EnginStar R300
- AC delivered · est.
226 Wh. Show source
estimated sourcem.media-amazon.com ↗2026-07-27- output
300 W. Show source
claimed sourcem.media-amazon.com ↗- surge
500 W. Show source
claimed sourcem.media-amazon.com ↗- weight
2.95 kg. Show source
claimed sourcem.media-amazon.com ↗
We're still sourcing enough verified data to publish a BatteryRank score for this model.
Not enough tracked history for a verdict.
See alternatives to the EnginStar R300 →At a glance
EnginStar R300 is a ultraportable / carry model best suited to buyers matching its sourced output and capacity. It supplies 300 W of continuous AC output. Its current tracked price is $129.98; there is not enough tracked history for a verdict. Its data coverage is not yet sufficient for a comparable score.
Capacity truth
The watt-hour number on the box isn't what reaches your devices. Rated on the label vs what actually leaves an outlet.
296 Wh. Show source
claimed sourcem.media-amazon.com ↗2026-07-27The marketing number — total cell capacity.
226 Wh. Show source
estimated sourceestimate = battery-side usable capacity × 85% inverter efficiencyWhat reaches an AC outlet — about 15% is lost turning battery power into household AC. How we estimate.
What it can run
Same sourced device assumptions used by our calculators, applied to this model's usable AC energy. Actual runtime varies with load, temperature, and standby draw.
| Device | Estimated runtime | Sourced assumption |
|---|---|---|
| CPAP (humidifier off) | about 3.1 nights | 9 W · |
| CPAP (heated humidifier on) | about 0.5 nights | 56 W · |
| Refrigerator (full-size) | about 3.6 hours | 180 W × 35% duty cycle · |
| Wi-Fi router + modem | about 13 hours | 18 W · |
| Laptop (65W charger) | about 7.0 hours | 65 W × 50% duty cycle · |
| Phone (one full charge) | about 11 full charges | 20 W · |
How it scores
Four buyer pillars over seven sub-scores — computed from sourced data with a published formula, price-independent by design.
Power
est.Battery-side usable capacity and how much you can run at once.
Usable watt-hours and how far you can grow it with add-on batteries, versus its size class.
Continuous and surge wattage, outlet count, and USB-C fast-charging.
Trust
Owner reputation, safety record, warranty, and build durability.
Owner ratings, brand reputation, recall record, and warranty backing.
Rated cycle life, warranty length, cell chemistry, and weather sealing.
Charging
Wall and solar recharge speed.
Wall recharge speed, solar input, and multi-source charging.
Livability
62% dataLightweight, portable, and quiet enough to live with.
Weight, footprint, handle, and wheels, versus its size class.
Fan noise under load — quieter is better for bedrooms and CPAP use.
How this score is computed
The BatteryRank score is computed from sourced data with a published formula — ranked by data, not lab testing. Seven sub-scores blend into a 0–100 composite, grouped into four buyer pillars. Price is deliberately not a scoring input: prices move daily, so value intelligence lives in the price section above, judged against this model's own history.
| Pillar | Built from |
|---|---|
| Power | Capacity & expansion + Output & versatility |
| Trust | Trust & reliability + Durability & longevity |
| Charging | Charging & solar |
| Livability | Portability + Quiet / livability |
Scores are cohort-relative — each model is ranked against others in its size class. Missing inputs renormalize out rather than scoring zero (a model is never penalized for a spec nobody in its class publishes), and any figure resting on a documented estimate is tagged est. A full methodology page is coming.
Full specifications
Manufacturer-claimed unless marked verified (FCC/UL/DOE/lab). Tap or focus a figure to view its source.
Capacity & battery
- Battery chemistry
Lithium-ion. Show source
claimed sourcem.media-amazon.com ↗- Rated capacity
296 Wh. Show source
claimed sourcem.media-amazon.com ↗
The type of battery cell. LiFePO4 (LFP) cells last far more cycles and are more thermally stable than older lithium-ion (NMC) cells.
The battery's nameplate energy capacity — the headline number on the box. Battery-side usable and AC-delivered capacity are shown separately.
Power output
- Continuous power output
300 W. Show source
claimed sourcem.media-amazon.com ↗- Surge power output
500 W. Show source
claimed sourcem.media-amazon.com ↗- AC outlets
2 outlets. Show source
claimed sourcem.media-amazon.com ↗- USB-C ports
1 ports. Show source
claimed sourcem.media-amazon.com ↗
The most power you can draw at once, sustained — this has to be higher than the running wattage of whatever you're plugging in.
A brief power spike the unit can absorb when a device first switches on — matters for things with motors or compressors, like fridges.
How many standard wall-style outlets are built in.
How many USB-C ports are built in — check the per-port wattage below if you need fast charging for a laptop.
Size & portability
- Weight
2.95 kg. Show source
claimed sourcem.media-amazon.com ↗
How much the unit weighs on its own, without accessories — relevant for portability and carrying it up stairs during an outage.
What reviewers & owners report
Aggregated from named outlets and marketplaces — we own no hardware and never fabricate impressions.
What else to consider instead of the EnginStar R300
Same or adjacent size class, ordered by the price-independent composite. Every alternative is better than the EnginStar R300 at something and worse at something else, so each row states both halves — each one arithmetic on two sourced readings, with a dimension skipped rather than guessed when either side is missing a figure.
- Goal Zero Yeti 300score 71 · same size class
- Why you would switch
- The Goal Zero Yeti 300 carries 17% more continuous output (350 W vs 300 W), which decides what it can run at all.
- What you give up
- The EnginStar R300 is $220 cheaper at the prices tracked on 2026-07-28 ($130 vs $350).
- EcoFlow RIVER 3 Plusscore 65 · same size class
- Why you would switch
- The EcoFlow RIVER 3 Plus delivers 8% more usable AC energy (243 Wh vs 226 Wh).
- What you give up
- The EnginStar R300 is $169 cheaper at the prices tracked on 2026-07-28 ($130 vs $299).
- Bluetti Elite 30 V2score 63 · same size class
- Why you would switch
- The Bluetti Elite 30 V2 carries 100% more continuous output (600 W vs 300 W), which decides what it can run at all.
- What you give up
- The EnginStar R300 is $109 cheaper at the prices tracked on 2026-07-28 ($130 vs $239).
- Anker SOLIX C300score 62 · same size class
- Why you would switch
- The Anker SOLIX C300 delivers 19% more usable AC energy (269 Wh vs 226 Wh).
- What you give up
- The EnginStar R300 is $170 cheaper at the prices tracked on 2026-07-28 ($130 vs $300).
- EcoFlow RIVER 3score 55 · same size class
- Why you would switch
- The EcoFlow RIVER 3 carries 5 years of warranty against 1.
- What you give up
- The EnginStar R300 is $49 cheaper at the prices tracked on 2026-07-28 ($130 vs $179).
Quick answers
Each answer restates a sourced figure from elsewhere on this page — nothing new, nothing guessed.
- How much does the EnginStar R300 weigh?
- 2.95 kg (6.5 lb), manufacturer-claimed, without accessories.
- What are the dimensions of the EnginStar R300?
- 230 × 194 × 140 mm (9.1 × 7.6 × 5.5 in), length × width × height, manufacturer-claimed.
- How much capacity does the EnginStar R300 deliver through an AC outlet?
- About 226 Wh of the rated 296 Wh reaches an AC outlet from a full charge — an estimate after our published 15% inverter-loss constant (marked est. on this page).
- How many watts can the EnginStar R300 output?
- 300 W continuous AC output and 500 W surge output, manufacturer-claimed. Appliance startup demand must stay within the relevant limit.