🔋 How Much Battery Capacity Do You Really Need for Vanlife?
February 24, 2026 · 5 min read
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Battery sizing is one of the most searched van build questions — and one of the most over-complicated. Too small and you're constantly running out of juice. Too big and you've wasted $1,000+ on capacity you'll never use. Let's find your sweet spot. ⚡
| Setup | Battery Size | Cost (Lithium) |
|---|---|---|
| 🟢 Minimal | 100Ah | $400 – $900 |
| 🟡 Typical | 200Ah | $900 – $2,000 |
| 🔴 Full Off-Grid | 400Ah+ | $2,000 – $5,000 |
Typical Van Appliances & Their Power Draw
Before sizing your battery, you need to know what you're powering. Here's what common van life devices actually use:
| Appliance | Watts | Daily Use | Wh/Day |
|---|---|---|---|
| Compressor fridge | 40W | 24 hrs* | ~500 |
| LED lights (6 pucks) | 30W | 4 hrs | ~120 |
| Laptop charging | 60W | 3 hrs | ~180 |
| Phone charging (×2) | 15W | 3 hrs | ~45 |
| Vent fan | 20W | 8 hrs | ~160 |
| Water pump | 60W | 0.3 hrs | ~18 |
| Diesel heater | 10W | 8 hrs | ~80 |
| Inverter standby | 15W | 24 hrs | ~360 |
| Typical Daily Total | ~1,463Wh | ||
*Fridge cycles on/off — actual draw is ~40-50% of rated watts over 24hrs
Daily Power Consumption by Lifestyle
🟢 Minimal (Weekend trips)
400 – 600 Wh/dayIncludes: Phones, lights, fan. No fridge, no laptop.
Battery: 100Ah lithium is plenty
🟡 Typical (Full-time van life)
1,000 – 1,500 Wh/dayIncludes: Fridge, laptop, lights, fans, phone, water pump.
Battery: 200Ah lithium is the sweet spot
🔴 Heavy (Full off-grid comfort)
2,000 – 3,500 Wh/dayIncludes: All of the above + induction cooking, AC, hair dryer, power tools.
Battery: 400Ah+ lithium — serious investment
Battery Size Examples
The formula is simple: Daily Wh ÷ 12V = Ah needed. Then multiply by 1.5–2× so you never drain below 20% (which kills battery lifespan).
Lithium vs AGM Cost Comparison
AGM batteries cost less upfront but you can only use 50% of the capacity (vs 80-100% for lithium) and they last 3-5 years (vs 8-10 for lithium). Over time, lithium is actually cheaper per usable watt-hour.
| Factor | AGM | Lithium (LiFePO4) |
|---|---|---|
| Cost per 100Ah | $100 – $250 | $400 – $900 |
| Usable capacity | 50% | 80 – 100% |
| Lifespan | 3 – 5 years | 8 – 10 years |
| Weight (100Ah) | ~65 lbs | ~25 lbs |
| Cycles | ~400 | 3,000+ |
| Cost per usable kWh (lifetime) | ~$0.42/kWh | ~$0.08/kWh |
💡 Bottom line: If you're building for full-time use, lithium pays for itself within 2–3 years. For weekend-only builds, AGM is fine.
🔋 Need a reliable battery? Browse Renogy LiFePO4 batteries — built-in BMS, expandable, and designed for van builds.
☀️ Pairing with panels? Browse Renogy solar kits — reliable, affordable, and the most popular choice for van life.
Estimate your full electrical system cost
Battery, solar, inverter, wiring — get it all sized and priced in minutes.
🔋 Try the Van Build Cost Estimator