How To Size Leisure Battery

# How to Size Your Leisure Battery for Van Life *Published: May 20, 2026 · Tutorial · 10 min read*  Your leisure battery is the heart of any van life electrical system. It powers your lights, fridge, phone chargers, water pump, and inverter — all the things that make living in a van comfortable. With the UK's long, dark winters meaning less solar charging, choosing the right battery is critical. This guide covers the best leisure batteries available on Amazon UK, from budget-friendly AGM models to premium LiFePO4 lithium systems that can last 2,000+ cycles. ## What You'll Need ### Choosing the Right Leisure Battery **Capacity (Ah):** Measured in Amp Hours. A 100Ah battery can theoretically deliver 100A for one hour, or 10A for 10 hours. Rule of thumb: plan for 200–300Wh per day of use. **Chemistry:** Lead-acid (cheaper, heavier), AGM (sealed, maintenance-free), or LiFePO4 (lighter, more cycles, higher upfront cost). **Depth of Discharge (DoD):** How much of the battery you can safely use. Lead-acid: 50%. AGM: 50–70%. LiFePO4: 80–100%. **Internal BMS:** A Battery Management System protects against overcharge, over-discharge, and short circuits. Essential for lithium batteries. ## Step by Step ### Installing Your Leisure Battery 1. **Disconnect all power.** Remove the engine battery. 2. **Choose location.** Dry, ventilated, near your DWCA. 3. **Secure the battery.** Use the battery strap or a custom wooden tray. 4. **Connect positive cable.** 50mm² for 100Ah, with fuse within 300mm. 5. **Connect negative cable.** To chassis earth. 6. **Test voltage.** Should read 13.2V+ when fully charged. 7. **Connect your DWCA.** Set the charge/discharge voltages correctly. ## Final Thoughts ### Top Pick: Vox 100Ah LiFePO4 **Pros:** - Best price-to-performance ratio at £329.99 - True 100Ah with 100% DoD - Built-in BMS with Bluetooth monitoring - 2000+ cycles to 80% - Compact and lightweight (9kg) **Cons:** - Brand less known than Battle Born - UK warranty claims can be slow - BMS can be overly conservative ### Best Premium: Battle Born Batteries 100Ah **Pros:** - Industry leader in lithium - 3000+ cycles - Proven reliability - Excellent BMS - 10-year warranty **Cons:** - Premium at ~£649 - Slightly heavier than competitors - No Bluetooth app