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If you are storing your RV trailer, camper van or motorhome for an extended time, protecting the batteries from over discharge is a good idea. When left unused an RV house or chassis battery will drop in voltage due to internal discharge and other factors like cold weather.
It is a good idea to remove the batteries and connect them to a trickle charger to prevent your batteries from discharging to a level below the manufacturer’s suggested voltage level. This can cause damage and reduce the overall lifespan of your batteries.
When RV season rolls around you don’t want to postpone your trip due to dead batteries in your rig. Following the storage and maintenance suggestions below will make sure your rig is ready to go in the spring time and save you money by reducing battery problems.
Should I Disconnect My Batteries When My RV is Stored?
Disconnecting the negative terminals from your RV batteries when it is in storage will prevent any phantom load from discharging your batteries below a 60% threshold. This is a good idea if you don’t have an onboard charging device keeping your batteries charged.
Make sure the master battery disconnect is shut off and all your appliances are set to storage mode and turned off before disconnecting the batteries.
If you live in a place where temperatures don’t drop below 50°F (10°C) you don’t need to remove your RV batteries. However, you still need to have a shore power connection or solar charger connected to maintain a proper battery voltage throughout storage.
How Do I Protect My Batteries From Discharging When Storing My RV
Without an onboard method of charging, like a solar panel or shore power connection, the best option to protect the life of your batteries is to remove them and connect to a trickle charger. This will protect them from over discharge and the impact of extreme hot and cold weather.
The next best alternative is to occasionally start the vehicle and allow the alternator to charge the batteries. This is easy to forget about in the off season because it isn’t automatic like connecting to a charging device.
When left unattended for prolonged periods, RV batteries can be damaged by excessive heat that can cause them to swell, or by extreme cold that will speed up the discharge rate. Other effects like corrosion buildup can also cause a reduction in a battery’s life span.
Here’s my video on how I cleaned the corrosion off of my RV house batteries using a baking soda and water solution. I also changed to these red and black battery terminal connectors to make connecting and disconnecting easier.
How To Disconnect An RV Battery
When removing the house or chassis from your travel trailer or motorhome for extended storage it is important to shut down all the electrical systems in the RV first. Use this checklist to help:
- Disconnect shore power
- Switch all appliances to storage mode
- Turn off the main battery disconnect switch
- Turn off the Inverter
- Shut off all the circuit breakers
- Turn off any supplemental chargers (solar, wind, etc)
Start by disconnecting the negative side of your batteries using a properly sized box wrench, This will open the circuit of your battery system reducing the chance of a short to any surrounding metal.
Once all the negative battery terminals are disconnected remove and bag the positive terminals from the batteries. Once all the wiring is removed from the batteries take off any straps or hardware holding the batteries in place and remove the batteries from the RV.
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Can I Leave My RV Plugged In Over The Winter?
If the temperature in your area doesn’t dip below 50oF (10oC) for extended periods while your RV is in storage, leaving it plugged in to shore power is a great solution for keeping the batteries charged.
Most RV’s and trailers have a built in battery monitoring system which constantly measures the voltage level of your batteries and charges them when the voltage falls below a certain level (usually 12v DC).
The base voltage level of RV lead acid deep cycle batteries is between 12.5v DC to 13.5v DC. If you don’t have a charger connected while your batteries are in storage for an extended period they may discharge down to 7v or lower due to the internal discharge rate. This will reduce their amp-hour capacity and shorten their lifespan.
Check out my recent article on the best ways to store your RV power cord to prevent it from being damaged.
Why Do My Batteries Die When Storing My RV
Batteries that are not connected to a charger tend to discharge for two reasons, internal discharge and phantom load. Both of these issues work together to drain the voltage of your batteries when in storage and can reduce the storage capacity of your batteries if left unchecked.
A reasonable internal discharge rate of deep cycle RV and marine batteries is around 3% in a good quality battery. This is a natural effect of the internal battery components and can’t be avoided.
Phantom load is a low current draw from appliances, smoke detectors or other electrical devices. Making sure that all the appliances are in storage mode and or unplugged is the best way to reduce the slow bleed from your batteries.
Turning off the master disconnect switch usually prevents these loads however over the years it’s common to add more devices to your RV and they often get connected directly to your batteries bypassing the master switch.
Using a trickle charger, solar charger or occasionally starting your motorhome and charging your batteries with the alternator are all ways to counter these effects.
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How To Maintain RV Batteries Over Winter
Once the batteries are removed from your RV or trailer they need to be stored in a location that isn’t subjected to extreme heat or cold. Storing them in a location with a stable temperature between 50-80oF (10-28oC) is ideal.
Keeping your batteries off of a concrete floor is important because concrete accelerates the discharge of batteries through the case. It is common to keep batteries stored on the floor due to their size and weight so placing a piece of wood underneath them is my preferred method.
If you are using unsealed batteries that are not maintenance free it is a good idea to check the electrolyte level before you put them to charge. If you find the liquid level is below the marks add some distilled water.
You’ll want to locate them near an electrical outlet as well to connect a trickle charger or charge maintainer to the terminals. I like to use a surge protector connected to the wall outlet and an individual battery maintainer for each battery because they are inexpensive and a single unit can be faulty and only affect one battery.
How Do I Know When My RV Batteries Need Replacing
If your interior lights tend to dim or your appliances operate erratically in your RV it could be a sign that your house batteries need to be replaced. Measuring the voltage or having a load test done on them are the best ways to determine if they need replacing.
My article on The Best Deep Cycle Batteries for Camping in your RV simplifies the differences between all the battery types and will help you identify and choose the best battery for your motorhome or trailer.
Checking RV Batteries For Damage
If your RV battery’s case looks swollen around the outside it is likely damaged. This is often accompanied by a sulfur or burning smell due to overcharging or another electrical problem in your battery monitoring and charging system.
If you find an issue like this, simply replacing your batteries may not be the solution because the issue may cause damage to any new batteries you connect.
Checking Your RV Battery Voltage
You can check the voltage of your batteries by disconnecting them and measuring the voltage with a voltmeter across the negative and positive terminals. It is important to have them disconnected to avoid measuring the voltage across the other batteries in your RV.
If the battery’s voltage is below 12.5Vdc without being connected it is likely that they require some attention. It could be as simple as checking the electrolyte level in a traditional wet cell lead acid battery and adding distilled water.
RV appliances and electronics are designed to work with a minimum of 12v DC supplied. As the voltage of your battery drops the electronics will start to draw a higher current reducing the battery capacity faster.
Alternatively, the appliances and electronics in your RV will turn off if the voltage level drops too far. This will quickly happen if the battery can not supply the current (amps) that the devices require.
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Checking Your RV Battery’s Storage Capacity: Amp-Hours
Many automotive part stores or automotive battery stores have a hand held load tester that will measure the amp-hour capacity of your batteries. Usually they will do this test for free if you bring the batteries to their location.
As batteries age or get over worked their storage capacity lessens dropping the amp-hour capacity. The amp hour capacity determines how many devices a battery can power and for how long.
How Low Can RV Batteries Discharge Before Being Damaged
Liquid filled lead acid, absorbent glass mat (AGM) and gel batteries are typically rated up to 50% discharge before longer term damage and life reduction sets in. Lithium batteries (LiFePO4) are designed to handle a discharge up to 80% before damage occurs.
Though RV house and chassis batteries can be discharged 50% or more, good practice is to prevent a discharge over 20%. This means that they should be charged once 80% of capacity remains.
Measuring and charging of the batteries in your trailer or motorhome is typically handled by an onboard charge controller or battery management system. These systems are designed to maximize the efficiency of charge to get the most out of your battery system without over cycling and reducing their lifespan.
Removing your RV batteries while your trailer, campervan or motorhome are in long term storage makes it easy to connect a trickle charger to maintain a proper voltage level. Preventing deep cycle batteries from discharging below a 60% threshold can cause damage and reduce their overall amp-hour capacity.