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How To Tell If Your RV Battery Is Bad

Power - by Joe Weber - updated on 9/18/2023

People in the woods with a small rv

RV batteries don't last forever. Sooner or later you will need to replace your starting battery and your deep-cycle batteries. So how can you tell if your batteries are starting to go bad? Can a bad converter look like a bad battery? Keep reading to learn more so you can be prepared for your next road trip.

Signs Your RV Batteries May Be Going Bad

The nice thing about batteries is that they will generally let you know when it's time to replace them. There are several telltale signs that your batteries might be on their way out.

Visual Signs

  • Old Age: If your battery is 5 years old and you're experiencing issues, it's probable that it's just old and has reached the end of its useful life.
  • Corrosion: Corrosion on the battery terminals or cables is a sign of unwanted chemical reactions occurring. Corrosion can hinder the battery's ability to charge and discharge effectively. Corrosion is also the number one cause of early battery failure.
  • Damage: Physical damage to the battery case, such as cracks or leaks, is a clear sign of a failing battery.

Operational Signs

  • Lower Capacity: If your battery isn't holding a charge as well as it used to and you're having to recharge it more frequently, this could be a sign of reduced battery capacity and may be time to replace the battery.
  • Difficulty Holding a Charge: If you notice your battery struggling to hold a charge after a charge, it could be a sign that its internal components are deteriorating.
  • Difficulty Starting: If you have a starting/cranking battery for your RV's engine and you're experiencing difficulty starting or a slow starting engine, it could be a sign of a weakening battery.
  • Electrical System Problems: Appliances, lights, the radio and other electrical components in your RV might not function properly or lights could flicker if the battery is struggling to provide consistent power.
  • Uneven Charging: If you have multiple batteries in your system and notice that one battery is charging unevenly compared to the others, it could be a sign that there is a problem with that particular battery.
  • Low Voltage: Many RVs have a low voltage indicator or alarm to let you know when your batteries are reading too low. You can also use a multimeter to check the voltage of your batteries. A fully charged 12-volt battery should read around 12.6 to 12.7 volts. If the reading is lower, it might be time for a new battery.

If you see any of these signs, you can bring your batteries into a Batteries Plus store to have them tested to see if the batteries are salvageable or if it is time to purchase a replacement.

How Long Do RV Batteries Last?

RVs can have two battery configurations. Smaller RVs may only have one battery that handles both starting and deep-cycle (running the house portion) whereas larger RVs may have separate batteries for both jobs, some large RVs can have several deep-cycle batteries to power the home portion of the RV.

Generally speaking, RV batteries should last you somewhere between 3 and 6 years or longer, depending on the type of battery, how it's used and how it's maintained.

Why Did My Battery Go Bad So Fast?

It's only been a year and a half and you are already seeing signs that your battery may be going bad. You are standing around shaking your head wondering why. Batteries can go bad early for many reasons.

  • Corrosion - This is a battery killer. Corrosion is such a simple thing to remove but if you don't, it can cause various issues with your battery. Some of the issues caused by corrosion are difficulty starting, reduced charging efficiency, voltage drops, unreliable electronics and the list goes on.
  • Sulfation - Sulfation occurs when sulfate crystals accumulate on the plates, inside the battery due to undercharging or storing the battery without a full charge. These crystals will affect the battery's ability to store and deliver energy, leading to reduced performance, shorter run times, and shorter battery life.
  • Extreme cold - If you've ever parked outside in sub-freezing temperatures, you know how hard it can be to start your engine. Batteries exposed to extreme cold weather will be affected by increased internal resistance, making it harder for the battery to deliver power. It slows chemical reactions, lowering the battery's capacity and making it more difficult to crank the engine.
  • Extreme heat - Heat can be bad too, it's not just the cold. Exposure to excessive heat can accelerate chemical reactions and evaporation of the electrolyte solution in car batteries, reducing capacity, causing a buildup of corrosion, sulfation, and reducing the battery's lifespan.
  • Undercharging - If the battery is regularly not allowed to come back to a full charge, lead sulfate will start to build on the plates (sulfation) and the battery will not have as long a life.
  • Overcharging - So if undercharging is bad, then overcharging must be good, right? Wrong! Overcharging your batteries is just as bad as undercharging and you should never do it. Repeated overcharging can lead to corrosion, evaporation of electrolyte and high temperatures internally caused by the excessive charging will deteriorate the internal components of the battery.
  • Discharging too low, too often - This may sound odd seeing deep-cycle batteries are designed to be discharged and recharged over and over. However, discharging deep-cycle batteries below 50% (80% for lithium) regularly can lead to a shortened battery life.

Tips To Extend Your Battery Life

It's surprisingly easy to get the most life out of your batteries. Follow these easy tips to ensure you get the best battery life possible.

  • Remove corrosion

    Corrosion is an absolute battery killer. It is important to check often for corrosion buildup on the battery terminals and connectors and remove any present. You can remove corrosion by using a mixture of baking soda and water with a wire brush. You can also purchase a terminal protection kit that includes a brush, cleaning spray, terminal protectors and a preventative spray to help keep pesky corrosion away.

  • Don't overcharge it

    Overcharging your battery repeatedly can send your battery to an early grave. It is best to remove the battery from the charger once the charge reaches 100% or use an automatic charger that will stop the charging process when the battery reaches that level.

  • Don't let it completely drain

    Letting batteries drain all the way is an easy way to ensure that sulfation will start to form, shortening the battery's usable life and forcing you to purchase replacement batteries earlier than needed. It's best to not let your deep-cycle batteries discharge below 50% for lead-acid and 80% for lithium.

  • Store them in optimal conditions

    The ambient temperature is very important while storing your batteries that aren't in use. You don't want to store batteries in temperatures that are too hot or too cold. Store your batteries in a cool, dry place with a temperature of around 60-70 degrees Fahrenheit.

  • Use a maintainer

    Using a maintainer goes hand in hand with storing in the best environment. When you have your battery connected to a battery maintainer, the maintainer will send small amounts of energy to the battery, keeping the battery at the optimal charge level for storage when the battery isn't being used for a longer period.

    Many new, automatic chargers will feature a maintenance mode that it will switch to once the battery has reached a full charge.

  • Ensure fluid levels are at ideal levels (flooded only)

    Many newer flooded batteries don't need to be filled with water but if you are using a flooded battery that needs watering it's important to check the electrolyte levels and add distilled water if the electrolyte is low.

What Should I Do if I Think My RV Batteries Are Going Bad?

If you are seeing some of the signs of an aging or failing battery, bring them to a Batteries Plus near you. Our team of experts will test your batteries to see if they are salvageable with some maintenance and conditioning or if it's time to look for a replacement.

Batteries Plus Has the RV Batteries You Need!

Whatever battery you need to make your next RV trip stress-free so you can enjoy the sights and sounds of nature, we have it. From starting to deep-cycle, we have what you need! We carry a large selection of RV starting batteries from brands such as Duracell Ultra, Optima and our own exclusive brand X2Power.

If you are looking for the best of the best, the cream of the crop, the ultimate RV deep-cycle battery, then you need to look at our X2Power Lithium Iron Phosphate (LiFePO4) deep-cycle batteries. The X2Power lithium RV deep-cycle battery comes with the relentless power you need in a much smaller package. The X2Power Lithium battery features

  • Half the weight of lead batteries.
  • Ready to use out of the box.
  • Ultra-fast recharging to a full charge within 1-3 hours.
  • Last up to 10 times longer than lead acid batteries.
  • Lithium has a very low self-discharge rate and can be stored for long periods with little maintenance.
  • Comes with either a 5-year or 10-year free replacement warranty.

Stop by a store today to see the next generation of lithium batteries and experience the greatness for yourself.

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