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JustNow 500W Portable Power Station Runtime Calculator
Quick answer: the JustNow 500W Portable Power Station stores 518 Wh and delivers up to 500 W of continuous AC power. Under this site's planning assumptions (85% inverter efficiency, 10% reserve), a steady 100 W AC load runs for roughly 4.0 hours. Last source check: 2026-08-27. This is an estimate, not a guarantee.
Battery capacity518 Wh
AC output500 W
Surge outputunknown
Battery chemistryLiFePO4
ConfidenceEstimated
Source regionGlobal/general sources
checked2026-08-27
Swipe table sideways
| Battery capacity | 518 Wh |
|---|---|
| Battery chemistry | LiFePO4 |
| AC output | 500 W |
| Surge output | unknown |
| DC output | 120 W |
| USB-C output | 60 W |
| Solar input | unknown |
| Weight | 6.6 kg |
| Confidence | Estimated |
| Lifecycle status | Unknown |
| Source region | Global/general sources |
| Last verified | 2026-08-27 |
Catalog notes (original English)
JustNow has no reachable first-party storefront, so this record uses a retailer-published copy of the manufacturer specification table and stays at estimated confidence. This listing carries no separate model code, so the descriptive product name is preserved. Surge and solar ceilings stay unknown because the table publishes neither.
Runtime estimate
Formula starting points use each scenario’s default watts, duty cycle and output path, with 10% reserve or 15% for CPAP. Linked detail pages use the same inputs. Hours apply only if the device can run and start; they are not measured runtimes.
Swipe table sideways
| Device scenario | Planning default | Estimated runtime | Device scenario: Confidence | Models |
|---|---|---|---|---|
| Full-size refrigerator | 500 W · 33% · AC inverter · Reserve: 10% | 2h 24m Output or startup compatibility is not established | Estimated | Calculator |
| CPAP without heated humidifier | 40 W · 100% · AC inverter · Reserve: 15% | 9h 21m Within the tracked power limits; compatibility still needs checking | Estimated | Calculator |
| Starlink Mini | 32 W · 100% · USB-C PD · Reserve: 10% | 13h 24m Exceeds a tracked power limit — do not rely on these hours | Estimated | Calculator |
| Wi-Fi router | 12 W · 100% · AC inverter · Reserve: 10% | 1d 10h Within the tracked power limits; compatibility still needs checking | Estimated | Calculator |
| LED TV | 100 W · 100% · AC inverter · Reserve: 10% | 3h 58m Within the tracked power limits; compatibility still needs checking | Estimated | Calculator |
Runtime calculator
Runtime is conditional on successful startup, compatible voltage/connectors and sufficient output. Verify the actual device setup before relying on these hours.
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Power station model
Battery capacity (Wh): 518 WhContinuous output rating (W): 500 WSurge output rating (W): n/a
Estimated runtime6h 36m4h 8m – 8h 12mEstimated runtime: 6h 36m, 4h 8m – 8h 12m
Output path
Estimated runtime
Within the tracked power limits; compatibility still needs checking
This is an estimate. Real runtime changes with load, temperature, battery age, AC/DC output, and device behavior. Runtime is conditional on successful startup, compatible voltage/connectors and sufficient output. Verify the actual device setup before relying on these hours.
6h 36mEstimated runtime: 6h 36mThis setup may cover a partial outage or single overnight session. Add capacity for more margin.
Conservative4h 8m
Estimated6h 36m
Optimistic8h 12m
These are calculated sensitivity cases, not a statistical confidence interval. Conservative uses lower efficiency and battery health, more reserve/temperature loss and higher load; optimistic changes these assumptions in the opposite direction.
- This is an estimate. Real runtime changes with load, temperature, battery age, AC/DC output, and device behavior. Runtime is conditional on successful startup, compatible voltage/connectors and sufficient output. Verify the actual device setup before relying on these hours.
- Within the tracked power limits; compatibility still needs checking
Show your work
Rated Wh is reduced by efficiency, reserve, battery health, and temperature before it is divided by average load.
- Rated battery
- 518 Wh
- Usable energy
- 396 Wh
- 518 Wh x 85% x 90% x 100% x 100%
- Running watts
- 60 W
- Average load
- 60 W
- Max surge
- n/a
- Fixed station overhead
- Unknown (not included)
- 60 W / 85% = 70.6 W battery draw; fixed overhead is unknown and excluded
- Estimated runtime
- 6h 36m
- 396 Wh / 60 W = 6h 36m
- Output path
- AC inverter
- Efficiency (%)
- 85
- Reserve kept unused (%)
- 10
- Battery health (%)
- 100
- Cold weather loss (%)
- 0
This link contains the numeric values you entered, but not custom load names.
Source-Backed Next Steps
Smallest matching record (8h)Jackery Explorer 600 Plus
WattRunTime.com
WattRunTime estimate
Estimated runtime
6h 36mThis setup may cover a partial outage or single overnight session. Add capacity for more margin.Usable energy396 Wh
Average load60 W
Fixed station overheadUnknown (not included)
Running watts60 W
Max surgen/a
Runtime range
Conservative4h 8m
Estimated6h 36m
Optimistic8h 12m
Show your work
Rated Wh is reduced by efficiency, reserve, battery health, and temperature before it is divided by average load.
Usable energy396 Wh518 Wh x 85% x 90% x 100% x 100%
Fixed station overheadUnknown (not included)60 W / 85% = 70.6 W battery draw; fixed overhead is unknown and excluded
Estimated runtime6h 36m396 Wh / 60 W = 6h 36m
Assumptions
- 518 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. Runtime is conditional on successful startup, compatible voltage/connectors and sufficient output. Verify the actual device setup before relying on these hours.
- Within the tracked power limits; compatibility still needs checking
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Planning notes
- Capacity class: 518 Wh. Size the battery for your measured average load and required hours, including reserve.
- Tracked output: 500 W. Compare both running demand and startup demand before using any runtime estimate.
- Solar input limit: unknown. Actual refill depends on panel voltage/current compatibility, sunlight, angle and charging losses.
Known data gaps
- Unverified or missing specifications remain visible. The confidence label describes the station record, not a tested runtime or approval for emergency use.
- Weight: 6.6 kg. Check the complete carrying setup, cables and battery extensions before choosing this model for travel.
- unknown: Surge output, Solar input
Models: JustNow
Compare nearby capacity records from the same brand, then check output, weight and missing fields. A larger battery does not establish device compatibility.
JustNow GT240 Pro
320 Wh · AC output: 240 W · Confidence: Estimated
JustNow GT240
240 Wh · AC output: 240 W · Confidence: Estimated
Sources
- JustNow 500W specification table published by retailer OOLACTIVE (Retailer; checked 2026-08-27)