Power Calculator
Tell us what you need to run and for how long. We calculate the energy and power you need and show which stations can actually deliver it — with the reasons.
Step 1 of 3 · Add Your Devices
Add your own devices below, or try a labeled example setup to see how the calculator works.
| Device | Power (W) | Qty | Hrs/day | Surge (W)optional — blank uses a 2× fallback | Wh/day | Remove |
|---|---|---|---|---|---|---|
| No devices yet. Add a custom device, an example appliance, or try the example setup above to begin. | ||||||
| Total | 0 W | ≈0 W peak | 0 | |||
Step 2 of 3 · Set Usage & Runtime
If you can recharge from solar or the grid each day, keep this at 1. Increase it for outages with no way to recharge.
Advanced settings(usable efficiency, reserve headroom, surge fallback)
Assumed usable share of nameplate capacity after inverter and conversion losses.
Extra capacity kept in reserve above the calculated requirement.
Surge fallback: 2× running watts
Fallback startup-surge multiple applied only when you leave a device's Surge (W) field blank — never a substitute for a real figure. Motors, compressors, pumps, refrigerators and air conditioners can have startup peaks well above or below this 2x estimate; check the device's nameplate or manual and enter its real surge watts whenever you can.
Step 3 of 3 · Your Power Needs
Trying to run an RV air conditioner? → Startup surge, not stored energy, is usually the real blocker. Use the dedicated RV Air Conditioner Runtime & Surge Calculator to check it against your specific unit — or see the other specialized calculators for CPAP, refrigerators, and home backup.
Power Calculator FAQ
How does the Power Calculator estimate the capacity I need?
It multiplies each device's running watts by quantity and hours per day to get daily energy, multiplies by your days of autonomy, divides by an assumed usable efficiency (default 85%), then adds reserve headroom (default 20%). All assumptions are adjustable.
Does it use my real device wattages?
It uses whatever you enter. The example appliances are starting points, not universal figures — you should edit every value to match your own devices.
Why is a product marked Not Suitable instead of hidden?
If a unit cannot meet your required continuous output or capacity, we label it Not Suitable and explain why, rather than removing it. That keeps the shortlist honest.