Many heavy duty diesel trucks have traditionally required two batteries in parallel to deliver the high starting power needed to start its engine. With the adoption of LiFepo4 heavy duty starter battery technology, a battery for diesel truck can not only meet the demanding starting requirements but also provide stable power for auxiliary equipment.

Some people assume that all truck batteries are basically the same, as long as they can ignite the engine. However, this is not the case. Diesel engines place far higher demands on start-stop batteries compared to regular passenger cars. In particular, heavy-duty trucks that still rely on low-cost, short-lifespan lead-acid options often face problems such as capacity loss and unstable voltage after a period of use. That’s why choosing advanced batteries for a diesel truck is critical for long-term reliability and performance.

Why Do Diesel Trucks Have 2 Batteries?

Starting a large-displacement diesel engine requires a very high instantaneous current (CCA), which is why traditional heavy duty trucks often rely on two lead-acid batteries connected in parallel to ensure stable voltage and provide additional redundancy.

Today, however, a single high-performance 24V LiFePO₄ starter battery can meet these high-current starting demands while delivering reliable power to auxiliary systems. Compared to a dual lead acid battery setup, a LiFePO₄ battery is lighter, more compact, and offers a longer cycle life, eliminating concerns about uneven discharge or frequent maintenance.

Deep-cycle truck battery for powering air conditioner: balancing AC runtime and starting power

When a diesel truck must deliver both dependable starting power and extended air-conditioning runtime, a purpose-built 24V LiFePO₄ deep-cycle battery offers a practical solution. Designed with a high peak current capability (2,500A CCA) and a usable energy capacity (for example ≈3.8 kWh), such batteries start heavy-duty engines even in sub-zero conditions and then transition to sustain cab AC for several hours during rest periods.

From the starting perspective, Cold Cranking Amps (CCA) measure the instantaneous current available to crank an engine at low temperature—this remains the primary metric for reliable cold starts. A LiFePO₄ pack engineered for trucks delivers high CCA through low internal resistance and a robust BMS, so it can match or exceed the cranking performance of paired lead-acid banks while occupying less space and weight. Note that competent low-temperature management (BMS settings or integrated heating) preserves both starting capability and battery life in cold climates.

From the deep-cycle perspective, these LiFePO₄ batteries are built to tolerate repeated deep discharges without the rapid capacity loss typical of lead-acid chemistry. Key advantages for powering AC loads include long cycle life (often ~2,000–3,000+ cycles at deep discharge), high usable depth-of-discharge (safe to discharge down to ~20% remaining), stable voltage under load (important for sensitive AC compressors and inverters), and much shorter recharge times. Together, these traits enable reliable multi-hour air-conditioning operation without sacrificing the reserve needed for dependable engine starts.

In short, a correctly specified LiFePO₄ deep-cycle truck battery bridges two traditionally separate needs—starting power (CCA) and long-duration AC supply—making it a strong candidate for long-haul trucks, RVs, and work fleets that want driver comfort, reduced idling, and lower lifecycle maintenance compared with conventional dual lead-acid setups.

AGM vs. Flooded vs. Lithium Batteries

In heavy-duty diesel truck applications, the choice of truck battery directly impacts uptime, cold-weather starting, and the ability to power auxiliary loads such as sleeper cab HVAC systems, refrigeration units, and onboard electronics. Among all options, LiFePO₄lithium truck batteries stand out as the most efficient and reliable solution.

*Flooded Truck Battery: The lowest upfront cost, but poor resistance to vibration, frequent maintenance, and major performance drop in low temperatures make it unsuitable for long-haul and cold-climate diesel trucks.

*AGM Truck Battery: Offers maintenance-free operation and better voltage stability than flooded batteries, and is widely used in fleets. However, below -20 °C, starting capacity and CCA drop sharply, limiting reliability for heavy-duty diesel truck engines.

*Lithium (LiFePO₄) Truck Battery: Retains about 70% usable capacity and CCA even at -40 °C, while supporting fast charging. More importantly, it provides consistent voltage under heavy load, ensuring both powerful engine starts and stable auxiliary power. With a cycle life of 3000+ cycles, its total cost of ownership is significantly lower than AGM and flooded truck batteries.

Why LiFePO₄ Is the Best Battery for Trucks

Cold Weather Starting Power: Even in extreme cold, LiFePO₄truck battery delivers strong cranking amps, preventing downtime caused by diesel truck engines failing to start.

Reliable Auxiliary Energy: Supports overnight hoteling, truck refrigeration systems, and in-cab electronics with stable voltage and no noticeable sag.

Lower Cost of Ownership: While the initial investment is higher, LiFePO₄ lasts far longer than AGM or flooded truck batteries, reducing replacements, maintenance, and unplanned breakdowns.

Fleet-Proven Performance: Ideal for long-haul logistics, cold chain transport, and any heavy-duty truck fleet prioritizing uptime and reliability.

Our Top Picks for Diesel Truck Batteries in 2025

For fleets seeking a next-generation heavy duty diesel truck battery, the CB-18 LiFePO₄ truck starting battery is a standout choice in 2025. Unlike traditional AGM or flooded truck batteries, the CB-18 combines both high cranking power and long-lasting auxiliary energy in one unit.

Powerful Starting Performance: With 2500A peak cranking amperage, the CB-18 ensures instant and reliable starts for large diesel engines, even in extreme cold weather conditions.

Built-in Auxiliary Energy: Delivering 3.84kWh capacity, this LiFePO₄ truck battery can run air conditioning systems and in-cab electronics during long rest periods with the engine switched off. This reduces fuel consumption and complies with anti-idling regulations.

Advanced Safety & Efficiency: Integrated BMS technology provides overcharge protection, thermal monitoring, and intelligent cell balancing, extending battery life while maintaining safe, stable performance.

LiFePO₄ Advantage: Compared to AGM and flooded truck batteries, LiFePO₄ offers longer cycle life, higher energy efficiency, and better cold-weather reliability, making it the best truck battery solution for modern diesel fleets.

For 2025, the CB-18 is a complete LiFePO₄ energy solution designed to support heavy-duty diesel trucks engines and auxiliary equipments.