Why Does My RV Have Two Batteries? Everything you need to know

In general, most RVs will have either one or two batteries. This applies to travel trailers, motorhomes, and fifth-wheel campers. Whether or not your camper has multiple batteries depends on several things. If your RV only has one battery, you also have the option of adding a second one. 

Most RVs have two batteries to provide more capacity for longer trips without plug in power. The bigger your RV is, the more batteries it needs to operate the electrical devices, lights, refrigerator, and external components. Some RVs also have more batteries for longer trips off grid.

The more batteries you have in your RV, the longer it can operate away from electrical hookups. However, it’s important to know how to keep your batteries charged and operating as they should when there are multiple batteries. 

Reasons Your RV Might Have Two Batteries 

The Size of Your RV 

If you have a larger camper, such as a fifth wheel or motorhome, there’s a good chance your RV has two batteries. Multiple batteries mean more juice and power to power all the battery-operated components of your RV. 

Off-Grid Living 

More than one battery increases the length of time you can spend living away from electrical hookups at a campground. Bear in mind that batteries will eventually run out of juice and can’t operate everything in your RV, however. In general, RV batteries power lights, a few outlets, external components, and certain appliances. 

Powering Appliances and Devices

If you spend long periods on the road traveling from place to place with your RV, there’s a good chance that you keep a fairly well-stocked refrigerator. It just so happens that the refrigerator is one of the main appliances that your RV battery powers. RVs are set up so that your RV batteries will keep electricity pumping to the refrigerator while you’re driving so that the contents don’t spoil. 

By having multiple batteries, you can power large refrigerators, and for longer periods of time. This ability also means that you can boondock for a night or so when you’re traveling extra-long distances and don’t want to go to a campground. 

How Many Batteries Do I Need on My RV? 

The amount of batteries you need depends on the size of your RV and batteries. The larger your RV is, the more batteries it will need. In general, however, most RVs won’t come with more than two batteries, which means you’ll have to add any extras. However, no matter how big your batteries are, they will eventually run out of juice if you don’t have a way of recharging them. 

If you don’t plan on camping off-grid or taking long road trips, one RV battery is all kinds of plenty. However, if you want the ability to boondock or have limited power away from campgrounds, more than one battery is necessary. A single battery will run out of juice within several hours if it’s powering more than just the refrigerator. 

What Operates on an RV Battery? 

While an RV battery can’t operate everything on your RV, such as all the outlets, water heater, or air conditioner, it can power a surprising number of things. 

• Several outlets (if you have an inverter)
• Most of the lights 
• The trailer jacks or stabilizers 
• The trailer coupler including the up and down mechanism 
• The water pump 
• Exhaust fans 
• The slideouts
• The refrigerator

Once again, RV batteries aren’t capable of powering everything in your RV, but they can do enough to allow you to live somewhat comfortably while off the grid. 

Wiring Batteries in Series Vs. Parallel 

If your RV only has a single battery and you want to add one or several more to it, you can wire them in series or parallel. 

Wiring Batteries in Series 

If you connect batteries in series, you’ll use cables to connect the positive terminal of one battery to the negative terminal of the next. Vice versa, you’ll connect the negative terminal of the first battery to the positive terminal of the next battery. 

The advantage of wiring batteries in series is that they have more voltage. So, by connecting two 12-volt batteries in series, you increase the voltage to 24, but it won’t increase the amount of time that your batteries can operate.

When wiring in a series, most people use two 6-volt golf cart batteries on their RV for more amp hours which provide longer run time.

The advantage of wiring batteries in series is that you can operate more demanding appliances such as air conditioners and water heaters. 

Wiring Batteries in Parallel

When you connect batteries in parallel, you connect the positive terminal of one battery to the next battery, and you do the same with the negative terminals. Wiring batteries in parallel increases the amperage, but not the voltage. In other words, you won’t be able to power high-voltage appliances, but you can power smaller ones for longer. 

So, if a single 12-volt battery can provide power to your RV while off-grid for 2 days, adding a second battery in parallel will increase it to 4 days. 

Want more detail on how long your batteries will last off grid? Read all about it here!

While there are advantages to both methods, most RVers prefer to wire batteries in parallel. Doing so increases the total amperage of the batteries, but not the voltage. In other words, your batteries will last longer, but won’t provide more juice to appliances. 

How to Wire Batteries in Parallel

1. Ensure that the batteries you’re connecting together are of the same voltage. 
2. Use a jumper wire to connect the terminals of the different batteries. 
3. Attach a jumper wire from the positive terminal of battery #1 to the positive terminal of battery #2. 
4. Attach a separate jumper wire from the negative terminal of battery #1 to the negative terminal of battery #2. 
5. You can do this with as many batteries as you like as long as they’re all connected to one another. 
6. The concept is the same as having outlets or lights connected together on the same circuit in a house. 

Frequently Asked Questions 

How do I charge my RV with two batteries? 

You can charge each battery individually, or connect a single charger to the first battery on the system. However, because you’re charging two batteries, the charging time will be double what it would be for a single battery. 

Do I need two batteries for my travel trailers? 

If you have a large RV or enjoy camping off-grid, you should have two batteries for your travel trailer. Multiple batteries will provide power for longer to vital components in your RV. 

How do you jumpstart an RV with two batteries? 

As long as the batteries are connected in parallel, you can easily jumpstart your RV. Simply connect the charging cables to the appropriate terminals on one of the batteries, and jumpstart it the same way you normally would.