Recreational vehicles, whether motorized or towed, consist of two primary operational house systems, these being electrical and propane. Both systems must be properly maintained for maximum reliability and safety. Since some newer RVs utilize no propane system at all, it can be said that the most important house system in all RV’s is the electrical system. The central figure in the electrical system is, of course, the batteries.
Just like your brick and mortar home, it is important to keep your home on wheels maintained and healthy. RV owners should understand the importance of proper battery maintenance in the primary areas of winter storage, charging, and regular inspection.
If you store your RV during the winter, taking the following steps will ensure your batteries stay fresh and last longer:
- If the RV is to be stored for more than a few months, the batteries should be removed and stored in a cool, dry location.
- Top off the cells with distilled water, fully charge the batteries and clean the surface and terminals prior to storage. Stored batteries should be recharged every two months.
- Do not place the batteries directly on a concrete floor. Place them on wooden planks to prevent direct contact with concrete.
- Store batteries where they will not be subjected to spark, flame, heat sources, or freezing.
Always be extremely careful and wear gloves and eye protection when working with batteries and electrolyte. Leaving batteries in the RV during storage subjects them to possible fluctuations in humidity, temperature, and parasitic loads, all of which can cause premature battery failure. Battery theft is also a risk in stored RVs. Before removing the batteries, be sure to create a wiring diagram for easier re-installation.
There are four fundamental stages of battery charge for wet cells:
- Bulk – The main part of the charging cycle, which quickly brings batteries to 80- 90% charge using the maximum current of the charger.
- Absorption – Tapers the charge current down and slowly charges the last 10-20% before entering float mode.
- Float – Keeps the batteries “topped up”, maintaining a lower voltage (around 13.7 V) to prevent electrolyte loss caused by overheating the water in the battery.
- Equalize – A high-voltage charge applied periodically to remove any sulfur buildup (sulfation) that accumulates on the battery plates (applies only to wet cell batteries).
Most entry level and many mid-level recreational vehicles utilize inexpensive single-stage chargers that only provide the “float” stage. This ultimately results in sulfation and the batteries never reaching full charge, which reduces the life of the batteries.
An upgrade to a multi-stage “smart” charger is recommended. These units monitor battery condition and apply the stages listed above based on battery charge state. Any single-stage charger can be upgraded, and it is well worth the price to increase battery life. Your RV manual should provide information as to what type of converter/charger you have.
It is important to perform regular inspection and maintenance of RV house batteries. Regularly wipe the battery cases clean, check the electrolyte level, and inspect the terminals and wiring. Also, look for sweating or bulging of the case, which normally indicates a failed battery. Clean the battery posts and tighten the wiring terminals as required. Corrosion may tend to build up on the house batteries, especially in the case of a motorhome. It is a good idea to keep steel wool, fine sandpaper, baking soda, and a toothbrush in your toolbox. Use the steel wool and sandpaper to keep the terminals and posts clean and mix the baking soda with water to create an effective battery post cleaner.
Following these simple steps will help keep your house batteries, the lifeline of your RV, working efficiently for longer.
About the Author:
Coach-Net is pleased to welcome Steve Froese to our team of writers. Steve, an avid RV owner, traveler, and Coach-Net member since 2013, is the principal of “A Word to the Wise Technical Communications”, a published RV author, certified RV technician, and licensed Professional Engineer. He frequently collaborates with the “RV Doctor”, Gary Bunzer, and has worked with the RVIA/RVDA as a technical and training writer and consultant. Professionally, he works as a quality engineer and musician. Watch for more of Steve’s work in upcoming Coach-Net publications.
*Images within the body content were provided by and used with permission from the author.
Gordon Maurer said:
Placing batteries on wood blocks is a waste of time! Tests made with storage on cement floors and on wood blocks have shown that there is NO measurable difference in discharge rate. If your battery had a wood case as they did many years ago, the wood would soak up condensed water from the floor and if they were dirty, they could discharge through this dirt path. This is where the old ” store on wood blocks ” wife’s tale comes from,
Tom Saroch said:
Totally agree with the man about setting batteries on concrete– no difference. Only my 2 cents worth, but tried it both ways, no difference with my $20.00 volt meter.
Author Steve said:
Actually, setting the batteries on wood has NOTHING to do with discharge rate. Wood is a much better temperature insulator than concrete, which is a very good temperature conductor. Placing the batteries on wood prevents the battery cases from being directly exposed to temperature swings, which can warp the plastic cases and damage the battery. Even though the cases are fairly resistant to damage, constant and repeated temperature cycling is not advised.
John Sherman said:
I don’t have any wet cells. How do I keep them going for the long term?
Great question! If you have AGM or Gel batteries, the part about topping off your cells would not apply. However, the batteries should still be cleaned, charged and stored in a cool, dry place.
Marda Jordan said:
I have my wet batteries on a maintainer during winter storage. Would I do this with AGM batteries?
Another great question! AGM batteries can benefit from a maintainer, but preferably a multi-stage type as opposed to the traditional float type.
I thought a “float charger” had a Floating circuit that maintains a full charge without overcharging
I feel someone will renames a device, which then requires them to charge more money for it!
Marda Jordan said:
I paid less than $30 for mine but it must be a “smart” one as it does all the 4 stages and has kept my battery in good shape for several years.
My 2006 diesel rig’s battery banks have been kept up for 8 years, up to 3 years at a time in outdoor storage by solar panel maintenance and the occasional plugging in for inverter charging to get the equalizing function.
But the nylon hold-down strap’s metal buckles and their tray anchor mounts corrode badly while in storage, I assume from heavy gases expelled from the batteries over time. Now, after the last 2 years in storage, even the tray bottom itself is deteriorating. I’ll likely remove the batteries and clean and repaint the tray with anti-rust paint this spring, assuming the corrosion hasn’t badly damaged the angle-iron framing enough to require a total rebuild.
I try to apply battery post paint to the strap components, sleeve the straps with the red and green battery post felt rings to try and halt fume migration down the straps, and use Corrosion-X wherever I can get it at susceptible metal strap parts; yet the metal strap components still bloom. What more can a fellow do to stop the eating-away of strap and other nearby fasteners? Even the original factory plastic buckles melted away within the first two years.
Thanks for the question!
Removing the batteries from the coach during storage is the best way. Storing them fully charged in a cold, dry place will reduce outgassing and obviously prevent the coach fixtures from corroding.
After you clean the battery tray and give it good enamel rust paint treatment, you can place battery mats between the tray and batteries so you can replace the mats instead of having the metal corrode.
A reasonably good battery corrosion cleaner can be made by mixing baking soda with water. This cheap solution does wonders in cleaning battery acid and corrosion.
Felt washers and rust paint are definitely good deterrents.
Finally, you might consider investing in gel or AGM batteries. They are expensive but don’t have the same outgassing or corrosion issues
We hope this helps!
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