Head-to-head test
BLUETTI AC300 + 4×B300 vs BLUETTI EP900 + 2×B500
The cheaper system here is also the bigger one, which settles nothing: what you are really choosing is whether your power comes out of a box with seven sockets or out of every outlet in the house.
Full profiles: BLUETTI AC300 + 4×B300 → · BLUETTI EP900 + 2×B500 →
Written by Gunner GustafsonUpdated
Whole-Home Backup Tester, Station Arena Test Desk
Spec deltas
The more expensive of these two holds less battery. $10,298 buys the EP900 + 2×B500 and 9,920Wh; $5,596 buys the AC300 + 4×B300 and 12,288Wh. If watt-hours per dollar were the question, this page would already be over.
The $4,702 buys wiring, not storage. The EP900 runs 7,600W continuous against the AC300 stack's 3,000W, carries 240V, and connects to your breaker panel rather than to your extension cords. It has no sockets on the box at all. It also accepts 9,000W of solar against 2,400W, is rated for 6,000 cycles against 3,500, and is covered for ten years against four.
Most people reading this should buy the AC300 stack. It covers every load profile we model with the bank barely dented, and it needs an outlet rather than an electrician. But it cannot do 240V at any size, and that is the one thing more B300 modules will never fix. If your outage list has a well pump or central air on it, stop reading the price column.
What the Numbers Reveal
Each conclusion stated first — the numbers behind it on one line, the full analysis below.
continuous output
The AC300 stack already carries 12,288Wh, more than the EP900's 9,920Wh, and still cannot run a 240V load, so capacity was never the thing stopping it. The output comparison goes the same way. The AC300's published peak is 6,000W; the EP900 publishes no surge figure at all and simply runs 7,600W continuously. Its everyday rating sits above the other system's best moment, and no amount of expansion closes that.
AC300 + 4×B300: 3,000W continuous, 6,000W published peak, 240V outlets recorded as 0EP900 + 2×B500: 7,600W continuous, 240V hardwired to the panel, no surge figure publishedboth records read expandable: Yes
Why it mattersIf a well pump, a dryer or central air is on your outage list, the AC300 stack is out at any size, and the only question left is whether the install is worth $4,702.
rated cycles
Bring in the cycle ratings and the size advantage stops being an advantage at all. 9,920Wh times 6,000 cycles is 59,520 kWh across the pack's rated life, against 43,008 kWh for the bigger bank at 3,500. The EP900 is the smaller battery in a photograph and the larger one over any horizon longer than a weekend. It refuses to show you that on the spec sheet, which is why the spec sheet is not where this gets decided.
AC300 + 4×B300: 12,288Wh, 2,400W maximum solar inputEP900 + 2×B500: 9,920Wh, 9,000W maximum solar input6,000 rated cycles against 3,500
Why it mattersAnyone building toward a roof array and years of daily cycling is buying the EP900's platform rather than its 9,920Wh. Anyone who wants the deepest buffer for the next storm already has it in the cheaper box.
You cannot switch that off and keep the fast transfer, either. A no-worse-than-20ms handover only happens on loads already plugged into a unit that is already running. So the AC300 stack offers two states: armed and drinking, or asleep and manual. The EP900 never has that choice to make, because sitting wired to the panel with the grid feeding it is the entire design.
idle draw close to 60W with the AC output switched onA2the 8-hour blackout profile asks for 1,645WhAC300 + 4×B300 UPS rated no worse than 20ms
Why it mattersIf the plan is to park it in the garage and grab it when the lights go out, leave it plugged in, and accept that grabbing it means running cords. A 367.2 lb stack does not come to you.
On a modular stack the fragile part is the single head unit all four modules plug into, and the one hard failure in our ledger is exactly thatA9A10. Ten years of cover on the EP900 is not a nicety on a system an electrician bolts to a wall. It is the difference between a service call and a demolition.
AC300 + 4×B300: 4-year warranty, 3,500 cycles, 9.6 years at daily useEP900 + 2×B500: 10-year warranty, 6,000 cycles, 16.4 years at daily useone owner's AC300 head unit failed outright, and the support reply they relayed said parts were unavailable and repair was not recommendedA9A10
Why it mattersIf you are buying this once and expecting it to outlast the mortgage, read the warranty column before the price column. It is the EP900's second-best argument after 240V.
The specific dimensions that decide these two units — everything else is a tie.
Lifetime Value
Selected because: The costlier system is also the smaller one, so cost per lifetime kilowatt-hour is the only honest way to read the difference.
cost / lifetime kWh
Thirteen cents a lifetime kilowatt-hour against seventeen. That is the AC300 stack's entire financial case, and it survives the awkward fact that the EP900's pack delivers more total energy over its life, 59,520 kWh against 43,008. You paid nearly twice as much for that extra throughput, which is the only reason the smaller pack loses this column at all.
One measure flips, and it is worth naming out loud: warranty. Spread each price across its covered term, four years against ten, and the EP900 becomes the cheaper of the two per year of cover. That is not a rounding artifact. It is BLUETTI pricing a wall-mounted system it expects to still be answerable for a decade from now.
Growth Path
Selected because: Both records say expandable, but one expands watt-hours and the other expands a 9,000W solar ceiling against 2,400W.
solar input
Expansion on the AC300 stack means more of what it already has too much of. Every profile on this page except a full van-life day leaves at least 80% of the bank untouched, so the honest question is not whether you can add a fifth B300. It is why you would.
The EP900's growth axis is the one that matters if you are genuinely heading off-grid: 9,000W of solar input against 2,400W. That is the difference between a roof and a few portable panels, and it is a ceiling you can grow into for years. It is also a cost sitting outside both prices on this page, standing next to the electrician.
What the Specs Don't Tell You
Selected because: Ten years of cover and 6,000 cycles against four years and 3,500 is where the EP900 earns back part of what it costs.
rated cycles
Six cards fire and four of them point at the EP900: longer warranty, more cycles, a faster rated transfer, and the only published noise figure on the page. The AC300 stack's answer on that last one is that BLUETTI publishes nothing for it, which is not the same as being quiet. It means there is no number to hold it to.
The card that refuses to pick a side is weight, and it is a wash for a good reason. 367.2 lbs against 343 lbs, and neither figure is the one that matters. One of these gets positioned once by two people and then lives where you put it. The other gets bolted to a wall by an electrician and stops being furniture altogether.
Your Life, Your Pick
Selected because: Two of the six profiles come back as neither, because neither system travels, which is the most useful thing this table says.
Camping and the tailgate come back as neither, and they are the two rows worth reading closely. Both systems clear the energy easily; 2,100Wh and 670Wh are nothing against banks this size. It is the going that does not happen. 367.2 lbs of AC300 stack rides in a truck bed if it rides at all, and the EP900 is attached to a building.
Van Life Daily is the one row with a winner, and the AC300 stack takes it partly by forfeit and partly on merit, covering 4,685Wh of daily draw with 5,760Wh still in the bank. Then look at the rest of the table and something less flattering appears: a CPAP night uses 3% of it, a workday 9%, an eight-hour blackout 16%. If your real list looks like those rows, both of these are the wrong size of answer.
Strengths & trade-offs
BLUETTI AC300 + 4×B300
Strengths
- +Costs $4,702 less
- +Larger battery capacity
Trade-offs
- –Significantly heavier (+24.2 lbs), making it harder to move.
- –Weaker inverter (-4,600W) limits appliance compatibility.
- –Very heavy unit that may be difficult for one person to lift.
- –Shorter-lived battery — rated for 3,500 charge cycles vs the EP900 + 2×B500's 6,000, so it wears out sooner.
BLUETTI EP900 + 2×B500
Strengths
- +Lighter by 24.2 lb
- +Higher AC output
- +Longer warranty
- +Faster solar charging
- +Rated for 6,000 charge cycles — much longer battery lifespan
Trade-offs
- –Substantially more expensive (+$4,702) than the AC300 + 4×B300.
- –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
Neither of these is going camping, and the 2,100Wh has nothing to do with it. Both clear that using a quarter of the bank or less. The AC300 stack weighs 367.2 lbs and rides in a truck bed if it rides anywhere; the EP900 is wired to your electrical panel. The campsite is the part that does not happen.
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
Either unit
Both ride out the 1,645Wh with most of the bank untouched, so this row gets decided in the first few milliseconds rather than over the eight hours. The EP900 is rated no worse than 10ms and switches your whole panel. The AC300 stack is rated no worse than 20ms and switches whatever you remembered to plug into it. Both figures are manufacturer ratings, not stopwatch readings.
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
Forty watts for eight hours takes 3% of the AC300 stack and 4% of the EP900, so capacity settles nothing here. Placement does. The EP900 lives at your electrical panel, which is almost certainly not your bedroom. The AC300 stack lives wherever you put it, and BLUETTI publishes no noise figure for it, so there is nothing to hold it to. If it is going at your bedside, find someone who has heard one.
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
Either unit
Both power your workstation all day without strain. The AC300 + 4×B300 lists 100W of USB-C for direct laptop charging; the EP900 + 2×B500 carries no USB-C at all, so a laptop there goes through the inverter — which is what a hardwired stack is: the power comes out of your wall sockets, not out of the box.
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
Four hundred watts of blender and speakers is the smallest ask on this page, and both systems clear it standing still. The parking lot is the problem. One of these needs a truck bed and a ramp. The other needs an electrician, and then it never moves again.
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
This one goes to the AC300 stack, partly by forfeit, since the EP900 is attached to a building and is not coming, and partly on merit: 4,685Wh of daily draw still leaves 5,760Wh in the bank. Getting 367.2 lbs mounted and secured in a van is your problem, not the battery's.
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 41.1h.
$5,596 list · direct from BLUETTI
Planning for more than this? Describe your whole setup and get it sized →
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
September 19, 2026
Verdict: the AC300 + 4×B300
Take the AC300 + 4×B300. It is the cheaper of the two, carries 2,368Wh more battery (12,288Wh against 9,920Wh), works out at $0.13 per lifetime kilowatt-hour against $0.17, and clears every load profile on this page without strain. The heaviest of them, a full van-life day at 4,685Wh, still leaves 5,760Wh in the bank. Its ceiling is real and it is not capacity: 3,000W continuous, zero 240V outlets on our record, and seven sockets you have to run cords to. The EP900 is the better machine on the spec sheet and our instrument scores it higher, but most of what it is better at is capability you have to wire a house to use. Buy it if your backup list includes a well pump, central air, an electric dryer or anything else living on two legs of 240V, because the AC300 stack cannot touch those with four B300 modules or forty.
Editor-assigned confidence, based on cited owner research and spec analysis.
List prices as of September 19, 2026. The links below open BLUETTI's current price.
$5,596.00 · direct from BLUETTI
Last checked 16 days ago. Prices move — check before you buy.
or check the EP900 + 2×B500 price$10,298.00 list
Written by Gunner Gustafson, Whole-Home Backup Tester · Station Arena Test Desk · Updated September 19, 2026
Black Friday · 38 days out
Prices to beat:AC300 + 4×B300 $5,596EP900 + 2×B500 $10,298
We have never seen either discounted, so any real cut would be a first.
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 — see Sources & Research Notes below.
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 EP900 + 2×B500 rates 3.7/5 (21st percentile of 29 Whole-Home / Off-Grid-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 EP900 + 2×B500 (343 lbs) is a wall-installed system — its weight matters to the installer on day one, then never again. The AC300 + 4×B300 (367.2 lbs) is spread across its boxes — no single lift, but nothing you reposition on a whim.
EP900 + 2×B500: 50dB Published
50dB is about as loud as moderate rainfall. It is BLUETTI's own rating rather than a reading on a shared bench — makers differ on whether they quote a best case or a figure under load, so treat it as a starting point rather than what you would hear at a bedside. For most people, fan noise around 45dB and up is where sleep starts to suffer.
UPS: No Worse Than 10ms vs 20ms, and Two Different Scopes
The speed gap is the smaller half of this. The EP900 is rated no worse than 10ms and the AC300 stack no worse than 20ms, both manufacturer ceilings rather than stopwatch readings, and both fine on paper for routers and most electronics. What actually differs is what sits behind the switch. The EP900 is at your panel, so every circuit in the house rides through. The AC300 stack protects the things you plugged into it, which at 3 a.m. is a shorter list than you think.
Warranty: 10 Years vs 4, on a System You Cannot Unbolt
Both packs are rated to outlive both terms. 6,000 cycles is 16.4 years of daily use and 3,500 is 9.6, so the warranty is not really about the batteries. It is about the electronics they plug into, and about what a repair costs once a system is mounted to a wall. Ten years is BLUETTI saying it expects to still be answerable for the EP900 long after the AC300 stack's four years have run out.
The Smaller Battery Is the Bigger One, Given Time
6,000 cycles against 3,500 turns the capacity comparison inside out. The EP900's 9,920Wh bank delivers 59,520 kWh across its rated life; the AC300 stack's 12,288Wh delivers 43,008 kWh. Today the AC300 stack is the deeper of the two. Over a decade of daily cycling it is the one that runs out first, at 9.6 years against 16.4. Hitting the cycle limit is not death, though. The pack drops to roughly 80% of original capacity and keeps working.
AC300 + 4×B300: Noise Level Not Disclosed
The EP900 + 2×B500 publishes its noise level (50dB); the AC300 + 4×B300 doesn't publish one. That isn't evidence the AC300 + 4×B300 is louder — it means there's no figure to hold it to, and no way to compare the two on this without hearing them. If you're buying for a bedroom, a CPAP, or an apartment, treat the EP900 + 2×B500's 50dB as the only published number on the table — a spec-sheet figure, not a measurement — and look for hands-on reports of the AC300 + 4×B300 before deciding.
Full record above — the Test Desk pick is the AC300 + 4×B300.
Check AC300 + 4×B300 price →or check the EP900 + 2×B500 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 AC300 + 4×B300 wins on both sticker price and long-term value. At $0.13/kWh over its lifetime, it's meaningfully cheaper to own. Clear value winner.
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.
Adequate ports for most setups, but heavy users may want a power strip.
Expansion batteries are BLUETTI-specific. You're investing in the BLUETTI ecosystem.
EP900 + 2×B500
EXPANDABLESupports BLUETTI expansion batteries, so you can add capacity later without replacing the base unit — useful if your needs may climb past 9,920Wh.
Accepts up to 9,000W 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, but the EP900 + 2×B500's higher solar ceiling (9,000W vs 2,400W) gives it the stronger off-grid growth path — more panels can feed a bigger bank as it grows.
What Owners Report
Patterns from published owner reports and long-term reviews — every claim cited to its source below.
BLUETTI AC300 + 4×B300
The AC300 has been out long enough to have a track record, and most of it is good. One hands-on reviewer was struck immediately by the quality, finish and clever designA1, and the fan, which is what people worry about with a box this size, gets described as audible but genuinely quiet for its class by both a lab reviewer and an owner running several unitsA5A6.
Two complaints recur and a third is expensive. The idle draw is the cheap one: close to 60W with the AC output switched on, which the reviewer who measured it flagged as highA2. The app is the second, called basic in one reviewA7 and reported hanging indefinitely on a unit whose own console said it was connectedA8. The expensive one is serviceability. An owner's head unit failed outright, and the support reply they relayed said parts were not available and repair was not recommendedA9A10. Worth knowing too that most runtime figures circulating for this product were measured on an AC300 carrying a single B300 rather than the four-module stack priced here. The much-quoted 31-hour fridge run came off a 3,072Wh machineA0A11.
“I was immediately impressed with the unit's quality, finish, and clever design.”
Sources
reviewed.com
BLUETTI EP900 + 2×B500
Field data on the EP900 is thin, and what exists reads like product-guide material rather than years of ownership. Our researcher's own coverage note says as muchB0. The substantive claims are platform-level: a whole-home system sized to run a washer, dryer, heater and refrigerator togetherB1, and a battery bank that grows well past what two B500 modules give youB2.
Two owner-level data points are worth having. One reported the grid-to-battery transfer as completely unnoticeable during outagesB3, which is what a no-worse-than-10ms rating is supposed to buy. Another, running it tied to solar, said they could effectively go off-grid and cut their utility billsB4. That same source is a useful reminder that quoted system prices exclude installationB4. Neither is a long-term reliability report, and we do not have one.
“A whole-home system: one EP900 inverter provides up to 9,000W (18,000W with two units), enough to run a washer, dryer, heater, and refrigerator.”
Sources
bluettipower.com · bestgeneratorsolar.com · mightygenerators.com · bgr.com · offgridsource.com
Sources & Research Notes
Every owner claim in this report is traceable to a published source. The bracketed references above resolve here.
Recurring owner themes
- Idle power draw is noticeably higher than expected and drains meaningful battery even with no connected load. [AC300 + 4×B300 · 2 entries]
- Reviewers and owners consistently describe the AC300's fan as audible under load but notably quiet for its size and class. [AC300 + 4×B300 · 2 entries]
- The companion app is described as basic/limited, and some owners report Bluetooth or app-pairing problems connecting to the AC300+B300. [AC300 + 4×B300 · 2 entries]
- After several years of service, some head units fail outright, and once discontinued Bluetti has no repair parts and does not recommend repairing out-of-warranty units. [AC300 + 4×B300 · 2 entries]
- Whole-home 9,000W output, large B500 expandability (to ~39.6kWh), 10ms UPS, and solar off-grid capability are the standout features. [EP900 + 2×B500 · 3 entries]
- A1
“I was immediately impressed with the unit's quality, finish, and clever design.”
Clean Energy Reviews Forum — "Bluetti Power Station Review (AC300) Off-grid Backup" (user Svarky) · 2023-07 · [positive]
- A2
“When the AC output is switched on, the idle power draw (with no load) appears to be close to 60W, which is high.”
Clean Energy Reviews Forum — "Bluetti Power Station Review (AC300) Off-grid Backup" (user Svarky) · 2023-10 · [negative]
- A5
“The AC300 + B300 has a little bit of noise coming from the fan. It's NOT silent. But considering the size and use case... you'll forget it's there.”
GreenCitizen — "Bluetti AC300 + B300 Power Station Review: Real-Life Lab Test Results" · 2025-01 · [positive]
- A6
“The powered fans within my AC300 units are extremely quiet when running – no detectible motor or bearing noise; only air movement is slightly heard.”
DIY Solar Power Forum — "Fan noise level of Bluetti AC200MAX?" thread (AC300 owner's comparison reply) · unknown · [positive]
- A7
“The companion app brings basic functionality to your fingertips but leaves you longing for more.”
GreenCitizen — "Bluetti AC300 + B300 Power Station Review: Real-Life Lab Test Results" · 2025-01 · [negative]
- A8
“App (v3.0.1) keeps loading indefinitely even when the AC300 itself shows it is "Connected."”
BLUETTI Community forum — "AC300+B300 doesn't connect to Bluetti App" thread · unknown · [negative]
- A9
“I just had my AC300 head unit fail with a007 App error, and 00 006 and 01 006 errors on the console screen and 2 days later.... click click click.. DEAD.”
DIY Solar Power Forum — "Bluetti - Screw you - AC300 dead and no parts to fix it anymore 5 years after launch" · 2026-03 · [negative]
- A10
“Due to the AC300 being discontinued, they don't have the necessary parts for repairs. Considering the repair costs and round-trip shipping fees, we don't recommend repairing it.”
DIY Solar Power Forum — "Bluetti - Screw you - AC300 dead and no parts to fix it anymore 5 years after launch" (Bluetti support reply relayed by OP) · 2026-03 · [negative]
- A11
“The Bluetti AC300 + B300 combo kept the fridge running for an average of 31 hours on a charge.”
Forbes — Brad Moon, "Review: Bluetti AC300 + B300 Home Battery Backup System" · 2023-10 · [positive]
- B1
“A whole-home system: one EP900 inverter provides up to 9,000W (18,000W with two units), enough to run a washer, dryer, heater, and refrigerator.”
bluettipower.com / bestgeneratorsolar.com — EP900 + B500 guide · 2026 · [positive]
- B2
“With B500 batteries (4,960Wh each), capacity expands from 9.9kWh up to about 39.6kWh with eight B500 modules — weeks of essential backup.”
bluettipower.com / mightygenerators.com — EP900 + B500 · 2026 · [positive]
- B3
“A fast UPS switches from grid to battery within 10 milliseconds; one owner reported the transfer is completely unnoticeable during outages.”
bgr.com / owner review — EP900 + B500 · 2026 · [positive]
- B4
“Built on reliable LiFePO4 cells; tied to solar, an owner said they can virtually go off-grid and minimize utility bills. Complete systems run roughly $14,500-$15,000 excluding installation.”
bgr.com / offgridsource.com — EP900 + B500 review · 2026 · [positive]
Research compiled September 19, 2026.
Who Should Buy Which
Buy the AC300 + 4×B300 if you…
- →You are backing up a 120V essentials list, fridge and freezer and router and a couple of lamps, maybe a CPAP, and you would like it working this weekend rather than after an electrician's next opening. Seven outlets, 100W of USB-C, and 12,288Wh covers that with the bank barely dented.
- →You are building a van, a cabin or a workshop where 240V never comes up. This is the only one of the two that can go there at all, and it covers a 4,685Wh day with 5,760Wh left over.
- →You want the most stored energy per dollar and you are comfortable that the ceiling you buy is the ceiling you keep. It is the cheaper system and it holds 2,368Wh more.
Buy the EP900 + 2×B500 if you…
- →Your outage list has a well pump, central air, an electric dryer or a range on it. The AC300 stack records zero 240V outlets, which ends the comparison before price enters it.
- →You want the backup automatic and whole-house: the grid drops, the panel switches over in no worse than 10ms, and nobody goes hunting for extension cords in the dark.
- →You are putting up a real solar array and expect to cycle this daily for a decade or more. A 9,000W input ceiling and 6,000 cycles are what that plan needs, and ten years of cover is what it deserves.
If neither fits
If your honest worst case looks like the blackout row, 1,645Wh, about a sixth of the AC300 stack's usable bank, you are shopping two tiers too high. One ordinary portable station will cover that night, cost a fraction of either system, and fit in the back of a car. Come back to this page when your list grows a 240V load or a second day.
The Bottom Line
Buy the AC300 + 4×B300. It is $4,702 cheaper, holds 2,368Wh more, costs less per lifetime kilowatt-hour, and clears every load profile on this page without breathing hard. That is a lot of page to argue with.
The EP900 is the better machine, and not narrowly: more output, more solar, more cycles, more warranty, and a transfer that covers your whole panel instead of your power strip. But every one of those advantages is unlocked by an electrician, and each is capability you either need or you do not. If your list has 240V on it, the AC300 stack was never a candidate and the price column is noise. If it does not, you are about to spend the difference on headroom you will never see.
Frequently Asked Questions
Answers drawn from the spec record and cited owner research.
Can the AC300 + 4×B300 back up my whole house?
Not the way the EP900 can. Our record shows zero 240V outlets on the AC300 stack and seven AC sockets, so it backs up whatever you can reach with a cord. It does not connect to your breaker panel. The EP900 does exactly that, hardwired, with 240V and 7,600W continuous. If whole house means the well pump and the central air, only one of these is in the conversation.
Why does the EP900 system cost more when it holds less battery?
Because the difference does not buy watt-hours. The EP900 runs 7,600W continuous against 3,000W, accepts 9,000W of solar against 2,400W, is rated for 6,000 cycles against 3,500, and carries a ten-year warranty against four. It also gets wired into your panel, a cost that sits outside the price on this page. Quoted prices for these systems exclude installation.
Which one is actually cheaper to own?
The AC300 + 4×B300, at $0.13 per lifetime kilowatt-hour against $0.17. The EP900's pack delivers more total energy across its rated life, 59,520 kWh against 43,008, but it costs enough more that the per-kilowatt-hour figure still favours the cheaper system. The one measure that flips is warranty: spread across four years against ten, the EP900 is the cheaper of the two per covered year.
How fast does each one switch over when the power goes out?
The EP900 is rated no worse than 10ms and the AC300 stack no worse than 20ms. Both are manufacturer ceilings rather than bench measurements, and both are fine on paper for routers and most electronics. The bigger difference is scope. The EP900 switches at the panel, so every circuit behind it rides through. The AC300 stack switches whatever you remembered to plug into it.
Can I take either of these camping?
No. The AC300 stack weighs 367.2 lbs across its boxes and the EP900 is bolted to your electrical panel. Our camping and tailgate profiles both come back as neither for exactly that reason. The energy is trivial for either system, at 2,100Wh and 670Wh, but the trip is not happening. If you want power away from the building, you are shopping the wrong class.
Where to buy
BLUETTI AC300 + 4×B300Pick
$5,596.00
$5,596.00 · direct from BLUETTI
Last checked 16 days ago. Prices move — check before you buy.
BLUETTI EP900 + 2×B500
$10,298.00
$10,298.00 · direct from BLUETTI
Last checked 16 days ago. Prices move — check before you buy.
Prices may vary by retailer and are subject to change.