Choosing the Right RV Battery

The first feature you look at when purchasing an RV is rarely the battery. Generally, you trust the OE (original equipment) batteries in your RV to last you for years and years and hope you never have to think about replacing it. If you noticed the plural on “batteries” there, it’s because your RV likely has multiple batteries. If you have a motorhome, you’ll have a chassis battery for starting the engine and at least one 12v deep-cycle house battery, or two 6v deep-cycle house batteries. If you have a travel trailer or camper, you will have a deep-cycle battery (or batteries) only. OE batteries are usually adequate for the average RVer, but depending on your RV lifestyle, maintenance issues that arise, or personal preference, you may need to start looking for the best RV battery for your particular situation.

There are several reasons that could prompt you to replace an RV battery or upgrade. Sometimes, due to a lack of maintenance, hard use, failure within your converter, “cannibalizing” of a good battery by a connected bad battery, and numerous other causes, your batteries can fail and it’s time to find a new one. Or perhaps your batteries are in fine condition, but you want to upgrade or add additional batteries. If you do a lot of unplugged, dry camping, you might need a battery with more power, or you might want to wire multiple batteries together to form a battery bank. Generally, the rule of thumb for RV batteries is one battery per person plus one extra.

Choosing the right RV battery is about more than finding the correct voltage— there’s a lot you need to know when finding a replacement for your existing RV battery:

Understanding RV Electrical Systems:

The first step to finding a battery replacement is to understand the electrical system on your RV and the different types of RV batteries.

Chassis Batteries: Also known as the starting battery, the chassis battery is responsible for starting the engine on a motorhome. These are pretty much the same as automotive batteries, except they have a higher CCA (Cold Cranking Amps) rating to accommodate the larger engine. When replacing this battery, choose one with the same CCA rating or larger.

Deep-Cycle Batteries: Deep-cycle batteries are the ones used for household power in your coach, travel trailer, or camper. These batteries send power to fuses in lights, refrigerators, slideout motors and mechanisms, water heater, other appliances, etc. They usually come in 6v or 12v configurations, but the output must always equal 12v. So, if 6v batteries are being used, two are required to achieve the appropriate output. If you want more power for longer periods of unplugged power and are using more than two 6v batteries, you will always need an even number to achieve the 12v output.

Deep-cycle batteries can be recharged more often and can be drained to a deeper level than starting batteries. This means a deep-cycle battery can power your lights and other functions and a lower level than your starting battery can start your engine. While starting batteries are good at providing short, high-powered boosts to get your engine going, deep-cycle batteries will be able to power your coach for longer periods of time. Batteries can be recharged by plugging into shoreline power, or sometimes, through solar panels with the right configurations. When recharging, your shore line runs power to your converter, which then converts that power to the 12 volts that your battery can use.

Varieties of Deep-Cycle Batteries:

Conventional Flooded Electrolyte:  Most traditional battery type. Typically OE that comes with the new RV. Occasional maintenance includes checking water levels and refilling with distilled water when necessary. Corrosion needs to be cleaned from terminals more often. Good capacity at affordable cost. Hot weather, fast charging, frequently used batteries will require water refilling more often.

Gel: Gel batteries cost more than the traditional flooded electrolyte, but they last longer and don’t require maintenance. The drawback is that they don’t tolerate fast charging as well as flooded electrolyte batteries.

Absorbed Glass Mat (AGM) Like Gel batteries, AGM batteries last longer and cost more than traditional batteries. They tolerate fast charging somewhat better than Gel.

What are Marine Batteries?

Another term that comes up related to RV batteries are “Marine Batteries.” These are a combination of a starting battery and deep cycling battery. They aren’t the best choice for either use, but they can be used for either purpose, if necessary. The reason why some people choose marine batteries over deep-cycle batteries, is that they are much less expensive, due to a manufacturing process very similar to that of the less expensive starting battery.

Power Ratings: There are two main power ratings for batteries: the AH rating and the RC rating. The higher number for both of these ratings, the more capacity the battery has and the longer it will last.

AH Rating: The AH stands for Amp-Hours and is the measurement of how many amps the battery can deliver over a 20-hour period.

RC Rating: RC stands for Reserve Capacity. The reserve capacity is the length of time, in minutes, a battery can sustain a load of 25 amps.

Caring for your RV Battery:

Now, after you choose the right RV battery for you, you’ll want to take the best care possible of it so it doesn’t fail on you in the future. Really only starting batteries and flooded electrolyte deep-cycle batteries require maintenance. The process is very similar to caring for automotive batteries and involves cleaning corrosion off of the terminals, cleaning the top of battery, checking water levels in the cells, and replenishing liquid with distilled water when necessary. All RV batteries should be disconnected when not in use because small amounts of current will be drawn from them even when the batteries are not active.

For help identifying the right RV battery to suit your needs, questions about wiring batteries, or to have a service professional install new batteries for you, contact us today, or come on by.

Top Photo: Corey Taratuta

Battery Photo: Ramon Salgado

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