Should I disconnect my RV's battery if it is connected?

In recreational vehicles (RVs), the house batteries play a crucial role in providing a comfortable experience. These batteries power various devices in your RV, such as the refrigerator, furnace, water heater, lights, stabilizer lifts, slides, and water pumps. Neglecting battery maintenance can lead to unexpected problems, such as the awning not being able to retract or extend, and you may end up stranded.

RV batteries are notorious for discharging when not in use, so it's important to take proper care of them. In this article, we'll address common questions about RV home batteries and provide useful tips to keep them in optimal condition.

Leaving the motorhome constantly plugged in – is that a problem?

In most cases, leaving your RV plugged in all the time is no problem thanks to the built-in modern smart chargers. Typically, RVs made in the last decade or so come with built-in converters that handle power distribution, converting alternating current (AC) from shore power or a generator into the 12V direct current (DC) needed to charge the batteries.

These built-in converters are designed to prevent overcharging, which can significantly reduce the lifespan of your batteries. To determine if your RV has a built-in converter with float mode, read the manual or check the model number of your power distribution box. If your RV does not have a built-in converter, don't worry. You can solve this problem with an MPPT solar charge controller or a DC-DC charger.

Can the motorhome battery be charged while connected to shore power?

Yes, as long as a few conditions are met. First, make sure the battery disconnect switch, usually located near the battery, is in the "off" position. Many RVs end up at the dealer because owners overlook or are unaware of this simple switch.

Second, make sure your RV has enough shore power to meet all power needs and still has enough power left to charge the batteries. For example, if you're running a small 1500W generator in August with the air conditioning on full blast while someone is using a hairdryer, there may not be enough power available to the converter to charge the batteries. Fortunately, modern converters work automatically and pass power to the batteries when power demand decreases.

Does an RV inverter work without a battery?

The question of whether an RV inverter can work without a battery is controversial. To find out, connect your RV to shore power, turn on some lights, water pumps and other 12V systems, and then turn off the battery disconnect switch mentioned earlier.

In most cases, almost everything will work fine without a battery. However, keep in mind that motors with high 12V power requirements, such as slide-out motors, may not work properly without a battery. These motors often require more power than a typical power converter can deliver at once. The battery, which is designed to handle a higher dose of power, compensates for this limitation.

While many slide-out RVs can operate without a battery, it is important to consult the documentation or look for a sticker near the slide-out switch to confirm if your particular RV requires a battery for proper operation.

Proper Use of a Battery Isolator Switch for RVs

The RV battery disconnect switch is an important feature for any vehicle with an onboard battery. Through a single action, usually a twist, you can easily and quickly disconnect the RV's main circuit from the battery. This not only protects the battery, but also other electrical components in your RV.

The battery disconnect switch is usually located near the battery itself, either in a compartment or in a nearby service bay. Unfortunately, this switch often goes unnoticed or forgotten and is hidden behind equipment in a storage compartment.

Even when connected devices are turned off, batteries gradually lose charge over time. Passive energy consumption by devices in standby mode and power outages caused by wiring can drain the battery's charge over time. To prevent unexpected battery discharge, it is important to use the battery disconnect switch in the following situations:

1. Carrying out maintenance work on electrical appliances or equipment

Whenever you work on your RV, whether it's replacing a light or servicing the water pump, be sure to pull the fuse for the electrical circuit and consider using the battery disconnect switch. This precaution will protect you from electrical accidents and help prevent future problems.

2. Storage of the motorhome without shore power

If your RV needs to take a temporary break of a week or two and you don't have the luxury of shore power, it's imperative that you take proactive measures to conserve your batteries. By disconnecting the batteries during these idle times, you ensure their longevity and keep your RV powered for uninterrupted adventures. This minimizes power loss caused by excessive cable runs and equipment, thus preserving battery charge.

3. Using a 7-pin socket on your towing vehicle

The 7-pin connection between your RV and the tow vehicle acts as a vital conduit, allowing for seamless power transfer. One of the seven pins holds the key to charging your RV's onboard battery. While this feature helps charge your batteries while you drive, it can also drain the vehicle's battery if the RV is left plugged in without the tow vehicle running. On some vehicles, power to the 7-pin outlet is automatically cut off when the engine is off, but it is still a good idea to use the battery isolator switch to prevent any potential discharge.

4. Long-term storage

If you plan to store your motorhome for a long period of time, for example in winter, it is advisable to disconnect the batteries. This prevents self-discharge and minimizes the risk of damage from sub-zero temperatures. However, to maintain health, it is important to regularly check the battery charge level and recharge it when necessary.

Remember: Disconnecting the batteries with the switch will disable the 12V electrical system in your RV. This means your lights, water pump, slide outs and other 12V devices will not work. However, the 120V AC devices (such as the refrigerator and air conditioner) and the outlets powered by shore power or a generator will still work.

If you are unsure about how to use the battery disconnect switch or have specific questions about your RV, it is best to always read the owner's manual or contact the manufacturer.

Best Batteries for RVs

Choosing the best RV batteries involves weighing the pros and cons of different options, with lead-acid and lithium batteries being the two main options. Due to their relatively low cost and familiarity with many RV owners, lead-acid batteries have historically dominated the market. Despite their widespread use, they do have some drawbacks, including limited lifespan, weight, and slower charging times.

In contrast, lithium batteries are rapidly growing in popularity in the RV community. Their advanced technology offers several advantages over traditional lead-acid batteries. Lithium batteries are significantly lighter, have a longer lifespan, and can be charged much faster. In addition, they have a higher energy density, offering more power in a smaller and lighter package. These factors contribute to the appeal of lithium batteries as an ideal choice for RV enthusiasts seeking an efficient and reliable power solution for their vehicles. Timeusb offers high-quality but affordable LiFePO4 lithium mobile home batteries.

Timeusb 12V 100Ah Pro LiFePO4 Lithium Battery

Conclusion

In summary, it depends on the situation whether you should disconnect your RV battery when it is plugged in. If you are using shore power or a generator and have a modern RV with a built-in converter that takes care of charging the battery, you can usually leave the battery connected without any problem.

However, there are certain circumstances where it is important to use the battery isolator switch, such as when performing maintenance, storing without shore power, or using a 7-pin socket on your tow vehicle. If you properly care for your RV's batteries, they will stay in good condition and provide you with reliable power when you need it.