BLUETTI B500K Expansion Battery

What extra runtime does it give you?

The B500K adds a substantial 5,120Wh to a compatible BLUETTI power station. Paired with the BLUETTI Apex 300 (2,764.8Wh, 3,840W) we stock, total capacity climbs to 7,884.8Wh — nearly triple the base unit, on the same 3,840W output:

• A full-size fridge (~150W): runtime extends from ~16 hours to ~45 hours (+29 hours)
• A small camping fridge (~60W): from ~39 hours to ~112 hours (+73 hours, over four and a half days)
• An induction cooktop or portable air conditioner (~2000W): from ~1 hour 10 minutes to ~3 hours 20 minutes (+2 hours 10 minutes)

At 45kg it's a serious addition best moved with two people or a trolley, but it's built to sit alongside an Apex 300 (or other compatible units) in a proper off-grid battery bank rather than as a portable accessory.

Figures are estimates based on typical appliance draw and around 15% inverter loss — actual runtime varies with the appliance, ambient temperature and load.

For those who need serious reserve capacity, the BLUETTI B500K adds a substantial 5,120Wh of LiFePO4 storage to any compatible power station, making it the go-to expansion for large households, remote properties or extended off-grid stretches where a single base unit just isn't enough. It shares the same rugged LiFePO4 chemistry BLUETTI is known for, rated to 4,000+ cycles while retaining 80% of its original capacity.

It links into the host system through a simple expansion port connection using the included long expansion cable, handling up to 65A charge and 70A discharge current for efficient power transfer. At 45kg it's a hefty addition, so plan for a two-person or trolley-assisted install, but the payoff is a big jump in usable energy without needing a second full power station. It's built to sit alongside compatible units in a proper off-grid battery bank setup.

• 5,120Wh LiFePO4 capacity, rated for 4,000+ cycles to 80% capacity
• Compatible with AC200L, AC200MAX, AC300, AC500, Apex 300 and B300K systems
• Expansion port connection: up to 65A max charge, 70A max discharge
• Dual expansion ports rated 58.4VDC, 90A max each
• Includes P090A long expansion cable and user manual
• Operating range: 0–40°C charging, -20–40°C discharging
• Weight 45kg, dimensions 520 × 327 × 308.5mm
• Backed by BLUETTI's multi-year manufacturer warranty