Why Is My RV Battery Draining So Fast? 7 Reasons

You’ve just had a great sleep in that fancy RV bed, you go to sit in front of the steering wheel, you turn the key, and oh no, the RV won’t turn on. It looks like your battery is dead. You just charged it last night, so what’s going on? Why is my RV battery draining so fast?

There are a number of reasons why your RV battery might be draining too quickly, including too much use, not being charged correctly, being overcharged, being undercharged, not being maintained correctly, and other common mistakes like leaving your headlights on all night.

Here is a summary of each of the common reasons, and some important tips on how to make your RV batteries last much longer.

why is my rv battery draining so fast

7 Reasons Why Your RV Battery Is Draining So Fast

There are a great many reasons why the battery in your RV is draining too quickly. Let’s take a closer look at each of these causes.

1.  You Are Draining It Too Quickly

One of the most common reasons is simply because you are using it too much. For instance, if you leave on the headlights or the dome lights by accident, when you are parked, it may be the cause. Headlights left on during the night can easily drain your battery over a period of a few hours. 

If you are using the RV battery to power a variety of appliances inside the RV, this could very well be to blame as well. Remember, all those appliances need to get energy from somewhere, and this is generally going to be from the RV battery. 

You might have a variety of appliances running at once that simply use way too much energy, more than your battery can handle. Therefore, you want to compare how powerful your RV battery is to all of the appliances, lights, and other energy using items that you have. 

When it comes to being in storage, you want to disconnect everything including fridges, carbon monoxide detectors, smoke detectors, propane detectors, and more.

At the same time, you should also be disconnecting the ground wire while your RV is in storage, as this will also help prevent the battery from being drained.

2. It Wasn’t Fully Charged To Begin With

Another reason is simply that you didn’t fully charge the battery to begin with. If you’re starting at between 60% and 90% of the power that you thought you originally had, then your battery is going to run out much sooner than you expected.

Of course, this doesn’t really mean that the battery is draining too quickly, it just didn’t have enough power to begin with.

One of the main causes of an RV battery being undercharged is if you were fast charging the battery using a fast charger, but then it didn’t switch to the float mode to top it off.

Fast chargers will get the battery to around 80% or 90%, but they won’t top it off. It needs to be able to switch to float charging mode in order to top it off. On that note, you might just not have let it charge for long enough before using it again. 

3. The Batteries Are Not Being Charged Properly

Another possible cause here is if your batteries aren’t being charged properly. For instance, you might be using solar panels or other charging sources that just aren’t producing enough power, or at least not nearly as much as you thought. 

For instance, if your gear isn’t up to par, or you are using mismatched solar panels, this could very well be the case. Of course, if your batteries aren’t receiving nearly as much power as you think they are, they’re going to die faster. 

No, this technically doesn’t mean that they are draining too quickly, but that they weren’t fully charged to begin with. That said, once again, you might just not be letting your RV battery charge for long enough. Keep in mind that it usually takes about 10 hours for these batteries to fully charge. 

Moreover, if we are talking about deep cycle batteries, these can take up to 12 hours. Keep in mind that when using solar panels, it also depends on how sunny it is. For instance, if you set up those solar panels in the middle of the afternoon, you’d be lucky to have a 50% charge by the time the sun goes down. 

4. You Don’t Charge Them Often Enough

One of the biggest mistakes made in this sense is that people don’t charge their batteries enough. They also store their batteries for two long periods of time without charging them. The simple reality is that batteries are slowly going to lose their charge when they aren’t used. After a certain amount of time, the batteries can even go dead. 

This is the especially the case when it comes to storing an RV over the winter. Yes, the cold air isn’t going to do the battery any good, so if it stays cold for too long, this can also decrease its ability to hold a charge.

However, in order for a battery to retain its chemical memory, which is its ability to fully recharge 100%, it needs to be fully charged and discharged every once in a while. 

You can’t let your RV sit in a garage for six months without charging the battery. If you let the battery fully discharge, and it stays that way for several months, chances are that you’ll never really be able to charge it again. A stored battery can lose up to 10% of its charge every single month.

5. Poor Battery Maintenance

Another reason why your RV battery drains so quickly is because you aren’t using it and maintaining it properly. For instance, if a battery is cold or nearly frozen, attempting to charge it can literally break it.

To be specific, it could actually cause it to explode. Some batteries also require you to add water, and if you neglect to do this, then your battery won’t be able to charge fully or hold a charge.

Lead-acid batteries will also suffer from something called sulfation, which is when sulfates build up on the plates of the battery. If this is not properly taken care of regularly, it will destroy the battery.

This is why these batteries generally come with an anti-sulfation mode or a battery maintenance mode. This causes the battery to run at a 20% higher voltage, and therefore breaks up sulfates that build up on those plates.

6. You Charge The Batteries Too Much

If you leave a battery plugged in far past the point where it has been fully charged, it can cause serious damage. It can cause the casing to crack, and it can even cause the electrolyte to explode or bubble out. 

This can also damage the wiring and the plates. Moreover, if you are using some kind of fast charging device on a battery that is not designed to handle fast charging, this can very well do it too. Remember, you want to charge that battery to 100%, but once it gets there, you want to stop charging.

7. Other Possible Mistakes

There are many other mistakes that people might make when trying to charge an RV battery. For instance, using a battery charger that is burned out or broken could be the cause. 

Using a broken battery charger well then often lead to the battery itself breaking. Moreover, if the battery has not been properly wired, or the charger is not properly wired, this can do it as well. You need to make sure that the battery is always properly connected to the charger.


How To Make Your RV Batteries Last Longer

helpful tips

Now that we know the common reasons why your RV battery drains fast, let’s look at some of the best ways to make your RV batteries last much longer;

1. Recharge Batteries to Prevent Sulfation

When it comes to lead-acid batteries, one of the leading causes of degradation is sulfation, which as mentioned above, is when a battery starts to build up small crystals on the plates due to being in a low state of charge.

When a 12-volt battery drops below 80% for a prolonged period of time, this can start to occur. Therefore, if you are planning to store your RV for a prolonged period, regularly charge the battery so that it does not drop below the 80% mark. 

2. Don’t Let A 12 Volt Battery Go Below 12 Volts

Yes, this does sound odd to say, but the reality is that a fully charged 12-volt battery actually has 12.7 volts. When this battery displays a charge of 12 volts, it’s actually just at a 50% charge.

You can use a voltmeter to measure the charge level of any RV battery. When the voltage drops to 12 volts, you know that it’s time for a recharge. Simply put, you need to reduce the depth of discharge from each charge.

If you let a battery discharge to no more than 50%, the battery will last twice as long as if you let it discharge to 20%. 

3. Get Rid of Parasitic Loads

As mentioned above, there are a variety of items that may still be drawing small amounts of power from your RV’s battery. These are what are known as parasitic loads.

Things like appliance circuit boards, gas leak detectors, propane detectors, TV antenna boosters, stereos, and other such things, when connected to the battery and not disconnected from power can draw small amounts of energy. 

Therefore, you want to ensure that anything and everything that could potentially use electricity is not connected. Another good is to switch the battery disconnect switch to the off position when you aren’t using the RV. This will prevent any such issues in regards to parasitic loads. 

4. Don’t Overcharge The Battery

Overcharging an RV battery can cause it to degrade over time, especially if it happens several times. Therefore, you need to keep a close eye on your RV battery and the charger while you are charging it. 

First of all, once the battery reaches 100%, disconnect the main charging unit from the battery. The battery cannot go above 100% anyway, and all you will do is ruin the battery. 

5. Maintain Ideal Water Levels

Lead-acid batteries require water to be added to them on a regular basis. There are some things you need to know about these batteries and water in order to maintain them.

First and foremost, when it is really hot out, always check the electrolyte levels and add water as needed. Always use distilled water, not tap water, as the minerals in taps water can cause calcium sulfation to occur. 

Moreover, beware that water should only be filled into the batteries after charging has been completed. Fill all of the cells to the bottom of the vent. This is the case unless the battery plates are exposed before charging. If they are exposed, add water before charging.

At the same time, you always want to leave the vent caps on the batteries while charging, as this will help prevent water loss from occurring. 

6. Proper Charging Practices And Charging Equipment

In terms of actually charging the battery, having the right equipment is going to make a big difference. Remember that a charger should use a bulk charging method for the first 90% of the charge.

It should then use an absorption charge to top off the remaining 10%. Then, to maintain a full charge, a float charge should be used. This is the proper way to charge and maintain an RV battery. 

Yes, this does also mean that you need to have the right kind of charger. Not only do you need to ensure that you have a proper RV battery charger, but you also need to make sure that it is in good condition.

A faulty charger can certainly be to blame for lackluster battery performance. On that note, always make sure that everything is well connected and that the terminals are properly hooked up. 

7. Don’t Try To Charge A Frozen Battery

As a rule of thumb, never charge an RV battery when it is frozen. This can cause massive amounts of damage, totally destroy its functionality, and yes, it may even cause an explosion too. Always warm an RV battery up before charging. 

8. If Using Solar, Make Sure Everything Is Up To Par

If you happen to be using solar panels to charge your RV battery, you need to ensure that they are the proper kind. You need to make sure that the solar panels in question are indeed designed for charging batteries, specifically RV batteries.

Also, keep in mind that the quality of the solar panels is going to make a difference here. 

9. Clean Battery Terminals Regularly

Something else that can help extend the lifespan of an RV battery is regularly cleaning the battery terminals. Using baking soda and water, with a one cup to one gallon ratio, you need to clean any existing corrosion off of the battery terminals. 

10. Pay Attention To Your Electricity Usage

Of course, if you don’t want the battery in your RV to drain as quickly, not using it as much is going to make a difference (this saves money on the bill too).

Having headlights, the fridge, the stereo, and a TV, as well as other electronics at once, is obviously going to drain that RV battery fairly quickly.

On that note, also don’t run the water pump in the RV when not necessary. Conserving water will also help to preserve battery life. 

How Long Should An RV Battery Hold A Charge?

To give you some perspective here, the battery in your RV should hold a charge for around two to three days, depending on usage.

If you use the fridge, the water pump, lights, and other basic electricity using appliances and electronics, you should get around three days out of a 12 volt RV battery. 

However, all of the above factors will influence how long an RV battery holds its charge, especially in terms of maintenance. If your RV battery doesn’t even last two days, then there is likely some kind of issue. 

Why Is My RV Battery Not Holding Charge?

As we have covered, there are many reasons why your RV battery might not be holding a charge. Refer to the list below for a summary as to why this may be the case. 

  • The battery has been corroded to the point where it can no longer charge or hold a charge. 
  • Your lead-acid batteries are damaged, potentially due to a lack of water. 
  • The circuit board could have damaged or broken resistors, fuses, or diodes.
  • Improper maintenance and charging have lead to battery damage that prevents it from charging properly or holding a charge. 

How Do I Know If My RV Battery Is Bad?

There are a few telltale signs to look out for that indicate that an RV battery is bad or even dead. Take a look at the following points to figure out whether or not your RV battery is dead. 

  • If your battery reads 0 Volts, then it is totally dead. If this is the case, it has most likely experienced a short circuit due to an electric overload or poor maintenance. If this is the case, the battery will need to be replaced. 
  • If your battery is in the middle of being charged, especially when getting close to fully charged, if it does not read higher than 10.5 volts, then there is a dead cell in the battery. 
  • If the fully charged battery reads 12.4 volts or less when the battery charger says it is fully charged, the battery has sulfated and has already deteriorated quite significantly. 

If your RV battery drains way too quickly or doesn’t really charge at all in the first place, then it is likely one of the above issues that are to blame.

That said, with proper care, due diligence, and the right equipment, you should be able to get past this issue and notice the difference in the longevity of your RV batteries.

Madeline Cooper