B500K for AC500 vs EcoFlow DELTA Pro 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 $950 cheaper ($1,099 vs $2,049).
- Cost per Wh: $0.40 vs $0.31 — EcoFlow DELTA Pro Smart Extra Battery gives you more battery per dollar today.
- Cycle-adjusted: 10.0¢ vs 4.7¢ per lifetime kWh (manufacturer cycle ratings).
| B500K for AC500 | EcoFlow DELTA Pro Smart Extra Battery | |
|---|---|---|
| Price today | $2,049 | $1,099 |
| Deal status | Tracking since 7d | Tracking since 7d |
| Capacity | 5120Wh | 3600Wh |
| $/Wh | $0.40 | $0.31 |
| Chemistry | LFP | LFP |
| Rated cycles | 4,000 | 6,500 |
| Output | — | — |
| Solar input | — | — |
| Weight | 99.2 lbs | 84 lbs |
| Expandable | to 100000Wh | to 10800Wh |
| Standalone use | No — link port only | No — link port only |
| Recharge without station | No — only through the station | No — only through the station |
| All-time low | $2,049 (2026-07-07) | $1,099 (2026-07-07) |
| View at BLUETTI — $2,049 | View at EcoFlow — $1,099 |
Full tech-spec comparison all specs
| B500K for AC500 | EcoFlow DELTA Pro Smart Extra Battery | |
|---|---|---|
| Battery | ||
| Chemistry | LFP | LFP |
| Capacity | 5,120Wh | 3,600Wh |
| Rated cycles | 4000 | 6,500 |
| Expandable | Yes | Yes |
| Max expanded | 100000 | 10800 |
| 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 | None — recharges via the station only | None — recharges via the station only |
| Car input | None — recharges via the station only | None — recharges via the station only |
| General & physical | ||
| Weight | 99.2 | 84 lbs |
| Warranty | 4 years | 5 years |
Also published by EcoFlow DELTA Pro Smart Extra Battery
| Cycle retention | 50% |
|---|
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 AC500
Price history — EcoFlow DELTA Pro 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.