What Is a Deep Cycle Battery? How It Works and Where It Belongs

A battery is "good" only insofar as it fits its job. Put an excellent starter battery on house duty and it will die within months — because these are two athletes trained for different sports.

Sprinter vs Marathon Runner

A starter battery creates a large surface area with many thin plates: it delivers 600–700 amps for 2–3 seconds, then immediately refills from the alternator. Giving more than 10% of its capacity strains it.

A deep cycle battery carries fewer but thicker plates. Its purpose isn't burst power but the ability to discharge to 80% of capacity again and again. Thick plates withstand the mechanical stress of deep discharge.

Where It Belongs

• Caravan and boat house systems: Fridge, lighting, inverter supply
• Solar energy storage: Daytime harvest, night-time use
• Golf carts and EVs: All-day traction
• Cleaning machines: Uninterrupted power through the shift
• Mobility vehicles: Dependable daily range

Sizing: The 50% Rule

Limiting daily discharge to 50% doubles the cycle life of lead-acid deep cycle batteries. Practical maths: calculate your daily consumption (Ah) and double it. A caravan using 80Ah per day needs a 160Ah+ bank. Our MPG series covers every capacity from 26 to 250Ah.

Charging Rules

Deep cycle batteries love slow, complete charges. Charge at 10–13% of capacity and don't unplug before the cycle finishes. In solar systems, an MPPT controller with the right voltage profile (14.1–14.4V for gel) is the key to longevity. Request a free capacity calculation for your system.