Core concept
Reserve keeps part of the battery unused for margin.
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Margin guide
Reserve and Battery Health
A runtime plan is safer when it leaves margin for age, cold, changing load, and measurement error.
Planning impact
Battery health reduces usable Wh as the pack ages.
What to verify
Cold weather and high loads can make a tight estimate fail.
Planning Wh = nominal Wh x efficiency x (1 - reserve) x battery health x temperature factor.
Reserve and Battery Health
A runtime plan is safer when it leaves margin for age, cold, changing load, and measurement error.
Reserve Is Intentional Unused Energy
A reserve setting prevents the estimate from assuming every last Wh is available. It is especially useful for overnight, medical-adjacent, or outage planning.
Battery Health Changes With Use
The calculator treats health as a percentage multiplier. It does not guess the condition of your pack; you choose a cautious value when the station is older.
Margin Beats False Precision
If the result barely clears the target, use a larger station, reduce the load, choose a supported DC path, or plan charging instead of trusting one exact number.
Evidence and review
These sources support the definitions and planning method. Calculator results are still estimates, not measurements or guarantees.
- DOE Explains...BatteriesU.S. Department of Energy · Government reference — Open source
- Electric Vehicle and Charging in Cold WeatherNational Renewable Energy Laboratory · Research report — Open source
Add Margin Before You Decide
Try 10-20% reserve, lower battery health, or temperature loss to see whether the setup still covers the needed hours.
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Power station model
Battery capacity (Wh): 1024 WhContinuous output rating (W): 1800 WSurge output rating (W): 2700 W
Estimated runtime13h 3m8h 10m – 16h 13mEstimated runtime: 13h 3m, 8h 10m – 16h 13m
Output path
Estimated runtime
13h 3mEstimated runtime: 13h 3mThis setup has comfortable headroom for overnight use, assuming the wattage estimate is realistic.
Conservative8h 10m
Estimated13h 3m
Optimistic16h 13m
Conservative assumes harder conditions; optimistic assumes favorable conditions.
- This is an estimate. Real runtime changes with load, temperature, battery age, AC/DC output, and device behavior.
- Usable energy
- 783 Wh
- Average load
- 60 W
- Fixed station overhead
- Unknown (not included)
- Running watts
- 60 W
- Max surge
- n/a
Show your work
Rated Wh is reduced by efficiency, reserve, battery health, and temperature before it is divided by average load.
- Rated battery
- 1024 Wh
- Battery capacity (Wh): 1024 Wh
- Usable energy
- 783 Wh
- 1024 Wh x 85% x 90% x 100% x 100%
- Average load
- 60 W
- 60 W running, 60 W average after duty cycle and quantity
- Fixed station overhead
- Unknown (not included)
- 60 W / 85% = 70.6 W battery draw; fixed overhead is unknown and excluded
- Estimated runtime
- 13h 3m
- 783 Wh / 60 W = 13h 3m
- 1024 Wh nominal battery capacity
- AC inverter output path
- 85% conversion efficiency
- 10% reserve kept unused
- 60 W average load from 1 load
- 100% battery health
- 0% temperature loss
- Fixed station overhead unknown; not included
This link contains the numeric values you entered, but not custom load names.
Source-Backed Next Steps
Smallest matching record (8h)Jackery Explorer 600 v2
WattRunTime.com
WattRunTime estimate
Estimated runtime
13h 3mThis setup has comfortable headroom for overnight use, assuming the wattage estimate is realistic.Usable energy783 Wh
Average load60 W
Fixed station overheadUnknown (not included)
Running watts60 W
Max surgen/a
Runtime range
Conservative8h 10m
Estimated13h 3m
Optimistic16h 13m
Show your work
Rated Wh is reduced by efficiency, reserve, battery health, and temperature before it is divided by average load.
Rated battery1024 WhBattery capacity (Wh): 1024 Wh
Usable energy783 Wh1024 Wh x 85% x 90% x 100% x 100%
Average load60 W60 W running, 60 W average after duty cycle and quantity
Fixed station overheadUnknown (not included)60 W / 85% = 70.6 W battery draw; fixed overhead is unknown and excluded
Estimated runtime13h 3m783 Wh / 60 W = 13h 3m
Assumptions
- 1024 Wh nominal battery capacity
- AC inverter output path
- 85% conversion efficiency
- 10% reserve kept unused
- 60 W average load from 1 load
- 100% battery health
- 0% temperature loss
- Fixed station overhead unknown; not included
Warnings
- This is an estimate. Real runtime changes with load, temperature, battery age, AC/DC output, and device behavior.
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Use With These Tools
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Capacity guide
Usable Capacity vs Rated Capacity
A 1,000 Wh label is the starting point, not a promise that 1,000 Wh reaches your device.
Efficiency guide
Inverter Efficiency Losses
AC is convenient, but the inverter changes battery energy into wall-style power and some energy is lost as heat.
FAQ
Plan portable power station runtime with reserve, aging, cold-weather loss, and margin instead of draining the battery to zero on paper.
How much reserve should I keep?
A 10-20% reserve is a practical planning range for many setups. Use more margin when the load is critical or conditions are uncertain.
Does the calculator know my battery health?
No. Battery health is an input. Lower it when the station is older, heavily used, cold, or when you want a more conservative plan.