EcoFlow DELTA 3 Ultra vs Anker 521 PowerHouse
Side-by-side on the specs that decide it — surge, capacity, runtime and price.
Both models' specs verified against manufacturer listings · Last updated
The short answer
Anker 521 PowerHouse costs $1550 less. Whether that gap is worth closing depends on what you need to run.
- EcoFlow DELTA 3 Ultra holds 1100% more energy (3072Wh vs 256Wh), so it runs the same load proportionally longer.
- EcoFlow DELTA 3 Ultra has 6900W more surge headroom (7200W vs 300W) — that decides whether a fridge, pump or AC compressor will actually start.
- Anker 521 PowerHouse is 75.6 lb lighter (8.2 lb vs 83.8 lb).
- EcoFlow DELTA 3 Ultra is rated for 4,000 cycles vs 3,000 — meaningful if you cycle it daily.
EcoFlow DELTA 3 Ultra
3kWh with 7200W surge at $1799 — this is whole-home territory at a mid-range price. The catch is the 800W solar input.
Best for: Grid-tied home backup where you recharge from the wall, not the sun.
Where it falls short:
- 800W solar input is low for 3kWh — slow off-grid refills
- 83.8 lb
Anker 521 PowerHouse
A pocket-scale LiFePO4 unit for keeping devices alive. 200W of output means it's a charger, not an appliance station.
Best for: Travelers and campers topping up phones, cameras and a laptop.
Where it falls short:
- 200W output runs devices only
- 256Wh is small
| Spec | EcoFlow DELTA 3 Ultra | Anker 521 PowerHouse |
|---|---|---|
| Price | $1799 | $249 |
| Capacity | 3072 Wh | 256 Wh |
| Continuous output | 3600 W | 200 W |
| Surge output | 7200 W | 300 W |
| Battery | LiFePO4 | LiFePO4 |
| Rated cycles | 4,000 | 3,000 |
| Weight (lighter wins) | 83.8 lb | 8.2 lb |
| Max solar | 800 W | 100 W |
| Recharge time (faster wins) | 1h 30m | 2h 30m |
Runtime head-to-head
| Appliance | EcoFlow DELTA 3 Ultra | Anker 521 PowerHouse |
|---|---|---|
| Refrigerator | 43.5 hrs | ❌ |
| Mini fridge | 82.9 hrs | ❌ |
| Chest freezer | 32.6 hrs | ❌ |
| CPAP machine | 65.3 hrs | 5.4 hrs |
| Sump pump | 3.3 hrs | ❌ |