Wattmargin: Outage Planner

About Wattmargin: Outage Planner

Wattmargin turns your appliances and your backup-power source into a practical, private outage plan. Enter a battery power station, portable generator, vehicle inverter, or UPS, list what you want to keep running, and see running and starting watts, battery runtime or generator fuel, and what to switch off first. No account, no subscription.

RUNTIME AND FUEL PLANNER
• Hour-by-hour outage timeline for the length and start time you choose
• Battery runtime that counts inverter efficiency, inverter idle draw, depth of discharge, and your reserve
• Peukert discharge-rate effect for lead-acid batteries (off for lithium)
• Optional daily recharge from solar panels or a vehicle
• Generator fuel for the whole outage, fuel per day, refuels, and hours per tank, interpolated from the runtime figures in your manual so light loads still burn fuel
• Chart of usable energy or fuel used over the outage

LOAD LIST WITH SCHEDULES
• Running watts, starting watts, power factor, duty cycle, priority, room, and notes for every appliance
• Set the hours each load runs, or spread its hours across the day
• 24-hour load profile chart
• Start from typical values for 20 common appliances, then replace them with your label readings
• Include, exclude, duplicate, or delete loads

CAPACITY CHECKS
• Running load against continuous output and the worst single startup against surge output
• Apparent load in VA against a UPS or inverter VA rating
• Output derating for heat, altitude, or aging
• Plain-language warnings when the plan is tight or over a limit

SCENARIO BENCH
• Compare your current plan, everything catalogued, must-run plus rotating loads, and must-run loads only
• Load-shedding order that protects must-run equipment and shows the runtime each switch-off gains

OUTAGE CHECKLIST AND NOTES
• Editable checklist with suggested preparation items, progress, and a reset for the next outage
• Household notes and a circuit directory linked to your loads

EXPORT AND BACKUP
• Multi-page PDF plan with source, loads, timeline, scenarios, checklist, notes, and circuits
• CSV export of the load list
• JSON backup and restore; your current plan is kept as a safety copy before any restore

PRIVATE BY DESIGN
No account, ads, analytics, or developer-operated cloud service. Your plan stays on your device unless you export it. The only network action is an optional link to the U.S. Consumer Product Safety Commission website.

IMPORTANT
Wattmargin gives planning estimates from the ratings you enter. Real runtime depends on temperature, battery age, fuel, and equipment condition. It is not an installation guide or a substitute for manufacturer instructions, electrical codes, permits, or a qualified professional. Never run a portable generator inside a home, garage, basement, shed, porch, or carport; keep it outdoors at least 20 feet from the home with exhaust directed away. Never backfeed home wiring through a wall outlet.