Why Does My RV Battery Keep Dying?

If you’ve ever found yourself asking the question, “Why does my RV battery keep dying?”, then this post is for you. And actually – this post is for every RVer with a battery! Proper care and maintenance is important for all sorts of reasons, not the least of which is to preserve the integrity of your RV’s battery so that it performs well for you for as long as possible. And let’s face it – batteries are expensive, and no one wants to have to replace them due to a simple lack of maintenance or care.

So, with this post, we’re not only hoping to help RVers whose batteries keep dying but anyone who could use a few good tips on how to keep their RV batteries in tip-top shape and performing optimally for as long as possible.

Let’s get to it!

So, Why DOES My RV Battery Keep Dying?

There are a number of potential answers to this question, and we’re going to lay them out below, followed by our tips on how you can avoid being someone who has to ask this question.

First, the most common reasons why your RV battery keeps dying:

You May Not Be Fully Charging Your Battery

You may have heard that overcharging your battery can shorten its life, but in fact, undercharging your battery can do the same, due to sulfation.

Sulfation, the accumulation of lead sulfate in your battery, not only shortens the life of your battery but can also completely destroy it.

Now – it’s important to note that this applies only to lead-acid batteries and not to lithium batteries. Lithium batteries aren’t damaged by undercharging. (See more in our post entitled, “Are RV Lithium Batteries Worth It?”)

However, it’s also important to note that this is one of the main reasons why a solar setup works best with lithium batteries as opposed to lead-acid batteries. Quite often, (due to circumstances outside your control, like the weather), your RV solar panels may not be able to fully charge your batteries. If your solar system is being used to recharge your lead-acid batteries, over time, the lack of complete charging can damage them. This could be a reason why your RV battery keeps dying.

Important: When you store your RV or store a battery, always fully charge a lead-acid battery prior to storing. Storing a partially discharged battery is asking for battery damage (and possibly battery loss). Always fully charge your RV batteries prior to storing.

Your Battery Is Thirsty!

Any flooded lead-acid battery requires water for proper performance (and in fact for survival), and dehydrating your battery will most certainly damage it.

When you have a battery that requires this type of maintenance, you really need to be vigilant about staying on top of it. You need to cautiously pop the caps off of your flooded lead-acid battery and check the fluid levels. The plates on your battery should never be exposed. If your battery is suffering from a lack of water, you’ll need to add distilled water before charging it (using plain tap water could seriously damage the battery).

This is a very common reason why an RV battery keeps dying, and it’s all due to a lack of proper maintenance.

We made a video back in 2011 in which we demonstrated how to properly service, maintain and equalize the 6-volt deep-cycle golf cart batteries in an RV. We’re posting it here for anyone who might be interested in seeing the process in action.

If you’ve got a lithium or AGM battery, you’re free of this type of maintenance. You won’t even find the little caps on those batteries allowing you to add distilled water.

However, you need to know that an AGM battery is still a lead-acid battery which means it still requires being fully charged (and, depending on the manufacturer, even equalized) from time to time.

AGM batteries are susceptible to sulfation if they’re allowed to go nearly or completely dead, (under around 10.5 volts). However, proper equalization (again, following the battery manufacturer’s guidelines) can often resuscitate them to their near-original capacity.

Sulfation Has Occurred

Sulfation, the build-up of lead sulfate crystals on the surface of a battery and/or inside the battery’s lead plates is very common, but proper battery maintenance can delay sulfation or make it less likely to occur.

As we noted above, sulfation is generally a result of repeated undercharging, but it can also occur if you store your battery at high temperatures (generally above 75 ℉). Sulfation will not only reduce the battery’s capacity and performance, but it can also be a reason why your RV battery keeps dying, as it frequently leads to early battery failure.

We remind you that sulfation is only an issue with lead-acid batteries.

You Have a Parasitic Battery Drain

If you have a parasitic drain on your battery, you will very likely experience the symptom of a battery that keeps dying.

In essence, a parasitic battery drain occurs when your electrical system continues to pull energy from the battery even when everything is turned off (including the engine). When everything is turned off, but electricity continues to be pulled from the battery, you very likely have a parasitic battery drain.

Now, this happens to some degree with regularity. Some electrical components such as computers, radios, and other “electronic” gadgets have internal clocks that continue to draw electricity in order to stay accurate. But when the drain goes beyond what’s normal for a vehicle or electrical system, that parasitic drain can easily cause your RV battery to keep dying. This impacts your battery’s performance and longevity.

To diagnose a parasitic drain, you’d want to use a multimeter to identify the systems that are draining power from your battery.

And if you want to ensure that, when stored, there’s NOTHING pulling power off your RV’s battery, you could install a battery terminal disconnect switch, like this one:

Just be sure that whatever disconnect switch you install is rated to handle the maximum flow of current you could see coming from your battery.

Your Battery Is Self-Discharging

Some amount of self-discharging is actually a characteristic of all batteries. However, poor battery care can exacerbate the increased self-discharge of your battery and can lead to permanent battery damage.

With that said, the age of your battery, regular cycling, and elevated temperature all increase battery self-discharge.

Many RVs use lead-acid batteries and they actually have relatively low self-discharge rates. (The loss is said to be around 5% per month.) But, as the battery ages, sludge from the byproducts of the charge/discharge cycle can accumulate in the sediment trap. Or repeated undercharging can leave lead sulfate crystals that can span the gap between the battery’s lead plates. This both can cause “soft shorts” or “micro shorts” (small contacts between electrodes) and this can lead to higher rates of self-discharge.

Self-discharge of a battery can’t be completely avoided, no matter what you do. Older batteries self-discharge more due to their age, and poorly manufactured batteries have higher self-discharge rates from the beginning.

However, you can lessen your battery’s self-discharge rate by being mindful of keeping it out of the heat. (A battery’s self-discharge rate doubles for every 18° F its temperature increases.)

Your Battery Is Overcharging

Another possible answer to why your RV battery keeps dying is overcharging. This is usually a matter of user error (for example, using a battery charger incorrectly). Overcharging could also be the result of an alternator that isn’t working properly to regulate the battery charge.

It could also be due to using improper charge voltage settings or leaving a charger connected to the battery for too long.

Overcharging your battery can cause corrosion of the positive battery plates, increased water consumption, and complete battery failure. Worse yet, an overcharged battery can overheat to the point of melting or swelling. If hydrogen (a highly flammable gas that’s a byproduct of the charging process) starts to accumulate inside the battery’s sealed cells, it can cause the casing to swell or lead to gas leakage. One tiny spark could ignite the gasses causing an explosion.

Once again you can test your battery using a digital multimeter to see if it’s overcharged. Follow these steps to test your battery:

1. Turn your engine on and run your RV at idle.
2. Connect your multimeter to the battery terminals. A properly charged battery will show around 12.6 volts.
3. Turn on the air conditioner, lights, and radio. You should now see a reading of around 14 volts. If your battery is showing more than 14 volts, it’s overcharging.

Your Battery Is Damaged/Flawed

Another potential reason why your RV battery keeps dying could be that the battery is damaged or flawed in some way. If you have a damaged/flawed battery, replace it immediately.

How Can I Properly Maintain My RV’s Lead-Acid Battery?

Fortunately, there are a number of things we can do to properly maintain a lead-acid RV battery, making a dying battery less likely.

Avoid Deep Discharges

Avoid deep discharges as they result in significantly shortened battery lives.

If you’re using your battery under a heavy load, you’ll want to take short (1 to 2-hour) breaks to briefly recharge it. This will help to prolong the life of the battery.

If you’re storing your RV, you’ll want to take proper care of the battery/batteries – and be mindful of the temperatures to which they’ll be subjected during the period of storage.

You’ll also want to monitor your batteries as carefully as possible, and this is where a good RV battery monitor comes into play. (If you’re in the market for a quality RV battery monitor, feel free to check out our post on the best RV battery monitors as well.)

Fully Charge Your Battery Before Storing

Before you store your RV or your RV’s batteries, be sure to fully charge them. You always want to store a lead-acid battery after it’s been fully charged.

Store Your Battery Properly

Store your batteries in a cool place in summer, and in winter be sure to store your fully charged batteries where they won’t freeze, as we noted in our post on RV winterizing tips.

And finally, even when stored, you want to check your batteries monthly to see if they need water replenishment. Remember that the plates shouldn’t be visible (more about that coming up).

Use a Battery Tender

A battery tender has safety features that prevent overcharging, so using a battery tender is a good idea. You can also use a battery tender when you bring the battery out of storage. While it will have lost a bit of current from lack of use, a battery tender will prevent leakage while keeping the battery from dying.

Maintain Proper Electrolyte Levels

Be sure to regularly check your battery’s electrolyte (liquid) levels and never allow the electrolyte to drop below the top of the plates. If you can see the plates, your battery is thirsty (and damage is being done), because when the plates are exposed, they become irrevocably damaged and, eventually, become completely inactive.

If the fluid level is low, add just enough distilled water to cover the plates BEFORE fully charging the battery. Once charging is complete, finish filling with water to the correct level, which is generally marked by a visible fill line (or until the liquid level just touches the bottom of the neck of the opening).

Remember to only use distilled or deionized water for your batteries. Any other water will bring minerals that could permanently damage the battery.

Don’t Allow Your Battery to Drop Below a 50% Charge

This doesn’t apply if you have lithium batteries. But if you don’t, be sure not to allow your batteries to drop below 50% before recharging them. It’s good to get down to 50% every once in a while. You need to do that. If you don’t, and you consistently recharge your batteries before they’ve been drained down to 50% state of charge, you can actually reduce the lifespan of the battery.

However, if you allow your lead-acid batteries to fall BELOW 50% state of charge, the internal resistance will increase, and your batteries won’t hold a charge due to the depletion of electrolytes. Doing this will significantly shorten your battery’s lifespan.

Don’t Allow Corrosion to Build Up

Battery terminals corrode over time, but regularly inspecting and cleaning them will prolong the life of your battery.

The electrolyte in lead-acid batteries contains sulfuric acid, which is highly corrosive. During the charging cycle, it’s normal for some of that acid to be expelled through the vent openings in the caps, which then corrodes the metal of the battery terminals.

It’s important to remember that corrosion on those terminals will add to resistance as electricity flows through, increasing the drain on your battery’s power. So, be sure to keep an eye on your battery terminals to keep your battery healthy. If you see that they’re beginning to corrode, it’s a good idea to clean them with a product like this (which includes a color-changing indicator to let you know when you’ve neutralized all the acid):

Or, you can mix baking soda (readily available at grocery stores) with water and spread that on the corrosion. The baking soda will react with the acid (you’ll know, because it will bubble), neutralizing it. Rinse the solution off carefully with plenty of fresh water and continue re-applying it until the bubbling stops.

When Is It Time to Replace My RV Battery That Keeps Dying?

In general, the lifespan of your RV batteries will be determined by the way you care for and maintain them. Managing the proper charging and discharging of your batteries is a very important part of prolonging their life.

If you take care to make sure your batteries never discharge below 30% of their maximum charge (i.e. only drain them from 100% charge down to 70% state of charge), for example, they’ll have a 50% longer lifespan than they will if you allow them to completely discharge. If you’ve been regularly allowing your battery to discharge deeply, and your battery keeps dying, it’s probably time to replace your battery.

The lifespan of your batteries is also affected by the temperature in which they operate. Lead-acid batteries tend to do best in an environment that stays somewhere between 50℉ – 75℉ (that’s 10℃ – 25℃). Of course, this isn’t always possible, but be aware that the longer a battery operates outside of this general range, the more the lifespan of the battery will be impacted.

Extreme heat and extreme cold have the greatest impact and can lead to a dramatic reduction in the life of the battery. If your battery has been subjected to either extreme heat or extreme cold, and your battery keeps dying or doesn’t hold a charge as it should, it’s probably time to invest in a new battery.

If your battery is 4-6 years old and keeps dying, its age is showing and you’ll do well to replace it.

And finally, if your battery no longer holds a charge or is damaged – or if you see corrosion accumulating regularly, you should replace your battery immediately.

Have a look at our post on how to replace RV house batteries, or watch our YouTube video and follow along with us as we show you how to replace deep cycle RV house batteries.

Have You Experienced an RV Battery that Keeps Dying?

Have you run into the problem of an RV battery that keeps dying? What was the issue in your case? We’d love to hear about your RV battery-related experiences.

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