if you know the voltage of your battery. While a 6V battery needs a 6V charger, a 12V battery needs a 12V charger.

The charger’s amperage shouldn’t be higher than 20% of the battery’s amperage (for example, 12V 20A battery = 12V 4A charger).

Most chargers have the useful capability to turn themselves off automatically after the battery is completely charged. To find out if your charger has such a feature, see the user handbook. Constantly charging the battery will harm it.

What Is the Deep-Cycle Battery Shelf Life?

What Is A Deep-Cycle Battery Shelf Life? To prolong the battery life, we advise recharging every three months. However, I would recommend reading this article about How to maintain a deep cycle battery as the technology and chemistry of each battery may have different needs, especially during the winter, and we are looking to not kill the battery by not maintaining it properly.

Are Gel Batteries Better?

I don’t understand why some people insist on saying on the internet that a gel battery lasts longer than an open lead-acid battery. It is simple: The battery that provides the greater number of cycles of life will be the one that lasts more, regardless of the battery chemistry.

A gel battery with 1,500 cycles at 50% will last the same as an open lead-acid battery with 1,500 cycles at 50%. Since the life of a battery is measured in cycles, it is evident that 2 batteries with the same number of cycles will last the same.

No matter whether it is gel or open lead acid, the life of the battery is determined by the number of cycles it supports. Typically, both technologies support the same number of cycles; the most significant difference is that the gel ones are sealed and do not need maintenance, but they are much more expensive.

It is a lie that a gel battery lasts longer than an open lead-acid or AGM battery just because it is a gel battery.

The number of cycles concerning the depth of discharge gives us information about the life of the battery, not its technology. The difference between lithium and other technologies is that lithium can be discharged to depths of 100% DoD without damaging the battery. In comparison, in the other technologies, the depths of discharge cannot exceed 80% DoD, or the battery will be damaged. For starter batteries, for example, exceeding 50% DoD will damage the battery.

On the other hand, gel batteries have some advantages over acid batteries. Gel batteries are more resistant to damage caused by very deep discharges. Gel batteries maintain a higher voltage while discharging, so your DC appliances work better. Gel batteries are completely sealed, so they are called “maintenance-free,” and you cannot open and fill them with water. There is no need for this kind of maintenance. The disadvantage is that gel batteries cost substantially more than acid batteries and have fewer cycles of life.

LiFePO4 Deep Cycle Battery – A Great Choice

The LiFePO4 battery is among the safest ones currently on the market. It is clear from the fact that there is no safety risk due to the high-temperature runaway in the case of aberrant battery conditions.

LiFePO4 batteries stand out for their high degree of safety and thermal stability. In addition, LiFePO4 batteries are much less sensitive to high temperatures. This reduces the chances of overheating problems or even cell fires or explosions.

In addition, LiFePO4 batteries are non-toxic and non-polluting, making them an environmentally friendly option.

Best RV Deep Cycle Battery for Cold Weather

When the temperature is lower, a LiFePO4 battery’s capacity decreases. At temperatures below zero degrees, lithium batteries cannot be charged at all. Therefore, during winter, if you are using your RV in extreme temperatures, a particular AGM deep cycle battery like the one below is a good option (Renogy Deep Cycle AGM Battery 12 Volt 100Ah) with a charge operating temperature from 5°F to ~104°F (-15°C~40°C).

Why do Lithium Batteries Cost so Much?

Comparing lithium batteries to AGM and gel batteries, which have shorter life cycles, the chemistry of lithium batteries may be fully used and can be totally drained. This increases the cost of the battery. Due to their three times longer life cycle than typical deep cycle batteries, these batteries are more cost-effective in the long run despite having a greater starting cost.

Why are LiFePO4 Deep Cycle Batteries the Best Choice for Solar Panels?

Issues such as lightweight, long life, high efficiency, easy maintenance, safety, and resistance to high temperatures position LiFePO4 technology as the best alternative when choosing a solar generator.

About Ward Greenway

Since I was 5 years old, I remember being inside my father's pop-up camper crossing the USA. My passion for RVs and Campers grew until I graduated in Mechanical Engineering (Tennessee). Then, I took my passion to the next level. Because I wanted to improve the design and engineering of the RVs I enjoyed them so much. I have been lucky to work for Central RV New Zealand, Jayco Corporation Pty Ltd (Australia), Forest River Inc., and Mercury Marine, as a Mechanical Design Engineer. I have seen and improved hundreds of RV floor plans. Nowadays, I enjoy RV living full time in my Mallard travel trailer and the joy of meeting new friends along the way who help me put the best on CamperOutdoor.com

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