An RV battery bank calculator helps you determine the right number and type of batteries for your RV, camper, or van based on daily power consumption. Enter your daily watt-hour usage, choose between lithium, AGM, or gel batteries, and get a complete recommendation including battery count, wiring configuration, total cost, and weight.
Daily Power Consumption
Enter your total daily watt-hours, or use the quick-add list below
System Configuration
Battery Bank Recommendation
Wiring Configuration
Battery Type Comparison
| Specification | Lithium (LiFePO4) | AGM | Gel |
|---|
Lifespan & Cost per Cycle
| Metric | Lithium | AGM | Gel |
|---|
How to Use the RV Battery Bank Calculator
Sizing a battery bank for your RV, camper van, or travel trailer is one of the most important decisions in building an off-grid electrical system. An undersized battery bank means running out of power on the second day of boondocking, while an oversized one adds unnecessary weight and cost. This RV battery bank calculator walks you through the sizing process step by step.
Step 1: Enter Your Daily Power Consumption
Start by entering your total daily power consumption in watt-hours (Wh). If you already know this number from an energy audit or another calculator, type it directly into the input field. Otherwise, use the quick-add appliance buttons to build up your daily usage. Each preset adds a typical watt-hour value for common RV appliances like LED lights, a 12V fridge, laptop, phone charger, and fan.
Step 2: Configure Your System
Choose your system voltage (12V or 24V), battery type (lithium, AGM, or gel), preferred battery size (100Ah, 200Ah, or 300Ah), and days of autonomy. Days of autonomy determines how many days your battery bank should last without recharging. For boondocking, 2 days is a common choice. The calculator automatically adjusts for each battery type's recommended depth of discharge: 80% for lithium and 50% for AGM and gel.
Step 3: Review Your Results
Click Calculate Battery Bank to see the full recommendation. The results show the required amp-hour capacity, number of batteries, wiring configuration (series, parallel, or both), estimated cost range, and total weight. The wiring diagram explains exactly how to connect your batteries for the chosen system voltage.
Step 4: Compare Battery Types
The comparison table shows how lithium, AGM, and gel batteries stack up for your specific power needs. It compares the number of batteries required, total weight, cost, and usable capacity for each type. The lifespan table shows cost per charge cycle, helping you understand the true long-term cost. Lithium batteries typically cost more upfront but deliver the lowest cost per cycle thanks to 2,000-5,000 cycle lifespans compared to 300-800 cycles for lead-acid types.
Tips for RV Battery Bank Sizing
Always round up to the next whole battery count. Never mix battery types or ages in the same bank. If your required capacity exceeds 600Ah at 12V, consider a 24V system for more efficient wiring and lower cable costs. For weight-sensitive builds like van conversions, lithium batteries save significant weight and space. Keep batteries in a ventilated compartment and protect them from extreme temperatures for maximum lifespan.
FAQ
Is this RV battery bank calculator really free?
Yes, completely free with no signup required. All calculations run locally in your browser. Use it as many times as you need to compare lithium, AGM, and gel batteries for your RV or van build.
Is my data safe when using this calculator?
Absolutely. Everything runs entirely in your browser using JavaScript. No power data or personal information is transmitted anywhere. You can even use it offline once the page loads.
What is depth of discharge and why does it matter?
Depth of discharge (DOD) is the percentage of battery capacity you can safely use before recharging. Lithium batteries allow 80% DOD, while AGM and gel batteries should only be discharged to 50% DOD. Using a battery below its recommended DOD dramatically shortens its lifespan.
Should I choose lithium or AGM batteries for my RV?
Lithium (LiFePO4) batteries cost more upfront but last 4-10 times longer, weigh half as much, and provide more usable capacity thanks to 80% DOD versus 50% for AGM. For frequent use and boondocking, lithium pays for itself over time. AGM is a good budget choice for occasional camping.
How many days of autonomy should I plan for?
For boondocking without solar or shore power, 2-3 days of autonomy gives a comfortable buffer for cloudy weather. If you have a solar setup or regularly visit campgrounds with hookups, 1 day is usually sufficient.
What is the difference between series and parallel battery wiring?
Parallel wiring connects batteries to increase total capacity while keeping the same voltage (e.g., two 100Ah 12V batteries = 200Ah at 12V). Series wiring increases voltage while keeping the same capacity (e.g., two 12V batteries in series = 24V). A 24V system needs series pairs wired in parallel.
How do I calculate my daily power consumption in watt-hours?
Multiply each appliance's wattage by the number of hours you use it per day. For example, a 50W fridge running 10 hours uses 500Wh. Add up all appliances for your daily total. This calculator's quick-add appliance list makes this process easy.
Can I mix different battery types in my RV?
No, you should never mix battery types (e.g., lithium with AGM) or batteries of different ages in the same bank. Mixing causes uneven charging and discharging, which reduces performance and can damage the batteries. Always use identical batteries from the same manufacturer and purchase.