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Installing A Battery Disconnect Switch

You may have heard about other RVers who disconnect their battery from time to time. Especially if you’re new to RVing, you may be wondering why they do this, and if there is a better way. Here we will cover why you want to disconnect your battery, and how to make the process much simpler by installing a battery disconnect switch.


What Is A Battery Disconnect Switch

If the RV has a battery disconnect switch, it will most likely look like a plunger switch. This can usually be found either outside just near the battery compartment, or in the control panel inside. This switch cuts the flow to the negative cable so that nothing can draw power from the battery. If your RV does not have a switch, you can get the same effect by simply removing the negative cable connection or installing an aftermarket switch.

Why It’s Important

The battery that is used to power your RV is a 12-v deep cycle battery. Inside these batteries is a series of positive and negative lead plates that are surrounded by an electrolyte solution of sulfuric acid and water. The positive plates give up electrons to the negative plate through the electrolyte solution, and this process creates the power in the battery. When this happens, the sulfuric acid is taken out of the water, and sticks to the plates. Once there is enough acid on the plates, the electron transfer can no longer happen. When you charge your battery, the electricity coming in removes the sulfuric acid from the plates and puts it back into the water.

In order to keep a healthy battery, there are two things you want to avoid: letting your battery dip below 80% continuously, and letting it ever dip below 50%. These two things will result in hardened sulfuric acid that will no longer displace back into the water. This means it can no longer assist in the transfer of the electrons and the battery will no longer hold a charge.

You may be starting to see now, why you want to occasionally cut the power to this battery: so that you can be sure you're not discharging it to the point that it no longer works. So now you just need to know when you should cut the power to the battery, and when to leave it on.

When to Use it

When your RV is not in use, it can and will still draw power from the battery if it’s not disconnected. Even if you shut everything off, there are things like the LP leak detector, smoke alarms, and other similar products that draw constant power. As stated above, depleting your battery too low and too often is harmful to it, so you want to ensure that it doesn't happen. Any time you are not using your RV, you want to throw the battery disconnect switch! This will keep any unnecessary power from being drained from the battery.

Many people will disconnect their battery when attached to shore power. You do not want to do this for two reasons! Many appliances such as the a/c system and the refrigerator have to use the 12-v power to operate their module boards. This means, if all you have is 110-v shore power coming in, it’s not going to work. The other reason is, shore power will recharge your house battery. If the switch is thrown, there is no power getting to the battery to recharge it.

So simply put, when your RV is in storage, or hanging out in the driveway waiting for the next weekend, throw the switch.

Installing the Disconnect Switch

If you don’t have one and you want to add one in, it’s a pretty quick and easy process. Certain switches may require some modification to the battery cover and some will not. This will vary depending on the type you get. For the most part, installing them will entail running the negative battery cable that comes from the RV to one side of the switch, and then a shorter one from the switch to the battery. When you turn this switch it will simply disconnect between these two cables. You then have a disconnected battery without having to get out a wrench every time.

Taking care of your battery can be a huge money saver! These batteries should be lasting you up to 10 years, but with improper care you could find yourself shelling out dough for a new one every camping season. Installing a battery disconnect switch can help keep the battery from depleting for no reason and keep those dollars in your pocket!

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