B500K for AC300/AC200L vs EcoFlow DELTA Pro 3 Smart Extra Battery
Compatibility note: expansion batteries only attach to their own brand's stations — this one pairs with BLUETTI systems, the other with EcoFlow's. Read this as a value and longevity comparison (which ecosystem is cheaper to expand), not a choice between interchangeable parts.
- Price today: EcoFlow is $100 cheaper ($1,899 vs $1,999).
- Cost per Wh: $0.39 vs $0.46 — B500K for AC300/AC200L gives you more battery per dollar today.
- Rated cycle-cost estimate: 9.8¢ vs 11.6¢ per lifetime kWh (manufacturer cycle ratings).
| B500K for AC300/AC200L | EcoFlow DELTA Pro 3 Smart Extra Battery | |
|---|---|---|
| Price today | $1,999 | $1,899 |
| Deal status | Unusually low | Normal price |
| Capacity | 5120Wh | 4096Wh |
| $/Wh | $0.39 | $0.46 |
| Chemistry | LFP | LFP |
| Rated cycles | 4,000 cycles to 80% | 4,000 cycles |
| Output | — | — |
| Solar input | 600W | — |
| Weight | 99.21 lbs | 72.8 lbs |
| Expandable | — | — |
| Standalone use | No — link port only | No — link port only |
| Recharge without station | Solar 600W · Car | No — only through the station |
| Recorded low | $1,599 (2026-08-20) | $1,814 (2026-09-29) |
| View at BLUETTI — $1,999 | View at EcoFlow — $1,899 |
Full tech-spec comparison all specs
| B500K for AC300/AC200L | EcoFlow DELTA Pro 3 Smart Extra Battery | |
|---|---|---|
| Battery | ||
| Chemistry | LFP | LFP |
| Capacity | 5,120Wh | 4,096Wh |
| Rated cycles | 4,000+ | 4,000 |
| Output | ||
| AC outlets | 0 (link port only) | 0 (link port only) |
| USB-C ports | 0 (link port only) | 0 (link port only) |
| USB-A ports | 0 (link port only) | 0 (link port only) |
| 12V / car output | 0 (link port only) | 0 (link port only) |
| Input & charging | ||
| AC input | None — recharges via the station only | None — recharges via the station only |
| Solar (PV) input | 600W | None — recharges via the station only |
| Car input | Alternator input 12.8V–62.5A / 25.6V–31.3A, 800W max (marketed as car charging with the Alternator Charger accessory) | None — recharges via the station only |
| General & physical | ||
| Weight | 99.21 lbs | 72.8 lbs |
| Operating temperature | -4°F to 104°F | 14°F to 113°F |
Also published by B500K for AC300/AC200L
| Cycle retention | 80% |
|---|---|
| Dimensions | 20.47 × 12.87 × 12.15 in |
| Warranty | 4 years |
Also published by EcoFlow DELTA Pro 3 Smart Extra Battery
| Max expanded | 12,000Wh |
|---|
Like-for-like specs both brands publish are shown first (✓ = better value); each brand's remaining published specs follow. Core figures are editorially verified; the rest come from each manufacturer's tech specs.
Price history — B500K for AC300/AC200L
Price history — EcoFlow DELTA Pro 3 Smart Extra Battery
Prices recorded daily from the official BLUETTI and EcoFlow stores. Deal statuses compare each product to its own 90-day history — methodology.