12V 100Ah LiFePO4 Group 31 (2-Pack) review

Are we looking for a durable, compact battery solution that can replace heavy lead-acid batteries in our RV, marine, solar, or backup setups?

Product Overview

We think the 12V 100Ah LiFePO4 Lithium Battery Group 31 (2-Pack) With Built-in 100A BMS, Low-Temp Protection Up to 15000 Deep Cycles Rechargeable Battery for RV, Marine, Solar System, Van, Trailer, Backup brings a lot of attractive features for a wide range of applications. The unit aims to deliver high cycle life, built-in safety systems, and lighter weight compared with SLA/AGM batteries, and the 2-pack offering targets users who need multiple batteries for increased capacity or parallel use.

What this product is

We see this as a drop-in energy storage replacement for many 12V lead-acid batteries used in leisure vehicles, marine craft, off-grid solar systems, and as portable backup. It is a 12.8–13.2V nominal LiFePO4 battery (commonly called 12V LiFePO4) with a 100Ah capacity and an internal Battery Management System (BMS).

Who this is for

We recommend this for RVers, van lifers, boaters using trolling motors, cabin owners, or anyone building a small off-grid system who wants a lightweight, long-life battery that tolerates deep cycling and offers safety protections. We would not recommend it as a starter battery for engine cranking.

Key Specifications

We like to have the core numbers up front so we can quickly assess fit for purpose. Below is a compact breakdown of the most important specs.

What’s in the Box

We appreciate clarity about packaging and what to expect. The seller provides each battery in its own box due to weight and handling constraints, and a 2-pack order will physically contain two separate boxes.

• One GRNOE 12V 100Ah LiFePO4 battery per box.
• Basic documentation including user manual and warranty details.
• No specialized charger, mounting brackets, or cables are included by default.

We suggest checking the documentation immediately upon receiving the battery so we can follow the activation and charger recommendations.

Build Quality and Design

We found the physical build to be compact and thoughtfully organized for a Group 31 form factor. The manufacturer uses A+ grade LiFePO4 cells and says the internal structure and components are optimized for compactness and safety.

• The compact dimensions and low weight (22.48 lbs) make it easy for two people to handle and mount in tight spaces where lead-acid batteries would normally be bulky.
• The IP65 rating gives us confidence that the battery can tolerate dust and water spray, which is useful in marine and outdoor settings.
• External terminals are standard and suitable for marine and RV battery trays, but we recommend securing them to prevent vibration-related loosening.

We feel the overall construction matches what we’d expect for a battery positioned as a performance-oriented replacement for SLA/AGM units.

Performance and Capacity

We like that this battery gives 100Ah of usable capacity with the ability to handle deep cycling repeatedly. LiFePO4 chemistry allows higher usable depth-of-discharge compared with lead-acid, meaning we can use more of the battery’s rated capacity without damaging it.

• The manufacturer claims up to 15,000 deep cycles—this is a very high number and, in practice, will depend on depth of discharge, temperature, and charging practices.
• With a high energy density (57 Wh/lb), we get substantial runtime while carrying far less weight than lead-acid equivalents. This is especially valuable for weight-sensitive applications like vans and small boats.

Cycle Life and Longevity

We are impressed by the advertised cycle life, but we also want to be practical about real-world expectations. Manufacturer cycle estimates often assume optimal conditions.

• If we cycle the battery shallowly (e.g., 20–30% DOD for daily use), the lifespan will be much longer than if we routinely discharge it to very low levels.
• The LiFePO4 chemistry itself is intrinsically stable and known for long calendar life; the built-in BMS helps prevent damaging conditions that shorten life.

We consider the practical advantage over lead-acid to be both cost-savings over time and fewer replacements to manage.

Discharge and Peak Current

We found the discharge capabilities suitable for bursts and secondary loads.

• The battery supports a maximum burst discharge of 300A for 3 seconds, which handles surge loads such as electric trolling motor draws or inverter startup surges (within reason).
• The continuous discharge rating isn’t explicitly stated in every spec sheet, but the 100A BMS limits continuous discharge protection; that aligns with many 12V LiFePO4 designs for continuous loads up to ~100A.

We recommend verifying the continuous amperage needs of our loads (inverter, motor, etc.) and ensuring the BMS-rated current is adequate.

Low-Temperature Protection and BMS

We appreciate that this model integrates low-temperature cut-off as part of the BMS. That’s a critical feature for cold-weather applications.

• The battery allows discharge down to -4°F (-20°C), so we can use it in very cold climates for running loads.
• Charging is disabled by the BMS below 32°F (0°C). This protects the battery from lithium plating and internal damage that can occur if charging at low temperatures.
• The BMS also provides protections for overcharge, over-discharge, over-current, short circuit, and overheating.

We find the low-temperature cut-off practical: if we keep the battery in an insulated compartment or heat it slightly before charging in cold weather, we maintain safety and longevity.

Charging Requirements and Best Practices

We need to be careful about charging protocol with any LiFePO4 battery, and this model comes with specific activation and charging instructions.

• We must use a charger that can reach 14.6V ±0.2V to properly charge and activate the battery. A standard 12V lead-acid charger will not fully charge it and may cause BMS protective shutdown in some cases.
• After first receiving the battery or after a long sleep state, charge it immediately with a 14.6V lithium activation charger to activate the battery.
• Avoid chargers with “repair/desulfation” modes or automotive chargers that can output voltages or sequences that confuse the BMS.
• Before connecting batteries in series, they should be fully charged and within 0.2V of each other to prevent imbalance and stress on the BMS.
• If we leave the battery idle for long stretches, charging it at least once every two to three months helps maintain health and prevents deep discharge due to BMS parasitic draws.

We suggest using a LiFePO4-compatible multi-stage charger or a charge controller set to LiFePO4 profile for solar systems.

Installation and Mounting

Installing the battery is straightforward, but we want to follow best practices to maximize life and safety.

• Mount in a ventilated, secure tray or bracket using non-conductive mounting straps if possible. Avoid direct contact with sharp metal edges.
• Make sure terminal connections are clean, tight, and protected from corrosion—especially in marine environments.
• If stacking batteries or installing multiple in a confined space, ensure they have adequate airflow and are secure from vibration.
• For parallel installations, match batteries in capacity and state-of-charge; for series installs, do not exceed recommended voltage and ensure identical charge states and models.

We recommend using properly sized cables and appropriate fuses or breakers near the battery positive terminal to protect wiring and equipment.

Series and Parallel Notes

We prefer parallel connection for increasing capacity at 12V; series connections to obtain higher voltage (24V, 48V) require extreme care.

• Series: Ensure each battery is fully charged and within 0.2V of each other before connecting. Mismatched voltages in series can cause BMS shutdown or damage.
• Parallel: Preferably use same-model batteries of similar age and state of charge. Parallel is typically safer for adding capacity at the same voltage.

Use Cases and Application Examples

We like practical examples to illustrate how this battery fits into common setups.

RV and Van Life

For van builds and RVs, the weight savings and long cycle life are game changers.

• We can replace heavy lead-acid batteries and reclaim payload capacity and interior space.
• The 100Ah capacity offers reliable power for lights, fridges, electronics, and small inverters when combined with efficient appliances or a small solar array.

We recommend pairing the battery with a LiFePO4-compatible solar charge controller and an inverter sized to our typical continuous loads.

Marine and Trolling Motors

This battery is suited for trolling motor applications where deep-cycle capacity and weight matter.

• The IP65 rating helps protect against spray, and the burst 300A capability covers surge draws associated with trolling motor thrust changes.
• The product notes explicitly that the battery is suitable for trolling motors and marine use, but not for engine starting.

We advise installing it in a secure battery box with proper marine-grade wiring and breakers.

Solar and Off-grid Systems

Off-grid cabins and small solar systems benefit from LiFePO4’s deep-discharge tolerance.

• We would pair this battery with a charge controller or inverter/charger configured for LiFePO4 charging at 14.6V.
• Its long life reduces replacement frequency and maintenance compared with lead-acid banks.

We recommend monitoring battery state-of-charge and temperature during winter months due to the BMS charging cutoff below 32°F.

Home Backup and Trailer

For emergency backup or trailer power, the battery is compact and transportable.

• The relatively low weight allows us to move and install the battery easily for seasonal backup needs.
• It’s important to remember that for heavy inverter start loads, we should check the inverter’s surge draw versus the battery’s BMS and wiring capacity.

We find it a practical choice for medium-duty backup systems and mobile power needs.

Safety Features

Safety is one of the main selling points of LiFePO4 chemistry and of this particular product’s design.

• The built-in BMS protects against many common hazards including overcharge, over-discharge, overcurrent, short circuits, and overheating.
• UL and UN38.3 certifications indicate the manufacturer has met certain safety and shipping standards.
• The low-temperature charge cutoff is crucial for avoiding lithium plating and internal cell damage.

We always recommend using proper fusing, following installation guidelines, and avoiding improper charging equipment to maintain safety.

Maintenance and Storage

We prefer low-maintenance solutions, and LiFePO4 batteries largely deliver.

• Charge at least once every two or three months during storage to prevent the battery from drifting to low voltage states and triggering BMS protective shutdowns.
• Store in a cool, dry place and avoid prolonged exposure to extreme temperatures, which accelerates capacity loss or can trip protections.
• Check terminals periodically for tightness and corrosion, especially after exposure to saltwater or humid environments.

We believe a small amount of routine attention will keep this battery performing well for years.

Shipping, Packaging, and Delivery Notes

We appreciate transparent shipping notes, because logistics matter for large batteries.

• Each battery ships one per box due to weight; this means a two-battery order may arrive in two separate deliveries and possibly via different trucks.
• If our order shows deliveries at different times, patience is required; the packages are intentionally split and not an error in fulfillment.
• Inspect each box and the battery upon arrival for transit damage and keep documentation handy if we need to contact support.

We feel this is a reasonable compromise given shipping constraints around heavy batteries.

Warranty and Customer Support

A 36-month warranty is included, which provides reasonable peace of mind. We want to summarize what to expect.

• The manufacturer offers replacement or money-back within 36 months for defects excluding human-caused damage.
• For activation or performance questions, contacting support is encouraged. The listing states that they are available for inquiries and lifetime support.
• Keep proof of purchase and any relevant documentation to speed up warranty claims.

We find the warranty length competitive and the availability of manufacturer support reassuring.

Pros and Cons

We like balanced analysis. Below we summarize main advantages and potential drawbacks.

Pros:

• Substantially lighter than lead-acid (about 33% of lead-acid weight).
• High cycle life potential and long calendar life.
• Built-in 100A BMS with multiple safety protections.
• Low-temperature discharge capability and charging cutoff for protection.
• IP65 water resistance and UL/UN38.3 certifications.
• Compact Group 31 form factor that fits many existing battery compartments.

Cons:

• Requires a 14.6V ±0.2V LiFePO4-compatible charger; standard 12V chargers will not fully charge or may trigger the BMS.
• Charging disabled below 32°F—must plan for winter charging strategy or insulation/heating.
• 2-pack orders ship each battery in a separate box, which can result in staggered delivery times.
• Not suitable for engine starting; intended for energy storage only.

We feel that the pros outweigh the cons for most users who need deep-cycle storage rather than starting capability.

How This Compares to Lead-Acid and Other LiFePO4 Options

We like to compare to common alternatives so we can make an informed decision.

• Versus SLA/AGM: The LiFePO4 battery is far lighter, supports deeper cycles without damage, and offers a higher usable capacity percentage. Over time we save money due to fewer replacements and better usable energy.
• Versus other LiFePO4 batteries: This model offers a strong BMS and low-temp protections that some cheaper LiFePO4 options omit. The claimed cycle life (up to 15,000) is high; actual longevity will vary, but the product sits competitively in its market segment.

We recommend checking continuous discharge ratings and warranty terms when comparing models, and ensuring charger compatibility.

Frequently Asked Questions

We like to answer the most common practical questions we encounter.

Q: Can we use a standard 12V lead-acid charger? A: No. We must use a 14.6V ±0.2V charger configured for LiFePO4 charging, especially for initial activation. Using a 12V lead-acid charger can leave the battery undercharged or trigger BMS protections.

Q: Can this battery start an engine? A: No. The battery is intended for energy storage and cycle use, not for starter applications. Use a dedicated starting battery or a battery model specified for cranking.

Q: Can we put two of these in series for 24V? A: Yes, but both batteries must be fully charged and within 0.2V of each other before connecting in series. We must ensure balanced state-of-charge and matching battery models.

Q: How often should we charge the battery in storage? A: Charge at least once every two to three months to maintain health and prevent deep-discharge shutdown from BMS parasitic draw.

Q: What happens when it’s cold? A: The battery allows discharge down to -4°F, but charging is disabled below 32°F by the BMS. We should avoid charging in freezing conditions or use insulation/heat to raise the battery temperature before charging.

Q: What does the 300A 3-second rating mean? A: It’s a burst current capability to handle short surges (e.g., motor start loads) but should not be used as a continuous rating. Use appropriate wiring and protection to handle high currents safely.

Setup Checklist and Best Practices

We like to give practical steps so we can get started without surprises.

• Purchase a LiFePO4-compatible charger or set our solar charge controller to LiFePO4 mode (14.6V).
• Inspect the battery and documentation upon receipt for any transit damage.
• Charge the battery immediately on receipt using a 14.6V activation charge.
• Securely mount and connect the battery using properly sized cables and a fuse or breaker near the positive terminal.
• Avoid charging below 32°F; if necessary, warm the battery to allow charging.
• If installing multiple batteries, match states of charge and voltages before paralleling or series connections.
• Keep records of purchase and warranty documentation in case support or replacement is needed.

We find that following these steps helps avoid common pitfalls and preserves battery life.

Final Thoughts and Recommendation

We think the 12V 100Ah LiFePO4 Lithium Battery Group 31 (2-Pack) With Built-in 100A BMS, Low-Temp Protection Up to 15000 Deep Cycles Rechargeable Battery for RV, Marine, Solar System, Van, Trailer, Backup represents a compelling option for users seeking to replace lead-acid batteries with a lighter, longer-lasting solution. Its built-in BMS, low-temperature protections, IP65 rating, and manufacturer certifications give us confidence in its safety and reliability for deep-cycle applications.

If we need robust energy storage for RVs, trolling motors, small off-grid solar arrays, or backup power and are prepared to use a proper LiFePO4 charger and follow the temperature/installation guidelines, this battery checks a lot of boxes. We should factor in the shipping note about each battery coming in its own box when ordering multiple units, and we must avoid using the battery for engine starting. Overall, we recommend this battery for practical deep-cycle energy storage needs where weight, cycle life, and safety matter.

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