12V Fridge Runtime Calculator
How long will your 12V camping fridge run on battery? Select your fridge, battery size, and solar setup below for an instant estimate. All calculations use manufacturer-rated average draw for popular Australian camping fridges.
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Fridge Runtime Calculator
Estimate how long your battery will power your fridge
Typical range: 0.5A (Engel) to 1.5A (budget fridges)
Estimated Runtime
80
hours
How the Calculator Works
The formula is straightforward: Usable battery capacity (Ah) ÷ Average fridge draw (A) = Runtime (hours).
The key variable is usable capacity. A lithium (LiFePO4) battery can safely use 80% of its rated capacity — so a 100Ah lithium gives you 80Ah. An AGM battery should only be discharged to 50% to preserve its lifespan — so a 100Ah AGM gives you just 50Ah. This is why lithium batteries effectively give you 60% more runtime than AGM at the same Ah rating.
Solar input is calculated assuming ~5 hours of effective peak sun per day in average Australian conditions. A 100W panel produces roughly 6.25Ah per day after conversion losses. This offsets your fridge's draw, extending runtime significantly.
Average Draw by Fridge Model
These are the manufacturer-rated average power draw figures we use in the calculator. Real-world draw varies with ambient temperature, how often you open the lid, and whether you're running in fridge or freezer mode.
| Fridge | Avg Draw | 100Ah Lithium | 100Ah AGM |
|---|---|---|---|
| Dometic CFX3 75DZ | 1.2A | ~67hrs (2.8 days) | ~42hrs (1.8 days) |
| Dometic CFX3 45 | 1A | ~80hrs (3.3 days) | ~50hrs (2.1 days) |
| Engel MT60FP | 0.9A | ~89hrs (3.7 days) | ~56hrs (2.3 days) |
| ARB Zero 73L Dual Zone | 1.1A | ~73hrs (3.0 days) | ~45hrs (1.9 days) |
| Engel MT45F | 0.7A | ~114hrs (4.8 days) | ~71hrs (3.0 days) |
| Engel MT35F | 0.7A | ~114hrs (4.8 days) | ~71hrs (3.0 days) |
| Bushman DC130-X | 1.4A | ~57hrs (2.4 days) | ~36hrs (1.5 days) |
| Dometic CFX3 35 | 0.8A | ~100hrs (4.2 days) | ~63hrs (2.6 days) |
| Dometic CFX3 55 | 1.2A | ~67hrs (2.8 days) | ~42hrs (1.8 days) |
| EcoFlow GLACIER Classic | 1A | ~80hrs (3.3 days) | ~50hrs (2.1 days) |
| ARB Elements 60L | 1.1A | ~73hrs (3.0 days) | ~45hrs (1.9 days) |
| myCOOLMAN 44L Dual Zone | 1.1A | ~73hrs (3.0 days) | ~45hrs (1.9 days) |
| myCOOLMAN 69L Dual Zone | 1.3A | ~62hrs (2.6 days) | ~38hrs (1.6 days) |
| myCOOLMAN 60L | 1.2A | ~67hrs (2.8 days) | ~42hrs (1.8 days) |
| myCOOLMAN 85L | 1.4A | ~57hrs (2.4 days) | ~36hrs (1.5 days) |
| EvaKool TMX 62L Dual Zone | 1.2A | ~67hrs (2.8 days) | ~42hrs (1.8 days) |
| EvaKool TMX 80L Dual Zone | 1.3A | ~62hrs (2.6 days) | ~38hrs (1.6 days) |
| BougeRV CRV35 | 1.2A | ~67hrs (2.8 days) | ~42hrs (1.8 days) |
| EvaKool Infinity 40L | 1A | ~80hrs (3.3 days) | ~50hrs (2.1 days) |
| Kings 60L Stayzcool | 1.3A | ~62hrs (2.6 days) | ~38hrs (1.6 days) |
| Kings 45L | 1.2A | ~67hrs (2.8 days) | ~42hrs (1.8 days) |
| Alpicool C20 | 1A | ~80hrs (3.3 days) | ~50hrs (2.1 days) |
Tips to Maximise Runtime
- Pre-cool on mains power before your trip — this saves 5–10Ah of battery that would otherwise go to the initial cool-down.
- Keep the fridge in shade and out of direct sun. Even partial shade reduces compressor cycling significantly.
- Minimise lid openings — each open lets cold air escape and forces the compressor to work harder.
- Pack the fridge full — thermal mass (even frozen water bottles) helps maintain temperature with less compressor cycling.
- Add a solar panel — a 120W panel is the sweet spot for most camping setups, adding ~7.5Ah per day to offset fridge draw.
Frequently Asked Questions
How long will a 12V fridge run on a 100Ah lithium battery?
A 100Ah lithium (LiFePO4) battery gives you 80Ah of usable capacity. Most 12V camping fridges draw 0.5–1.5A average, so runtime ranges from 53 to 160 hours (2.2 to 6.7 days). Use our calculator above for your exact fridge model.
How long will a 12V fridge run on a 100Ah AGM battery?
A 100Ah AGM battery should only be discharged to 50%, giving you 50Ah usable. Most fridges will run 33–100 hours (1.4 to 4.2 days) depending on the model. Lithium batteries effectively double your usable runtime.
What size solar panel do I need to run a 12V fridge indefinitely?
A 120W solar panel produces roughly 7.5Ah per day in average Australian conditions (5 hours peak sun). Since most camping fridges draw 15–30Ah per day, a 120W panel significantly extends runtime but may not fully offset draw. A 200W panel can keep most fridges running indefinitely in good sun.
Does the ambient temperature affect fridge battery runtime?
Yes — significantly. In hot conditions (35°C+), your fridge compressor runs more frequently, increasing average draw by 20–50%. Our calculator uses the manufacturer average draw, which is typically measured at 32°C ambient. In cooler conditions you will get longer runtime; in extreme heat, shorter.