Portable power stations, 300 Wh class

Model names mislead (a “535” is 512 Wh, “1000” models are 1,024 or 1,056 Wh); the stated Wh is the figure. PCWorld measured 80–83 % of it at AC on a 200 W load (87 % at best) and 71–84 % at 800 W; USB and 12 V outputs waste less. A 1,024 Wh station at 71 % gives about 725 Wh.

The continuous rating must exceed the largest steady load, the surge rating the largest start-up: a fridge runs at 150–250 W and starts at about 1,200 W. “Boost” modes run resistive loads such as kettles above the rating by lowering the voltage. Per-outlet limits are in the fine print.

Near-universal above 300 Wh now, and required for CPAP machines, microwaves and anything with a motor or a transformer; a modified sine wave inverter is a sign of a very cheap unit.

LiFePO4 (LFP) is rated for 3,000 cycles and more to 80 % capacity; NMC or plain Li-ion for 500–800 cycles to 60–80 %. LFP is heavier per Wh and more stable in heat. A reviewer measured 94 % capacity on an LFP station after about 1,100 daily UPS cycles.

Switches the outlets from mains to battery in 10–20 ms by the makers’ claims, 15 ms in a user’s measurement with a small fridge; enough for routers, PCs and fridges, not a true online UPS. Daily UPS duty consumes about a cycle a day.

AC input of 500–2,400 W refills modern LFP units to 80 % in 1–2 h; a car’s 12 V socket gives about 100–120 W and takes 8–20 h; alternator chargers give 500–800 W. Solar input has a maximum W and a voltage window (11–60 V or 11–150 V); the panel’s open-circuit voltage must stay inside it, and cold mornings raise it.

The cigarette socket is limited to 10 A, 120 W; a diesel heater needs about 180 W at start and will not run from it. Better units add a 30 A XT60 or Anderson port.

With the inverter on, standby draw runs from 1 to 30 W; 3 W is praised in tests. Eco or auto-off timers can cut the output when a fridge cycles off.

Expansion batteries are proprietary and cost about the same per Wh as the base unit. Some apps require an account to use every feature; others work offline. Warranties run 2–5 years. UL 2743 is the North American standard for portable power packs with inverters; it replaced UL 1236 for this class from 1 June 2025.

A station sold for the US is 120 V 60 Hz, for Japan 100 V, for the UK, Europe, Australia and India 230 V 50 Hz; a US-market unit does not run 230 V appliances and vice versa, and the outlet shape (Schuko, BS 1363, AS/NZS 3112) follows the market.