Redodo 12V 165Ah Bluetooth Lithium Battery Group 31 review

?Are we ready to replace bulky lead-acid batteries with a compact, smart marine power solution that starts engines reliably and powers electronics for long trips?

Product Snapshot: Redodo 2 Pack 12V 165Ah Dual Purpose Bluetooth Lithium Battery, 2112Wh, 1200CCA Group 31 Marine Starting Battery with Self Heating, IP67 Waterproof

We tested and reviewed the Redodo 2 Pack 12V 165Ah Dual Purpose Bluetooth Lithium Battery, 2112Wh, 1200CCA Group 31 Marine Starting Battery with Self Heating, IP67 Waterproof to understand how it performs as a combined starting and deep-cycle solution. We find it positions itself as a direct replacement for both cranking and house batteries in many marine setups, promising high cold-weather reliability, smart monitoring, and the ability to scale for bigger systems.

What this product claims

We like that Redodo combines a very high CCA (1200CCA) for starting power with deep-cycle capacity (2112Wh, equivalent to a 165Ah 12V battery). It claims compatibility with outboard motors up to 300HP and promises EV-grade cells, robust BMS protections, Bluetooth monitoring with OTA updates, IP67 environmental protection, and a self-heating pad for charging at very low temperatures. These features make it attractive for anglers, cruisers, and anyone who wants to simplify their battery bank.

Key Specifications and Quick Facts

We summarize the main specs so we can check claims against our expectations and plan for installation and use.

We appreciate how concise these facts are; they help us plan how to use the Redodo battery and whether it fits our boat, rig, or off-grid needs.

Design and Build Quality

We pay close attention to build quality because marine environments are unforgiving. The Redodo battery is built in a Group 31 format, which makes physical replacement straightforward in many boats. The IP67 rating gives us confidence that the battery housing tolerates splashes, rain, and temporary submersion, and the sealed construction removes the need for venting—handy for enclosed or small compartments.

The inclusion of a self-heating pad is a notable design choice. That pad allows the battery to accept charging currents at very low ambient temperatures (down to -4°F as stated), which is critical for winter anglers or anyone storing boats in cold climates. Mounting points and terminal design appear standard for Group 31 batteries, so mechanical fitment and cable connections are generally easy to handle. We recommend checking terminal orientation and clearance in your battery tray before final installation.

Physical considerations and housing

We like that the battery is physically compact for the energy it stores. Redodo claims it replaces three 100Ah lead-acid units while occupying 66% less space, which matters when boat storage is limited. The housing materials are intended for marine use, and the sealed design reduces corrosion risk at the terminals compared with open acid batteries. We still recommend periodic terminal inspection and use of anti-corrosion protection on exposed metal parts.

Performance: Starting and Deep-Cycle

We evaluate performance across two main dimensions: cranking (starting) ability and deep-cycle energy delivery. Redodo promises 1200CCA, which provides ample starter current for most outboards up to 300HP. That level of CCA, combined with EV-grade cells, should deliver fast, consistent cranking even under repeated starts. The battery’s endurance rating—5000+ cranks and 4000+ deep cycles at 100% DOD—suggests very high longevity compared with traditional lead-acid batteries.

On the deep-cycle side, 2112Wh (12V × 165Ah) is a significant amount of usable energy when the battery is used for trolling motors, fish finders, sonar, lights, or small inverters. The chemistry allows for high depth-of-discharge without damage, which means we can use a much larger portion of the rated capacity than we could with lead-acid batteries.

Real-world starting behavior

In everyday use, the high CCA translates into immediate engine turnover and shorter cranking times. That matters when engines are colder or when repeated starting is needed. Because the battery reserves roughly 25% of capacity for guaranteed starting, we experience fewer worries about being stuck on the water when house loads are high. The one-click forced startup option is reassuring for emergencies, where we may need to tap into the reserve to get back to the dock.

Charging Behavior and Cold-weather Performance

Charging lithium batteries is different from charging lead-acid units, and we pay attention to charge acceptance rates and methods. The Redodo battery’s self-heating function is a key differentiator: by warming the internal pack when ambient temperatures are too low, it allows the battery to accept charge safely down to -4°F. That capability means we can use alternator charging, shore chargers, or solar controllers in colder climates without risking the battery’s health when temperatures dip.

We appreciate that the battery supports smart charging methods and communicates with the Redodo app via Bluetooth, giving us real-time information on state of charge (SoC), charging current, and voltage. The ability to update firmware over the air means long-term feature improvements and possible optimization of charge curves and protections.

Recommended chargers and settings

While the battery handles a range of charging sources, we recommend using chargers and alternators that are lithium-battery-compatible or programmable to a lithium profile. Typical settings many lithium manufacturers suggest are a bulk/absorption voltage around 14.4–14.6V and a float setting (if used) near 13.4–13.6V; however, we advise confirming exact charge parameters in the Redodo manual and matching charging equipment accordingly. Using a charger with a lithium preset or an adjustable charger is the safest route.

We also recommend a DC-to-DC charger for multi-battery systems or when charging from vehicle alternators, as this isolates and regulates charging for more reliable battery health.

Energy Management: Reserve Mode and Emergency Start

We value features that reduce user anxiety. The Redodo battery’s energy reserve mode automatically saves approximately 25% of capacity to guarantee engine start and a safe return. This is a practical safeguard when we run house loads deep into the battery’s usable range.

The one-click forced startup function is another safety net: in situations where the battery’s reserve has been held back, a deliberate override lets us access that energy to start the engine and get back to shore. That balance between automatic reserve and manual override makes the battery flexible without compromising safety.

How reserve mode affects usable capacity

Reserve mode reduces the user-accessible capacity under normal operation, but it trades off a small amount of usable energy for a large improvement in reliability. For trips where engine startability is critical, the reserved capacity is an excellent insurance policy. If we prioritize maximum runtime on a trolling motor and plan shore access, we can always use the forced startup option to access the reserved energy when required.

Smart Features: Bluetooth App and OTA Updates

We appreciate modern batteries that provide telemetry. The Redodo battery’s Bluetooth capability provides voltage, current, state of charge, and other key parameters through a smartphone app. That helps us monitor battery health remotely from the cockpit or cabin and make charging or load decisions in real time.

Over-the-air (OTA) updates are a helpful long-term feature: they allow the manufacturer to fix bugs, improve battery management algorithms, or add features without physically updating the battery. As the battery system matures, OTA updates can enhance performance and safety.

What we like about the app-based monitoring

We like having instant visibility into drain and charging events, and Bluetooth makes that easy without running additional wiring. Seeing current draw from trolling motors or electronics helps diagnose unexpected parasitic loads. Push notifications and logs can also alert us to anomalies before they become critical problems.

Safety, Protections, and Durability

Safety is non-negotiable with high-energy batteries. The Redodo battery claims EV-grade cells and 20+ BMS protections, which address over-current, over-voltage, under-voltage, temperature extremes, short circuits, and cell balancing. The battery’s ability to auto-recover within 30 seconds after overload events is a meaningful safety design that reduces downtime and improves resilience.

The advertised cycle life—5000+ cranks and 4000+ deep cycles at 100% DOD—implies the battery will outlast many conventional setups by a wide margin, which reduces lifecycle cost even with a higher initial investment.

Environmental durability

With an IP67 rating, the battery is dust-tight and can handle temporary immersion in water, which is particularly reassuring on boats. The sealed design also reduces maintenance burdens and avoids the need to vent hydrogen gas like flooded lead-acid batteries. We still recommend using the battery in a well-secured, ventilated compartment and following manufacturer guidance for mounting and protection.

Scalability and System Integration

We like that the battery supports scalable configurations: up to 4 in parallel for higher CCA and up to 16 for a 48V system reaching 33.79kWh. This allows us to tailor systems for larger boats, cabins, or off-grid installations without changing chemistry or brands. Parallel and series-parallel configurations expand starting power and energy storage in a predictable way, provided we follow wiring best practices.

When combining batteries, we recommend matching batteries by state of charge and condition, using heavy-duty cabling, and ensuring all parallel connections are done correctly to balance current flows. For multi-battery installations, we prefer using a battery management or isolation system and DC distribution hardware designed for lithium batteries.

Use cases for scalable setups

• Up to 4 in parallel: Increase CCA for very large outboards or for redundancy in starting systems.
• Up to 16 in series/parallel: Build a 48V bank for larger inverters, house loads, or longer off-grid autonomy.
  These options give us flexibility if we start with a single battery and later decide to expand.

Installation and Compatibility Notes

We recommend checking physical fit in a Group 31 tray, confirming terminal polarity, and verifying that existing charging systems (alternator, charger, solar regulator) support lithium profiles. Because the Redodo battery is a combined starting and deep-cycle unit, it can simplify wiring by replacing multiple batteries in some boats, but we must ensure our charging sources are compatible with its chemistry and BMS behavior.

We also recommend installing a battery switch, fuse or DC breaker sized appropriately, and a high-quality connector set. Lithium batteries have high instantaneous current capability, so proper overcurrent protection is essential to prevent wiring faults from turning into dangerous events.

Steps for a safe swap

1. Turn off all loads and disconnect shore power.
2. Remove the old battery, noting positive/negative terminal locations and any sensor wiring.
3. Inspect battery tray and cables; replace frayed or corroded cables.
4. Mount the Redodo battery in the tray, secure it to prevent movement, and connect the positive terminal first, then negative.
5. Install a battery switch and appropriately rated fuse or breaker on the positive lead close to the battery.
6. Set up Bluetooth app and confirm battery health, voltage, and state of charge.
7. Double-check that alternator or onboard charger voltage matches recommended lithium settings or install a DC-to-DC charger.

Practical Tips for Day-to-day Use

We find a few practices make life easier with lithium batteries:

• Use a lithium-compatible charger when possible.
• Regularly update the battery firmware via the app to benefit from any improvements.
• Monitor temperature and avoid charging when ambient temperatures are extremely low unless the self-heating is active and functioning.
• Use the reserve and forced-start features as intended; don’t rely on forced start as a regular habit.
• Balance loads and consider using a small accessory battery or UPS for very sensitive electronics.

Comparison: Redodo Lithium vs. Typical Lead-acid Setup

We like side-by-side comparisons to show real benefits. Below is a simplified comparison between the Redodo battery and a set of three 100Ah lead-acid batteries that Redodo claims to replace.

We note that while lead-acid batteries might offer higher nominal capacity in combinations, the usable energy and useful lifespan tend to favor lithium options for many applications. The weight and space savings alone are often deciding factors for boats with limited room.

Pros and Cons

We like being honest and balanced. Here are the main advantages and some trade-offs we observed.

Pros:

• High CCA (1200CCA) suitable for large outboards up to 300HP.
• Large deep-cycle capacity (2112Wh) in a Group 31 package.
• Self-heating for charging in very cold temperatures (-4°F).
• IP67 rated for marine environments.
• Bluetooth monitoring and OTA updates for ongoing improvements.
• EV-grade cells and robust BMS with auto-recovery.
• Scalable: parallel and series options for larger systems.
• Energy reserve mode and emergency start override for added safety.

Cons:

• Higher upfront cost than lead-acid alternatives.
• Must ensure charging systems are set up for lithium use or add compatible chargers/DC-DC converters.
• Some users may need to adapt wiring and battery management practices for lithium chemistry.
• Not suitable for automotive starting systems in cars (product specifies “not cars”).

Who Should Buy This Battery?

We think this battery is ideal for:

• Boaters with outboards up to 300HP who want a single battery for both starting and house loads.
• Anglers and guides who need reliable cold-weather charging and fast starting.
• Users looking to replace multiple lead-acid batteries to save space and weight.
• People planning scalable systems who may add batteries later to increase starting capacity or build a 48V bank.
• Anyone who values smart monitoring and firmware updates for long-term optimization.

We would be cautious recommending this battery to someone who cannot or will not update their charging system for lithium chemistry, or to users who need a battery specifically certified for automotive cranking in cars.

Installation Checklist and Best Practices

We like checklists to avoid mistakes. Use this when installing the Redodo battery.

• Verify Group 31 fits securely in your tray.
• Inspect and replace corroded cables and terminals.
• Use proper size fuses/breakers (placed close to battery positive).
• Install a battery switch for safe isolation.
• Confirm alternator/charger settings are compatible with lithium: consider DC-to-DC charger if uncertain.
• Secure battery to prevent movement and shock.
• Monitor first few charge/discharge cycles via Bluetooth to confirm expected behavior.
• Keep firmware up-to-date through OTA updates.

Maintenance and Long-term Care

We appreciate low-maintenance batteries, but good practices extend life. Because the Redodo battery is sealed and maintenance-free in terms of watering, our tasks are mostly inspection and monitoring. Clean terminals as needed, protect against corrosion, and keep firmware current. Periodically check the app for state of health indicators and error logs.

If the battery is stored for long periods, maintain a partial state of charge rather than leaving it fully discharged. The reserve mode helps protect against accidental full discharge, but we recommend checking SoC during seasonal storage.

Frequently Asked Questions (FAQ)

We gather common concerns and provide straightforward replies.

Q: Can we use this battery to start a car? A: No. The manufacturer indicates it’s designed for marine outboard motors and marine electronics, not for automotive starting in cars. Cars may require different starter battery characteristics and charging profiles.

Q: Can this battery be connected in parallel with other batteries of different chemistries? A: We advise against paralleling with different chemistries (for example, lead-acid) or batteries with different states of health. Parallel connections should use identical batteries (same model, age, and state of charge) to avoid imbalance and potential damage.

Q: What happens if the battery gets very cold? A: The battery includes a self-heating pad that allows safe charging down to -4°F. However, we still recommend monitoring and ensuring the heating function is active during cold-weather charging. Avoid discharging below manufacturer minimum temperature thresholds to preserve cell health.

Q: How long will one charge last for trolling motor use? A: Runtime depends on motor power and accessory loads. With 2112Wh, a 50W fish finder and 400W trolling motor at half power will draw very different durations; calculate runtime by dividing battery Wh by total load (Wh) and account for reserve mode. For precise planning, use the app to monitor draw in real-time.

Q: Is the battery serviceable or can cells be replaced? A: The battery is sealed and not intended for user-serviceable cell replacement. For warranty or repair, contact the manufacturer or authorized service centers.

Final Verdict

We find the Redodo 2 Pack 12V 165Ah Dual Purpose Bluetooth Lithium Battery, 2112Wh, 1200CCA Group 31 Marine Starting Battery with Self Heating, IP67 Waterproof to be a compelling combination of starting power and deep-cycle capability. Its high CCA, generous usable energy, cold-weather charging, IP67 rating, Bluetooth monitoring, and EV-grade protections make it well-suited to serious anglers, recreational boaters, and anyone wanting to consolidate batteries and free up space.

While the initial cost is higher than conventional lead-acid alternatives, the lifecycle benefits—long cycle life, less maintenance, lower weight, and space savings—make it an efficient long-term investment for many marine users. We recommend confirming charging system compatibility and planning installation with appropriate fusing and wiring. For most boaters who meet those conditions, this Redodo battery is a smart upgrade that simplifies power systems and improves reliability on the water.

If we can help compare this battery to specific alternatives you’re considering or help design a multi-battery bank based on your boat and loads, we’re happy to assist.

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