12V Camping Power Calculators
Free calculators for your camping power setup, in the order you need them: energy use, battery, solar, charging and planning.
Work through your power setup in order, from what you use each day to the cables that carry it. Each calculator explains its assumptions and limits, and some pass your figures on to the next step. They're free planning estimates, worked out in your browser. Nothing is saved or sent anywhere.
1. Daily energy use
2. Battery capacity and runtime
Battery Size Calculator
Turn your daily use into the battery capacity you need in Ah, with days of autonomy and a margin.
Open calculator →Battery Runtime Calculator
Estimate how long a battery or portable power station will run a load, from its Ah or Wh rating.
Open calculator →Battery Bank Series & Parallel Calculator
Work out the voltage, capacity and energy of batteries wired in series, parallel or both, and how many you need.
Open calculator →Lithium vs AGM Battery for Camping · Power Station vs DIY Battery Box
3. Solar
Solar Blanket vs Rigid Solar Panel · Solar Power
4. Charging
DC-DC Charger Size Calculator
Estimate the DC-DC charger size to recharge your auxiliary battery while driving, with input current and alternator load.
Open calculator →Battery Charging Time Calculator
Estimate how long a mains, DC-DC or solar charger takes to bring your battery from one charge level to another.
Open calculator →DC-DC Charging (in the Solar & Charging Check)
Add the energy a DC-DC charger puts back while you drive.
Open calculator →Charger Sizing (in the Charger & Inverter Calculator)
Work out the charger current needed to refill your battery in the time you have.
Open calculator →What Size DC-DC Charger Do I Need? · Charging From a Generator · Grid Supply
5. System planning
Inverter Sizing (in the Charger & Inverter Calculator)
Size an inverter for your 240V appliances, including start-up surge and DC current.
Open calculator →12V Voltage Drop Calculator
Estimate the voltage drop and power loss on a DC copper cable run.
Open calculator →12V Cable Size Estimator (Voltage Drop Only)
Find the smallest copper size that meets a voltage drop target. Voltage drop only.
Open calculator →Check My System
Answer a few questions about your existing 12V gear and get a checklist of what to confirm.
Start the check →Plan Your DIY Power Setup · 12V Cable and Fuse Size Guide · Camping Inverter Guide
6. Your trip
About these calculators
- They're educational planning estimates, not guaranteed results or a complete system design. Each page lists what it does and doesn't take into account.
- Cable, fuse and protection results are not compliant electrical engineering. Check the maker's data and the Australian requirements that apply, and get a qualified auto electrician or licensed electrician to review your installation.
- Work on 240V AC wiring must be done by a licensed electrician.
Planning a whole setup?
Our Build Your System guide takes you through a full 12V setup step by step. We're also preparing the Bush & Bench 12V Camping Power Planner, a planning workbook that follows these same steps. For planning resources from the Bush & Bench family, visit the Wired For The Wild section of the Bush & Bench shop.