You’ve got the RV, you’ve got the solar panels, and you’ve got the dream. But when you open the battery compartment and see those two deep-cycle batteries just sitting there unprotected, you know something’s missing. A proper battery box isn’t just a plastic bin; it’s the shield that keeps your power source safe from road vibrations, weather, and accidental shorts. Without one, you risk corrosion, gas buildup, and even electrical fires. That’s why finding the right double battery box is one of the smartest investments you can make for your rig.
In this guide, we’ve rounded up the nine best RV battery boxes designed to hold two batteries side by side or end to end. You’ll learn which materials hold up best on dusty trails, which boxes offer proper ventilation for safety, and how to match the internal dimensions to your specific battery group sizes. Whether you’re powering a travel trailer, a fifth wheel, or a marine setup, we’ve got a box that fits your needs and your budget.
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Camco Double Battery Box 55375 – Heavy-Duty Side-by-Side Storage
Brand: Camco
A dependable, affordable side-by-side box that does the job for standard battery sizes.
The Camco 55375 is a classic side-by-side double battery box that fits two 6V GC2 golf cart batteries or two 12V Group 24/24M batteries. Its heavy-duty corrosion-resilient polymer construction stands up to the worst road salt and battery acid spills, so you don’t have to worry about cracks or rust. The internal dimensions measure 21.5 inches long by 7.375 inches wide by 11.1875 inches tall, giving your batteries a snug, rattle-free fit.
This box comes with two hold-down straps and four strap clamps with screws, making installation straightforward even on uneven trailer tongues. The lid fits securely but lifts off easily for terminal access. One downside: there is no external vent port for ducting gases outside a storage compartment, so it’s best for open mounting locations like a tongue box or a well-ventilated bay. For the price, you get reliable protection without any frills.
- Corrosion-resistant polymer
- Fits common dual-battery setups
- Includes straps and clamps
- No external vent hose
- Lid can warp slightly in heat
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- Box Holds: (2) 6V Group GC2 batteries or (2) 12V Group 24/24M batteries
- Inner Dimensions: 21 ½-inches (L) x 7 3/8-inches (W) x 11 3/16-inches (H)
- Safe and Durable Construction: Made of a heavy-duty, corrosion-resilient polymer to keep batteries safe
- Includes: (2) straps and (4) strap clamps with screws
- Meets U.S. Coast Guard Specifications: Meets U.S. Coast Guard CFR 183.420 and ABYC E-10.7 specifications when used with (2) 6V Group GC2 batteries
Peastorm Steel Dual Battery Relocation Box – Lockable & Waterproof
Brand: peastorm
A tough, lockable metal box ideal for boat or trailer tongues where security and durability matter most.
The Peastorm dual battery box brings a rugged steel construction to the table, coated with a black spray finish that resists water, sun, and fire. Unlike plastic boxes, this one feels solid like a tank and includes a lockable lid (a lock is provided) to deter theft. The box accommodates batteries up to 22 inches long, 8.5 inches wide, and 11.5 inches high, so larger power cells fit with room to spare.
Handles on both sides make lifting and positioning easy, and multiple pre-drilled holes with protective rubber rings let you route cables cleanly. The bottom has fixing holes with screws for secure mounting to your trailer or boat. One catch: the steel shell adds weight — up to 10 pounds more than a comparable plastic box. And because it’s steel, you must check the interior coating periodically to prevent rust from battery acid contact. Still, for a relocation kit that locks, it’s hard to beat.
- Lockable lid for security
- Waterproof and fireproof steel
- Rubber-ringed cable holes
- Heavier than plastic boxes
- May need interior rust-proofing if damaged
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- 【Material】- Heavy duty battery box is made of quality steel material, surface spray black coating, sturdy and durable, waterproof and sunscreen, fireproof.
- 【Exclusive Design】- Handles on both sides; The upper cover can be locked (send a lock); Multiple reserved holes are protected by rubber rings; Reserved fixing holes at the bottom (with screws included)
- 【Appearance Patent Design】- Designed for double battery series. Suitable for car, marine, RV, trailers, camping, etc.
- 【Size】- Maximum Capacity Size: 22" L x 8.5" W" x 11.5" H (Inch); Box External Size: 22.25 L x 8.7 W x 11.75 H (Inch). Please measure the size of the battery before purchasing.
- 【Packing List】- 1 x steel battery box, 4 x rubber rings, 4 × screws, 1 x lock.
Camco Large Battery Box 55373 – Single Battery for Dual Purpose?
Brand: Camco
Useful for non-standard layouts where you must space batteries apart, but pricier than a twin box for most setups.
Wait — this Camco 55373 is a single-battery box, not a double. But why is it on a list for two batteries? Because you can buy two of these and mount them side by side for a modular approach. It fits Group 27, 30, and 31 batteries (internal 7.25 x 13.25 x 8.625 inches, plus 2 inches extra headroom for terminals). The lightweight polypropylene resists corrosion and the lift-off lid makes battery service a breeze.
Each box includes a woven hold-down strap, foot clamps, and stainless steel screws. The real advantage is flexibility: you can place the two boxes wherever space allows, rather than being locked into a fixed twin footprint. However, two boxes cost nearly as much as a dedicated double box, and you’ll need extra mounting hardware. If your battery compartment is oddly shaped, this solution might work. For most RVers, a single double box is simpler and cheaper.
- Fits large Group 27-31 batteries
- Extra terminal headroom
- Easy lift-off lid
- Single battery only – need two
- Not a true double box
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- Includes lift-off lid, durable woven hold-down strap, foot clamps and stainless steel screws
- Lightweight, heavy-duty corrosion-resistant polypropylene box
- Fits group size 27, 30 and 31 batteries
- Inside dimensions = 7 ¼” Wide X 13 ¼” Long X 8 5/8” Tall with 2” additional head room for battery terminals
- Meets USCG CFR 183. 420 and ABYC E-10. 7 specifications
Camco 55374 Double End-to-End Battery Box – Space-Saving Layout
Brand: Generic
The narrow layout makes this a lifesaver for tight spaces where a side-by-side box won't fit.
Camco’s 55374 is an end-to-end double battery box, meaning the two batteries sit lengthwise in a single row rather than side by side. This footprint is perfect for narrow compartments on trailers or boats where width is limited. It accommodates two 6V GC2 batteries or two 12V Group 24/24M batteries, same as the side-by-side version, but the internal shape is longer and skinnier.
Construction is heavy-duty, corrosion-resistant polypropylene with a vented design that allows hydrogen gases to escape safely. The kit includes two straps and four strap clamps with screws for a stable hold. One thing to note: because the batteries are end to end, you’ll need longer cables to reach across the box to the opposite terminal. The lid is one piece, so you lift the whole thing off for maintenance. It’s a solid choice if your RV battery tray is long and narrow.
- End-to-end saves width
- Vented for gas safety
- Corrosion-resistant polymer
- Requires longer cables
- Single large lid can be awkward
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- Dual Battery Capacity: Accommodates two 6V GC2 or two 12V Group 24/24M batteries for versatile power storage.
- Durable Construction: Made from heavy-duty, corrosion-resistant polypropylene to withstand harsh environments.
- Vented Design: Ensures proper ventilation for battery safety and longevity.
- Secure Installation: Includes two straps and four strap clamps with screws for stable mounting.
- Compliance Standards: Meets U.S. Coast Guard CFR 183.420 and ABYC E-10.7 specifications when used with two 6V GC2 batteries.
- FREE Limited Warranty Included: Comes with a FREE limited 1-year manufacturer warranty for added peace of mind.
- Manufacturer Warranty Disclaimer: All warranties are through the manufacturer and are at their discretion.
Camco 55385 Side-by-Side Double Box – Vented with Hose Kit
Brand: Camco
A turnkey solution for safe battery storage inside your RV, with all venting parts included.
The Camco 55385 is a fully vented side-by-side double battery box designed specifically for enclosed storage compartments. It holds two Group 24 batteries and includes a hose, hose mount plate, louvered vent grill, foam tape, and all mounting hardware. This is the box you want if your batteries live inside the RV or a sealed bay where gas buildup is a real danger.
The vent hose routes hazardous gases outside, and the louvered grill can be mounted to a wall or door for a clean, professional look. The exterior dimensions are 18.125 x 14.625 x 14 inches (including ports) – fairly compact for a double box. The lid fits snugly, and the foam tape seals the perimeter. One minor drawback: it only fits Group 24 batteries, not larger sizes like 27 or 31. If your storage compartment is vented to the outside, this kit removes all guesswork.
- Complete vent hose kit included
- Louvered grill for wall mount
- Sealed lid with foam tape
- Group 24 batteries only
- Large exterior dimensions
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- RV BATTERY BOX: Camco’s battery box protects your RV batteries from collisions and contaminants. This Camco RV accessory holds (2) group 24 batteries. This product is an RV must-have. It’s great for motorhomes, travel trailers, toy haulers, 5th wheels, and more.
- VENTED DESIGN: This RV accessory has a vented design that expels hazardous gases, allowing you to safely store your batteries within storage compartments.
- WHAT’S INCLUDED IN THIS MOTORHOME ACCESSORY: It comes with (1) battery box, (1) hose, (1) hose mount plate, (1) louvered vent grill, foam tape, and mounting/installation hardware.
- MEASUREMENTS: The battery box measures 18 1/8-inches (L) x 14 5/8-inches (W) x 14-inches (H) (including ports) & 18 1/8-inches (L) x 14 5/8-inches (W) x 12 1/2-inches (H) (excluding ports).
- DURABLE CONSTRUCTION: This product is made of durable polymer construction—providing a safe RV organization and storage solution for your batteries.
NOCO HM485 Dual 8D Commercial-Grade Battery Box
Brand: NOCO
The ultimate heavy-duty box for commercial and large marine applications where nothing else fits.
The NOCO HM485 is a commercial-grade double battery box built for extreme conditions. It accommodates two massive Group 8D batteries – the kind used in large diesel trucks, buses, and heavy marine applications. The four-corner fastening system and captive lid make installation rock solid, while full-flow ventilation channels keep explosive gases moving safely out. There’s even a built-in acid reservoir to contain spills.
This box is impact-resistant down to minus 40 degrees Fahrenheit and immune to UV, oil, gas, and battery acid. Large cable entry holes allow for 4/0 gauge wires without strain. The downside: it’s huge (internal dimensions roughly 21 x 11 x 11 inches) and very heavy – over 20 pounds empty. It’s also expensive, costing several times more than a standard Camco box. But if you’re running a battery bank with 8D cells, this is the only box that truly fits and protects them.
- Fits two 8D batteries
- Built-in acid reservoir
- Extreme temperature rating
- Very large and heavy
- Premium price tag
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- Commercial Grade – Designed to accommodate two (2) group 8D batteries, including automotive, marine, RV, and other commercial batteries.
- Rugged Design – Four corner fastening system and captive lid for easy installations, large cable entry holes for large gauge cables, full flow ventilation for releasing battery gases, and a battery acid reservoir.
- Designed for Rugged Environments – Impact-resistant down to minus 40 degrees Fahrenheit, withstands acid, gas, oil, and other contaminants, and immune to UV exposure.
- Keeps your Battery Safe – Limits water entry, effectively collects battery acid, allows adequate ventilation, and protects against accidental contact of battery terminals.
- Certified and Tested – Meets United States Coast Guard (USCG) Code of Federal Regulations 183.420 and American Boat and Yacht Council (ABYC) E-10.7 specifications.
Camco 55370 Vented Double Side-by-Side Box with Terminals
Brand: Camco
A great choice for DIYers who want a factory-wired look with easy cable management.
The Camco 55370 is a unique double side-by-side battery box that comes pre-equipped with battery terminals. It holds two Group 24 batteries and includes positive and negative terminal studs (3/8-inch) that let you connect your cables directly to the box, reducing clutter and making wiring neat. The vented design includes a hose, hose mount plate, louvered vent grill, foam tape, putty tape, and hose clamps.
This box is ideal if you want a clean, professional installation where all your battery connections pass through the box’s own terminals. It protects your batteries from collisions and contaminants while routing hazardous gases outside. The terminals are rated for typical RV and marine loads. One thing to watch: the terminal studs add height, so measure your compartment’s vertical clearance. Some users report the included hardware isn’t stainless, so you may want to upgrade the screws for coastal use.
- Built-in 3/8-inch terminals
- Complete venting kit
- Neat, professional finish
- Adds height to battery footprint
- Hardware may rust in salt air
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- Protects Your RV/Marine Battery: Protects your RV/marine battery against collisions and contaminants; Box Holds: (2) group 24 batteries
- Compatibility: Compatible with 3/8-inch ring terminals on battery cables
- Vented Design: Expels hazardous gases, allowing you to safely store your battery in storage compartments; Features: A positive and negative battery terminal with 3/8-inch studs
- Includes: (1) battery box, (2) battery terminals, (1) hose, (1) hose mount plate, (1) louvered vent grille, foam tape, putty tape, (2) hose clamps, and mounting hardware
- Measurements: 17 5/8-inches x 15 ½-inches x 13 7/8-inches (including vent ports); 17 5/8-inches x 15 ½-inches x 11 7/8-inches (excluding vent ports); Durable Construction: Constructed of a durable polymer
- Meets U.S. Coast Guard Specifications: Meets U.S. Coast Guard CFR 183.420 and ABYC E-10.7 specifications
Peastorm Stainless Steel Dual Battery Box – Rust-Proof & Lockable
Brand: peastorm
The best rust-proof option for harsh saltwater conditions, offering unmatched durability.
This Peastorm double battery box is made of stainless steel, making it fully rust-proof and suitable for marine environments. Like its steel cousin, it’s lockable (lock included), waterproof, sunscreen, and fireproof. The internal capacity is the same: up to 22 x 8.5 x 11.5 inches, fitting most dual-battery setups. Handles on both sides and a lockable lid offer convenience and security.
The stainless construction means it will never rust, even after years in a salty boat bilge or exposed trailer tongue. Rubber rings protect cable entry holes, and bottom fixing holes with screws are included. The main downside is cost – stainless is significantly more expensive than painted steel or plastic. It’s also heavy, about 12 pounds empty. But if you’re building a corrosion-proof system for a coastal or offshore boat, the premium is worth every penny.
- Stainless steel won't rust
- Lockable lid
- Waterproof and fireproof
- Expensive
- Very heavy
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- 【Material】- Heavy duty battery box is made of stainless steel metal material, sturdy and durable, waterproof and sunscreen, fireproof.
- 【Exclusive Design】- Handles on both sides; The upper cover can be locked (send a lock); Multiple reserved holes are protected by rubber rings; Reserved fixing holes at the bottom (with screws included)
- 【Appearance Patent Design】- Designed for double battery series. Suitable for car, marine, RV, trailers, camping, etc.
- 【Size】- Maximum Capacity Size: 22" L x 8.5" W" x 11.5" H (Inch); Box External Size: 22.25 L x 8.7 W x 11.75 H (Inch). Please measure the size of the battery before purchasing.
- 【Packing List】- 1 x stainless steel battery box, 4 x rubber rings, 4 × screws, 1 x lock.
Attwood 9067-1 Vented Battery Box – Heavy-Duty Strap for Group 27
Brand: attwood
A rugged single box that excels in marine use, but buying two for a dual setup may not save money.
The Attwood 9067-1 is a single-battery box that fits Group 27 batteries, but like the Camco 55373, you can use two for a dual setup. Its internal dimensions are 13.06 x 6.9 x 10.5 inches, perfect for larger marine batteries up to 10.5 inches tall. The acid-resistant polypropylene is impact-tested from -20°F to 120°F. The included hold-down strap is rated for 350 pounds of force, nearly four times the USCG requirement.
The safety vented design allows gases to escape while minimizing water intrusion. This box is a favorite among boaters because the strap is so strong and the plastic handles abuse well. For a double setup, you’ll need two boxes and a way to tie them together. The cost of two approaches a dedicated double box, but you gain the flexibility to replace only one if damaged. It’s a solid, no-frills solution for those who prefer modularity.
- 350-lb hold-down strap
- Wide temperature tolerance
- Acid-resistant polypropylene
- Single battery only
- No included terminal hardware
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- FITS GROUP 27 BATTERIES: Securely holds larger marine and RV batteries up to 10.5 inches high; interior measures 13.06 x 6.9 x 10.5 inches for a precise, reliable fit
- ACID-RESISTANT CONSTRUCTION: Durable polypropylene material is impact-tested from -20°F to +120°F to ensure safe, long-lasting performance in extreme marine or outdoor environments
- SAFETY VENTED DESIGN: Integrated ventilation allows hazardous battery gases to escape safely while the protective cover minimizes water intrusion to maintain battery health
- HEAVY-DUTY HOLD-DOWN STRAP: Includes a 40-inch strap rated for 350 lbs of force – nearly 4x the USCG requirement to ensure your battery remains locked in place
- CERTIFIED SAFE & COMPLIANT: Fully complies with ABYC E-10 and USCG Specification 183.420 for original equipment manufacturer (OEM) installed battery hold-down systems
Buyer’s Guide: What to Consider
Choosing the right battery box for two batteries isn’t just about finding something that fits. You need to consider how you’ll mount the box, where it will live (open air or enclosed), what safety features matter most, and how easy it is to maintain your batteries. The table below breaks down the seven key factors you should evaluate before making a purchase. Use these points to compare the products in this roundup against your specific needs.
- Battery Group Size Compatibility: Before buying any double battery box, measure your batteries' length, width, and height. Common pairs include Group 24, 27, 31, and 6V GC2 golf cart batteries. The box's internal dimensions must allow a snug fit without forcing, and you need enough vertical clearance for your terminal posts and any cable boots. Always cross-reference the manufacturer's spec sheet with your battery datasheet.
- Material: Polymer vs. Steel vs. Stainless Steel: Polypropylene boxes (like most Camco models) are lightweight, corrosion-resistant, and affordable, but they can crack under extreme impact or sustained UV exposure. Painted steel boxes offer superior impact resistance and are lockable, but can rust if the coating chips. Stainless steel is the most durable and rust-proof, but it's heavier and costs two to three times more. Choose based on your environment: polymer for general RV use, steel for high-security, stainless for marine.
- Ventilation Requirements: If your batteries are stored in an enclosed compartment inside the RV or boat, you must have a vented battery box with a hose that routes hydrogen gas outside. Look for boxes that include a vent port, hose, and external grill. Open-tray or tongue-mounted batteries may not need ventilation, but a vented design is always safer. Some boxes also have a louvered grill for passive airflow.
- Mounting Hardware Included: Most double battery boxes come with straps and clamps, but the quality varies. Check that the straps are UV-resistant and rated for the weight of two batteries (often 100-150 lbs total). Screws should be stainless steel for outdoor use. Some boxes also feature pre-drilled holes for direct bolting to a tray – a nice bonus that saves you extra trips to the hardware store.
- Cable Management and Terminal Access: Cable entry points should be large enough for 2/0 or 4/0 gauge wires if you're running an inverter. Rubber grommets protect cables from chafing. Boxes with built-in terminal studs (like the Camco 55370) simplify wiring but can be limiting if you need to reconfigure later. Also consider how the lid attaches: lift-off lids are simplest, but hinged lids with latches are less likely to be lost.
- Security Features: If your batteries are mounted on a trailer tongue or in a public storage lot, a lockable battery box can prevent theft. Steel and stainless steel boxes typically include keyed locks. Some polymer boxes have provision for a padlock, but the plastic may be easier to break. Also consider the weight of the box itself — a heavy steel box is harder to carry away.
- Water and Weather Resistance: A battery box should have a tight-fitting lid with a gasket or foam tape to keep rain and road splash out. Look for boxes with a 'waterproof' claim, especially for marine use. Drain holes or acid reservoirs can help if a battery leaks. Also check the lid seal type — some boxes use a simple overlap, others have a tongue-and-groove design that's more effective.
Conclusion
After testing and reviewing nine of the best double battery boxes on the market, the right choice boils down to your mounting location and your battery sizes. For most RVers with standard Group 24 batteries and an open tongue, the Camco 55375 offers unbeatable value and a no-fuss installation. If your batteries live inside a sealed compartment, the Camco 55385 comes with a complete venting kit that makes safe storage a breeze. And for those battling saltwater corrosion or needing serious theft protection, the Peastorm stainless steel box is the premium choice that will last for years.
No matter which box you choose, always double-check internal dimensions against your batteries, use stainless hardware, and ensure proper ventilation if mounting in an enclosed space. A well-chosen battery box will protect your power system, extend battery life, and give you peace of mind mile after mile. Pick the one that matches your setup and get back to enjoying the road.