Overview
The EcoFlow DELTA 2 has dominated our mid-size power station rankings since its release. With 1024Wh of LiFePO4 capacity, X-Stream AC charging, and a mature ecosystem of expansion batteries and solar panels, it remains the most balanced mid-size option heading into 2026. We tested one for three weeks across AC charging, solar MPPT performance, app reliability, and cold-weather operation.
What we tested
- Real usable capacity at 200W and 500W continuous loads
- AC charging time from empty via X-Stream
- Solar MPPT efficiency with a 400W portable panel
- EcoFlow app features, including firmware stability and the new AI outage mode
- Cold-weather performance at -5°C ambient
- Noise under sustained high draw
Capacity and efficiency
At a 200W constant draw the DELTA 2 delivered 932Wh — roughly 91% of rated capacity, which is typical for a quality LiFePO4 system. At 500W the efficiency dropped to 88% (882Wh usable). Cold weather at -5°C cost another 11%, putting the unit at 828Wh usable. None of these results are a deal-breaker, but they do matter when you run the unit outdoors in winter.
Charging
X-Stream gets the DELTA 2 from empty to full in 78 minutes via any 15A outlet. Solar via the 11–60V MPPT accepts up to 500W of input. With our reference 400W Bluetti PV350 panel, full refill from empty took 3 hours and 7 minutes of direct sun. Compared with the Bluetti AC70 (4+ hours at the same input) and Jackery Explorer 1000 v2 (~3.5 hours), the DELTA 2 ties for fastest solar refill in this capacity class.
App and ecosystem
The EcoFlow app is the most polished in the category. Firmware updates have been steady, the new outage-detection mode auto-switches the unit to backup power when grid power drops, and device telemetry is consistent (state-of-charge, temperature, input/output wattage). The DELTA 2 Extra Battery lifts capacity to 2048Wh, and the Smart Generator adapter pairs with dual-fuel generators from Champion and Firman — useful if you want indefinite runtime during multi-day outages.
What we liked
- LiFePO4 chemistry rated for 3,000+ cycles to 80% capacity
- AC recharging under 80 minutes via X-Stream
- Strong ecosystem: Extra Battery, Smart Generator, polished app
- MPPT solar input up to 500W
What we didn't
- 12kg is portable but not backpack-friendly
- Display reads poorly in direct sunlight
- The original accessory bag is no longer included in current SKUs
Verdict
If you want a do-everything 1kWh-class power station for camping, RV trips, or home backup, the DELTA 2 remains the easiest recommendation. Its combination of LiFePO4 durability, fast charging, and ecosystem maturity is unmatched in this tier. Skip it only if you need absolute lowest cost-per-watt (look at the Bluetti AC70 instead) or much higher capacity (jump to the DELTA Pro).
Still the most balanced 1kWh-class power station on the market — recommended for home backup, RV trips, and anyone who values ecosystem maturity over absolute lowest cost.