Most of us don’t pay much attention to where the electricity that powers our homes, vehicles and devices comes from. We just plug stuff in and things usually work without any thought. We don’t have to monitor the supply of power coming into our toaster and if the flashlight goes dead, we just find a couple new batteries in the junk drawer. Our camping trailers are different habitats entirely though and knowing how yours stores and consumes electricity (at least generally) will make your trips more enjoyable and could save you several hundreds of dollars by avoiding having to replace your expensive trailer battery prematurely.
So let’s get a quick crash course! We are going to keep this as simple as possible, but still be meaningful. We’re not going to cover every power possibility with your teardrop trailer- just the basics.
Your house runs on AC electricity (Alternating Current) where most of the outlets you plug appliances into serve up “120 volts” to provide enough power for those appliances to run properly. You'll often hear voltages in your home referred to as “110V”, “115V”, or “120V”. This can be confusing but the bottom line is it referring to the same approximate voltage level. Some outlets in your home are rated for higher voltage appliances (240 volts) like an electric oven or electric dryer, but this is still AC power and not a voltage found on teardrop trailers. However, you may have a couple 120 volt outlets in your camping trailer kitchen or cabin. These are likely either directly powered when you plug your trailer into shore power, or run through and Inverter, to transform the 12 volt power stored in your battery to 120 volt power needed to make your coffee maker work.
Now! Usually, your camping trailer is not connected to the AC power grid like your home is, so it needs a battery to store electricity and discharge it to appliances when needed (just like your cell phone). Every camping trailer manufacturer will provide some type of battery to power lights, fans, etc… whether as standard equipment, or as an upgrade/option.
Teardrop trailer batteries produce DC power (Direct Current) at a lower voltage. So your battery is usually a 12 volt battery (occasionally two 6 volt batteries wired together to produce 12 volts).
The type of battery that is needed to power teardrop appliances is called a “Deep Cycle battery”. A deep cycle battery is a battery specifically designed to provide sustained power over a long period of time. They are intended to be discharged (used) and recharged repeatedly. Depending on the battery manufacturer, you can use between 50% and 80% of a deep cycle battery’s capacity before it needs to be recharged. In contrast, an automotive “Starter battery” is designed to provide short, bursts of high voltage power to start an engine, not to run appliances for long periods of time. In between the two is what is known as a “Dual Purpose battery” essentially it can delivery both starting power and deep cycle power, but does neither particularly well. Since your camping trailer does not have an engine, you should not be using a starter battery or dual purpose battery.
Here’s where some choices come in! We’ve established that our usual batteries produce 12 volt electricity. Now! There are generally four “types” of batteries
Wet-cell flooded lead acid battery
AGM (Absorbed Glass Mat) lead acid battery
Gel cell battery
Lithium-based batteries (usually Lithium Iron Phosphate)
The four battery types are defined by their chemistry & structure (batteries produce power via an electro-chemical reaction). As promised, we won’t get too deep into what makes each chemistry different but let’s quickly cover the pros/cons of each:
Wet-cell Flooded Lead Acid Batteries-
The most common type of battery used in trailers is the wet-cell flooded lead-acid (FLA) battery. Flooded batteries were invented more than 150 years ago, and they remain firmly entrenched as standard equipment in most budget travel trailers, campers and RVs primarily because of their relatively low initial cost. These batteries use a liquid electrolyte-containing medium to trigger a chemical reaction. When the battery is connected to a load, the battery acid bonds to the lead plates. This causes a reaction that sends an electric current through the attached circuit thereby providing power to the load.
The cons: These batteries are not sealed or maintenance-free. Flooded batteries vent small amounts of oxygen and hydrogen gas while charging; an explosion can occur if this gas is exposed to a spark or flame. As a result, wet-cell batteries must be stored either in a well-ventilated compartment or a sealed battery box with an external vent. The amount of off-gassing increases when a flooded battery is charged at higher amps, such as with a deeply discharged battery. These gases are produced from the electrolysis of water from the electrolyte. Because water is lost during this process, flooded batteries require distilled water to be added periodically, or the exposed lead plates can become damaged. In our opinion, they are a poor choice of battery to equip on a camping trailer because of the maintenance required and risks incurred.
AGM Lead Acid Batteries-
A variation of lead-acid battery technology is the AGM battery. AGM batteries have an ultrafine fiberglass mat embedded between the lead plates that absorbs the electrolyte. AGM batteries have several advantages over flooded batteries including a spill-proof design, lower internal resistance, faster charging times and a longer life cycle. They are less likely to self-discharge, are less prone to sulfation and can be mounted in any position. On the negative side, AGM batteries are more expensive and require an AGM-compatible battery charger.
Gel-cell Batteries-
Gel-cell batteries offer similar advantages over flooded batteries. Gel cells contain no liquid. The sulfuric acid is mixed with a thickening agent to form a gel-like substance. Gel-cell batteries are expensive and require a charger that is designed for their charging profile. They offer a slight performance advantage over AGM batteries at high ambient temperatures and under slow-discharge conditions, but their significantly higher price makes AGM batteries the more popular choice.
AGM and gel-cell batteries are valve-regulated lead-acid (VRLA) batteries. VRLA batteries do not vent hydrogen under normal conditions. Hydrogen and oxygen are recombined inside the battery to prevent outgassing and loss of water. However, if a VRLA battery is overcharged or overheated, a safety valve will open, allowing gases to be vented. For this reason, proper ventilation is still required. VRLA batteries are considered sealed, maintenance-free batteries that require no periodic adding of water.
Lithium Batteries-
There’s a lot of talk about lithium RV batteries, and with good reason. RV lithium batteries are rechargeable 12-volt batteries that have become a popular alternative to lead-acid batteries, particularly for RVers who spend a lot of time off the grid and/or who use solar power.
RV lithium batteries are based on a newer, more efficient lithium-ion technology known as lithium iron phosphate (or LiFePO4 for short). They’ve earned their popularity for many reasons. Not only do lithium RV batteries have a significantly longer lifespan than lead-acid batteries do, but they’re also lighter. And, because they’re more efficient, they charge faster. But there are several common misconceptions floating around about lithium RV batteries, let’s explore each a little…
(Misconception #1) Lithium Batteries Are Dangerous
Prior to several technological advancements, lithium batteries used in some electronics could overheat and would sometimes even catch on fire. But technology has advanced substantially since that time, and today RV lithium batteries are made with lithium iron phosphate (LiFePO4) technology which uses non-combustible lithium chemistry. They’re different from the other “lithium-ion” battery formulations used for cell phones, laptops, and other portable devices… and are much safer for use on RVs.
Even so, lithium RV batteries can be prone to a condition called thermal runaway which occurs when the interior temperature of the battery rises so high that it causes a chemical reaction leading to excessive heat that can lead to a dangerous condition resulting in an explosion. F
However, this is precisely why most lithium RV batteries have a battery management system (BMS). A battery management system ensures that the battery operates safely by monitoring and managing the advanced features of the battery.
So, technology has advanced to the degree that the concern that lithium batteries are dangerous is no longer valid.
(Misconception #2) Lithium Batteries Can’t Be Used in Cold Weather
Misconception #2 is that lithium RV batteries can’t be used in cold weather. Again, this isn’t entirely true. In fact, some brands of lithium RV batteries allow you to continue to draw power to as low as -4℉. But the bigger issue is that, when the temperature of a lithium battery drops to or below freezing, it can’t be recharged without permanently damaging it. That’s because, at those temperatures, supplying power to recharge the battery can cause the lithium to form crystals, which pierce the membranes that form the cells of the battery, destroying it.
That recharging issue is addressed in two different ways.
First, with virtually all lithium RV batteries that we’re aware of, the BMS (Battery Management System) built into the battery will monitor the internal temperature, ensuring that it does not allow any charging current to flow into the battery if it has reached a dangerous temperature. This will protect the battery from damage, but if that was all you were relying on, it could mean that your battery won’t recharge when you need it to. Lastly, even without these protective mechanisms, lithium batteries have another advantage. Unlike flooded lead-acid batteries (which must be installed in vented compartments due to the flammable gas they produce during their charge/recharge cycles), lithium RV batteries don’t outgas at all. As a result, they can be installed inside your RV and, thus, be better insulated from outside temperatures causing a problem.
(Misconception #3) Lithium Batteries Are More Expensive
This is true, initially. Lithium batteries do cost more to buy. However, they also last significantly longer than lead-acid batteries, so they’re often less expensive in the long run. In fact, a quality lithium RV battery can last up to ten times longer than a lead-acid RV battery.
So, over the duration of the lifetime of a lithium battery, you’d be likely to replace a lead-acid battery several times. That adds up (and can be a real pain in the neck).
Plus, because lithium batteries for RVs can be drained/discharged much lower than flooded lead-acid batteries can be (lead-acid batteries shouldn’t be drained more than 50%-80% of their capacity before their lifespan is significantly reduced), you can typically install half as many of them.
For example, if you require 200 Ah of battery capacity, you can achieve that with a single 206 Ah lithium battery that can be drained all the way down to 0% State of Charge (SOC). With comparable flooded or AGM lead-acid batteries, you’d need to install 3 batteries x 100Ah (for a total of 300 Ah), assuming you use approximately 70% of their capacity (300Ah x 0.7 = 206Ah of usable capacity).
