Head-to-head test
EcoFlow DELTA Pro Ultra vs BLUETTI Apex 300 + B300K
The Apex 300 + B300K is cheaper to own per kWh and quieter on paper only in the sense that no one has finished stress-testing it yet — the DELTA Pro Ultra is the one with a decade of 3,500-cycle LFP and an online 0ms UPS already proven at 7,200W.
Written by Gunner GustafsonUpdated
Whole-Home Backup Tester, Station Arena Test Desk
EcoFlow
DELTA Pro Ultra
8,600Power Score · The AC & Fridge Zone
$3,999.00 list · direct from EcoFlow
BLUETTI
Apex 300 + B300K
6,552Power Score · The AC & Fridge Zone
$2,599.00 list · direct from BLUETTI
Spec deltas
The EcoFlow DELTA Pro Ultra outputs 7,200W continuous against the BLUETTI Apex 300 + B300K's 3,840W — nearly double, on a base unit that costs $1,500 more at $4,099 versus $2,599.
That gap isn't cosmetic. The Pro Ultra's inverter can start and hold a 3-ton central air conditionerA4; the Apex's smaller inverter is built for a household's rolling loads, not a single large compressor. Both units are expandable and both run 3,500-cycle LFP cells, so the difference isn't longevity — it's how much power you can draw from either box at once.
The Apex counters on cost: $0.13 per lifetime kWh against the Pro Ultra's $0.19, and it's the cheaper unit to own outright. Whether that trade is worth it depends on what's plugged in when the grid goes down.
What the Numbers Reveal
Each conclusion stated first — the numbers behind it on one line, the full analysis below.
A true online UPS never actually drops the load — it's always running through the battery, so there's no gap to bridge in the first place. The Apex's 10ms figure is fast for line-interactive, but it's still a gap; the Pro Ultra has none.
DELTA Pro Ultra switches over in 0ms as a true online UPSApex 300 + B300K switches over in under 10ms as a line-interactive UPS
Why it mattersAnyone running always-on servers, medical equipment, or a home lab that can't tolerate even a blink should pay the premium for the Pro Ultra's genuine 0ms design.
solar input
In a multi-day outage, that difference compounds daily — the Pro Ultra can be topped off and ready again before lunch, while the Apex is still soaking up sun into the afternoon [A12 shows a fast AC recharge, but solar is throttled well below that].
DELTA Pro Ultra: 5,600W max solar input against a 6,144Wh capacityApex 300 + B300K: 2,400W max solar input against a 5,529.6Wh capacity
Why it mattersOff-grid or extended-outage buyers who depend on solar refill, not wall power, should weight the Pro Ultra's higher solar ceiling heavily; anyone charging mainly from an outlet won't notice the gap.
weight
The 33-lb gap between them barely changes the physical reality: both require a trolley or two people, and both are semi-stationary installs, not grab-and-go units. Weight isn't the axis that separates these two.
Apex 300 + B300K weighs 148.8 lbs stacked, and reviewers call it near-150 lbs of lithium and inverterB5DELTA Pro Ultra weighs 181.8 lbs
Why it mattersBuyers choosing based on portability should look elsewhere entirely; between these two, weight is a wash and the decision comes down to inverter size and UPS type instead.
cost / lifetime kWh
Run the warranty-year math instead: the Pro Ultra costs $410 per warranty-year against the Apex's $520. The unit with the higher price tag is actually the cheaper one per year of coverage, because EcoFlow backs it twice as long.
Apex 300 + B300K costs $0.13 per lifetime kWh; DELTA Pro Ultra costs $0.19Apex 300 + B300K carries a 5-year warranty against the Pro Ultra's 10-year warranty
Why it mattersBuyers comparing sticker price alone will pick the Apex; buyers comparing what they're actually paying for per year of protection should note the Pro Ultra wins that math.
The specific dimensions that decide these two units — everything else is a tie.
PowerScore Breakdown
Selected because: The 7,200W vs 3,840W inverter gap is the single biggest number separating these two and drives every downstream section.
overall power score
7,200W continuous against 3,840W is not a spec-sheet rounding error — it's the difference between running a 3-ton central AC compressor and needing a smaller, rolling set of household loads insteadA4. The Pro Ultra's 10,800W surge rating gives it another 3,120W of headroom over its own continuous figure, room the Apex's 7,680W surge doesn't match in absolute terms even though both ratios are roughly 2x.
For anyone whose backup plan includes a single large compressor load — central air, a well pump, a workshop tool — the Apex's smaller inverter is the harder ceiling to work around. For rolling household loads spread across circuits, the gap matters less.
What the Specs Don't Tell You
Selected because: UPS type and surge ratio both fire and directly support the verdict.
The Pro Ultra's 0ms online UPS is the cleanest structural win on this page: it's not faster than the Apex's line-interactive design, it's a different design that never actually breaks the circuit. The Apex's under-10ms switchover is fast for its category, but it's still a switch, and a switch is a gap by definition.
The surge ratio also favors the Pro Ultra in absolute terms — 10,800W of headroom against 7,680W — which is the spec that determines whether a compressor actually starts rather than just runs once it's already spinning. Neither unit's inverter class is a mismatch for the price it charges; the Pro Ultra is simply built for a heavier tier of load.
Lifetime Value
Selected because: Cost-per-kWh favors the Apex but warranty-year cost favors the Pro Ultra — worth surfacing both.
cost / lifetime kWh
Cost-per-kWh favors the Apex clearly: $0.13 against the Pro Ultra's $0.19, because $1,500 less money is buying nearly as much lifetime energy throughput. That's a real number for anyone who cycles the unit hard and cares about the cost of the electrons.
But the warranty math flips it. At $410 per warranty-year against the Apex's $520, the Pro Ultra's 10-year term means EcoFlow is standing behind it twice as long as BLUETTI backs the Apex. Cheaper energy and cheaper coverage aren't the same thing, and this pair splits them across the two units.
Growth Path
Selected because: Both expand, but solar ceiling gives the Pro Ultra a real edge for off-grid growth.
solar input
Both units are expandable, so neither buyer is locked into today's capacity. The real difference is what you can add to that expanded system from the sky: 5,600W of solar input against 2,400W means the Pro Ultra's growth path includes faster off-grid refill as you scale up panels, not just more batteries.
If your growth plan is adding storage capacity only, both paths work equally well. If it includes adding solar arrays over time, the Pro Ultra's higher ceiling means you won't hit a charging bottleneck before you hit a battery one.
Strengths & trade-offs
EcoFlow DELTA Pro Ultra
Strengths
- +Larger battery capacity
- +Higher AC output
- +Longer warranty
- +Faster solar charging
Trade-offs
- –Substantially more expensive (+$1,400) than the Apex 300 + B300K.
- –Significantly heavier (+33 lbs), making it harder to move.
- –Very heavy unit that may be difficult for one person to lift.
BLUETTI Apex 300 + B300K
Strengths
- +Costs $1,400 less
- +Lighter by 33 lb
Trade-offs
- –Weaker inverter (-3,360W) limits appliance compatibility.
- –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
Either unit
Both handle two nights comfortably. The Apex 300 + B300K uses 45% and the DELTA Pro Ultra uses 40%. With this little difference, pick based on weight and portability instead. The lighter unit wins for car camping.
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 survive the blackout with similar margin. Since the capacity difference doesn't matter here, focus on which unit has UPS mode — seamless switchover protects your router and PC from the split-second power gap.
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
Both are wildly overqualified for CPAP. You're using 7% or less. Save your money and buy whichever is cheaper; the extra capacity is completely wasted on a 40W overnight load. Put the savings toward a second battery for multi-night trips.
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 breaking a sweat. At these utilization levels, prioritize the unit with better USB-C output for direct laptop charging. It's more convenient than using the AC inverter and wastes less energy.
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
Either unit
Both handle game day easily. Since capacity isn't the deciding factor, consider weight: the lighter unit is easier to load into a truck bed. Also check if either has Bluetooth speaker-level noise. Fan sound matters in social settings.
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
DELTA Pro Ultra
The Apex 300 + B300K uses 100% of its battery. Doable but tight. Miss a day of solar recharge and you're in trouble. The DELTA Pro Ultra at 90% gives a much more sustainable daily rhythm. For full-time van life, miss a recharge day with the tighter unit and the next 24 hours get stressful fast.
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 six 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: DELTA Pro Ultra runs 25.5h vs 22.9h.
$3,999 list · direct from EcoFlow
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 0–348.2hComfort & Convenience
Makes off-grid life actually enjoyablescale 0–69.6hHigh-Draw Appliances
These reveal the real limitsscale 0–5.2h¹ 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 15, 2026
Verdict: the DELTA Pro Ultra, on Power Score margin
The DELTA Pro Ultra costs $1,500 more, but it backs that up with a true online UPS (0ms switchover, versus the Apex's 10ms line-interactive), a 7,200W continuous inverter that can run a 3-ton central AC, and a 5,600W solar ceiling that outpaces the Apex's 2,400W by more than double. The Apex 300 + B300K is the cheaper unit to run per kWh ($0.13 vs $0.19) and comes in 33 lbs lighter, and for a buyer who just needs whole-home-adjacent backup without the true zero-gap UPS, it's the more sensible check to write. But for anyone protecting equipment that can't tolerate a power gap, or planning to run heavy compressor loads, the Pro Ultra's inverter headroom and instant switchover settle it.
Editor-assigned confidence, based on cited owner research and spec analysis.
List prices as of July 15, 2026. The links below open EcoFlow's and BLUETTI's current prices.
$3,999.00 list · direct from EcoFlow
or check the Apex 300 + B300K price$2,599.00 list
Written by Gunner Gustafson, Whole-Home Backup Tester · Station Arena Test Desk · Updated July 15, 2026
Measured Data
Benchmark scores and the full spec record, side by side.
Benchmark scores
Not rated for both units (minimum threshold unmet): Solar Generator.
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, DELTA Pro Ultra rates 4.9/5 (93rd percentile of 16 Home Backup-class units), and Apex 300 + B300K rates 4.4/5 (67th 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.
Neither of these is a picnic carry
148.8 lbs stacked versus 181.8 lbs — a 33-lb gap that doesn't change the physical reality. Both need a trolley or two people to move. Choose based on inverter size and UPS type, not the scale.
Apex 300 + B300K: 45dB Under Load
45dB is about as loud as a running refrigerator. If you're running a CPAP or sleeping near this unit, the fan noise may be noticeable. Most people find anything above 45dB disruptive for sleep.
The Pro Ultra's surge headroom is the bigger number that matters
10,800W of surge against 7,680W. That's the spec that decides whether a compressor actually starts, not just whether it runs once already spinning.
0ms online beats 10ms line-interactive, structurally
The Apex's switchover is fast for its design category, but it's still a switch — a real gap, just a short one. The Pro Ultra's online UPS never breaks the circuit in the first place.
Full record above — the Test Desk pick is the DELTA Pro Ultra.
Check DELTA Pro Ultra price →or check the Apex 300 + B300K 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 Apex 300 + B300K 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.
Brand trust
EcoFlow
Ecosystem
Largest in portable power — 12-15 models across DELTA Pro, DELTA 3, and RIVER 3 series, plus solar panels and smart home panels
Support
US-based phone/email/chat support (1-800-368-8604). Experiences are polarized — many report hassle-free prepaid-label replacements, but others report long waits and refurbished units sent for new claims. Pro tip: buying from Costco or Amazon gives you a stronger return safety net.
Community
Largest community in the space — Reddit r/Ecoflow_community (~31K members), multiple Facebook groups, and an official community forum
App experience
Rated 4.6/5 iOS (~8,400 ratings) · 4.2/5 Android (~17,000 ratings)
Unique strength
Fastest-charging technology (X-Stream), deepest product ecosystem, and most active innovation cadence. Supports up to 180kWh modular expansion with DELTA Pro Ultra X.
Worth knowing
The Oct 2025 DELTA Max 2000 recall (overheating/fire risk, 6 incidents) is worth noting. Also tested subscription paywalls for advanced app features in early 2025 before community backlash paused the plan. No parts or service offered out of warranty.
BLUETTI
Ecosystem
One of the broadest lineups — 15-20+ models from budget (AC2A) to flagship (Apex 300, 3072Wh). Includes specialized products: vehicle solar hubs, sodium-ion cold-weather units, and balcony storage systems.
Support
The most inconsistent support in the space. Heavily email-based with China timezone delays. Some users get smooth, efficient service; others report weeks of troubleshooting runarounds, being offered discounts on new units instead of repairs, and confusing third-party purchase claim processes. Buying direct from Bluetti's website tends to produce better support outcomes.
Community
Active and growing — Reddit r/bluetti has a dedicated community. Second-largest after EcoFlow in engagement.
App experience
Rated 4.5/5 iOS and Android — tied for best app experience in the category. V3.0 UI redesign was well-received.
Unique strength
Among the best capacity-to-price ratios available — several Elite and Apex units are the lowest $/Wh in the catalog. Widest product diversity including industry-firsts like sodium-ion cold-weather units and dual solar+alternator vehicle hubs. Full LFP standardization across lineup (3,500-6,000+ cycles). Dual-voltage (120V/240V) in flagships.
Worth knowing
Customer support inconsistency is the #1 risk factor. Older/discontinued units may become unrepairable — no spare parts policy for some models. Some reports of erratic communication from support agents.
Analyst note
EcoFlow positions itself as a mid-to-premium brand with stronger support infrastructure, while BLUETTI competes on value. The question is whether the EcoFlow ecosystem and support premium is worth it for your use case.
Growth path
DELTA Pro Ultra
EXPANDABLESupports EcoFlow expansion batteries, so you can add capacity later without replacing the base unit — useful if your needs may climb past 6,144Wh.
Accepts up to 5,600W 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 EcoFlow-specific. You're investing in the EcoFlow ecosystem.
Apex 300 + 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 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.
Realistic full solar rechargeat 70% of rated panel output — see methodology
Analyst note
Both expand, but the DELTA Pro Ultra's higher solar ceiling (5,600W 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.
EcoFlow DELTA Pro Ultra
Owners consistently praise the DELTA Pro Ultra's scale and speed: it charges two batteries in about 2 hours on 8,800W input, runs silently under 2,000W of draw, and its online UPS protects sensitive electronics around the clockA3. Home Depot reviewers specifically call out that its 7,200W inverter handles a 3-ton central AC, alongside quick setup and strong app monitoringA4.
The LFP cells are rated past 3,500 cycles, which reviewers translate to 10-plus years of service lifeA2, and the expandable architecture scales to 90kWh for a household — over 30 days of essential backup on one platformA1. There's no negative pattern in this ledger; the coverage skews toward professional and retailer reviews rather than long-term Reddit threads, so treat the multi-year durability claims as directionally solid rather than exhaustively field-tested.
“6,144Wh per battery with 7,200W continuous output (10.8kW surge), expandable to 90kWh across a system for a household — over 30 days of essential backup.”
Sources
ecoflow.com · homedepot.com · autoboosting.com · ecogadgethub.com
BLUETTI Apex 300 + B300K
This is a new product — the ledger is dominated by 2025-2026 professional reviews, not a mature owner community, so treat it as early-adopter data rather than long-term field reports. Within that limit, the recurring complaint is the base Apex 300 shipping with no USB or DC ports at all beyond its six AC plugsB1, requiring a separate $300 Hub D1 accessory that reviewers call steep for what it deliversB2. One reviewer measured just 8W out of the Hub's USB-C port trying to charge a phoneB6.
On the positive side, reviewers who tested it against real loads were impressed: one called it one of the few systems that could genuinely replace a generator without noise, fumes, or maintenanceB4, and another measured recharge from empty in under an hourB12. A load test in Australia drained the Apex from 100% to 65% running a single wash cycle, then down to 20% after also running a heat-pump dryerB9B10 — real numbers for anyone sizing it against household appliances.
“The Apex 300 doesn't have USB ports, DC ports, or much of anything beyond its six AC plugs and high-voltage connectors.”
Sources
thesolarlab.com · techspective.net · digitalreviews.net · thesolarpit.com · cleantechnica.com · trustedreviews.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
- Whole-home scale (to 90kWh), 7,200W output, online UPS, silent operation under load, and industry-fast charging are the standout features. [DELTA Pro Ultra · 2 entries]
- Reviewers consistently flag that the base Apex 300 has no USB/DC ports and requires a separate paid Hub D1 accessory, which some feel is overpriced for what it offers. [Apex 300 + B300K · 3 entries]
- Multiple sources note the extreme weight/bulk of the stacked Apex 300 + B300K system, making 'portable' a stretch despite handles/trolley options. [Apex 300 + B300K · 2 entries]
- Reviewers praise fast recharge and the system's ability to genuinely replace a generator for home backup and heavy loads like washers/dryers. [Apex 300 + B300K · 4 entries]
- A1
“6,144Wh per battery with 7,200W continuous output (10.8kW surge), expandable to 90kWh across a system for a household — over 30 days of essential backup.”
ecoflow.com / homedepot.com — DELTA Pro Ultra · 2026 · [positive]
- A2
“LFP chemistry rated for over 3,500 cycles to 80% (10+ years of use).”
ecoflow.com / autoboosting.com — DELTA Pro Ultra review · 2026 · [positive]
- A3
“Industry-fast 8,800W charging tops up two batteries in about 2 hours; an online UPS protects sensitive electronics round the clock, and it runs at 0 dB (silent) for draws under 2,000W.”
ecoflow.com / ecogadgethub.com — DELTA Pro Ultra review · 2026 · [positive]
- A4
“Owners call it a powerful, easy-to-use whole-home backup with quick setup, strong solar input, and good app monitoring; its 7,200W inverter can power a 3-ton central AC.”
homedepot.com owner reviews — DELTA Pro Ultra · 2026 · [positive]
- B1
“The Apex 300 doesn't have USB ports, DC ports, or much of anything beyond its six AC plugs and high-voltage connectors.”
thesolarlab.com — Bluetti Apex 300 Review: Cheap, Practical Home Backup? · unknown (2025/2026) · [mixed]
- B2
“That Bluetti D1 Power Hub that gives you your DC and USB ports costs about $300, which is a steep price for what you're getting.”
thesolarlab.com — Bluetti Apex 300 Review: Cheap, Practical Home Backup? · unknown (2025/2026) · [negative]
- B4
“It's one of the few systems I've tested that feels like it could genuinely replace a generator, without the noise, fumes, or maintenance.”
techspective.net — Bluetti Apex 300 with B300K Review · 2025-09-21 · [positive]
- B5
“Stacked, you're near 150 pounds of lithium iron phosphate and inverter muscle—movable with the built-in handles or a trolley... but not something you'll casually lug to a picnic.”
techspective.net — Bluetti Apex 300 with B300K Review · 2025-09-21 · [mixed]
- B6
“I just wonder why Bluetti did not include a USB-C port with some decent output, like 100 or 140W as I only got a measly 8W charge out of it for my phone.”
digitalreviews.net — Bluetti B300K Expansion Battery Review · 2025-12 · [negative]
- B9
“Results: 1 wash took about 1 hour and drained the Apex from 100% down to 65%.”
digitalreviews.net — Bluetti Apex 300 Power Station Tests (Australia) Part II · 2025-09 · [positive]
- B10
“Just for fun we then turned on our heat pump dryer to see that over 1½ hours it would further drain it down to 20%.”
digitalreviews.net — Bluetti Apex 300 Power Station Tests (Australia) Part II · 2025-09 · [mixed]
- B12
“During my testing, the recharge speed was astonishing. In under an hour, I had a system ready to go again.”
thesolarpit.com — Bluetti Apex 300 Review · 2025-10-28 · [positive]
- B13
“For van lifers, the Apex 300 is a great base station, and the ability to add another 2.7kWh of capacity by simply purchasing another B300K expansion pack is a game-changer.”
cleantechnica.com — The Bluetti Apex 300 & B300K Portable Power Station Tested · 2025-08-05 · [positive]
- B14
“As will you: it weighs in at 38kg, and is probably much too big and heavy for most people to carry alone.”
trustedreviews.com — Bluetti Apex 300 Review · 2025-10-10 · [negative]
Research compiled July 15, 2026.
Who Should Buy Which
Buy the DELTA Pro Ultra if you…
- →Buyers who need to start and hold a single large compressor load, like central air or a well pump, where the extra 3,360W of continuous headroom is the difference between running and tripping.
- →Anyone protecting equipment that genuinely cannot tolerate a power gap — a home server, medical device, or networking closet — where the 0ms online UPS is worth the premium on its own.
- →Off-grid or extended-outage users who plan to scale solar arrays over time and want the higher 5,600W charging ceiling waiting for them.
Buy the Apex 300 + B300K if you…
- →Buyers who want most of the Pro Ultra's whole-home-adjacent capability at $1,500 less, and whose loads are rolling household draws rather than a single big compressor.
- →Anyone comfortable with a fast line-interactive UPS instead of a true online one, and who wants the lower $0.13 cost-per-lifetime-kWh.
- →Van-lifers or workshop users planning to add a second B300K expansion battery rather than buy solar headroom they won't useB13.
If neither fits
Anyone whose actual need is a grab-and-go unit under 50 lbs should skip both — these are stationary, trolley-class systems, and neither one is getting carried to a tailgate without wheels.
The Bottom Line
The DELTA Pro Ultra costs $1,500 more, but that money buys a genuinely different tier of inverter: 7,200W continuous with a true 0ms online UPS, against the Apex's 3,840W and 10ms line-interactive switchover. For heavy single-load draws or zero-tolerance UPS needs, that gap doesn't close.
If your loads are ordinary household draws and you're comfortable with a fast-but-not-instant switchover, the Apex 300 + B300K is the cheaper unit to buy and the cheaper one to run per kWh. Buy the Pro Ultra for the inverter headroom; buy the Apex for the price.
Frequently Asked Questions
Answers drawn from the spec record and cited owner research.
Can the BLUETTI Apex 300 + B300K run a central air conditioner like the DELTA Pro Ultra?
Not the same way. The Apex 300 + B300K tops out at 3,840W continuous output, while the DELTA Pro Ultra runs 7,200W continuous and 10,800W surge — enough headroom that Home Depot reviewers specifically confirm it holds a 3-ton central AC compressor. A large single compressor load is the clearest reason to pick the Pro Ultra over the Apex.
Is the DELTA Pro Ultra worth $1,500 more than the Apex 300 + B300K?
It depends on the load and the warranty math you care about. The Apex is cheaper per lifetime kWh ($0.13 vs $0.19), but the Pro Ultra is cheaper per warranty-year ($410 vs $520) because its coverage runs twice as long. If you need the true 0ms UPS or the larger inverter, the premium buys something real; if not, the Apex delivers most of the capability for less.
Do both of these units need a hub or accessory for basic ports?
Yes for the Apex — reviewers note the base unit ships with no USB or DC ports at all beyond its AC outlets, requiring a separate Hub D1 accessory that costs roughly $300. The DELTA Pro Ultra's ledger doesn't show the same complaint pattern, so budget for the Hub if you're pricing out the Apex.
Which one recharges faster from solar?
The DELTA Pro Ultra, by a wide margin — it accepts up to 5,600W of solar input against the Apex's 2,400W, more than double. Both refill quickly from an AC outlet (the Apex's owners report full recharge in under an hour on wall power), but for solar-dependent off-grid use, the Pro Ultra's ceiling matters more.
Where to buy
EcoFlow DELTA Pro UltraPick
$3,999.00
$3,999.00 list · direct from EcoFlow
BLUETTI Apex 300 + B300K
$2,599.00
$2,599.00 list · direct from BLUETTI
Prices may vary by retailer and are subject to change.