RVers, sailors, and overlanders who aren’t traveling full-time often have to leave their batteries in storage for an extended period of time. While this can bring concerns about diminished capacity, many people opt to use a trickle charger to maintain their batteries while they’re away, as they can be a game-changer regarding battery storage. Although trickle chargers are commonly used with a car battery, they can also benefit from deep-cycle storage batteries. But what exactly does a trickle charger do? And how long should you leave your batteries plugged into one?  

Let’s dive into the science behind trickle chargers and why you might consider purchasing one for your batteries.  

What Is a Trickle Charger? 

A trickle charger is a device that attaches to your batteries to maintain their charge. Since all batteries experience some degree of self-discharge (even when they’re not drawing any loads), keeping them hooked up to a power source when stored for long periods is essential. Otherwise, your batteries may be dead the next time you attempt to use them.  

Luckily, trickle chargers are relatively simple and easy-to-use devices that keep your batteries from fully dying when not in use. They attach to a power source with a display screen and connect to your battery with negative and positive cables. Most trickle chargers will cost between $35 and $100, with the higher-end chargers providing more safety features. 

What Does a Trickle Charger Do?

A trickle charger supplies just enough power to keep your batteries topped off. Also called a battery maintainer, trickle chargers slowly emit approximately one to three amps of power. Additionally, trickle chargers can keep up with small loads, pulling constant power from your batteries. This ensures your battery’s charge level stays equal to its full capacity.

If your batteries will be in storage for an extended period of time, it’s essential to pay close attention to the capabilities of your trickle charger. Manual trickle chargers emit a low amperage but don’t have internal protocols to signal when it’s time to shut off. This can lead to overcharging your batteries, which can have potentially damaging effects. 

Is Trickle Charging or Rapid Charging Better for Your Batteries? 

Well, that depends on the chemistry of the batteries you are using. With lithium batteries, the charge rate used during the charging process has a minimal impact on the health of the batteries. However, the charge rate can make all the difference for lead-acid batteries. This is primarily caused by the electrochemistry operating within lead-acid batteries.  

When a lead-acid battery discharges, the lead electrodes turn into lead sulfate, and the sulfuric acid electrolyte dilutes. Then, when the lead-acid battery recharges, the chemical reaction reverses, turning the lead sulfate back into lead and the electrolyte into a more robust sulfuric acid solution. During this process, a lead-acid battery can overheat, producing off-gassing if it charges too quickly, potentially damaging the battery.  

A good trickle charger can prevent this. Not only does it charge the batteries slowly, but it can also detect the state of charge and slow the amperage as the battery nears a full charge. This prevents off-gassing and battery damage. It also limits the risk of a battery explosion.  

When Should You Use a Trickle Charger? 

A trickle charger can come in handy anytime you need to store your batteries. Whether you’re leaving your car parked for an extended period of time, storing your RV for the winter, or want to prevent your boat batteries from dying, there are various reasons to invest in one.  

The type of batteries you own might influence your decision as well. Different batteries experience varying degrees of self-discharge rates. For example, lead acid batteries self-discharge 10-15% per month. Meanwhile, LiFePO4 batteries tend to have much slower rates of self-discharge. Battle Born Batteries experience only self-discharge 2-3% per month.  

So, depending on how long your batteries will be sitting, the type of batteries you own, and the number of safety features you desire will help you choose the most appropriate trickle charger.  

Does a Trickle Charger Fully Charge a Battery?

Yes, a trickle charger can fully charge a battery; it will just take a very long time. Since trickle chargers only emit between 1 and 3 amps. In this case, you can expect to wait days for a fully charged battery. For example, a 1-amp trickle charger will take 100 hours to completely charge a dead 100Ah battery. This is very inefficient as the primary function of trickle chargers is to keep your batteries topped off.  

If your batteries are completely dead or have a low charge, we highly recommend using a regular battery charger to get them charged up quickly. While lead acid batteries will take around 8 hours to fully charge, a 100Ah Battle Born Battery should only take about two to three hours to charge with the appropriate standard charger.  

How Long Should You Leave a Trickle Charger on a Battery? 

Nearly all trickle chargers are designed to stay on your batteries for long periods of time. They were specifically created to keep batteries fully charged even in long-term storage. These devices help give battery owners peace of mind that they will still have a fully functioning battery when it comes time to pull it out and use it again.   

However, not all trickle chargers are created equal. If you want a “set it and forget it” battery charger, opting for an “automatic” or “smart” trickle charger may be the way to go. These devices generally have more safety features, allowing them to automatically reduce the amperage they emit as the battery nears a full charge. This way, your batteries will always stay topped off but never overcharge.  

→ Pro Tip: Depending on your battery setup and application, you may need additional charger accessories to keep your system charged and ready for use. 

Can a Trickle Charger Save a Battery? 

Yes! Trickle chargers can be life savers when storing your batteries for extended periods of time.  

First and foremost, most batteries should not drain 100% of their charge capacity. Lead-acid batteries should not discharge below 50% to maintain good health. Many lithium batteries recommend only a 90-95% discharge to avoid damage. On the other hand, Battle Born Batteries have a 100% depth of discharge without worry of damage. However, it’s best not to let them sit completely discharged. Trickle chargers prevent batteries from encountering damage from over-discharging and uphold the integrity and lifecycle of your batteries.  

Also, a fully drained battery can suffer more damage in cold weather. Thus, if you plan on storing your batteries in a cold garage all winter, a trickle charger can make all the difference when you return in the spring.  

100Ah 12V LiFePO4 Deep Cycle Battery

Learn More

100Ah 12V GC2 LiFePO4 Deep Cycle Battery

Learn More

270Ah 12V LiFePO4 Deep Cycle GC3 Battery

Learn More

12V LiFePO4 Deep Cycle Heated Battery Kits

Learn More

Want To Learn More About Electrical Systems and Lithium Batteries?

We know that building or upgrading an electrical system can be overwhelming, so we’re here to help. Our Reno, Nevada-based sales and customer service team is standing by at (855) 292-2831 to take your questions!

Also, join us on Facebook, Instagram, and YouTube to learn more about how lithium battery systems can power your lifestyle, see how others have built their systems, and gain the confidence to get out there and stay out there.