Instant off-grid battery endurance, solar balance & cable guides
Calculated for continuous draw with safety headroom across typical 3–5m DC runs:
Dynamic hardware recommendations matched directly to your calculated load and solar needs:
Under standard conditions (20°C to 28°C), a typical 40L to 65L single-zone camping fridge draws around 40W to 50W while cooling. Because modern fridges cycle on and off (roughly a 35% duty cycle once down to temperature), the average draw is about 15W to 18W (1.2A to 1.4A at 12.8V).
On a 100Ah LiFePO4 battery (providing ~90Ah or ~1,150Wh of usable power), you can expect between 60 and 75 hours of continuous runtime (approx. 2.5 to 3 full days) without solar or alternator charging.
• AGM / Lead-Acid: Should not be discharged below 50% Depth of Discharge (DoD) without damaging cell life and causing severe voltage drop. A 100Ah AGM only delivers 50Ah of usable capacity.
• LiFePO4 Lithium: Safely discharges to 10% remaining capacity (90% DoD) for thousands of cycles while maintaining a rock-steady 12.8V–13.2V output. A 100Ah lithium battery delivers 90Ah of real usable power at half the weight.
Multiply your continuous daily draw in Wh by 24 hours. Divide that by (4.5 peak sun hours × 0.75 derating efficiency). For a typical 30W continuous touring load (720Wh/day), you require approximately a 200W to 250W solar blanket or roof panel to break even.
Pure sine wave inverters run at 85% to 92% efficiency under load. Idle inverters also draw 0.8A to 1.5A (10W to 20W) purely while turned on without loads, draining 15Ah to 20Ah of battery capacity overnight if left switched on.