Skip to content
  • Facebook
  • X (Twitter)
  • Instagram
  • YouTube
  • TikTok

BROUGHT TO YOU BY BASS BOAT WIRED

BROUGHT TO YOU BY BASS BOAT WIRED

  • Home
  • Shop
  • Brands
  • Boat Nation
  • About
  • Support
Login
  • Facebook
  • X (Twitter)
  • Instagram
  • YouTube
  • TikTok
Search
Boat Nation OutdoorsBoat Nation Outdoors Logo
Search Login Cart 0
  • HomeHome
  • ShopShop
    • Shop by Category
      • Marine Electronics
      • Trolling Motors
      • Wiring, Electrical, & Power
      • Mounts, Hardware, & Rigging
      • Boat Storage, Organization, & Accessories
      • Engines & Maintenance
      • Anchoring, Docking, & Positioning
      • Marine Lighting
      • Boat Decking & Flooring
      • Fishing Rods, Reels, & Combos
      • Fishing Tackle, Bait, & Terminal
      • Fishing Accessories
      • Waterfowl & Hunting Gear
      • Bowfishing
      • Safety & Boat Essentials
      • Apparel & Lifestyle
      • Kayaks & Paddlesports
      • Boat Decking & Flooring
    • Shop by Boat Brand
      • Allison
      • Avid
      • Bass Cat
      • Blazer
      • Bullet
      • Caymas
      • Champion
      • Charger
      • Contender
      • Falcon
      • G3
      • Ikon
      • Legend
      • Nitro
      • Phoenix
      • Ranger
      • Skeeter
      • Stratos
      • Tracker
      • Triton
      • Vexus
    Shop Marine Electronics

    Shop Marine Electronics

    Shop Boat Storage & Accessories

    Shop Boat Storage & Accessories

    Shop Trolling Motors

    Shop Trolling Motors

    Shop Mounts & Hardware

    Shop Mounts & Hardware

  • BrandsBrands
    • Shop by Brand A-H
      • Airmar
      • AMPD Marine
      • Ancor
      • Arco Marine
      • Attwood Marine
      • ATX Lure Company
      • Bass Boat Tech
      • Bass Boat Wired
      • Blue Sea
      • C-Map
      • Connect Ease
      • Cornfield Fishing Gear
      • DD26 Fishing
      • Digital Antenna
      • Dual Pro Chargers
      • Durasafe
      • Firefly
      • Fish Obsessed
      • Fusion Electronics
      • Garmin
      • HD Innovations
      • Humminbird
      • Hydrilla Gear
    • Shop by Brand I-O
      • Icom
      • Infinity Audio
      • JBL
      • Jensen Marine
      • JL Audio
      • Johnson Pump
      • Lithium Pros
      • Lowrance
      • Lumitec
      • Marinco
      • Marine Audio
      • Millenium
      • Minn Kota
      • Monster Marine Lithium
      • Mustang Survival
      • Navionics
      • Newmar
      • NOCO
      • Onyx Outdoor
      • Orion
    • Shop by Brand P-Z
      • Plano
      • Pro Charging Systems
      • Protec Products
      • Raymarine
      • Relion
      • Rigid Industries
      • RULE
      • Russel Marine Products
      • Scotty Inc.
      • Sea Clear
      • SeaStar
      • SeeLite
      • Shakespeare
      • SierraMarine
      • Simrad
      • Sionyx
      • Standard
      • T-H Marine
      • Transducer Shield & Saver
      • U-Call USA
      • Uniden
      • Whitecap Industries
      • XCite Baits
    Shop Garmin

    Shop Garmin

    Shop Humminbird

    Shop Humminbird

  • Boat NationBoat Nation
    • Bass Boat Wired
      Bass Boat Wired
    • Duck Boat Nation
      Duck Boat Nation
    • Kayak Boat Nation
      Kayak Boat Nation
    • Mud Boat Nation
      Mud Boat Nation
    • Salty Boat Nation
      Salty Boat Nation
  • AboutAbout
    • Our Story

    • Our Partners

  • SupportSupport
    • Contact

    • FAQs

    • Shipping & Returns

    • Warranty

Cart

Your cart is currently empty.

Not sure where to start?
Try these collections:

  • Continue shopping
Spend $1,000.00 more to reach free shipping!
    Order special instructions
    Estimate shipping
    Discount
      Taxes and shipping calculated at checkout
      Subtotal
      $0.00 USD
      Recently viewed
      Search

      We use cookies

      This site uses cookies for better user experience and analytics.

      Home Search Shop 0 Cart Account
      12v 40Ah Deep Cycle  Lithium Marine Battery "Viper" -  Bluetooth - MML-CW1240B
      12v 40Ah Deep Cycle  Lithium Marine Battery "Viper" -  Bluetooth - MML-CW1240B
      12v 40Ah Deep Cycle  Lithium Marine Battery "Viper" -  Bluetooth - MML-CW1240B
      12v 40Ah Deep Cycle  Lithium Marine Battery "Viper" -  Bluetooth - MML-CW1240B

      Monster Marine Lithium

      12v 40Ah Deep Cycle Lithium Marine Battery "Viper" - Bluetooth - MML-CW1240B

      $300.00

       

      ⚡ Monster Marine Lithium™ “Viper”

      12V • 40Ah Portable Bluetooth Deep Cycle Lithium Battery

      Model: MML-CW1240B


      Overview

      Portable, lightweight, and efficient — meet The Viper, a compact 12V lithium battery built for versatility and reliability.
      Weighing only 13 lbs, this battery is perfect for powering your 12V electronics, kayak systems, or outdoor power setups, delivering high performance in a small footprint.

      Built with Lithium Iron Phosphate (LiFePO₄) technology, The Viper provides twice the power, a fraction of the weight, and four times the lifespan of traditional lead-acid batteries.
      It features Bluetooth monitoring via the MMLithium App (iOS & Android), allowing you to track voltage, state of charge, and overall health in real time.

      Installation is simple — a true plug-and-play setup — and up to four batteries can be wired in series for higher voltage systems.
      Compact, rugged, and dependable, The Viper is also perfect for ice fishing bundles and mobile power boxes.


      Key Features

      ⚙️ Lightweight, Portable Design
      At just 13 lbs, The Viper is built for mobility — ideal for kayaks, ice fishing, go-boats, and small 12V setups.

      🔋 Reliable Deep-Cycle Power
      Delivers 40Ah of steady 12.8V power — perfect for fish finders, sonar units, and outdoor gear.

      📱 Bluetooth Smart Monitoring
      Stay informed with real-time tracking through the MMLithium Bluetooth App on your phone.

      🧠 Advanced LiFePO₄ Technology
      Safe, stable, and durable — with 4000+ charge cycles and consistent voltage output under load.

      🔌 Plug-and-Play Setup
      Quick and easy installation — connect your power leads, and you’re ready to go. Supports series and parallel wiring for expanded systems.

      ⚡ Charger Compatibility
      Compatible with AGM marine chargers (use AGM setting):

      • Minn Kota (Precision & Digital)

      • Dual Pro

      • NOCO

      • Real Pro

      • ProSport


      ⚙️ Specifications

      Category Details
      Weight 13 lbs
      Dimensions (L × W × H) 7.5 in × 5 in × 6.5 in (195 × 130 × 154 mm)
      Nominal Voltage 12.8 V
      Nominal Capacity 40 Ah
      Energy 512 Wh
      Charge Voltage Range 14.4 – 14.6 V
      Max Charge Current 40 A
      Continuous Discharge Current 60 A max
      Battery Chemistry Lithium Iron Phosphate (LiFePO₄)
      Cycle Life 4000+ cycles
      Terminal Type M8 Bolt
      Configuration Options Up to 4 in series for 48V max / parallel for higher capacity
      Bluetooth Functionality Built-in Smart Monitoring via MMLithium App

      ⚓ Applications

      Use Case Compatibility
      Primary Use Portable power for 12V electronics, kayaks, and ice fishing setups
      Voltage Systems Compatible with 12V, 24V, 36V, and 48V configurations
      Other Uses Fish finders, sonar units, power boxes, camping, and outdoor setups
      Replacement For 12V AGM or lead-acid batteries
      Weight Advantage Roughly 70% lighter than standard batteries
      In stock, ready to ship
       
       

      Share:

      • Share on Facebook
      • Share on X
      • Pin on Pinterest
      • Share by Email
      Share
      Share
      • Facebook Share on Facebook
      • X (Twitter) Share on X
      • Pinterest Pin on Pinterest
      • E-mail Share by Email

      Pairs well with

      In stock! Ships within 1-2 business days.

      90-day risk-free trial

      2-Year Warranty

      Complimentary shipping & returns

      12v 40Ah Deep Cycle  Lithium Marine Battery "Viper" -  Bluetooth - MML-CW1240B

      12v 40Ah Deep Cycle Lithium Marine Battery "Viper" - Bluetooth - MML-CW1240B

      $300.00
      Need help?

      If you have any questions, you are always welcome to contact us. We'll get back to you as soon as possible, within 24 hours on weekdays.

      • Shipping Information

        Use this text to answer questions in as much detail as possible for your customers.

      • Customer Support

        Use this text to answer questions in as much detail as possible for your customers.

      • FAQ’s

        Use this text to answer questions in as much detail as possible for your customers.

      • Contact Us

        Use this text to answer questions in as much detail as possible for your customers.

      Shop by Company
      • Bass Boat Wired
      • Duck Boat Nation
      • Kayak Boat Nation
      • Mud Boat Nation
      • Salty Boat Nation
      Support

      support@boatnationoutdoors.com

      Boat Nation Outdoors

      Join the Nation

      Don't miss out on new product alerts!

      • Facebook
      • X (Twitter)
      • Instagram
      • YouTube
      • TikTok
      © 2026 Boat Nation Outdoors. 
      • Refund policy
      • Privacy policy
      • Terms of service
      • Shipping policy
      • Amazon
      • Apple Pay
      • Discover
      • Google Pay
      • Mastercard
      • PayPal
      • Shop Pay
      • Visa
      • Choosing a selection results in a full page refresh.
      • Opens in a new window.