CampWatt

PORTABLE POWER, WITHOUT GUESSWORK

Size your power
before you buy.

Enter each device's watts and runtime to estimate the battery capacity and inverter output you need.

Calculate for free Learn W vs. Wh →
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FIELD ESTIMATEEXAMPLE

24 hours · fridge + lights

1,500Wh class
AC continuous
Check load
Energy reserve
20%
Example only. Replace every input with a label, manual, or measured value.

If a verified product link appears, CampWatt may earn a commission from a qualifying purchase. The calculation is independent of merchant relationships.

POWER LOAD PLANNER · U.S. BETA

Size your portable power

Replace the examples with each device label or a measured value. The result is a conservative planning estimate, not guaranteed runtime.

01 Devices to power
DEVICE 01
DEVICE 02
02 Schedule and battery
Change advanced assumptions

Keep the conservative defaults unless a product manual gives you a better value.

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CALCULATED RANGEEXAMPLE RESULT

These numbers use the example devices. Replace them with your own labels or measured values, then calculate again.

Required nameplate capacity

1,354WhCompare from the 1,500–2,000Wh class

Shopping starting point: 1,500Wh

Device energy
914Wh
AC continuous output
No AC devices
Surge output
Check manufacturer values
Estimated charge time
About 7.9 hours
Simultaneous DC load
70W · check port limits

Estimated battery use by device

Portable fridge960Wh
LED light56Wh
Calculation assumptions
  • AC path efficiency 85%
  • DC path efficiency 90%
  • LiFePO₄ usable fraction 90%
  • Schedule, temperature, and aging reserve 20%
  • Continuous-output margin 20%

CampWatt divides energy by path efficiency and usable battery fraction, then applies the reserve. It never rounds down to a smaller capacity tier. Entered AC surge loads are combined as a conservative simultaneous-start case.

This is a planning estimate, not a guarantee.

Runtime changes with temperature, battery age, standby draw, device behavior, and product settings. The latest appliance and power-station manuals take priority.

NEXT CHECK

This is an example result.

Enter your actual devices and calculate before comparing verified product links.

Product links stay hidden while this is an example or the inputs have changed.

HOW IT WORKS

Find three numbers first

Product labels and manuals take priority over examples. When a value is unknown, compare a conservative scenario instead of assuming a small load.

  1. 01
    Running watts

    The device label or measured watts while it is operating

  2. 02
    Hours and duty cycle

    How long it runs each day and what share of that time it is on

  3. 03
    Connection path

    120V AC outlet or USB/DC, including the relevant port limits

U.S. FIELD GUIDES

Check the assumptions

View all guides →
01
Power basicsW vs. Wh vs. Ah: Size a Portable Power Station

Learn what watts, watt-hours, and amp-hours mean, then turn device labels and hours of use into a conservative portable-power estimate.

02
Car campingHow Much Power Does a 12 V Car Fridge Use?

Estimate daily Wh for a compressor car fridge without confusing its rated draw with its temperature-dependent average energy use.

03
Output limitsContinuous vs. Surge Output on a Power Station

Check continuous watts, startup surge, duration, temperature derating, and 120 V compatibility before connecting AC appliances.

04
Outage planningPortable Power Station Planning for an Outage

Prioritize communications, lighting, and refrigeration; estimate an energy budget; and keep medical and fuel-generator safety in separate plans.

CALCULATOR, NOT A GUARANTEE

The estimate shows its assumptions
and never rounds capacity down.

Temperature, battery age, standby draw, BMS limits, and device behavior change real runtime. CampWatt separates energy from continuous and surge output, while leaving product compatibility to the latest manufacturer documentation.

Read our operating principles