BLUETTI B300K Expansion Battery for the AC500
The BLUETTI B300K is a 2,764.8Wh LiFePO₄ expansion battery that powers and expands the BLUETTI AC500. Because the AC500 has no built-in battery, it needs at least one B300K, B300 or B300S to run. Stack up to six B300K packs for 16,588.8Wh of storage for NZ home backup and off-grid living.
Key Features and Benefits
Build your AC500 system one pack at a time
Start with one B300K and add more as your needs grow. Each pack adds 2,764.8Wh, so you can scale from about 2.8kWh to 16.6kWh on a single AC500.
Mix and match on the AC500
The AC500 accepts B300K, B300 and B300S packs in the same system, up to six in total. If your setup includes a B300, the maximum is four packs.
Fast charging through the AC500
Connected to the AC500, the B300K charges to 80% in about 45 minutes using a 30A charging cable. Solar and AC charging both run through the AC500.
Monitor every pack in the app
When the B300K is connected to the AC500, you can check the status of each battery pack and control the whole system through the BLUETTI app.
Built for safety and durability
Prismatic LiFePO₄ cells, AI-BMS battery management, an aluminium casing and a cooling fan protect against overcharging, over-discharging, overcurrent, short circuits and overheating.
USB-A port for standalone use
A 12W USB-A port lets you charge a phone or tablet directly from the B300K when it isn’t connected to the AC500.
How Much Capacity Can You Build With the AC500?
| Configuration | Total capacity |
|---|---|
| AC500 + 1 × B300K | 2,764.8Wh |
| AC500 + 2 × B300K | 5,529.6Wh |
| AC500 + 4 × B300K | 11,059.2Wh |
| AC500 + 6 × B300K | 16,588.8Wh |
The B300K also works with the Apex 300, AC300, AC200L and AC200MAX. See the BLUETTI B300K Expansion Battery page for full compatibility details, or the B500K for 5,120Wh per pack.
How Long Will the AC500 and B300K Run My Appliances?
BLUETTI’s runtime formula is: battery capacity × 90% depth of discharge × 90% inverter efficiency ÷ device power. Each B300K provides about 2,239Wh of usable AC energy.
| Continuous load | 1 × B300K | 6 × B300K |
|---|---|---|
| 100W | About 22.4 hours | About 5.6 days |
| 500W | About 4.5 hours | About 27 hours |
| 1,000W | About 2.2 hours | About 13.4 hours |
Estimates are for reference only. The formula doesn’t apply to appliances with compressors, such as fridges and heat pumps, whose power draw cycles on and off.
Who Is This For in New Zealand?
- AC500 owners: power your AC500 for the first time, or add capacity to an existing system.
- Whole-home backup: keep essential circuits running through extended storm-related outages.
- Solar storage: store more daytime solar generation for evening and overnight use.
- Off-grid homes and workshops: build a large battery bank for daily off-grid power.
Each B300K weighs 29.5kg and is not waterproof, so install packs in a dry, sheltered space. Don’t charge below 0°C. After a full discharge, recharge promptly, and let the battery sit at 10°C or above for 12 hours first.
BLUETTI B300K Specifications
| Capacity | 2,764.8Wh (51.2V, 54Ah) |
|---|---|
| Battery type | LiFePO₄ (lithium iron phosphate) |
| Cycle life | 3,500+ cycles to 80% original capacity |
| USB-A output | 1 × 12W max (5V/2.4A) |
| Expansion ports | 2 × 58.4V DC max, 90A max |
| Charging current | 60A max |
| Discharging current | 70A max |
| AC500 connection cable | P150D to P090A (sold separately) |
| Max packs per AC500 | 6 (4 if a B300 is included) |
| Weight | 29.5kg |
| Dimensions (L × W × H) | 525 × 327 × 209mm |
| Charging temperature | 0°C to 40°C |
| Discharging temperature | -20°C to 40°C |
| Working humidity | 5% to 95% RH |
| Compatibility | AC500, Apex 300, AC300, AC200L, AC200MAX |
| Warranty | 3 + 1 years (extra year on registration) |
What’s in the Box
- 1 × BLUETTI B300K expansion battery
- [CONFIRM: included cable(s) and user manual]
Note: the P150D to P090A cable needed to connect the AC500 is sold separately.
Warranty and Support in New Zealand
The B300K comes with a 3-year BLUETTI warranty, extended by one year when you register it on BLUETTI’s website after delivery. Your purchase is also covered by your rights under the Consumer Guarantees Act 1993. For help planning your AC500 system, contact the Cybotix Energy team.
How many B300K batteries can I connect to the BLUETTI AC500?
The AC500 supports up to six B300K batteries, for a total of 16,588.8Wh. If your system includes a B300 battery, the maximum drops to four packs in total. You can start with a single B300K and add more over time, so your AC500 system grows as your backup needs increase.
What cable do I need to connect the B300K to the AC500?
You need a BLUETTI P150D to P090A cable to connect the B300K to the AC500. This cable is sold separately and isn’t included with the B300K. The same cable is used when connecting B300K packs to B300S packs in a mixed AC500 system. Contact us if you’re unsure which cables your setup needs.
Does the AC500 need a battery to work?
Yes, the BLUETTI AC500 has no built-in battery, so it needs at least one expansion battery to run. It works with the B300K, B300 and B300S. The B300K is a common choice because it pairs 2,764.8Wh of capacity with fast charging, and it can also be used with the Apex 300 and AC300 if you upgrade later.
How long will an AC500 with B300K batteries run my appliances?
Each B300K gives about 2,239Wh of usable energy, based on BLUETTI’s 90% depth of discharge and 90% inverter efficiency. One pack runs a 100W load for about 22 hours. Six packs run a 1,000W load for about 13 hours. Fridges and heat pumps cycle on and off, so their runtime varies.
Can I mix B300K, B300 and B300S batteries on the AC500?
Yes, the AC500 can mix B300K, B300 and B300S batteries in one system, up to six packs in total. If any B300 is included, the limit is four packs. Once connected, you can monitor the status of each pack individually through the BLUETTI app, which helps you manage a mixed system.
How fast does the B300K charge with the AC500?
Connected to the AC500, the B300K charges to 80% in about 45 minutes using a 30A charging cable. The B300K can’t be charged directly from solar panels or a car socket. All charging, including solar, runs through the AC500 or another compatible BLUETTI power station.
Can I use the B300K as a UPS on its own?
No, the B300K can’t work as a UPS on its own, and it doesn’t support Power Bank Mode. It needs to be connected to the AC500 or another compatible BLUETTI power station to supply AC power. On its own, it can only charge small devices through its 12W USB-A port.
What warranty does the B300K have in NZ?
The BLUETTI B300K comes with a 3-year manufacturer warranty, with an extra year added when you register it on BLUETTI’s website after delivery. In New Zealand, your purchase is also covered by your rights under the Consumer Guarantees Act 1993. If you have a problem, contact Cybotix Energy and we’ll help with your claim.
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