Dealectric

Portable power stations: what the numbers mean

A portable power station is a large battery with an inverter and a set of outlets. Six specifications decide whether one fits a given job. Here is how to read each of them.

1. Capacity (Wh)

Capacity is quoted in watt-hours. Divide by the appliance's draw to estimate runtime, then subtract 10–15% for inverter losses. A 1,000 Wh unit runs a 60 W laptop for roughly 14 hours, a 150 W fridge compressor (cycling) for a day or more, or a 1,500 W space heater for about half an hour. Common tiers: 300–500 Wh (camping, phones, lights), 1,000–1,500 Wh (weekend trips, CPAP, small appliances), 2,000–4,000 Wh (home-outage backup, expandable with extra batteries).

2. Chemistry: LiFePO4 vs NMC

Most current models use LiFePO4 (LFP) cells, rated for 3,000–4,000+ charge cycles to 80% capacity and more tolerant of heat. Older or lighter designs use NMC (lithium nickel manganese cobalt), typically 500–800 cycles, which packs more energy per kilogram but ages faster. For anything used daily or kept as backup for years, LFP is the better buy; NMC still makes sense when weight is the priority.

3. Inverter output: continuous vs surge

The continuous (rated) wattage is what the AC outlets can supply indefinitely; surge (peak) is a brief allowance for motor start-up. A refrigerator may run at 150 W but surge to 1,000 W for a second. Match continuous watts to the sum of what you will run at once and make sure surge covers any motor or compressor. Some brands advertise a "boost" mode that runs resistive loads (kettles, heaters) above the continuous rating by lowering voltage — useful, but not the same as true capacity.

4. Recharge speed and inputs

AC recharge has improved sharply: many 1 kWh-class units now go 0–80% in about an hour from a wall outlet. Check the maximum AC input watts and whether fast charging needs an app toggle. For solar, the MPPT input ceiling (watts and voltage range) sets how many panels you can connect; a 1,000 Wh unit with a 200 W solar ceiling takes a full sunny day to fill. Car (12 V) charging is slow — usually 100–120 W.

5. UPS / pass-through

If the unit will sit between the wall and a device that must not lose power (modem, CPAP, aquarium), look for a stated UPS switchover time — typically under 20 ms for consumer units, which is fast enough for most electronics but is not a certified online UPS. Pass-through charging (powering devices while the unit itself charges) is common but check that it is supported on the ports you need.

6. Ports and expandability

Count AC outlets and their total, USB-C ports and their wattage (100 W PD ports are now standard on mid-range units; 140 W PD 3.1 ports appear on premium models), and 12 V DC outputs. Larger models accept expansion batteries, sometimes doubling or tripling capacity; verify the expansion battery's price and availability before relying on that path.

Practical notes

Quick sizing guide

UseCapacityContinuous outputNotes
Phones, lights, camera batteries300–500 Wh300 WFits under an airline seat? No — power stations don't fly.
Laptop work, CPAP, mini fridge for a weekend1,000–1,500 Wh1,500–1,800 WCheck the CPAP's DC input to skip the inverter and extend runtime.
Outage backup: fridge + router + lights, 1–2 days2,000–3,000 Wh2,000–2,400 WPrefer LFP, expansion battery support, <20 ms UPS.
Power tools, induction cooktop, well pump3,000 Wh+3,000–3,600 W, high surgeConfirm surge rating against the motor's start-up draw.

Last reviewed October 8, 2026. Corrections welcome at hello@dealectric.com.