Did you know that your RV battery loses charge as it sits idle? Did you also know that a charge that is too low can actually damage the battery? Don’t find yourself with a battery that needs replacing in the spring! Let's look at how to extend the life of your RV's battery by trickle charging it correctly with these Handling Trickle Charging and Storage tips.
What Is a Trickle Charge?
Imagine you have a swimming pool in your backyard. The water in the pool slowly evaporates over time, and if you were to leave a hose on and slowly trickle water into the pool, this would slowly replenish the water that has evaporated. In a sense, you are "trickle charging" the pool. The same is true for a trickle charge on an RV battery. This type of charge is perfect for lead acid batteries that are going to be sitting idle for a while. As they sit, they slowly lose their charge. A trickle charge will slowly recharge the battery.
Lead Acid Battery
There are generally two types of batteries that you will find in an RV. What many call the “house battery,” the deep cycle battery
is the one that will power the things inside your RV. Inside a motorhome, there is also a “starting battery,” which is an SLI
(Starting, Lighting, & Ignition) battery. The difference between the two is that a deep cycle battery is meant for constant use whereas the SLI battery is meant for small bursts of energy and to get things going. Both types are lead acid batteries. Inside a lead acid battery is a line of several plates. These plates are alternating lead and lead oxide plates. Within the battery is an electrolyte solution of sulfuric acid and water that surrounds the plates. This solution allows the current to flow from one plate to another. The batteries have small partitions in them that divide the battery up into cells. Each cell contributes a specific amount of volts. The more cells the battery has, the higher the voltage of the battery.
How a Lead Acid Battery Obtains a Charge
Due to the way this battery is assembled, it charges in three stages. The first charge is the bulk charge. This charges the battery to between 75% and 90% of its full capacity. This first stage requires a constant current to reach completion. The second stage is called the “absorption stage” which brings the battery up to around 98% of its full charge. This stage requires constant voltage to be completed. The third stage of charging is a low voltage stage. This brings the battery to 100% and also keeps it from depleting. This is where a trickle charge comes in (see above). Because lead acid batteries lose charge as they sit unused, the trickle charge keeps them powered up.
Why Trickle Charge a Battery?
Trickle charging your lead acid battery is an important step in keeping it healthy and strong and maintaining its life cycle. If the battery consistently drops below 80%, you have to worry about acid stratification
. The water that is in the battery contains sulfuric acid. The sulfuric acid is what helps move the current through the battery. If the battery gets below 80% too often, the acid tends to rest at the bottom of the battery and the top contains mostly water. You then get more sulfation at the bottom of the battery and the current cannot remain even. While keeping the charge above 80% is important, keeping it above a 50% charge is imperative. Lead sulfate starts to build up between the plates when it's below a 50% charge and current flow will be inhibited. This is called battery sulfation.
At this low of a charge, your battery will suffer irreversible damage and you'll be faced with having to replace it. Trickle charging it correctly while it's in storage is important for the overall health of your RV's battery.
Trickle Charging While In Storage
When you store your RV battery at the end of camping season, make sure it has a full charge. In order to maintain its charge during storage, find a charger that will trickle when it’s down, but will stop when it’s full, such as the BatteryMINDer
. This will prevent overcharging and you won't have to constantly check on it over the winter. The BatteryMINDer will test the battery to determine its charge, and it will then determine what type of charge it needs. It will even determine the amount of sulfation in the battery and give it a special kind of charge to break it down. One thing to keep in mind is that it works best between 33-130°
F, so if you live in a cold place like we do here in Michigan, make sure you store your battery where it won’t dip below that temperature.
Taking care of your lead acid battery will extend its life! With proper care, it should last up to 10 years! If you’re finding that you’re having to replace your batteries often, then try our trickle charging steps that should extend the lifetime of your RV's battery.