RV Battery – Basics, Maintenance, Storage

Automotive batteries have come a long way since they became widely used in 1920 as cars began to come equipped with electric starters. What started out as inefficient, 6 volt lead acid type wet cell batteries have evolved into AGM (Absorbed Glass Mat) sealed batteries and now even Lithium Ion batteries that have incredible amounts of available power and tremendous life spans. For sake of simplicity and because those fancy Lithium Ion batteries deal with cathodes and anodes, which I am sure are super boring even if I fully understood them, we will concentrate on the most common type of RV battery. The 12volt deep cycle wet cell lead acid battery.

Click here for a great explanation of how a lead acid battery works from our friends at Progressive Dynamics

Deep Cycle VS. Starting Battery
A deep cycle battery can be used as a starting battery in a pinch, but is designed to deliver a flow of voltage at a steady rate, making it ideal to power appliances and systems that require voltage long term versus in short bursts. Its available power is measured in amp hours, with the average group 24 deep cycle battery having around 100 amp hours. A starting battery can be used for this purpose but it is designed to deliver large doses of voltage on a sporadic basis. Its available power is measured in Cold Cranking Amps, which are specific to a vehicle starters demand for amperage. If a starting battery is completely drained of power it often will never recover where as a deep cycle battery is designed to be run nearly dead over and over again and still be able to return to full capacity. In fact with a deep cycle battery running it low and recharging it is actually good for the battery, like how exercise is good for you, from what I have heard. That doesn’t mean a deep cycle battery is maintenance free however.

To get the optimum life out of your battery keeping the fluid levels up is paramount. The liquid in the battery is a crucial part of the electrical process and if the levels are low damage can be done to cells and or the entire battery. Just like a chain is only as strong as its weakest link a battery that has a bad cell is unfortunately now a bad battery. There are several simple tools available to help maintain the proper water levels in a deep cycle battery, all of which can be found at the Guaranty Travel Center & RV Park.  
The simplest is a battery fill jug that has a built in float that prevents the overfilling of any of the battery cells, but this requires you to have easy access to the batteries. If the batteries are on the tongue of your trailer or in the expansive front compartment of a fifth wheel you should have little trouble using the jug. If the batteries are in a compartment, even on a battery slide tray, some of the batteries may be harder to access.
This leads us to a second system, this particular system is from Flow-Rite and it replaces the battery caps with a semi permanent (the system is removable if you replace batteries and should fit provided you stay with the same voltage battery you are replacing) fill valve system. The system also has a series of floats that prevent overfilling and is designed to pump water into each of the batteries cells evenly and without having to remove and reinstall heavy batteries. More exercise? Not if I can help it!

Okay, so maintenance is vital to a long battery life and that maintenance has mostly to do with the water levels in the battery, but a visual inspection and cleaning of any corrosion at the battery terminals should be addressed as well. Corrosion can hinder the performance of the entire system both during charging and battery usage. Again there are products available at the Guaranty Travel Center that clean and prevent terminal corrosion and our experts can help you determine which product suits your needs.
Testing – Knowing Is Half The Battle
You’ve done all the maintenance but your battery is not lasting as long as it used to. It is time to test the battery’s performance and overall health. The most common battery tester is what is called a “toaster” tester, named because it works much like a toaster by using a resistance element to test the batteries performance. A resistance element demands a large amount of amperage and works by passing electricity over the element, which converts the energy to heat. Ohm’s law has some part in the math here, but we are already getting off track. The toaster tester will tell you how your batteries respond to being put under load, but if the response is poor it does not give you much diagnostic information. A hydrometer is a very useful tool because it gives you an accurate reading of the condition of each individual cell, allowing you to determine if you have a bad cell or just need a deeper charge. As I mentioned before a bad cell means a bad battery, which is always disappointing but is better caught ahead of a trip than discovered during. A bad cell can even pose a very minute safety risk, as the converter will continually try to charge that cell, to no avail, leading to boiling of the battery and in some extreme cases an electrical fire.

Maintenance is important for battery life and for safety, but you only use your RV part of the year. What about when it’s stored? If you are fortunate enough to have RV parking where you live and you can plug the unit in you can almost “set it and forget it”. Almost because even though the modern converters have charge controllers built in to prevent overcharging, over time fluid is lost due to the normal charge and discharge processes so checking your fluid level is still important. Some seasoned RVers will alternate weekly or bi-weekly between leaving the RV Plugged in and unplugging it, allowing the slow natural discharge of the battery to occur. This can “exercise” the battery, but if we forget and let the battery stay discharged too long it may have difficulty recovering as it ages, just like me. If you store your RV at a facility and do not have the ability to plug the unit in and your RV does not have solar panels then disconnecting the batteries is a good idea. There are many components in the RV that use small amounts of voltage even when they are “off”, like the propane/co2 detectors and the station “memory” in the house stereo etc., that can drain a battery surprisingly quickly. More and more RVs come with a battery disconnect switch, but if yours did not they are easy to install and multiple options are available at the Guaranty Travel Center. Yes, the Travel Center has just about everything for your RV. Be warned however that in my twenty-five plus years in this wonderful industry I would say, conservatively, 99.9% of theft or vandalism occurs while the RV is in storage. This means leaving your batteries disconnected but still easily accessible really only makes them easier to steal. Placing the disconnected batteries inside the RV makes them harder to steal, but does not address the fact they will most likely be dead when you return. Often the batteries are taken home and left on a trickle charger in the garage. Remember this will cause the fluid levels to naturally deplete, so we are right back to maintenance, and the lesser expensive trickle chargers may not have the correct setting for deep cycle charging and may not have a charge regulator. Don’t cost yourself money by saving money on the battery charger! There are some old timers that will tell you to never put a battery on the ground or concrete, as it will drain it. In the very early versions of the car battery the construction included wooden boxes holding glass plates and if those wooden plates absorbed moisture from the ground or concrete they could swell and break the glass plates, but the chances of a modern battery being affected are negated by its plastic construction. Temperature is going to have an effect on the charging and discharging of a battery, and the colder it is the less efficient it becomes, so garage storage on a concrete floor can affect a battery vicariously.

The moral of todays story is that no matter if it is mid camping season or the darkest days of winter, battery maintenance is the best way to ensure optimum battery operation and prolong a battery’s life span. Make it part of your pre-trip or post-trip checklist and the extra few minutes you spend might just ensure all your RV adventures are electric!

Please remember Guaranty RV Super Centers is here to help when you need it. We can test your battery, your vehicles 12 volt system, or anything in between. If you need to replace your battery Guaranty RV Parts can provide you with a direct replacement or an upgrade. For assistance from Guaranty’s RV Service or Parts departments fill out our simple contact form or call us at 1 (800) 283-9163 seven days a week.

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