SunSee Score
A transparent, formula-driven benchmark that evaluates every portable power station across 6 dimensions. No subjective opinions. No sponsored rankings. Just math.
The 6 Dimensions
1. Value ($/Wh)
30% weightHow much energy storage you get per dollar spent. The single most important metric for most buyers.
Score = normalize(price_usd ÷ capacity_wh)
Best: $0.20/Wh (score 100) → Worst: $1.50/Wh (score 0)
Why 30%: For most buyers, getting the most Wh for their budget is the primary decision factor. A $500 unit with 1000Wh ($0.50/Wh) scores much higher than a $500 unit with 300Wh ($1.67/Wh).
2. Longevity (Cycle Life)
20% weightHow many charge/discharge cycles before the battery drops to 80% capacity. Directly determines how many years the product lasts.
Score = normalize(cycle_life)
Best: 6,500 cycles (score 100) → Worst: 500 cycles (score 0)
Why 20%: A LiFePO4 unit with 3,000 cycles lasts 8+ years of daily use. A Li-ion unit with 500 cycles degrades in under 2 years. This dramatically affects true cost of ownership.
3. Power Density (W/kg)
15% weightHow much AC output power you get per kilogram of weight. Measures how efficiently the inverter and design deliver power relative to portability.
Score = normalize(ac_output_watts ÷ weight_kg)
Best: 200 W/kg (score 100) → Worst: 30 W/kg (score 0)
Why 15%: A lightweight unit that delivers high output is better engineered. A 10kg unit outputting 2000W (200 W/kg) is far superior to a 30kg unit outputting 1000W (33 W/kg).
4. Charge Speed (Wh/h)
15% weightHow fast the unit charges from AC wall power, measured in watt-hours gained per hour of charging.
Score = normalize(capacity_wh ÷ charge_time_hours)
Best: 3,000 Wh/h (score 100) → Worst: 100 Wh/h (score 0)
Why 15%: Fast charging means less downtime. A unit that charges 2000Wh in 1 hour (2000 Wh/h) is far more practical than one taking 6 hours (333 Wh/h), especially for emergency use or overnight charging.
5. Solar Capability
10% weightThe ratio of maximum solar input to battery capacity. Higher means faster solar recharging relative to the battery size.
Score = normalize(solar_input_watts ÷ capacity_wh)
Best: 0.8 ratio (score 100) → Worst: 0.1 ratio (score 0)
Why 10%: A 2000Wh battery with 1000W solar input (ratio 0.5) can fully recharge from sun in ~3 hours of peak sun. A 2000Wh battery limited to 200W solar input (ratio 0.1) would take 15+ hours — effectively unusable for daily solar cycling.
6. Output Power
10% weightThe continuous AC output wattage. Determines what appliances the unit can run simultaneously.
Score = normalize(ac_output_watts)
Best: 5,000W (score 100) → Worst: 200W (score 0)
Why 10%: Higher output means more versatility. A 3000W unit can run a microwave, while a 300W unit cannot. However, this is weighted lower because many users don't need high simultaneous output — they need capacity (Wh) more than peak power (W).
Final Formula
SunSee Score =
Value Score × 0.30
+ Longevity Score × 0.20
+ Power Density Score × 0.15
+ Charge Speed Score × 0.15
+ Solar Capability Score × 0.10
+ Output Power Score × 0.10
Each sub-score is normalized to 0–100 using linear interpolation between defined best/worst benchmarks. The weighted sum produces the final SunSee Score.
Design Principles
No Pay-to-Play
Brands cannot pay for a higher score. The formula is applied uniformly to all 102 products regardless of affiliate relationships.
Spec-Based Only
We use manufacturer-stated specifications. No subjective "build quality" or "brand reputation" factors that can't be objectively measured.
Transparent & Reproducible
The formula, weights, and benchmarks are published here. Anyone can verify a product's score by plugging its specs into the formula.
Market-Calibrated Benchmarks
Best/worst boundaries are set based on the actual range of products available in 2026, not theoretical limits. We recalibrate annually.
Limitations
SunSee Score is a starting point for comparison, not the final word. It does not capture:
- •Build quality, materials, or IP rating
- •App quality or smart features
- •Expandability or ecosystem compatibility
- •Warranty length or customer service quality
- •Real-world noise levels or thermal performance
- •Port variety (USB-C count, 12V outlets, etc.)
Always read the full product page — including pros, cons, and best-for scenarios — before making a purchase decision.