How we rate
Short version: we size your need with arithmetic, filter to units that meet it, and rank by fit, then price. Commission never enters the ranking.
1. Sizing your need
For each device you pick we use a typical average draw, a running draw for motors, and a startup surge. Then:
- Battery capacity = daily watt-hours × days ÷ 0.85 (inverter losses) × 1 (so you never run it flat).
- Continuous output = everything running at once × 1.25.
- Surge = everything running + the biggest single startup spike.
- If you tick solar, we assume panels cover about a third of daily use, which is typical for a 200 W panel on an average day.
Typical device figures are listed on each chip. Your own device's label or a $15 plug-in meter beats our estimate, and the fine-tune step lets you change hours.
2. Which units qualify
A unit qualifies when its capacity, rated output and surge all meet or beat your numbers. If a maker publishes no surge figure, we assume 1.8× rated output, which is conservative for this class.
3. Ranking
- Best fit: the smallest qualifying unit, which is usually the lightest and cheapest way to cover your list.
- Budget pick: the cheapest qualifying unit, if it is cheaper than the best fit.
- Room to grow: a qualifying unit with at least 60% more capacity, so you can add devices later.
4. The brands
We cover 20 models from Bluetti, EcoFlow, Jackery, Goal Zero and Anker SOLIX. All five sell LiFePO4 units rated for thousands of cycles, publish real specs, offer multi-year warranties and have US support. We do not list no-name or marketplace-only brands, because warranty claims on those often go nowhere.
5. Where the numbers come from
Every spec is taken from the maker's product page or, when that page would not load, a major retailer's listing. Each product shows a "Spec source" link so you can check it. Prices are what the page showed on October 12, 2026. We do not run a lab and never claim hands-on testing we have not done.
6. How we get paid
Buy links go to Amazon, and as an Amazon Associate we earn from qualifying purchases. The rate is the same whichever unit you choose, and the ranking logic above has no input for commission. If a brand's program ever paid us to favor it, we would drop the brand rather than the honesty. Full disclosure.