Head-to-head test
EcoFlow DELTA 3 Ultra vs BLUETTI Apex 300 + B500K
The whole decision is carry-it or park-it: 72 pounds and 3,072Wh that travels anywhere, against a 183-pound, 7,885Wh home-backup box that never leaves the spot two people set it down.
Full profiles: EcoFlow DELTA 3 Ultra → · BLUETTI Apex 300 + B500K →
Written by Gunner GustafsonUpdated
Whole-Home Backup Tester, Station Arena Test Desk
$1,399.00 · direct from EcoFlow
Last checked 3 days ago. Prices move — check before you buy.
$3,299.00 · direct from BLUETTI
Last checked 3 days ago. Prices move — check before you buy.
Spec deltas
The DELTA 3 Ultra weighs 72 pounds and costs $1,399. The Apex 300 + B500K weighs 183 pounds and costs $3,299. That gap isn't two trims of one product. It's a portable you lift into a trunk against a home-backup system two people lower onto the floor and leave there, and which of those two sentences describes your plan is very nearly the whole decision.
The price gap isn't a premium, either. The DELTA holds 3,072Wh, the Apex 7,885Wh, and the two cost within a cent of each other for every lifetime kilowatt-hour they deliver. So the extra $1,900 isn't brand tax, it's just more energy. The only thing you're really deciding is whether you'll ever use the difference.
For most people, you won't, and the DELTA is the buy: lighter, half the money, and plenty for camping, blackouts, and a work-from-anywhere day. The Apex is for the narrower buyer who needs capacity that stays put: multi-day outages, full-time van power, a seed for partial-home backup. Here's where each one wins, and the one place the DELTA can't follow.
What the Numbers Reveal
Each conclusion stated first — the numbers behind it on one line, the full analysis below.
Capacity
When a $1,399 unit and a $3,299 unit come out even on cost-per-energy, the $1,900 between them isn't buying quality, it's buying quantity. The Apex holds well over twice the DELTA's capacity (7,884.8Wh against 3,072Wh) and costs a bit over twice as much ($3,299 against $1,399). The two roughly track, which is exactly why the per-energy cost is a wash. You're paying, almost linearly, for watt-hours.
DELTA 3 Ultra: $1,399, 46 cents per nameplate Wh, 11 cents per lifetime kWh, rated 4,000 cyclesApex 300 + B500K: $3,299, 42 cents per nameplate Wh, 12 cents per lifetime kWh, rated 3,500 cyclescapacity 3,072Wh vs 7,884.8Wh
Why it mattersStop comparing the price tags and size your need instead: if 3,072Wh covers you, the extra money is capacity you'll never draw; if it doesn't, the Apex isn't a splurge, it's the right size.
weight
Only one of the six isn't a close call. Van Life Daily asks for 4,685Wh, and the DELTA's 2,611Wh usable leaves it 2,074Wh short, just over half the day covered. Every scenario the DELTA wins, it wins on being liftable. So the DELTA loses exactly one contest on raw capacity, and it's the one where you'd have parked the unit in the van and never moved it anyway.
DELTA 3 Ultra 72.1 lbs, not stationaryApex 300 + B500K 183 lbs, stationaryscenario split: DELTA wins Weekend Camping and Tailgate; Apex wins 8-Hour Blackout, Remote Workday, Van Life DailyVan Life Daily needs 4,685Wh; DELTA usable 2,611Wh, short by 2,074Wh
Why it mattersAnswer 'will I carry this, or does it live in one spot?' before anything else. That single question resolves most of this page the moment you say it out loud.
That 15dB spread is mostly a difference in how each brand quotes its quiet number, not a difference you'd hear across a room. For the one person noise genuinely matters to, asleep two feet away, either box is quiet enough. So the spec that actually decides the bedside unit isn't decibels, it's the 111 pounds separating one you can carry to the bedroom from one you can't.
DELTA lists 30dB, Apex lists 45dB, both manufacturer best-case floorsreviewers found the DELTA's fans never annoying even at maximum outputA1A2reviewers found the Apex's fans quiet and even under loadB1B2B13
Why it mattersIf this is a CPAP or bedroom unit, don't let the dB line pick it for you; pick the one you can physically place where you sleep.
The specific dimensions that decide these two units — everything else is a tie.
Portability & Form Factor
Selected because: The 72.1-lb versus 183-lb gap decides where each unit can be used at all, and that settles most of this matchup before capacity is counted.
weight
Weight is the spec that quietly settles this page. The DELTA's 72.1 pounds is a one-person, bend-your-knees lift into a trunk. No fun, but you can do it alone. The Apex's 183 is not a lift, it's a delivery: two people set it down and it stays there, which is the polite way of saying it never sees a campsite.
That 111-pound gap isn't a portability footnote. It's the reason half the scenarios below are decided before anyone counts a watt-hour.
Your Life, Your Pick
Selected because: The six use-case tests split 3-3, and which three you care about is the actual decision here.
A 3-3 split reads like a coin toss until you notice the pattern. The DELTA wins everything you carry to, Weekend Camping and the Tailgate, and the Apex wins everything that sits still and runs long, taking the 8-Hour Blackout and Van Life outright and edging the Remote Workday on leftover headroom (the DELTA clears that day too, finishing at 35% used).
Only one result isn't close. Van Life Daily needs 4,685Wh, and the DELTA's 2,611Wh usable leaves it 2,074Wh short, a little over half the day. For that daily-cycling, sun-dependent life the Apex has a second edge that matters: it accepts 2,400W of solar against the DELTA's 800W, so it refills roughly three times faster from the same panels. Every scenario the DELTA wins, it wins on being movable. The one it loses badly is the one day you'd never move it anyway.
Growth Path
Selected because: The DELTA is sealed at 3,072Wh while the Apex starts at 7,885Wh and expands, which is the capacity question the $1,900 price gap is really about.
solar input
The DELTA is sealed at 3,072Wh, and that number is the ceiling. Check it against your longest unplugged stretch, because there's no adding to it later. The quiet upside of a sealed box: nothing to sync, and no expansion firmware to misbehave. The Apex takes the opposite bet, starting at 7,885Wh and daisy-chaining BLUETTI batteries toward genuine partial-home backup, real headroom the DELTA can't reach at any price.
The catch lands right on that headline feature. Owners running Apex packs in parallel report them charging at uneven rates, leaning on unofficial community workarounds to keep them in stepB3B4, and this exact 7,885Wh configuration has almost no long-term ownership record behind it yetB0. Expansion is the best reason to choose the Apex and, today, the least-proven thing about it. If you only ever need 3,072Wh, the sealed unit simply has less that can go wrong.
Lifetime Value
Selected because: The two cost within a cent per lifetime kWh (11 vs 12), so price-per-energy doesn't separate them, only how much energy you need does.
cost / lifetime kWh
Here's the twist in the money: it's a dead heat, and it's a dead heat in both directions. The Apex is a hair cheaper per nameplate watt-hour, while the DELTA is a hair cheaper per lifetime kilowatt-hour because it's rated for more charge cycles. Two ways of saying the same thing, which is that neither one is overpriced.
So 'which is the better value' has no answer, because value-per-energy is identical. The only real variable is the $1,900 between the sticker prices, and every dollar of it buys capacity. Decide how much capacity your life actually needs and you've decided this. The money won't.
Brand Trust
Selected because: At $3,299 on a brand-new platform, BLUETTI's support record and firmware teething are a real cost the $1,399 DELTA doesn't carry.
At $1,399 you can laugh off a clunky support experience. At $3,299 on a platform this young, you can't. The DELTA sits on the largest, most-shipped ecosystem in portable power, a big installed base means most of the bugs have already been found and filed, and EcoFlow's support is polarized but US-based.
The Apex is the other profile. Support inconsistency is BLUETTI's best-known weakness, and the platform is new enough that firmware updates have mode-locked owners' units and thrown inverter error codes before later patches cleared themB7B8B9. None of that is disqualifying, the errors got fixed and its app rates every bit as well as EcoFlow's, but it's the difference between a proven box and an early platform. If you want the thing to work the day it lands and never ask for attention again, that points at the DELTA.
Strengths & trade-offs
EcoFlow DELTA 3 Ultra
Strengths
- +Costs $1,900 less
- +Lighter by 110.9 lb
Trade-offs
- –Sealed capacity — the Apex 300 + B500K can add batteries to grow past 3,072Wh; this one can't.
- –Shorter-lived battery — rated for 4,000 charge cycles vs the Apex 300 + B500K's 6,000, so it wears out sooner.
BLUETTI Apex 300 + B500K
Strengths
- +Larger battery capacity
- +Higher AC output
- +Faster solar charging
- +Rated for 6,000 charge cycles — much longer battery lifespan
Trade-offs
- –Substantially more expensive (+$1,900) than the DELTA 3 Ultra.
- –Significantly heavier (+110.9 lbs), making it harder to move.
- –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
DELTA 3 Ultra
The Apex 300 + B500K at 183 lbs is not a take-along — it rolls off a truck bed if it travels at all, so this scenario belongs to the DELTA 3 Ultra by default — and it earns it, covering the 2,100Wh with 511Wh to spare. Capacity was never the Apex 300 + B500K's problem here; getting to a campsite was.
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
Apex 300 + B500K
Both survive the night. The Apex 300 + B500K finishes at 25% used with 5,057Wh left — 3.1 more nights like it. The DELTA 3 Ultra finishes at 63% with 966Wh, 59% of a second night. 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
DELTA 3 Ultra
A CPAP pulls about 40W, so both of these coast through the night many times over; capacity isn't the question. The question is which box you can get to the bedside. The DELTA is a 72-pound one-person move; the Apex is 183 pounds that lives wherever two people set it down. For the unit running eighteen inches from your head, being able to put it there wins.
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
Apex 300 + B500K
The Apex 300 + B500K clears the workday at 14% used, banking 5,792Wh — late work, extra calls, or a second laptop charge without arithmetic. The DELTA 3 Ultra at 35% also finishes, with 1,701Wh 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
DELTA 3 Ultra
A tailgate is a parking lot, a few hours, and something that heats or spins. The DELTA carries in and covers the 670Wh easily, with 1,941Wh to spare. The Apex at 183 pounds is home-backup that was never getting to the lot in the first place, so this one goes to the DELTA before capacity is even on the table.
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
Apex 300 + B500K
The DELTA 3 Ultra doesn't finish — 2,611Wh usable against the 4,685Wh this needs leaves it 2,074Wh short, about 56% of the scenario covered. The Apex 300 + B500K covers it with 2,017Wh to spare.
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: Apex 300 + B500K runs 32.7h vs 12.7h.
$3,299 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 0–446.8hComfort & Convenience
Makes off-grid life actually enjoyablescale 0–89.4hHigh-Draw Appliances
These reveal the real limitsscale 0–6.7h¹ 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
August 30, 2026
Verdict: the EcoFlow DELTA 3 Ultra
Take the DELTA 3 Ultra unless you specifically need what only the Apex can do. At $1,399 it's $1,900 cheaper, it's the only one of the two you can actually pick up and move, and 3,072Wh covers most real use. And since the two land within a cent of each other per lifetime kilowatt-hour, choosing the smaller box costs you nothing in energy economics. The Apex 300 + B500K earns its price only for the buyer who needs stationary capacity the DELTA can't physically reach: multi-day outages, daily van-life cycling where the DELTA runs 2,074Wh short, or a base to expand toward partial-home backup. For that buyer it's the right call. For everyone else, it's $1,900 of headroom that never gets used.
Editor-assigned confidence, based on cited owner research and spec analysis.
List prices as of August 30, 2026. The links below open EcoFlow's and BLUETTI's current prices.
$1,399.00 · direct from EcoFlow
Last checked 3 days ago. Prices move — check before you buy.
or check the Apex 300 + B500K price$3,299.00 list
Written by Gunner Gustafson, Whole-Home Backup Tester · Station Arena Test Desk · Updated August 30, 2026
Measured Data
Benchmark scores and the full spec record, side by side.
Benchmark scores
Not rated for both units (minimum threshold unmet): UPS, RV Living, Solar Generator, Tailgating.
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 3 Ultra rates 4.6/5 (79th percentile of 25 Large-class units), and Apex 300 + B500K rates 3.5/5 (11th 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 DELTA 3 Ultra (72.1 lbs) is manageable solo but heavier than a large checked suitcase. The Apex 300 + B500K (183 lbs) is firmly a two-person lift. It goes where you put it and stays there. That's a 111 lb difference, which you'll feel every time you relocate.
Apex 300 + B500K: 45dB Under Load
45dB is about as loud as a running refrigerator. The DELTA 3 Ultra's listed 30dB sits well under it — if you're running a CPAP or sleeping nearby, that gap is the comparison. For most people, fan noise around 45dB and up is where sleep starts to suffer.
DELTA 3 Ultra: Fixed Capacity
The DELTA 3 Ultra is sealed at 3,072Wh — fine if that covers you, but it's the ceiling. By contrast the Apex 300 + B500K can add expansion batteries, so if your needs grow past 3,072Wh it has somewhere to go the DELTA 3 Ultra doesn't — and at this size that path genuinely points toward partial-home backup.
Warranty: No Difference
Both units carry the same 5-year warranty, so coverage isn't a tiebreaker here. Worth saying because the per-dollar framing can suggest otherwise: the DELTA 3 Ultra works out at 3.6 years of cover per $1,000 spent against the Apex 300 + B500K's 1.5, but that spread is the price gap, not the terms.
Battery Lifespan in Real Years
The Apex 300 + B500K is rated for 6,000 cycles vs 4,000. In real life: at daily use, that's 16.4 vs 11 years. At weekend use (twice a week), it's 58 vs 38 years. One caution reading years across different sizes: a cycle is 7,885Wh on the Apex 300 + B500K and 3,072Wh on the DELTA 3 Ultra, so count lifetime energy — roughly 47,309 kWh against 12,288 kWh over the rated life. After hitting the cycle limit, the battery doesn't die — it drops to ~80% of original capacity, which is still very usable.
Full record above — the Test Desk pick is the DELTA 3 Ultra.
Check DELTA 3 Ultra price →or check the Apex 300 + B500K 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 DELTA 3 Ultra is cheaper to buy, but the Apex 300 + B500K is cheaper to own. At $0.07/kWh over its lifetime vs $0.11/kWh, the Apex 300 + B500K's higher cycle life and capacity make each dollar go further over the years.
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. At the very top of the range, the DELTA Pro Ultra platform stacks batteries and inverters into whole-home backup — a flagship path, not a line-wide feature.
Worth knowing
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 portable (Apex 300, 2764.8Wh). 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 the lineup, though rated cycle life spans 2,500 (EB3A) to 6,000 (Elite units) — check the specific model. 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
One of these is a mature platform with a large installed base already debugged in the field; the other is a newer, more capable one still ironing out its firmware. Neither company's support is a selling point, so whichever you pick, buy from a retailer with a real return window. It's the cheapest insurance on a purchase this size.
Growth path
DELTA 3 Ultra
FIXED CAPACITYFixed at 3,072Wh — a sealed, complete system rather than a starting point. There's no expansion port, so that figure is the ceiling: check it against your longest unplugged stretch before you buy.
Accepts up to 800W of solar. Suitable for a 1-2 panel setup.
Generous port selection supports complex multi-device setups.
Apex 300 + B500K
EXPANDABLESupports BLUETTI expansion batteries, so you can add capacity later without replacing the base unit — useful if your needs may climb past 7,885Wh.
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
The DELTA 3 Ultra is sealed at 3,072Wh, which is fine if that covers you. The Apex 300 + B500K starts at 7,885Wh and can grow beyond it with BLUETTI expansion batteries — real headroom the DELTA 3 Ultra doesn't have if your needs climb toward partial-home backup.
What Owners Report
Patterns from published owner reports and long-term reviews — every claim cited to its source below.
EcoFlow DELTA 3 Ultra
Start with a caveat, because honesty demands it: there's barely any field record for the base DELTA 3 Ultra. Nearly all the coverage we found is of the pricier Ultra Plus, which shares this unit's chassis, capacity, output and inverter but not its solar input or expansionA0, so the notes below describe the hardware you're buying, but from press reviews rather than long-term owners. With that stated, reviewers consistently praised how quiet the fans stay even at full outputA1A2, and the UPS behavior drew the strongest agreement: testers who yanked the wall power saw no dips or shutdowns, the way a good desktop UPS behavesA5A6. Build quality earned repeated marks for feeling substantial rather than plastickyA9. None of it is six-months-in ownership data, but the professional consensus is a quiet, solid, well-behaved box.
“Even when you're pushing it hard, the DELTA 3 Ultra Plus runs much quieter than older EcoFlow models, like the DELTA 2 Max.”
Sources
thesolarlab.com · postperspective.com · appleinsider.com · digitaltrends.com · popsci.com
BLUETTI Apex 300 + B500K
The Apex 300 + B500K is new enough that its field record is essentially a blank page: no Reddit threads, no six-month ownership reports, and none of the sources we found even cover this exact 7,885Wh pairing rather than the bare Apex 300 or the smaller B300K comboB0. What exists is encouraging on noise: multiple reviewers describe the fans as quiet and even under load, on par with the quietest units in the classB1B2B13, which, if it holds, narrows the 45dB spec gap considerably. The worries are two, and both are the kind a new platform tends to have. Firmware updates have repeatedly caused trouble, units mode-locked in Backup, failed app updates, an inverter throwing an E004 output-failure error, though several owners report the issues clearing after a later patch or a support callB7B8B9. And owners running Apex packs in parallel report them charging at uneven rates, needing unofficial community workarounds to stay in syncB3B4, which is worth weighing since parallel expansion is the whole reason to buy this over a sealed unit. One reviewer also flagged the obvious: it's so heavy they couldn't lift it onto a tableB11.
“Turns out the Apex 300's noise control is on par with the quietest power stations on the market, like those on offer from EcoFlow and DJI.”
Sources & Research Notes
Every owner claim in this report is traceable to a published source. The bracketed references above resolve here.
Recurring owner themes
- Reviewers consistently praise the quiet fan operation of the Ultra-tier unit compared to older EcoFlow models, though this is described in professional test conditions rather than long-term ownership. [DELTA 3 Ultra · 2 entries]
- UPS/switchover performance is repeatedly called seamless with no observed dips or shutdowns during power interruption tests. [DELTA 3 Ultra · 3 entries]
- The unit's substantial 74 lb weight is flagged across multiple reviews as a portability drawback, mitigated somewhat by wheels and handle design. [DELTA 3 Ultra · 2 entries]
- Build quality/durability (casing, cable, port covers) is repeatedly highlighted as premium and well-engineered. [DELTA 3 Ultra · 2 entries]
- Multiple independent reviewers describe the dual-fan cooling as noticeably quiet/even for a unit of this output class, even under load. [Apex 300 + B500K · 3 entries]
- Firmware and app updates have repeatedly caused mode-lock, download failures, or inverter error codes; several threads show the issue eventually resolved after further updates or support contact. [Apex 300 + B500K · 4 entries]
- When running multiple Apex 300 units or expansion batteries in parallel, owners report uneven charge rates between units, with community-devised (unofficial) workarounds needed to keep them in sync. [Apex 300 + B500K · 2 entries]
- The stripped-down, modular design draws criticism for real-world handling: extreme weight makes it hard to move, and lack of native USB/DC ports forces reliance on a separate paid hub accessory. [Apex 300 + B500K · 2 entries]
- A1
“Even when you're pushing it hard, the DELTA 3 Ultra Plus runs much quieter than older EcoFlow models, like the DELTA 2 Max.”
thesolarlab.com — EcoFlow DELTA 3 Ultra Plus Review: The Ultimate DELTA? · 2025-09/10 (approx) · [positive]
- A2
“Even when you're pushing the inverter to its maximum output, the fans never become annoying or distracting.”
thesolarlab.com — EcoFlow DELTA 3 Ultra Plus Review: The Ultimate DELTA? · 2025-09/10 (approx) · [positive]
- A5
“Over my career I have become accustomed to APC batteries immediately switching on when there is a power hit or power shut-off, and the EcoFlow Delta 3 Ultra Plus works in the exact same way.”
postperspective.com — Review: EcoFlow Delta 3 Ultra Plus Portable Power Station · 2026-04 · [positive]
- A6
“I didn't experience any shut-offs or dips when I unplugged the EcoFlow from the wall.”
postperspective.com — Review: EcoFlow Delta 3 Ultra Plus Portable Power Station · 2026-04 · [positive]
- A9
“It does not feel cheap or fragile. Everything from the outer shell case to the plastic buttons and the AC cable feels substantial and durable enough to withstand day-to-day wear and tear.”
appleinsider.com — EcoFlow Delta 3 Ultra Plus review: Premium, but solid power · 2025-11-16 · [positive]
- B1
“Turns out the Apex 300's noise control is on par with the quietest power stations on the market, like those on offer from EcoFlow and DJI.”
The Solar Lab — "Bluetti Apex 300 Review: Cheap, Practical Home Backup?" · unknown · [positive]
- B2
“Some units sound like small jet engines under load, but the Apex 300's fans are relatively tame.”
Techspective — "Bluetti Apex 300 with B300K Review" · 2025-09 · [positive]
- B3
“The Apex 300 have some major charging problems... When the units are charging from the grid they charge at different rates and not together.”
DIY Solar Power Forum — "Bluetti Apex 300 problems" · 2025-09 · [negative]
- B4
“I have found a simple way to get around some of the solar charging limitations with multiple APEX 300s hooked up in parallel... So far, I have not had any problems with my setup.”
DIY Solar Power Forum — "Bluetti Apex 300 problems" · 2025-09 · [mixed]
- B7
“I updated my Apex 300 to the latest firmware yesterday. Now it's stuck in 'Backup' mode... when I go into the app to try to change it back, it flashes to...”
BLUETTI Community — "Apex 300 stuck in Backup mode after last firmware update" · 2025-11 · [negative]
- B8
“There was an update on my Apex 300 a few days ago IOT v8026.12... Problem is every time I connect to the power st[ation]... Edit - This seems fixed now hooray!”
BLUETTI Community — "Check For Update App issue" · 2025-09 · [mixed]
- B9
“After the update completed, the charging stopped and I received Error 004... I have error E004 Inverter Output Failure.”
BLUETTI Community — "Error E004 Apex 300" · 2025-11 · [negative]
- B11
“it's so heavy I can hardly carry it more than a few feet at a time and have been unable to lift it onto a table.”
T3 — "Bluetti Apex 300 review: transform your off-grid life" · 2025-11 · [negative]
- B13
“Fan noise remains even, with no distracting pitch or rattle. This makes the Apex 300 usable near sleeping areas or indoor workspaces without disturbance.”
Yanko Design — "BLUETTI Apex 300 Review" · 2025-05 · [positive]
Research compiled August 30, 2026.
Who Should Buy Which
Buy the DELTA 3 Ultra if you…
- →You'll move it. Camping, tailgates, a job site, room to room during an outage, anything that needs the power to travel takes the 72-pound unit by default; the Apex simply can't come.
- →3,072Wh is enough for your reality. A weekend, a single-night blackout, a work-from-anywhere day all fit inside its 2,611Wh usable with room left, and you keep the $1,900.
- →You want to buy it and forget it. The bigger installed base and US-based support make the DELTA the lower-drama ownership experience of the two.
Buy the Apex 300 + B500K if you…
- →You need capacity that stays put. Multi-day outages, full-time van or off-grid living that cycles roughly 4,685Wh a day (where the DELTA falls 2,074Wh short), or a home you want partly backed up, this is the box that finishes those jobs.
- →You're buying a foundation to grow. The path from 7,885Wh toward partial-home backup is real, and it's the one thing a sealed DELTA can't sell you at any price. Just budget patience for a new platform's firmware, since this exact pairing has almost no ownership track record yetB0.
- →You run big solar. At 2,400W of solar input it refills about three times faster than the DELTA's 800W from the same array, decisive if you're recharging off panels every single day.
If neither fits
If your loads are small, a phone, a laptop, a CPAP, some lights, both of these are wild overkill; a 1,000Wh-class portable does the job for a fraction of the money and weight, and you'll actually carry it. And if you're after true whole-house backup, neither of these is that: that's a permanently wired system or a home battery like a Powerwall, not a plug-in box you set on the floor.
The Bottom Line
Take the DELTA 3 Ultra. It's the one you can actually move, it's $1,900 cheaper, and because the two are a dead heat on cost per unit of energy, the smaller box gives up nothing but capacity you probably won't use. It handles camping, blackouts and a full work-from-home day with margin to spare, and it does it on a proven, widely-shipped platform that mostly just works.
Buy the Apex 300 + B500K only where the DELTA physically can't follow: stationary capacity that runs for days, a van's full daily cycle (where the DELTA lands 2,074Wh short), or a base you'll expand toward backing up part of a house. For that buyer it's the right tool and honestly priced for its size. For everyone else, 183 pounds is a lot of answer to a question you're not asking. Get the DELTA, and put the $1,900 toward panels or a retailer with a generous return window.
Frequently Asked Questions
Answers drawn from the spec record and cited owner research.
Is the BLUETTI Apex 300 + B500K worth nearly twice the price of the EcoFlow DELTA 3 Ultra?
Only if you need the extra capacity. The two cost almost exactly the same per unit of energy, so you're not paying a flagship premium, you're paying for 7,885Wh instead of 3,072Wh. If 3,072Wh covers your longest unplugged stretch, the DELTA does the same job for $1,900 less; if it doesn't, the Apex is fairly priced for the bigger task.
Can the EcoFlow DELTA 3 Ultra run a whole house?
No, it's a 3,072Wh portable, not a wired-in backup. It'll carry the essentials through an outage, fridge, lights, internet, phones and laptops in rotation, but running central AC or electric heat off it isn't realistic. Even the much larger Apex, fully expanded, only edges toward partial-home backup; true whole-house coverage is a transfer-switch installation, a different category entirely.
Which is quieter for CPAP or bedroom use?
On paper the DELTA lists 30dB against the Apex's 45dB, but both are manufacturer best-case floors, and in testing reviewers called both units quiet even under load. At a roughly 40W CPAP draw neither is likely to wake you. The bigger bedside question is weight: you can move the 72-pound DELTA to the nightstand; the 183-pound Apex goes where two people put it and stays there.
How long will each one last before the battery wears out?
Both use LFP cells with long rated lives: the DELTA is rated for at least 4,000 charge cycles, the Apex at least 3,500, and both carry a 5-year warranty. At everyday use that works out to roughly 11 years for the DELTA and about 9.6 for the Apex before they reach that rated cycle count, longer than most people will want to own either one. Neither is the unit you'll be replacing soon.
Do I actually need the Apex's expansion, or is the DELTA's fixed capacity enough?
If you can name your single biggest power session and it fits inside about 2,600Wh usable, the DELTA's sealed 3,072Wh is enough, and simpler, with nothing to sync. Expansion earns its keep only if your needs will climb toward partial-home backup. One caveat if they might: owners running Apex batteries in parallel report uneven charge rates that need unofficial workarounds, so the growth path, while real, isn't friction-free yet.
Brand matchup
EcoFlow vs BLUETTI: measured across every matchup →Where to buy
EcoFlow DELTA 3 UltraPick
$1,399.00
$1,399.00 · direct from EcoFlow
Last checked 3 days ago. Prices move — check before you buy.
BLUETTI Apex 300 + B500K
$3,299.00
$3,299.00 · direct from BLUETTI
Last checked 3 days ago. Prices move — check before you buy.
Prices may vary by retailer and are subject to change.