Head-to-head test
BLUETTI AC300 + 4×B300 vs BLUETTI AC500 + 2×B300K
Real-world runtimes, scenario verdicts, and ownership costs compared — which wins for your use case.
Written by Gunner GustafsonUpdated
Whole-Home Backup Tester, Station Arena Test Desk
BLUETTI
AC300 + 4×B300
8,760Power Score · The AC & Fridge Zone
$5,596.00 · direct from BLUETTI
Last checked 6 days ago. Prices move — check before you buy.
BLUETTI
AC500 + 2×B300K
5,894Power Score · The AC & Fridge Zone
$3,948.00 · direct from BLUETTI
Last checked 22 days ago. Prices move — check before you buy.
Spec deltas
Two sizes from BLUETTI's AC lineup: AC500 + 2×B300K at 5,530Wh, AC300 + 4×B300 at 12,288Wh. The $1,648 gap between them buys a fundamentally different tool. One you carry. One you place and leave. We'd buy the AC500 + 2×B300K.
What the spec gap means in practice: the AC300 + 4×B300's 3,000W inverter has the headroom for a window AC, a full-size fridge, and power tools. The AC500 + 2×B300K's 5,000W inverter still runs most single appliances; the AC300 + 4×B300's real edge is surge headroom for the biggest motor starts and stacking several heavy loads at once. On stamina, the AC300 + 4×B300 keeps a fridge alive for roughly 70 hours vs the AC500 + 2×B300K's 31 hours. The cost? Portability. At 367.2 lbs, the AC300 + 4×B300 is a two-person lift you set down once and leave. The AC500 + 2×B300K at 196.1 lbs is more manageable, though still not light.
Pick the AC500 + 2×B300K if you want the unit that wins the head-to-head on balance. Go with the AC300 + 4×B300 if you primarily need it for 8-hour blackout or remote workday. Most buyers stop at the sticker price and miss this: over a full lifespan the AC300 + 4×B300 works out to about $0.13/kWh against the AC500 + 2×B300K's $0.2, a gap that compounds in the AC300 + 4×B300's favor the more you cycle it. Keep scrolling for the full breakdown. The scenario verdicts below hold a few surprises.
Bench Notes
What each unit does well, where it falls short, and the trade-offs that matter.
BLUETTI AC300 + 4×B300
With a massive 3,000W output (and 6,000W surge), the AC300 + 4×B300 can run high-wattage appliances like space heaters, hair dryers, and electric grills without tripping. Weighing in at 367.2 lbs, this is not a unit you want to carry far. It's best suited as a stationary backup or RV companion. A standout feature is the value proposition: at roughly $0.46 per watt-hour, it's one of the most cost-effective options on the market.
Strengths
- +Larger battery capacity
- +Longer warranty
Trade-offs
- –Substantially more expensive (+$1,648) than the AC500 + 2×B300K.
- –Significantly heavier (+171.1 lbs), making it harder to move.
- –Weaker inverter (-2,000W) limits appliance compatibility.
- –Very heavy unit that may be difficult for one person to lift.
BLUETTI AC500 + 2×B300K
With a massive 5,000W output (and 10,000W surge), the AC500 + 2×B300K can run high-wattage appliances like space heaters, hair dryers, and electric grills without tripping. Weighing in at 196.1 lbs, this is not a unit you want to carry far. It's best suited as a stationary backup or RV companion.
Strengths
- +Costs $1,648 less
- +Lighter by 171.1 lb
- +Higher AC output
- +Faster solar charging
Trade-offs
- –Very heavy unit that may be difficult for one person to lift.
Will It Power Your Gear?
Scenario math and per-appliance runtimes, modeled from the spec record.
Scenario verdicts
We ran the math on six real-world scenarios. Here's which unit survives your actual life.
SCN-01 · 2 nights · needs 2,100Wh
Weekend Camping
Two nights off-grid with essential comfort
Neither unit
Scoring these two at a campsite is a category error: the AC300 + 4×B300 at 367 lbs is not a take-along — it rolls off a truck bed if it travels at all, and the AC500 + 2×B300K at 196 lbs is not a take-along — it rolls off a truck bed if it travels at all. The 2,100Wh here is trivial for either — it's the going that doesn't happen. If you need power away from the building, you're shopping the wrong class.
Battery budget usedlower = more headroom
LOAD Phone Charger 15W×6h · LED Lights 40W×8h · Box Fan 75W×14h · CPAP Machine 40W×16h
SCN-02 · 8 hours · needs 1,645Wh
8-Hour Blackout
Keep the essentials running through a night without power
AC300 + 4×B300
Both survive the night. The AC300 + 4×B300 finishes at 16% used with 8,800Wh left — 5.3 more nights like it. The AC500 + 2×B300K finishes at 35% with 3,056Wh, 1.9 more nights like it. If your outages tend to run past one evening, that difference is the whole argument between them.
Battery budget usedlower = more headroom
LOAD Fridge 150W×8h · Router + Modem 20W×8h · LED Lights (4 bulbs) 40W×6h · Phone Charger 15W×3h
SCN-03 · 8 hours · needs 320Wh
CPAP Overnight
Sleep therapy without interruption — the #1 medical use case
Either unit
A CPAP is about 40W for eight hours, so both cover the night with room to spare and capacity decides nothing. Fan noise would — but AC300 + 4×B300 doesn't publish a figure, so there's nothing to hold it to. Buy on price, weight, and whether you can live with a fan you haven't heard.
Battery budget usedlower = more headroom
LOAD CPAP Machine 40W×8h
SCN-04 · 8 hours · needs 910Wh
Remote Workday
Full work day off-grid without power anxiety
AC300 + 4×B300
The AC300 + 4×B300 clears the workday at 9% used, banking 9,535Wh — late work, extra calls, or a second laptop charge without arithmetic. The AC500 + 2×B300K at 19% also finishes, with 3,791Wh of slack for the unplanned.
Battery budget usedlower = more headroom
LOAD Laptop 60W×8h · External Monitor 30W×8h · Router + Modem 20W×8h · Phone Charger 15W×2h
SCN-05 · 4 hours · needs 670Wh
Tailgate Party
Game day power for the crew
Neither unit
Scoring these two at a tailgate is a category error: the AC300 + 4×B300 at 367 lbs is not a take-along — it rolls off a truck bed if it travels at all, and the AC500 + 2×B300K at 196 lbs is not a take-along — it rolls off a truck bed if it travels at all. The 670Wh here is trivial for either — it's the going that doesn't happen. If you need power away from the building, you're shopping the wrong class.
Battery budget usedlower = more headroom
LOAD Blender 400W×0.5h · LED TV (55") 80W×4h · Bluetooth Speaker 15W×4h · Phone Charger (×3) 45W×2h
SCN-06 · 24 hours · needs 4,685Wh
Van Life Daily
A full day of mobile living — the ultimate endurance test
AC300 + 4×B300
The AC500 + 2×B300K uses 100% of its battery on a full day, leaving 16Wh — miss a solar day and that is the entire cushion. The AC300 + 4×B300 at 45% keeps 5,760Wh in hand, a far more forgiving rhythm for full-time living.
Battery budget usedlower = more headroom
LOAD Mini-Fridge 150W×24h · Laptop 60W×4h · Phone Charger 15W×3h · LED Lights 40W×5h · Fan 75W×8h
The Load Test
RUNTIME = (Wh × 0.85) ÷ LOAD
None of the scenarios above exactly yours? Build it. Toggle what you'd plug in; both units are tested against the combined draw.
Essentials
Comfort & Convenience
High-Draw Appliances
Test duration
8h
Continuous draw
205W
Projected runtime
For this load: AC300 + 4×B300 runs 51h vs 22.9h.
$5,596 list · direct from BLUETTI
Modeled from the spec record — same math as the tables below. Methodology
Runtime by appliance
Real-world runtime estimates for common appliances, modeled at 85% inverter efficiency.¹
Essentials
The basics you need runningscale 0–696.3hComfort & Convenience
Makes off-grid life actually enjoyablescale 0–139.3hHigh-Draw Appliances
These reveal the real limitsscale 0–10.4h¹ Runtime = (capacity × 0.85) ÷ appliance watts. Within each group, all bars share one time scale (the group's longest runtime), so lengths are comparable across appliances; identical runtimes collapse into a single blue/orange bar. Actual runtime varies with battery age, temperature, and simultaneous loads — see methodology.
Conclusion
July 10, 2026
Verdict: the AC500 + 2×B300K
The AC500 + 2×B300K takes the lead. and delivers 2,000W more power than the AC300 + 4×B300. With a price tag that is $1,648 lower, it provides significantly better value.
Overall score margin: 8,760 vs 5,894 (+48.6%)
List prices as of July 10, 2026. The links below open BLUETTI's current price.
$3,948.00 · direct from BLUETTI
Last checked 22 days ago. Prices move — check before you buy.
or check the AC300 + 4×B300 price$5,596.00 list
Written by Gunner Gustafson, Whole-Home Backup Tester · Station Arena Test Desk · Updated July 10, 2026
Measured Data
Benchmark scores and the full spec record, side by side.
Benchmark scores
Full specifications
ᵈ Derived: price ÷ rated capacity. See the data behind our comparisons →
Comparison ToolAdd more power stations, side by sideOpen Tool →How these numbers are produced
Numeric verification
Every figure on this page traces to our spec database or arithmetic on it — no estimated numbers.
Owner claims
Statements about owner experience are cited to published reviews.
Runtime model
Runtime = (rated capacity × 0.85 inverter efficiency) ÷ device wattage. Solar recharge estimates assume panels deliver 70% of rated output. Cold weather, battery age, and stacked loads reduce real-world results.
Power Score
Computed from 14 published spec dimensions, weighted per use-case bench. Higher is better; a unit must meet a bench's minimum threshold to be rated.
See the full weight table and data sourcing on our methodology page →Class ranking (the star rating)
Each unit's star score is a category ranking, not customer reviews — no buyer opinions feed it. We score every station on size-independent quality (value, output, portability, endurance, ports, warranty, and more), then percentile-rank it against the other units in its capacity class, so a class-leading compact unit and a class-leading whole-home unit can both earn 5★. Here, AC300 + 4×B300 rates 3.3/5 (1st percentile of 29 Whole-Home / Off-Grid-class units), and AC500 + 2×B300K rates 4.1/5 (47th percentile of 16 Home Backup-class units).
How the class ranking is computed →Test Notes & Caveats
Hidden gotchas and advantages we spotted that you won't find on the product page.
Weight Reality Check
Neither unit is grab-and-go. The AC500 + 2×B300K (196.1 lbs) is a two-person lift. The AC300 + 4×B300 (367.2 lbs) is firmly a two-person lift. It goes where you put it and stays there. That's a 171 lb difference, which you'll feel every time you relocate.
Full record above — the Test Desk pick is the AC500 + 2×B300K.
Check AC500 + 2×B300K price →or check the AC300 + 4×B300 priceOwnership Analysis
What happens after you buy — true cost of ownership, brand trust, and growth potential.
Lifetime value
Service lifeyears at one full cycle per day
Lifetime energy delivered
Cost per delivered kWh
│ warranty ends · Reaching the cycle rating means ~80% capacity remains — degraded, not dead.
Analyst note
The AC500 + 2×B300K is cheaper to buy, but the AC300 + 4×B300 is cheaper to own. At $0.13/kWh over its lifetime vs $0.2/kWh, the AC300 + 4×B300's higher cycle life and capacity make each dollar go further over the years. One thing to know reading the table: both carry the same 3,500-cycle rating, so the lifetime rows are sticker price and capacity in disguise — the wear horizon is identical and decides nothing here.
Growth path
AC300 + 4×B300
EXPANDABLESupports BLUETTI expansion batteries, so you can add capacity later without replacing the base unit — useful if your needs may climb past 12,288Wh.
Accepts up to 2,400W of solar. Enough for a serious multi-panel array.
Generous port selection supports complex multi-device setups.
Expansion batteries are BLUETTI-specific. You're investing in the BLUETTI ecosystem.
AC500 + 2×B300K
EXPANDABLESupports BLUETTI expansion batteries, so you can add capacity later without replacing the base unit — useful if your needs may climb past 5,530Wh.
Accepts up to 3,000W of solar. Enough for a serious multi-panel array.
Limited ports. You'll likely need a power strip or splitter.
Expansion batteries are BLUETTI-specific. You're investing in the BLUETTI ecosystem.
Realistic full solar rechargeat 70% of rated panel output — see methodology
Analyst note
Both expand, so neither locks you out of growth — decide on capacity, price, and the rest, not the expansion checkbox.
The Bottom Line
The full picture comes down to this. The AC500 + 2×B300K edges ahead on our overall analysis, but the margin is narrow enough that your specific use case should drive the decision. Review the scenario verdicts above — if the AC300 + 4×B300 wins in the scenarios that match your life, it's the right choice regardless of aggregate scores.
If neither the AC300 + 4×B300 nor the AC500 + 2×B300K feels like the right fit, your power needs probably sit outside what these two target. For lighter use — weekend camping or phone/laptop charging — you'd be overpaying for capacity you'll rarely tap. Consider a unit in the 500–1,500Wh range instead. Prices on portable power stations fluctuate frequently. Both BLUETTI discount regularly, so check the current price before committing. Prime Day and Black Friday pricing typically drops 20-30%.
Frequently Asked Questions
Answers drawn from the spec record and cited owner research.
Is the AC300 + 4×B300 worth $1,648 more than the AC500 + 2×B300K?
A tough sell. The AC300 + 4×B300 offers 6,758Wh more battery capacity (that's 38 extra hours of running a mini-fridge), but $1,648 is a steep premium for a single upgrade. At $0.71/Wh, the AC500 + 2×B300K delivers better bang for your buck. Unless that advantage is non-negotiable, save the cash. Better yet, put it toward a solar panel that pays for itself in free charges.
How does the 6,758Wh capacity difference actually affect daily use?
The AC300 + 4×B300's 12,288Wh battery keeps a mini-fridge running for roughly 70 hours vs the AC500 + 2×B300K's 31 hours. Both can handle a full 8-hour blackout setup (fridge + router + lights + phone charging ≈ 1,645Wh), but the AC300 + 4×B300 finishes with significantly more margin. That matters if conditions aren't ideal or the outage runs long. What specs don't mention: runtime drops 20-30% in cold weather (below 32°F/0°C) as battery chemistry slows down. The AC300 + 4×B300's extra capacity provides a critical cold-weather buffer. For occasional phone and laptop charging, both are overkill. This gap only matters for sustained, multi-appliance use.
Can I actually carry the AC300 + 4×B300, or is the AC500 + 2×B300K the only portable option?
Neither is "portable" in any hiking sense. The AC500 + 2×B300K (196.1 lbs) and the AC300 + 4×B300 (367.2 lbs) are both appliances you place and leave. The 171.1-lb difference matters when loading into a vehicle or moving between rooms, but that's about it. If true portability is your priority, look at units under 20 lbs in a different class entirely.
How fast can each unit recharge from solar panels in real conditions?
On paper, the AC500 + 2×B300K accepts 3,000W vs the AC300 + 4×B300's 2,400W of solar input. What the spec sheet won't tell you: solar panels typically deliver only 60-80% of their rated output due to panel angle, cloud cover, and temperature. In realistic conditions, expect full recharge in about 2.6 hours for the AC500 + 2×B300K and 7.3 hours for the AC300 + 4×B300. That gap widens on cloudy days, when the AC500 + 2×B300K's higher input ceiling captures more of whatever sunlight is available. One more thing: summer gives you ~7 productive solar hours per day. Winter drops to ~4. If solar is your primary recharge method, the AC500 + 2×B300K's advantage is substantial.
Bottom line: should I buy the AC300 + 4×B300 or the AC500 + 2×B300K?
We'd buy the AC500 + 2×B300K. Strong value at a lower price, and for most real-world use cases the spec gaps don't translate to meaningful capability gaps. The AC300 + 4×B300 makes sense only if you specifically need its higher capacity for demanding sustained loads like full-home backup or commercial use.
Where to buy
BLUETTI AC300 + 4×B300
$5,596.00
$5,596.00 · direct from BLUETTI
Last checked 6 days ago. Prices move — check before you buy.
BLUETTI AC500 + 2×B300KPick
$3,948.00
$3,948.00 · direct from BLUETTI
Last checked 22 days ago. Prices move — check before you buy.
Prices may vary by retailer and are subject to change.