Can you use a deep cycle battery for cranking?

Deep cycle batteries and cranking (starting) batteries are designed for different purposes, but under certain conditions, a deep cycle battery can be used for cranking. Here’s a detailed breakdown:

1. Primary Differences Between Deep Cycle and Cranking Batteries

• Cranking Batteries: Designed to deliver a high burst of current (Cold Cranking Amps, CCA) for a short time to start an engine. They have thinner plates for maximum surface area and quick energy discharge 4.

• Deep Cycle Batteries: Built to provide steady, lower current over a long period (e.g., for trolling motors, RVs, or solar systems). They have thicker plates to withstand repeated deep discharges 46.

2. Can a Deep Cycle Battery Be Used for Cranking?

• Yes, but with limitations:

  • Lower CCA: Most deep cycle batteries have lower CCA ratings than dedicated cranking batteries, which may struggle in cold weather or with large engines 14.

  • Durability Concerns: Frequent high-current draws (like engine starts) can shorten the lifespan of a deep cycle battery, as they’re optimized for sustained discharge, not bursts 46.

  • Hybrid Options: Some AGM (Absorbent Glass Mat) deep cycle batteries (e.g., 1AUTODEPOT BCI Group 47) offer higher CCA (680CCA) and can handle cranking, especially in start-stop vehicles 1.

3. When It Might Work

• Small Engines: For motorcycles, lawnmowers, or small marine engines, a deep cycle battery with sufficient CCA may suffice 4.

• Dual-Purpose Batteries: Batteries labeled "marine" or "dual-purpose" (like some AGM or lithium models) combine cranking and deep cycle capabilities 46.

• Emergency Use: In a pinch, a deep cycle battery can start an engine, but it’s not ideal for daily use 4.

4. Risks of Using a Deep Cycle Battery for Cranking

• Reduced Lifespan: Repeated high-current draws can damage thick plates, leading to premature failure 4.

• Performance Issues: In cold climates, the lower CCA may result in slow or failed starts 1.

5. Best Alternatives

• AGM Batteries: Like the 1AUTODEPOT BCI Group 47, which balances cranking power and deep cycle resilience 1.

• Lithium Iron Phosphate (LiFePO4): Some lithium batteries (e.g., Renogy 12V 20Ah) offer high discharge rates and can handle cranking, but check manufacturer specs 26.

Conclusion

While possible, using a deep cycle battery for cranking is not recommended for regular use. Opt for a dual-purpose or high-CCA AGM battery if you need both functionalities. For critical applications (e.g., cars, boats), stick to purpose-built cranking batteries