Last updated: August 3, 2026
The Camper Battery Size Calculator below estimates the battery capacity your camper van, motorhome or RV needs in amp-hours, watt-hours and kilowatt-hours. It also calculates battery quantity, expected runtime, usable energy and whether the selected battery-management system can support your inverter load.
Battery size should be based on energy use, not on a generic recommendation such as “every van needs 200Ah.” A weekend camper running lights, a roof fan and a small refrigerator has very different requirements from a full-time van using computers, induction cooking, an espresso machine or electric water heating.
Use this battery-focused calculator when you already know your approximate daily energy use. For a complete load-by-load calculation that also sizes solar, inverter, MPPT, alternator charging and shore charging, start with the complete camper van electrical system calculator.
Quick Answer: How Many Amp-Hours Does a Camper Need?
A light-use camper often needs 100–150Ah of LiFePO4 at 12V. A three-season van with a refrigerator, roof fan, lighting and laptop use may need 200–300Ah. Full-time or high-power builds can require 300–500Ah or more.
The correct capacity depends on daily watt-hours, autonomy days, battery chemistry, usable depth of discharge, inverter losses, temperature, battery condition and charging availability. Amp-hours must always be interpreted together with system voltage: 100Ah at 24V stores twice the nominal energy of 100Ah at 12V.
Camper Battery Size Calculator
Calculate required Ah, Wh, kWh, battery quantity, runtime and BMS current suitability for a 12V, 24V or 48V camper battery bank.
Your Camper Battery Results
LiFePO4 vs AGM planning comparison
Calculation summary
How the Camper Battery Size Calculator Works
The calculator accepts daily consumption in watt-hours or amp-hours. If amp-hours are entered, the tool converts them into watt-hours using the selected system voltage. It then accounts for the percentage of energy used through an inverter, inverter efficiency, the selected safety margin and the number of desired autonomy days.
Battery chemistry determines the default usable fraction and efficiency. The tool uses conservative planning defaults of 80% usable capacity and 95% efficiency for LiFePO4, and 50% usable capacity with 85% efficiency for AGM and gel. These are planning assumptions, not universal manufacturer limits.
Use Manufacturer Data for the Final Design
Battery models vary in usable depth of discharge, charge efficiency, low-temperature behavior, maximum series or parallel configuration, continuous discharge current and BMS limits. The result is a planning estimate and must be checked against the exact battery manual.
Battery Ah vs Wh vs kWh
Amp-hours describe electrical charge, while watt-hours describe energy. Watt-hours are more useful for comparing batteries at different voltages because they include both current capacity and voltage.
A 100Ah battery at 12V stores approximately 1,200Wh of nominal energy. A 100Ah battery at 24V stores about 2,400Wh, and a 100Ah battery at 48V stores about 4,800Wh. The amp-hour figure is the same, but the stored energy is not.
| Battery Rating | Nominal Energy | Approximate LiFePO4 Usable Energy* | Approximate AGM/Gel Usable Energy* |
|---|---|---|---|
| 100Ah at 12V | 1,200Wh | 912Wh | 510Wh |
| 100Ah at 24V | 2,400Wh | 1,824Wh | 1,020Wh |
| 100Ah at 48V | 4,800Wh | 3,648Wh | 2,040Wh |
*Using the calculator’s planning assumptions of 80% usable capacity and 95% efficiency for LiFePO4, or 50% usable capacity and 85% efficiency for AGM and gel. Actual values vary by product and operating conditions.
How to Calculate Camper Battery Capacity
The basic calculation starts with daily energy use and desired autonomy. It then adjusts for usable depth of discharge, battery efficiency and planning margins.
The nominal amp-hour requirement is then calculated from system voltage:
Example: 1,500Wh per Day for Two Days
Assume a 12V LiFePO4 system, 1,500Wh of daily appliance energy, two autonomy days, a 20% safety margin, 80% usable capacity and 95% efficiency.
- Daily energy after 20% margin: 1,800Wh
- Energy for two days: 3,600Wh
- Required nominal capacity: 3,600 ÷ 0.80 ÷ 0.95 = approximately 4,737Wh
- Required amp-hours at 12V: 4,737 ÷ 12 = approximately 395Ah
A practical bank could therefore be four 100Ah modules or two 200Ah modules, provided those batteries are designed for the proposed parallel configuration and their combined BMS current is sufficient.
LiFePO4 vs AGM vs Gel for a Camper Battery Bank
LiFePO4 and lead-acid batteries behave differently. A lead-acid bank is more affected by discharge rate through the Peukert effect, while lithium batteries typically deliver capacity more consistently at higher loads. Battery monitor settings and planning assumptions should match the chosen chemistry.
| Feature | LiFePO4 | AGM | Gel |
|---|---|---|---|
| Planning usable fraction | About 80% | About 50% | About 50% |
| Planning efficiency | About 95% | About 85% | About 85% |
| High-load behavior | Generally strong when BMS limits are respected | Capacity falls more noticeably at high discharge rates | Charging and discharge limits require careful matching |
| Cold-weather concern | Charging below the manufacturer’s minimum temperature may be prohibited | Reduced capacity and slower charge acceptance in cold conditions | Reduced capacity and chemistry-specific charge requirements |
| Weight for equal usable energy | Usually lower | Usually higher | Usually higher |
| System requirement | Compatible BMS and charging profile | Correct multistage charging profile | Strict voltage and current limits from the manufacturer |
The correct choice depends on budget, climate, expected cycle frequency, available payload, charging hardware and whether the battery compartment can remain within the required temperature range.
When replacing an existing lead-acid system, use our lead-acid to LiFePO4 calculator to compare equivalent usable capacity.
Typical Camper Battery Size by Use Case
| Use Pattern | Typical Daily Energy | Example LiFePO4 Bank at 12V | Main Loads |
|---|---|---|---|
| Minimal weekend camper | 500–900Wh/day | 100–150Ah | Lights, phone charging, fan and small refrigerator |
| Three-season touring van | 1,000–1,800Wh/day | 150–300Ah | Refrigerator, fan, lighting, pump, devices and occasional laptop |
| Full-time remote worker | 1,800–3,000Wh/day | 300–500Ah | Multiple computers, connectivity equipment and heavier daily charging |
| Electric cooking build | 2,500–4,500Wh/day | 400–700Ah or higher-voltage equivalent | Induction cooking, coffee machine and other 230V appliances |
| Heating or air-conditioning loads | Highly variable and often above 4,000Wh/day | Large 24V or 48V system may be required | Electric space heating, water heating or air conditioning |
These ranges are only examples. An efficient refrigerator in a cool climate may consume much less than the same unit in hot weather. Electric heating and air conditioning can dominate the entire energy budget.
How Long Will a 100Ah Camper Battery Last?
Runtime depends on system voltage, battery chemistry, usable capacity and load efficiency. The following 12V table uses approximately 912Wh of usable energy for LiFePO4 and 510Wh for AGM or gel under the calculator’s planning assumptions.
| Continuous Load | 100Ah LiFePO4 at 12V | 100Ah AGM/Gel at 12V | Planning Example |
|---|---|---|---|
| 20W | About 45.6 hours | About 25.5 hours | Lighting and small electronics |
| 50W | About 18.2 hours | About 10.2 hours | Small compressor or mixed light loads |
| 100W | About 9.1 hours | About 5.1 hours | Laptop and communication equipment |
| 500W through a 90% inverter | About 1.6 hours | About 0.9 hours | Short-duration AC appliance |
| 1,500W through a 90% inverter | About 0.55 hours | About 0.31 hours | Induction cooking at high power |
These are mathematical estimates. At high discharge rates, lead-acid batteries may deliver less capacity than the simple watt-hour calculation suggests. BMS current and inverter surge limits may also prevent a battery from supporting a high-power load even when enough energy is theoretically stored.
How Long Will a 200Ah Camper Battery Last?
A 200Ah bank at the same voltage stores twice the nominal energy of a 100Ah bank. Under the same assumptions, a 12V 200Ah LiFePO4 bank provides approximately 1,824Wh of usable energy, while an AGM or gel bank provides about 1,020Wh.
| Continuous Load | 200Ah LiFePO4 at 12V | 200Ah AGM/Gel at 12V |
|---|---|---|
| 20W | About 91 hours | About 51 hours |
| 50W | About 36.5 hours | About 20.4 hours |
| 100W | About 18.2 hours | About 10.2 hours |
| 500W through a 90% inverter | About 3.3 hours | About 1.8 hours |
| 1,500W through a 90% inverter | About 1.1 hours | About 0.6 hours |
12V vs 24V vs 48V Battery Capacity
Increasing system voltage does not reduce the energy needed by the appliances. It changes the amp-hour requirement and the current flowing through the system.
| Energy Requirement | Equivalent at 12V | Equivalent at 24V | Equivalent at 48V |
|---|---|---|---|
| 1,200Wh nominal | 100Ah | 50Ah | 25Ah |
| 2,400Wh nominal | 200Ah | 100Ah | 50Ah |
| 4,800Wh nominal | 400Ah | 200Ah | 100Ah |
| 9,600Wh nominal | 800Ah | 400Ah | 200Ah |
Higher voltage reduces current for the same power, which can make high-power inverter installations easier to manage. It can also require converters for native 12V appliances. Read our 12V vs 24V vs 48V guide before selecting the final architecture.
How Many Camper Batteries Do You Need?
Divide the required bank capacity by the capacity of one battery module and round upward:
A required capacity of 395Ah needs four 100Ah modules or two 200Ah modules. The calculator rounds to whole modules and reports the installed nominal capacity.
Series and Parallel Rules Matter
Do not assume every battery can be connected in any series or parallel arrangement. Check the manufacturer’s permitted configuration, required balancing procedure, maximum bank current and communication requirements. Parallel batteries should normally be the same model, capacity, age and state of charge.
For inverter-focused battery quantity, also see how many batteries are needed for a 3000W inverter.
Battery Size for Refrigerators, Laptops and Induction Cooking
Refrigerator and Laptop Use
A refrigerator and laptop are energy loads rather than only power loads. A 45W refrigerator compressor running effectively for 12 hours consumes about 540Wh. A 65W laptop used for four hours adds 260Wh before charging losses. Combined with lights, a fan and pumps, daily consumption may reach 1,000–1,500Wh.
Induction Cooking
Induction cooking creates both a high power requirement and a significant energy requirement. A 1,500W cooktop used for 30 minutes consumes 750Wh before inverter losses. The battery must store enough energy, and its BMS must support the high DC current.
At 12V and 90% inverter efficiency, a 1,500W load draws approximately 139A before additional cable and inverter-idle losses. A battery bank with a 100A total BMS limit cannot safely support that continuous load even if the bank stores enough watt-hours.
Electric Heating and Air Conditioning
Electric resistance heating can consume several kilowatt-hours in a short period. Air-conditioning demand depends on climate, insulation, equipment efficiency and duty cycle. These loads often require a large battery, a high-power inverter and multiple charging sources.
Cold-Weather Camper Battery Planning
Battery behavior changes with temperature. The exact limits are model-specific. Some LiFePO4 batteries prohibit charging below a stated minimum temperature unless internal heating or external temperature control is provided.
Victron’s current lithium manuals, for example, specify charging only within the product’s permitted temperature range and use the BMS to stop chargers outside that range. This does not mean every LiFePO4 battery has the same limit; always use the actual battery manual.
Do Not Rely on Extra Capacity to Solve Unsafe Cold Charging
A larger battery does not make low-temperature charging safe. Use a battery with suitable low-temperature protection, locate it in a protected compartment or provide a manufacturer-approved heating strategy.
The calculator’s temperature setting applies an additional design margin. It does not simulate the exact electrochemical performance of a particular battery.
Battery Weight and Camper Payload
Battery weight counts against the vehicle’s available payload along with passengers, water, fuel, furniture, appliances and luggage. Large lead-acid banks can become one of the heaviest parts of a camper electrical system.
The calculator allows you to enter the weight of one planned battery module. It then estimates the total installed battery weight from the required number of modules. Use the exact product weight rather than a chemistry-wide average.
Battery position also affects axle loading and handling. Heavy equipment should be securely mounted and positioned with vehicle balance, crash loads, ventilation and service access in mind.
Common Camper Battery Sizing Mistakes
Comparing Batteries Only by Amp-Hours
Amp-hours without voltage do not show total stored energy. Compare watt-hours or kilowatt-hours when evaluating systems with different voltages.
Ignoring Usable Capacity
A 200Ah bank does not necessarily provide 200Ah of planned usable capacity. The usable fraction depends on chemistry, manufacturer limits and desired service life.
Forgetting Inverter Losses
AC appliances draw more energy from the battery than they deliver to the appliance because the inverter is not 100% efficient.
Using One Good-Sun Day as the Autonomy Target
Cloud, shade, winter and stationary parking can reduce charging. Select autonomy based on the worst realistic travel pattern rather than the best summer day.
Checking Energy but Not Current
A battery may store enough energy but still be unable to supply the continuous or surge current required by an inverter. Check the BMS, battery terminals, busbars, cable and fuse ratings.
Using Old and New Batteries Together
Mixing different ages, capacities, chemistries or models can produce imbalance and uneven current sharing. Follow the battery manufacturer’s bank-building rules.
Charging LiFePO4 Below Its Approved Temperature
Low-temperature charging limits are safety requirements, not optional efficiency recommendations. Use BMS-controlled charge protection.
Ignoring Cable Voltage Drop
High-current loads require cable sized for both ampacity and voltage drop. Use the battery cable size calculator after determining the maximum current.
Camper Battery Planning Checklist
- Calculate daily energy in watt-hours.
- Separate DC and inverter-powered consumption.
- Add realistic inverter losses.
- Select the required number of autonomy days.
- Choose a conservative safety reserve.
- Use manufacturer-approved usable depth of discharge.
- Confirm battery efficiency and Peukert behavior where applicable.
- Check minimum and maximum charging temperatures.
- Check continuous and surge discharge-current limits.
- Verify BMS current against the largest inverter load.
- Confirm permitted series and parallel configurations.
- Use batteries of the same model, age and state of charge in one bank.
- Calculate total battery weight and vehicle payload.
- Measure the physical battery compartment.
- Allow safe access, restraint and ventilation.
- Match alternator, solar and shore chargers to the battery profile.
- Calculate cable size and voltage drop.
- Install appropriately rated circuit protection and disconnects.
- Use a shunt-based battery monitor for reliable state-of-charge tracking.
- Document all component limits and settings.
Camper Battery Size Calculator FAQ
How many Ah does a camper van need?
A small camper may use 100–150Ah of LiFePO4 at 12V. A full-time van commonly needs 200–500Ah or more. Calculate the answer from daily watt-hours, autonomy, usable capacity and charging conditions.
Is a 100Ah lithium battery enough for a camper?
It can be enough for efficient refrigeration, lighting, a fan and device charging when daily use and charging are modest. It is usually too small for long autonomy or regular high-power electric cooking.
How long will a 100Ah battery run a 12V fridge?
Runtime depends on the refrigerator’s measured daily watt-hours, ambient temperature and other loads. A 100Ah 12V LiFePO4 battery using the calculator’s assumptions provides about 912Wh of planned usable energy.
How many batteries are needed for two days off-grid?
Multiply adjusted daily consumption by two and divide by usable depth of discharge and battery efficiency. Then divide the required amp-hours by the capacity of one battery module and round upward.
Is 200Ah enough for full-time van life?
It may be enough for an efficient system with regular solar or alternator charging. Remote work, winter use, electric cooking or poor sunlight may require more capacity.
Why does AGM require more Ah than LiFePO4?
The calculator plans around a lower usable fraction and lower efficiency for AGM. Lead-acid capacity is also more affected by high discharge rates through the Peukert effect.
Does a 24V battery last longer than a 12V battery?
Only when it stores more watt-hours. A 100Ah 24V battery stores twice the nominal energy of a 100Ah 12V battery. Compare watt-hours rather than amp-hours alone.
What battery size is needed for an induction cooktop?
The answer depends on cooking power, daily runtime and autonomy. The battery must also have enough BMS current to support the cooktop through the inverter.
Can LiFePO4 batteries be charged below freezing?
Only when the specific battery manufacturer allows it or an approved heating and protection system keeps the cells within the permitted charging range. Many systems use BMS-controlled low-temperature charge protection.
Should I use one large battery or several smaller batteries?
A single large battery reduces the number of interconnections. Several modules may improve packaging and serviceability. The manufacturer must permit the planned parallel or series configuration.
How accurate is the camper battery calculator?
It provides a detailed planning estimate based on the values entered. Accuracy depends on realistic energy use, battery assumptions, temperature and condition. Final sizing must use the exact battery and equipment manuals.
Final Recommendation
Calculate energy in watt-hours first, then convert the final bank requirement into amp-hours at the selected system voltage. Do not choose a battery from amp-hours alone.
Run the calculator with normal daily use, a high-consumption day and a poor-charging scenario. The most useful battery bank is not simply the largest one that fits; it is the smallest bank that safely supports realistic energy, current, temperature and autonomy requirements with an appropriate reserve.
Technical Sources and Further Reading
- Victron Energy: Service Van Battery Planning
- Victron Energy: SmartShunt Battery Settings
- Victron Energy: Lithium Smart Battery Technical Data
- Victron Energy: Lithium Battery Operating Conditions
- Victron Energy: Battery Capacity and Peukert Exponent
- Blue Sea Systems: Choosing the Correct Wire Size for a DC Circuit
- Blue Sea Systems: DC Circuit Protection