When to Leave Your RV Battery Disconnect Switch On?

The latest RVs offer a built-in battery disconnect switch. RVers even request to add this component in RV models that don't have this feature. Simply put, an RV battery disconnect switch is a great safety component for an RV model. When you plan to upgrade electrical equipment in your RV or want to store the RV itself, the disconnect switch plays a key role.

The disconnect switch is used for various purposes, including keeping the battery healthy, preserving more power, and making the most of your time on the road. If you are wondering how does a battery disconnect switch work and what does it do, don't miss this read, as it covers everything you are looking for.

What does an RV battery disconnect switch do?

An RV battery disconnect switch is used as a safety device to cut the power supply from the battery to the rest of your RV's circuit. If you want to connect your batteries to an RV, you need to turn on the switch. In contrast, you can turn it off to cut the RV's electrical system off from batteries.

Simply put, this switch provides a convenient and simple way to disconnect your power system from the primary circuit. Once the batteries are disconnected from the main electrical circuit, they will remain in the same state of charge that they were in before you shut the power off. The disconnect switch extends the batteries life and protects them from facing a constant drain from low-power appliances.

All batteries discharge even if they sit idle, but this process is slow. However, it becomes faster when batteries are connected to the circuit. Appliances like radios, LP detectors, and freezers constantly draw some amount of power. The disconnect switch offers a safe option while storing your RV and eliminates unnecessary power loss.

Moreover, the installation and removal of batteries becomes easier with the disconnect switch. Since you can't turn off the batteries, it is better to isolate them from the RV's circuit to reduce the risk of sparks and short circuits while adding or removing the batteries.

Why should I use an RV battery disconnect switch?

Are you wondering why you should use an RV battery disconnect switch? Well, it serves various purposes, including but not limited to safe maintenance, prevent from drain, battery protection, and theft deterrence.

As stated earlier, appliances draw a small amount of power even if they are turned off. This slow drainage can deplete a battery over time. It is common when batteries are stored for extended periods. The disconnect switch prevents batteries from losing their power this way.

Moreover, when you disconnect the batteries from the circuit with the disconnect switch, the maintenance becomes a super easy and safe job. Furthermore, the reason why the disconnect switch extends the battery's lifespan is that it prevents them from frequent deep discharges.

The added benefit of disconnecting your batteries is that they may deter thieves from accessing the electrical system of the RV. When you install this switch and you go away from your RV for a few days, it ensures that your batteries discharge at as slow a rate as possible.

How does an RV battery disconnect switch function?

Have you ever added batteries to the RV? If so, you must have noticed that the negative cable from the deep cycle batteries delivers power to the main cabin. Many people disconnect the negative cable while planning for extended storage or when they need to work on the RV. Installing a battery disconnect switch is always recommended.

The disconnect switch first interrupts the connection of the negative cable running an RV. Then, a shorter negative cable runs from the switch to the RV's electrical system. With the switch in place, you can easily shut off the amps-flow from the batteries. You can install the disconnect switch on either the positive or negative lead of your battery. It has proven to be an effective tool for disconnecting the whole circuit.

Remember, adding the switch on the negative lead adds more safety. When you add or remove the battery, there is a chance that the tool can short between the RV's frame and the positive battery lead (even if it is disconnected).

This disconnect makes the battery removal easier. If the disconnect switch is connected to the positive lead of your battery, don't forget to disconnect the negative lead first. It will reduce the risk of short-circuiting the battery bank. Even if the disconnect switch is red, see if it is connected to the negative lead of your battery.

Where can I find my RV battery disconnect switch?

You can find this switch somewhere near the battery compartment on the motor home, in a nearby maintenance bay, or in the fifth wheel. You may also find it in the main part of your RV.

Installing an RV battery disconnect switch is a DIY task. It can easily be completed within 30 minutes. The most effective location for installing the switch is on the negative side of the battery, as it adds an extra layer of safety. A half-inch combination wrench and a 10ml wrench are the tools required to self-install a disconnect switch.

When should I use my RV battery disconnect switch?

This switch offers a range of uses. The primary use is to install batteries easily by turning off the power from the battery bank. Once you turn it off, you don't have to worry about replacing light fixtures or drilling through the walls, as the RV does not receive any current.

Similarly, the disconnect switch lends you a helping hand while doing maintenance on the electrical system or batteries. In addition, it plays a crucial role when you plan to prepare your RV for storage.

With this switch, you are always sure about the charge state of your batteries, as it does not drain their power or make them overcharged. Turn on the switch while using the RV and turn it off if you plan to store an RV for a long time. Another potential use of the disconnect switch is to protect against power surges.

How long will RV batteries last when they're not used?

AGM batteries discharge at the rate of 1-2% per month. In contrast, the self-discharge rate of lead-acid batteries is slightly high: 2-3% a month. But, it does not mean that you can allow them to discharge completely. If you let your lead-acid batteries sit for any length of time, they can be damaged badly.

The same is the case with the deep cycle batteries. Though they are designed to discharge deeply, you should not let them stay discharged for days. If they remain discharged for a longer time, the internal components will get hard. The sulfation process makes the components stuck in the discharged position. In case you don't know, sulfation means the build-up of lead sulfate crystals on the battery's terminals.

Usually, you do not need to worry about the batteries staying discharged for long, as the alternator will keep them charged as you drive. But, it is only possible if you have turned on the RV battery disconnect switch.

One thing you should keep in mind is that starting batteries must not be discharged more than 75%. It means you can't let them sit for more than 5 to 6 months. Otherwise, they may experience permanent damage. If you are looking for a reliable RV power kit, try the Renogy RV solution.

How can I protect my RV batteries from summer heat?

If you want to maintain your RV batteries in summer to get the maximum out of them, you need to charge them regularly, use a corrosion-preventive spray, and place them in the shade.

1. Charge batteries whenever you can

Your 12-volt RV batteries should not discharge below 12 volts. Otherwise, they won't be able to deliver the desired power. When your RV batteries are not in use, don't forget to ensure that they are at 100% state of charge. If they are not, they will stop conducting electricity.

The RV's alternator charges batteries automatically if the battery disconnect switch is on. Don't use this switch until you hit the road.

2. Use a corrosion preventive spray

To protect your RV batteries from the summer heat, you should use corrosion preventative and corrosion cleaner. Battery users know that corrosion is natural. It occurs when electricity passes through the metal and makes it reactive to the environment. It occurs more quickly in higher temperatures.

3. Place your batteries in a shady area

Excessive heat allows water to evaporate from the battery's electrolyte. Lead-acid batteries contain a mixture of water and sulfuric acid. When the temperature increases, the water inside the battery starts evaporating. This is where battery chargers play a crucial role and keep batteries away from getting too hot.

Conclusion

The RV battery disconnect switch is a useful tool to cut the power connection between the batteries and the RV to ensure greater safety during maintenance, electrical upgradation, or when you are not driving. Electrical components, such as a radio and freezer, consume a small amount of power, even when they are not in use. In that case, the disconnect switch doesn't allow them to drain the battery's power.

Frequently asked questions

Should my RV battery disconnect be on or off?

Generally, the disconnect should be on for as long as you use your RV. It enables converters to run 12 volt systems and charge the batteries. In contrast, you should turn this switch off when you plan to store the RV for a long time to prevent constant battery drain.

Should I disconnect my RV battery when plugged into shore power?

Generally, you should not disconnect the RV battery switch when plugged into shore power. The reason behind this fact is that the converter manages the battery charge automatically. However, if you want to store an RV for an extended period or it has an old charging system, turning the switch is a viable solution.

Which terminal do you disconnect first on the RV battery?

If you have to disconnect the RV battery, be sure to remove the negative terminal first. The negative terminal is marked with a negative or minus sign. All you need to do is loosen the connector and remove the clasp carefully.