No, you should not use a leisure battery to start a car. While both are 12-volt batteries, they are engineered for fundamentally different purposes. A leisure battery (also known as a deep-cycle battery) is designed to provide a steady, low amount of power over a long period to run accessories like lights, refrigerators, or audio systems in a campervan or RV. It can be discharged significantly and recharged repeatedly. A car starting battery, however, is built to deliver a very high burst of power for a few seconds to crank the engine. This is measured as Cold Cranking Amps (CCA).
Attempting a jump-start with a leisure battery can be ineffective and may damage the leisure battery. Its internal lead plates are thicker and not designed to handle the massive current demand required by a starter motor. Repeatedly trying could overheat the battery, warping the plates and permanently reducing its capacity for its intended deep-cycle use.
The following table compares the key specifications of a typical car battery versus a common leisure battery:
| Specification | Typical Car Starting Battery | Typical Leisure Battery (Deep-Cycle) |
|---|
| Primary Function | Deliver short, high-power bursts for engine cranking | Provide sustained, low-power output for accessories |
| Cold Cranking Amps (CCA) | 500 - 800 A | 100 - 250 A (if rated at all) |
| Amp-Hour (Ah) Capacity | 40 - 60 Ah | 75 - 120 Ah |
| Plate Design | Thin plates for maximum surface area | Thick plates to withstand deep discharging |
| Cycle Life | 300 - 500 cycles | 1000 - 2000+ cycles |
For a reliable jump-start, always use jumper cables connected to a proper car starting battery in another vehicle or a dedicated jump starter pack. A jump pack is a much safer and more effective portable solution for this specific task.
