VANPOWERCALC

Lithium Battery Sizing Tool for Campers

Determine the perfect lithium battery bank capacity (Ah) for your camper van conversion with our free sizing tool.

Upgrading to LiFePO4? Use our calculator to find the exact battery capacity you need. Enter your 12V and 230V devices to calculate your daily Ah consumption and required battery bank size.
Lithium batteries offer 100% depth of discharge compared to AGM. Our algorithm precisely calculates the optimal Ah for 1, 2, or 3 days of total autonomy without sun.
⚡ Expert tip
For most full-time van lifers, 200Ah LiFePO4 + 400W solar is the proven sweet spot. It provides ~3 days of autonomy for typical couple consumption (800Wh/day), recharges fully in 2-3 summer days, and weighs ~22-23kg — manageable for battery swaps between vehicles. Scale up only if your measured consumption (not estimated) demands it. Measure first with a battery monitor for 2-3 weeks, then size your permanent bank.

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Comparison table

Battery typeUsable capacityCycle lifeWeight 200AhCost/usable Ah
LiFePO480-95%3,000-6,00040-48 lbs$1.50-2.50
AGM deep cycle50%400-700128-144 lbs$1.50-3.00
GEL50-60%600-1,000121-132 lbs$2.00-3.50
Flooded lead30-40%200-400132-150 lbs$0.80-1.50

About this tool

Lithium Battery Size Guide for Campervan Builds

Lithium iron phosphate (LiFePO4) batteries have become the definitive choice for serious campervan electrical systems. Unlike AGM, LiFePO4 delivers 80% usable depth of discharge (DoD), meaning a 200Ah LiFePO4 provides 160Ah of usable energy — while a 200Ah AGM only delivers 100Ah safely. This difference changes the entire sizing calculation.

Why LiFePO4 for Campervans?

Feature LiFePO4 AGM Why It Matters
Usable DoD 80% 50% LiFePO4 packs double the usable energy
Weight (100Ah) 11-13 kg 27-32 kg Critical for van weight limits
Cycle life 3,000-5,000 300-600 5-10× longer lifespan
Charge speed Fast (C/2+) Slow (C/5 max) Recharges faster from solar/alternator
BMS protection Built-in None Overcharge/overdischarge protection

How Much Lithium Battery Capacity Do You Need?

Formula: Required Ah = (Daily Wh × Days autonomy) ÷ (12V × 0.80 DoD)

Include a 15% loss factor for wiring, inverter inefficiency, and BMS draw:

Final formula: Ah = (Daily Wh × Days × 1.15) ÷ (Voltage × 0.80)

Daily Use Profile Daily Wh 1-day Ah 3-day Ah Recommendation
Minimalist (fridge + lights) 500-700 60-84 180-253 100-150Ah
Typical (fridge + laptops) 800-1,200 96-144 288-432 200-300Ah
Remote worker (+ Starlink) 1,200-1,800 144-216 432-648 300-400Ah
Heavy user (+ coffee, kettle) 1,800-2,500 216-300 648-900 400-600Ah

3 days autonomy: essential buffer for rainy periods in Northern Europe or overcast mountain camping

Popular LiFePO4 Battery Options for Campervans

Model Capacity Weight BMS Price Range
Battle Born 100Ah 100Ah 14 kg Built-in $400-500
Renogy 200Ah 200Ah 23 kg Built-in $600-800
LITIME 200Ah 200Ah 21 kg Built-in $400-550
SOK 200Ah 200Ah 22 kg Built-in $500-650
DIY 280Ah EVE cells (4S) 280Ah 28 kg Separate required $250-400

Charging Your LiFePO4 in a Campervan

LiFePO4 accepts charge at up to C/2 (50A for 100Ah batteries) — dramatically faster than AGM (C/5 max). This means:

  • A 50A MPPT solar controller can charge a 100Ah battery from 10% to full in under 2.5 hours of good sun
  • A 30A DC-DC B2B charger delivers 360Wh per hour of driving (enough to replace daily consumption on most travel days)
  • You must use a LiFePO4-specific charging profile: absorption at 14.2-14.4V, float at 13.3-13.5V or disabled — AGM mode slowly damages LiFePO4 cells

Cold Weather Behavior

LiFePO4 discharges normally down to -20°C. Charging is restricted below 0°C — the BMS will block it to prevent lithium plating. If you camp in sub-zero temperatures, choose a battery with a built-in low-temperature charge cutoff (most quality brands include this after 2022) or add a heating pad with thermostat to your battery box.

Frequently asked questions

How many Ah of lithium battery do I need in a campervan?▼
Use this formula: Ah = (Daily Wh × Days autonomy × 1.15) ÷ (12 × 0.80). For a couple using 900Wh/day with 3 days autonomy: (900 × 3 × 1.15) ÷ 9.6 = 323Ah — round up to 300-400Ah. For minimalist solo use: 100Ah. For a remote worker with Starlink: 300-400Ah.
What is the difference between LiFePO4 and AGM for a campervan?▼
Three critical differences: (1) Usable energy — 200Ah LiFePO4 gives 160Ah usable vs 100Ah from 200Ah AGM. (2) Weight — 200Ah LiFePO4 weighs ~23kg vs ~55kg for 200Ah AGM. (3) Lifespan — 3,000-5,000 cycles LiFePO4 vs 300-600 for AGM. For any use beyond occasional weekends, LiFePO4 is cheaper over 3 years.
Can I mix LiFePO4 batteries of different brands in a campervan?▼
Not recommended. Batteries from different manufacturers have different internal resistance and cell characteristics. When connected in parallel, the BMS units can conflict and the weaker battery gets over-stressed. Always use identical batteries from the same manufacturer, same Ah rating, and ideally the same production batch.
What BMS do I need for LiFePO4 in a campervan?▼
Most branded LiFePO4 batteries (Battle Born, Renogy, LITIME, SOK) include a built-in BMS — no separate unit needed. For DIY cell builds (EVE 280Ah prismatic cells), you need an external BMS rated for your max discharge current. JBD (JiaoBaDian) and JK BMS are popular, reliable choices for van builds at $40-120.
How long do LiFePO4 batteries last in a campervan?▼
3,000-5,000 full cycles at 80% DoD, which translates to 10-15 years with daily cycling. For comparison, AGM batteries used daily last 1-3 years (300-600 cycles). Any van lifer doing 200+ nights per year will replace AGM batteries every 2-3 years — LiFePO4 pays for itself by the second AGM replacement cycle.
Should I use 12V or 24V LiFePO4 for a campervan?▼
For most campervans with inverters under 2,000W: 12V is simpler — more appliances are natively 12V (fridges, fans, water pumps) and fewer conversions are needed. Move to 24V when your inverter loads regularly exceed 2,000W, as cable savings are substantial (same wattage at 24V requires half the current and wire gauge).

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