BLUETTI B300K Expansion Battery
The BLUETTI B300K is a 2,764.8Wh LiFePO₄ expansion battery that adds stored energy to selected BLUETTI power stations. It has no AC outlets and works as part of a system. Swapping a whole external module is a cable job, but the pack weighs about 29.5kg.
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Will This Battery Work With Your Setup?
The B300K is an external expansion battery. It does not replace the internal battery of a power station. BLUETTI lists the AC200L, AC200MAX, AC300, AC500 and Apex 300 as compatible hosts. Run this quick check before you buy.
A B300K is not an identical swap for every BLUETTI battery. A B300 holds 3,072Wh, while the B300K holds 2,764.8Wh. On an AC500, one B300K limits AC output to 3,000W. Two or more B300K packs allow the full 5,000W.
BLUETTI B300K Specifications
| Property | Detail |
|---|---|
| Brand / model | BLUETTI B300K Expansion Battery |
| Type | External expansion battery, no AC outlets |
| Chemistry | LiFePO₄ (lithium iron phosphate) |
| Rated energy | 2,764.8 Wh |
| Rated voltage | 51.2 V |
| Rated capacity | 54 Ah |
| Net weight | Approx. 29.5 kg (65.04 lb) |
| Dimensions (L × W × H) | 525 × 327 × 209 mm (20.67 × 12.87 × 8.23 in) |
| Max charging current | 60 A (may decrease outside the specified temperatures) |
| Max discharging current | 70 A |
| Expansion ports | 2 (port rating 58.4 V DC max, 90 A max) |
| Direct output | 1 × USB-A, 5 V / 2.4 A, 12 W max |
| Charging temperature | 0°C to 40°C (15°C to 30°C recommended) |
| Discharging temperature | −20°C to 40°C |
| Storage temperature | −20°C to 40°C (up to 1 month); −20°C to 25°C (up to 6 months) |
| Humidity | 5% to 95% RH |
| Pass-through | Charges and discharges at the same time |
| Indicators | LED indicators, each lit LED is about 20% charge |
| Cycle life rating | 4,000+ or 6,000+ cycles to 80%, depending on the BLUETTI source |
| Advertised warranty | 3+1 years with registration (check regional terms) |
| Compatible hosts | AC200L, AC200MAX, AC300, AC500, Apex 300 |
Rated energy is not the same as usable AC energy. The battery keeps some energy in reserve, and the host inverter has losses. BLUETTI’s own sources differ on cycle life, so confirm the rating for your exact listing. Specs come from BLUETTI’s B300K manual, data sheet and product pages.
B300K Replacement Difficulty
Swapping a complete external B300K is a low-skill job. The casing stays closed and only cables are involved. At about 29.5kg, the pack makes lifting the main physical task. Matching the host, cable and pack count is the part that needs care. Tap a slice to highlight it.
- 20% Connecting the cable
- 25% Lifting & positioning
- 40% Matching host, cable & pack count
- 15% Checking the system afterwards
The score and effort split are an editorial estimate, not an official BLUETTI rating. Replacing the cells inside a B300K is not a supported user task. The manual prohibits disassembly.
How to Swap an External B300K
This covers exchanging a whole external module. Your power station manual has the full details for your model. Tap each step to tick it off as you go.
- 1Power down the systemStop all loads and charging first, because a connected B300K turns on automatically when the system charges from AC or solar. Then switch off the power station and the battery.
- 2Disconnect the old batteryUnplug the expansion cable and move the old module. At about 29.5kg, it is worth getting a second pair of hands. Do not open the casing.
- 3Connect the new B300KUse the cable listed for your host: P090A for AC200L, AC200MAX and AC300, P090D to P150D for AC500, or CA90 for Apex 300. Press the cable down into the port, then push the lock into place.
- 4Power up and checkSwitch the system on and confirm the battery shows in the BLUETTI app with no warning indicator. A new pack needs a charge cycle before first use, and firmware updates are under Settings > Firmware Upgrade.
Two flashes followed by a four-second pause mean the expansion cable is not locked. Power down, reseat the cable and lock it fully. Never use damaged cables or plugs.
Devices That Work With the B300K
These power stations and batteries are documented for B300K use by BLUETTI. Pack limits count B300K units. Confirm your exact setup in the manual first.
- BLUETTI AC200LUp to 2 B300K
- BLUETTI AC200MAXUp to 2 B300K
- BLUETTI AC300Up to 4 B300K
- BLUETTI AC500Up to 6 B300K
- BLUETTI Apex 300Up to 6 B300K, CA90 cable
- BLUETTI B300Mixing documented for AC300 and AC500
- BLUETTI B300SMixing documented for AC500
- Phones & small USB gadgetsVia the 12W USB-A port
BLUETTI recommends the B300K for its own listed power stations. Use with third-party power stations is not documented.
Safety, Storage & Care
The B300K weighs about 29.5kg. The manual says to use and store it in a cool, dry, ventilated place, avoid submerging it or cleaning it with liquids, and never disassemble it. If a pack leaks or gives off an odour, keep away and contact professionals.
- Charge only within 0°C to 40°C, with 15°C to 30°C recommended.
- Do not use damaged batteries, plugs or cables.
- For storage, keep it at 60% to 80% charge and run a full cycle every six months.
- For storage beyond six months, keep it at 40% to 60% and run a full cycle every three months.
- Recharge promptly after a full discharge and clean the outside with a dry, soft towel.
BLUETTI B300K: FAQ
What is the BLUETTI B300K?
The B300K is a 2,764.8Wh LiFePO₄ expansion battery for selected BLUETTI power stations. It has no AC outlets.
Which power stations work with the B300K?
BLUETTI lists the AC200L, AC200MAX, AC300, AC500 and Apex 300 as compatible hosts. Each host has its own pack limit and cable.
Can the B300K be used on its own?
It can charge small USB devices through its 12W USB-A port. AC appliances need a compatible power station.
Can I replace the cells inside a B300K?
There is no supported user procedure. The manual prohibits disassembly and directs hardware faults to BLUETTI support for repair or replacement.
Is the B300K a direct replacement for a B300 or B300S?
It can be an alternative in supported setups, but it is not identical. The B300K holds 2,764.8Wh against 3,072Wh for the B300, and one B300K limits an AC500 to 3,000W AC output. BLUETTI documents mixing with the B300 on AC300 and AC500, and with the B300S on AC500.
Can I clean the B300K with water?
No. The manual says to avoid submerging it or cleaning it with liquids. Wipe the outside with a dry, soft towel.
Can the B300K charge in freezing weather?
No. The specified charging range is 0°C to 40°C. Discharging is rated from −20°C to 40°C.
How fast does the B300K charge?
BLUETTI states about 45 minutes from 5% to 80% on an AC300 or AC500, with its data sheet citing a 30A AC charging cable. This is a manufacturer figure, not a full-charge time.
