Size your power station, battery and solar panels without guesswork
Whether you're preparing for outages, camping off-grid or setting up an RV, these free tools turn your device list into real numbers: watt-hours, inverter watts and solar panel size. Every formula is shown, so you can check the math yourself.
Calculators
Power station size
List your devices and get the capacity (Wh), continuous watts and surge watts you need.
SolarSolar panel size
How many panel watts cover your daily use, and how long a full recharge takes.
RuntimeBattery runtime
How many hours a battery or power station will run a specific device.
ConvertWatts ↔ amps
Convert at 12 V, 120 V or any voltage, including the battery current behind an inverter.
ConvertAh ↔ Wh converter
Compare batteries rated in amp-hours with ones rated in watt-hours.
CostElectricity cost
What an appliance costs to run, and what a power station costs to recharge.
Wiring12 V wire size
Pick a cable gauge that keeps voltage drop low and stays within its current rating.
Guides
What size power station do I need?
A step-by-step sizing method with worked examples for outages, camping and RVs.
Watts vs. watt-hours
The one distinction that makes every spec sheet make sense.
How long will a power station run a fridge?
Find your fridge's real daily use and estimate runtime accurately.
Peak sun hours explained
What the number means and how to look it up for your location.
Running vs. surge watts
Why motors trip inverters, and how to size for startup surges.
LiFePO4 vs. NMC
Cycle life, weight, safety and cold-weather limits of the two common lithium chemistries.
Series vs. parallel
How wiring batteries or solar panels changes voltage, current and safety limits.
How long will a 12 V battery last?
Runtime for a 100 Ah battery at common loads, and what shortens it.
How we approach this
Most sizing advice online is either a sales pitch for a specific product or a vague "it depends." We try to do better by showing the formulas, using conservative assumptions, and telling you which spec to check on your own equipment. Read our editorial policy to see how the tools and guides are made and checked.