Photo from the manufacturer
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The B300K is an expansion battery: on its own it powers nothing, it connects with a dedicated cable to a BLUETTI power station from the same family - AC200L, AC200MAX, AC300 or AC500 - and extends its runtime without adding a second inverter. Connecting to the AC500 needs a different cable than the one included in the box, bought separately: that needs to be factored in before ordering. Pass-through lets it charge and discharge at the same time, so charging the main power station doesn't stop when the B300K kicks in.
It's designed to stay put next to the power station, not to be moved every day: anyone taking it in a camper van or a boat needs to plan for a stable mount, not just resting it in place. It has its own USB-A port to charge a device directly from the pack, useful when the main power station's outlets are already in use.
It makes sense for anyone who already owns one of these power stations and wants more runtime for a home power outage or for days away from the grid, not for anyone looking for an independent battery: without a compatible BLUETTI power station connected, the B300K does nothing on its own.
official manufacturer list price — on nominal capacity
| Parameter | Value | Source |
|---|---|---|
| Dimensions | 52.5 × 32.7 × 20.9 cm (20.7 × 12.9 × 8.2 in) | manufacturer website |
| Weight | 29.5 kg (65.0 lb) | manufacturer website |
| Compatible models | AC200L, AC200MAX, AC300, AC500 | Declared by the brand |
| Nominal capacity | 2.7648 kWh | Declared by the brand |
| Cell chemistry | LFP (lithium iron phosphate) | Declared by the brand |
| Warranty | 3 anni | Declared by the brand |
| Official list price | 1399 € | Declared by the brand |
| Usable capacity | — | Not declared |
| Depth of discharge | — | Not declared |
| Cell supplier | — | Not declared |
| Expandable | — | Not declared |
| Maximum expanded capacity | — | Not declared |
| Continuous output | — | Not declared |
| Peak output | — | Not declared |
| Peak duration | — | Not declared |
| AC outlets | — | Not declared |
| Fastest USB-C | — | Not declared |
| Maximum charge power | — | Not declared |
| 0–80% charge time | — | Not declared |
| Maximum solar input | — | Not declared |
| Backup power | — | Not declared |
| Switchover time | — | Not declared |
| Rated cycles | — | Not declared |
| Capacity at end of cycle life | — | Not declared |
| Guaranteed throughput | — | Not declared |
| Guaranteed remaining capacity | — | Not declared |
| Round-trip efficiency | — | Not declared |
| Standby consumption | — | Not declared |
| Ingress protection | — | Not declared |
| Mounting | — | Not declared |
| Minimum temperature | — | Not declared |
| Maximum temperature | — | Not declared |
| Cell heating | — | Not declared |
| Noise level | — | Not declared |
| Wheels and handle | — | Not declared |
| Works without internet | — | Not declared |
| Local control | — | Not declared |
| Open protocols | — | Not declared |
| Home Assistant integration | — | Not declared |
| Where the data is hosted | — | Not declared |
| Remote updates | — | Not declared |
| App required for setup | — | Not declared |
| Declared standards | — | Not declared |
The rest of the data comes from one page on the manufacturer's site, cited row by row in the table above.
A manual or a datasheet counts as a source even when the original file is hosted elsewhere: what matters is the document, not the server. Where that happens, it is stated above.
These numbers are calculated, not stated: they have no source to cite, they have a formula you can redo. The price used is the manufacturer's list price, which is stable and the same in every country — not a shop's price on the day.
Chosen by the declared use tier and footprint, not by price: we don't publish prices.
