Head-to-head test
EcoFlow DELTA 3 Ultra Plus vs BLUETTI Apex 300 + B500K
Buy the Apex 300 + B500K if your heaviest day tops 4,685Wh of draw; buy the DELTA 3 Ultra Plus and pocket $1,800 and 105.8 fewer pounds if it doesn't.
Full profiles: EcoFlow DELTA 3 Ultra Plus → · BLUETTI Apex 300 + B500K →
Written by Gunner GustafsonUpdated
Whole-Home Backup Tester, Station Arena Test Desk
$1,599.00 · 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
Push both through a full 4,685Wh van-life day and only one survives it: the Apex 300 + B500K uses 70% of its capacity and has plenty left, while the DELTA 3 Ultra Plus would need 179% of its usable capacity to finish and runs out first.
That capacity costs real money and real weight. The Apex 300 + B500K runs $3,299 against the DELTA 3 Ultra Plus's $1,499, and weighs 183 lbs to the DELTA's 77.2 — more than double on both counts. Per watt-hour of storage the Apex 300 + B500K is actually the better deal, at $0.42 against $0.49, but the lifetime-value math still calls the DELTA 3 Ultra Plus the cheaper unit to own, at $300 a year of warranty coverage against $660.
Every smaller scenario here — a camping weekend, a blackout, a CPAP night, a workday, a tailgate — both units handle without strain. The gap only opens up at whole-home, daily-use scale, so the real work of this page is figuring out which of those two categories your actual heaviest day falls into.
What the Numbers Reveal
Each conclusion stated first — the numbers behind it on one line, the full analysis below.
Weekend Camping, the 8-hour blackout, CPAP, a workday, and a tailgate all land the DELTA 3 Ultra Plus somewhere between 12% and 80% used — never dry. Van Life Daily is where that stops being true, and it's the scenario that actually tells you which battery you need.
Van Life Daily needs 4,685WhDELTA 3 Ultra Plus would need 179% of its usable capacity to cover itApex 300 + B500K covers it using 70% of its capacity
Why it mattersIf your heaviest real day looks like daily van life or off-grid home use, the extra capacity isn't optional — buy the Apex 300 + B500K. If it looks like any of the other five scenarios, you're paying for headroom you won't use.
Both are true at once because they answer different questions: $/Wh rewards buying a bigger tank once, cost-per-warranty-year rewards spending less up front. A buyer who will actually use the Apex 300 + B500K's extra capacity is getting a real discount on that Wh; a buyer who wouldn't have used it anyway is just paying $1,800 more for the same coverage window.
DELTA 3 Ultra Plus costs $0.49 per Wh of capacityApex 300 + B500K costs $0.42 per Wh of capacityCost per warranty year is $300 for the DELTA 3 Ultra Plus and $660 for the Apex 300 + B500K
Why it mattersDecide which question is yours before comparing the numbers — what a Wh costs, or what owning the thing costs — because they point to different units.
183 lbs isn't a 'heavier' version of 77.2 lbs, it's a different relationship to the object — the Apex 300 + B500K is something you position once near an outlet or a panel array and leave, not something that rides along between the garage and the campsiteB11.
DELTA 3 Ultra Plus weighs 77.2 lbs and is rated at 30dBApex 300 + B500K weighs 183 lbs and is rated at 45dBOne reviewer said the Apex 300 could hardly be carried a few feet or lifted onto a tableB11
Why it mattersIf the unit needs to move with you, that alone should push you toward the DELTA 3 Ultra Plus regardless of capacity; if it's going to sit bolted in a van or a utility closet, weight stops being the deciding factor.
solar input
A bigger battery that refills through the same size panel array takes proportionally longer per charge. The Apex 300 + B500K's higher solar ceiling keeps that ratio from getting worse as you add capacity, which is exactly the direction a buyer who expands later is headed.
DELTA 3 Ultra Plus caps solar input at 1,600WApex 300 + B500K caps solar input at 2,400WBoth support further expansion batteries beyond their current capacity
Why it mattersAnyone planning to add expansion batteries down the line should weigh the solar ceiling now — it decides whether future capacity actually recharges in a reasonable day.
The specific dimensions that decide these two units — everything else is a tie.
Lifetime Value
Selected because: Price, $/Wh, and cost-per-warranty-year point in different directions and need untangling.
cost / lifetime kWh
Per watt-hour of battery, the Apex 300 + B500K is the better-priced unit: $0.42 against the DELTA 3 Ultra Plus's $0.49. That's the number that matters if you'll actually draw on its extra capacity. Cost-to-own asks a different question, and there the DELTA 3 Ultra Plus wins clearly — $300 a year of its 5-year warranty against $660 a year for the Apex 300 + B500K, because you're committing $1,499 instead of $3,299 up front for coverage of the same length.
Measured per lifetime kilowatt-hour delivered over each unit's rated cycle life, they land in a dead heat at $0.12 — proof neither battery is a bad deal on raw longevity, they're just sized for different jobs. The real question isn't which is 'cheaper' in the abstract, it's whether you need 7,884.8Wh of capacity badly enough to pay $1,800 more for it than the DELTA 3 Ultra Plus's 3,072Wh.
Your Life, Your Pick
Selected because: Five of six scenario wins go to the Apex, but only Van Life Daily is a real capability gap.
Van Life Daily is the outlier. A 4,685Wh day is the one load in this set that actually stresses these batteries, and it's the one the DELTA 3 Ultra Plus can't finish — it would need 179% of its usable capacity, while the Apex 300 + B500K covers it using 70%. Every other scenario here, from an 8-hour, 1,645Wh blackout down to a 320Wh CPAP night, uses somewhere between 5% and 63% of either unit's tank.
Worth saying plainly: the Apex 300 + B500K 'wins' Weekend Camping, the blackout, a remote workday, and a tailgate mostly because a bigger battery uses a smaller percentage of itself for the same job, not because the DELTA 3 Ultra Plus can't do them. Buy on Van Life Daily if your days actually look like that; buy on price and weight if they look like the other five.
What the Specs Don't Tell You
Selected because: Weight, noise, and warranty-value all fire for this pair with real numbers behind each.
rated cycles
The DELTA 3 Ultra Plus is 77.2 lbs; the Apex 300 + B500K is 183 lbs, more than double, which is less about the spec sheet and more about whether you're moving this thing by yourself. Noise runs the same direction: the Apex 300 + B500K is rated at 45dB under load, 15dB above the DELTA 3 Ultra Plus's 30dB, a real difference if either one is going to sit near where someone sleeps or works.
Warranty length is identical at 5 years for both, so the gotcha is what that coverage costs: $300 a year on the DELTA 3 Ultra Plus, $660 a year on the Apex 300 + B500K. Same promise, different price of entry.
Portability & Form Factor
Selected because: 77.2 lbs vs 183 lbs is the most physically obvious difference and shapes where each unit lives.
weight
At 77.2 lbs, the DELTA 3 Ultra Plus is still a real lift, but it's the kind one determined person gets into a trunk or up a few stairs. The Apex 300 + B500K's 183 lbs is a different category of object entirely — something you position once, near an outlet or a solar array, and don't relocate on a whim. One reviewer said they could barely move it a few feet and never got it up onto a tableB11, which tracks with a unit more than double the DELTA's weight.
Where they match: both switch over to battery in 10ms and both cap out at 100W USB-C, so neither is meaningfully faster or slower to react to an outage or top up a laptop. The real difference is entirely about how far you're willing to carry the box, not how either performs once it's sitting still.
Brand Trust
Selected because: Cross-brand pair with a real 2025 recall on one side and support inconsistency on the other.
EcoFlow is the larger ecosystem by a wide margin — a dozen-plus models, its own solar panels and smart home panels — and support skews toward reachable, if inconsistent in how claims get resolved. It's also the brand with an actual recall on the books: the DELTA Max 2000 was recalled in October 2025 over an overheating and fire risk. That's a different product line than the DELTA 3 Ultra Plus, but it's on the company's record, and worth knowing about the company backing a 5-year warranty.
BLUETTI's pitch is the strongest capacity-per-dollar in the category and full LFP cells across its lineup, but support is the widest wildcard here — some buyers get quick, smooth service, others describe long troubleshooting threads and being steered toward a discounted new unit instead of a repair. Both companies' apps are well-reviewed; the meaningful difference is what happens after the sale, not before it.
Strengths & trade-offs
EcoFlow DELTA 3 Ultra Plus
Strengths
- +Costs $1,700 less
- +Lighter by 108.7 lb
Trade-offs
- –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 (+$1,700) than the DELTA 3 Ultra Plus.
- –Significantly heavier (+108.7 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 Plus
A 2,100Wh weekend pulls 80% out of the DELTA 3 Ultra Plus's tank against 31% of the Apex 300 + B500K's — both make it through, but the DELTA finishes on fumes while the Apex barely notices.
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
An 8-hour, 1,645Wh outage draws the DELTA 3 Ultra Plus down to 63% used and the Apex 300 + B500K to just 25% — both ride it out, the Apex with three-quarters of its capacity still in reserve.
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 Plus
A CPAP pulling 320Wh overnight barely registers on either unit — 12% of the DELTA 3 Ultra Plus, 5% of the Apex 300 + B500K. This one's a wash; buy on price and portability instead.
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
A 910Wh remote workday uses 35% of the DELTA 3 Ultra Plus and 14% of the Apex 300 + B500K. Both finish the day with power to spare, so this scenario is more a tiebreaker than a hard requirement.
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 Plus
A 670Wh tailgate spends 26% of the DELTA 3 Ultra Plus and 10% of the Apex 300 + B500K — again, both handle it easily; the percentage gap matters more if this is one stop on a longer trip.
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
This is the one that actually separates them: a 4,685Wh day asks for 179% of the DELTA 3 Ultra Plus's usable capacity, so it runs out. The Apex 300 + B500K uses 70% and has almost a third of its tank left. Daily van life is where the bigger bank stops being optional.
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
July 28, 2026
Verdict: the Apex 300 + B500K, on Power Score margin
The Apex 300 + B500K wins on capability: it's the only one of these two that finishes a 4,685Wh Van Life Daily load without running dry, it costs less per watt-hour of capacity ($0.42 versus $0.49), and it carries a meaningfully higher power score (7,760 versus 5,220). The DELTA 3 Ultra Plus is genuinely the cheaper unit to own — $1,499 against $3,299, and $300 versus $660 per year of an identical 5-year warranty — so if your heaviest day looks like camping, a blackout, or a workday rather than daily van life, its lower price, 77.2 lbs, and 30dB rating make it the smarter buy. Pick based on your actual heaviest day, not the sticker price alone.
Editor-assigned confidence, based on cited owner research and spec analysis.
List prices as of July 28, 2026. The links below open EcoFlow's and BLUETTI's current prices.
$3,299.00 · direct from BLUETTI
Last checked 3 days ago. Prices move — check before you buy.
or check the DELTA 3 Ultra Plus price$1,599.00 list
Written by Gunner Gustafson, Whole-Home Backup Tester · Station Arena Test Desk · Updated July 28, 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 Plus rates 4.9/5 (92nd 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.
Two Very Different Lifts
The DELTA 3 Ultra Plus is 77.2 lbs — awkward but a one-person lift. The Apex 300 + B500K is 183 lbs, more than double that, and it's built to be set down once and left there.
45 Decibels Is the Number to Plan Around
The Apex 300 + B500K is spec'd at 45dB under load, 15dB above the DELTA 3 Ultra Plus's 30dB. That's the difference between background hum and a window AC unit running nearby — worth knowing if either will sit near where people sleep or work.
Same Coverage Length, Different Price of Entry
Both units carry a 5-year warranty, but that coverage costs $300 a year on the DELTA 3 Ultra Plus and $660 a year on the Apex 300 + B500K — more than double for the same length of protection.
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 Plus, 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 Apex 300 + B500K.
Check Apex 300 + B500K price →or check the DELTA 3 Ultra Plus 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 Plus is cheaper to buy, but the Apex 300 + B500K is cheaper to own. At $0.07/kWh over its lifetime vs $0.13/kWh, the Apex 300 + B500K's higher cycle life and capacity make each dollar go further over the years.
Brand trust
EcoFlow
Ecosystem
The broadest lineup in the category — DELTA Pro, DELTA 3, and RIVER 3 series plus solar panels and smart home panels, so there's a clear upgrade path within the brand.
Support
US-based phone, email, and chat support. Outcomes are polarized: plenty of easy, prepaid-label replacements, but also reports of long waits and refurbished swaps. Buying through a major retailer tends to add a stronger return safety net on top.
Community
The biggest community by far, with an active Reddit presence, multiple Facebook groups, and an official forum — the easiest brand to crowd-source an answer from.
App experience
Rated 4.6/5 iOS (~8,400 ratings) · 4.2/5 Android (~17,000 ratings)
Unique strength
Fastest charging tech in the category and the most active release cadence, with a modular ceiling that goes well beyond what this specific pairing uses.
Worth knowing
The DELTA Max 2000 was recalled in October 2025 over overheating and fire risk. It's a different product line than the DELTA 3 Ultra Plus, but it's on the company's record. EcoFlow also tested locking advanced app features behind a subscription in early 2025 before dropping the idea under community pushback.
BLUETTI
Ecosystem
One of the widest lineups in the category, from budget units up to the Apex 300, with genuine industry-firsts like sodium-ion cold-weather batteries and dual solar-plus-alternator vehicle hubs.
Support
The most inconsistent support record in this comparison, leaning email-heavy with delays tied to a distant time zone. Some buyers get smooth resolutions; others describe long troubleshooting threads and being offered a discount on a new unit instead of a repair. Buying direct from BLUETTI's own site tends to produce better outcomes than third-party.
Community
Smaller than EcoFlow's but active and growing, anchored by a dedicated Reddit community — second-most engaged brand in the category.
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
The strongest capacity-for-the-price in the market, full LFP cells across the lineup, and dual-voltage output on flagship units like this one.
Worth knowing
No official recalls on record, but older or discontinued units have gone unsupported with no spare-parts policy — worth asking about long-term parts support before buying into the ecosystem.
Analyst note
Same warranty length, very different company personalities: EcoFlow is the bigger, faster-moving brand with a recall in its recent past; BLUETTI is the better-value brand with the shakier support reputation. Neither is a clean pick on brand trust alone — factor it in alongside the hardware, not instead of it.
Growth path
DELTA 3 Ultra Plus
EXPANDABLESupports EcoFlow expansion batteries, so you can add capacity later without replacing the base unit — useful if your needs may climb past 3,072Wh.
Accepts up to 1,600W of solar. Enough for a serious multi-panel array.
Generous port selection supports complex multi-device setups.
Expansion batteries are EcoFlow-specific. You're investing in the EcoFlow ecosystem.
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
Both expand, but the Apex 300 + B500K's higher solar ceiling (2,400W vs 1,600W) 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 3 Ultra Plus
The DELTA 3 Ultra Plus is new enough to market that there's no real long-term owner chatter yet — what's available is professional and enthusiast review coverage, not multi-month forum threads. Within that window, reviewers describe it as quiet even under heavy load, on par with EcoFlow's premium DELTA Pro Ultra lineA1A2. Build quality reads as solid rather than cheap: one reviewer called the shell, buttons, and AC cable substantial and durableA8, and a separate test found it shrugging off drops and overnight dew without issueA14.
The recurring complaint is weight — reviewers consistently flag it as a genuinely heavy lift, not a light or compact unitA9. In direct sun, one tester needed to cup their hands over the screen to read the display clearlyA7, and another noted it always sheds its 30A port first if the unit gets overloaded, an odd but consistent behaviorA3. On the upside, one reviewer ran it through a full remote workday without any shutoffs or dips when unplugging it from the wall, and still had power left over by the endA5A6.
“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 · storagereview.com
BLUETTI Apex 300 + B500K
Field reports here come with a caveat: almost none of the available commentary confirms the exact Apex 300 + B500K pairing — most owner posts reference the bare Apex 300 or the Apex 300 paired with the smaller B300K battery, so treat this as base-platform experience rather than a test of this specific rig. With that said, reviewers describe the base unit's fan noise as tame, on par with the quietest units on the marketB1B2B13 — worth weighing against this pairing's own 45dB rating under load, which is the more relevant number for the stacked configuration actually being sold here.
Owners running multiple Apex 300 units in parallel report uneven charge rates between them, relying on community workarounds rather than an official fixB3B4 — a real consideration for anyone stacking toward whole-home capacity. At 183 lbs, the weight complaints track the spec sheet: one reviewer said they could barely carry it a few feet and never got it onto a tableB11. Firmware updates have occasionally locked the unit into the wrong mode or thrown inverter errors, though the threads describing these issues generally end with the problem resolvedB7B9B10. The base unit also skips USB and DC ports in favor of AC and high-voltage connectors onlyB12, so budget for adapters if you need to charge phones or laptops directly.
“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
- Professional reviewers consistently describe the fan noise as very quiet even under heavy load, comparable to EcoFlow's premium DELTA Pro Ultra line. [DELTA 3 Ultra Plus · 3 entries]
- Reviewers report solid UPS/pass-through charging performance with no noticeable switchover issues or output throttling tied to input wattage. [DELTA 3 Ultra Plus · 2 entries]
- The unit's high weight (~74 lbs) and premium MSRP are repeatedly flagged as drawbacks, though discounted street pricing is seen as making the value proposition much stronger. [DELTA 3 Ultra Plus · 3 entries]
- Build quality/durability is praised as substantial and non-fragile across multiple independent reviews. [DELTA 3 Ultra Plus · 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? · unknown · [positive]
- A2
“we'd probably say the noise it creates is similar to what you hear when you run the DELTA Pro Ultra, which is pretty amazing”
thesolarlab.com — EcoFlow DELTA 3 Ultra Plus Review: The Ultimate DELTA? · unknown · [positive]
- A3
“One weird thing we noticed was the fact that the unit always seems to shut down the 30A port first when you overload the unit”
thesolarlab.com — EcoFlow DELTA 3 Ultra Plus Review: The Ultimate DELTA? · unknown · [mixed]
- A5
“I was able to work remotely for an eight-hour day with 40% power left, which included running my laptop, desktop workstation and monitors”
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]
- A7
“while facing the sun, I had to employ the classic "cup hands cover" maneuver to get a clear look at the screen status”
appleinsider.com — EcoFlow Delta 3 Ultra Plus review: Premium, but solid power · 2025-11 · [mixed]
- A8
“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”
appleinsider.com — EcoFlow Delta 3 Ultra Plus review: Premium, but solid power · 2025-11 · [positive]
- A9
“Weighing in at a thunderous 74 pounds, the Ultra is not considered lightweight by any standards”
appleinsider.com — EcoFlow Delta 3 Ultra Plus review: Premium, but solid power · 2025-11 · [mixed]
- A14
“the Delta 3 Ultra Plus can withstand drops of up to 0.2m, and both models feature moisture resistance to mitigate risks from overnight dew”
storagereview.com — EcoFlow DELTA 3 Max Plus & Ultra Plus Review · 2025-09-30 · [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]
- 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]
- B10
“I had a power outage in the middle of the night, so I hooked everything (Hub A1 and all 300's) back up and now HA is populating. YEA!!!”
GitHub bluetti-official/bluetti-home-assistant — "APEX 300 and Hub A1 now working" (Issue #95) · 2026-05 · [mixed]
- 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]
- B12
“The Apex 300 doesn't have USB ports, DC ports, or much of anything beyond its six AC plugs and high-voltage connectors.”
The Solar Lab — "Bluetti Apex 300 Review: Cheap, Practical Home Backup?" · unknown · [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 July 28, 2026.
Who Should Buy Which
Buy the DELTA 3 Ultra Plus if you…
- →You want whole-home-adjacent backup — camping, blackouts, remote work, tailgates — without paying for van-life-scale capacity you'll rarely touch. All four of those scenarios use less than 80% of this unit's tank.
- →You're moving this thing yourself: into a trunk, up a flight of stairs, between rooms. At 77.2 lbs and 30dB, it's built to be portable and quiet, not just powerful.
- →You want the lower-risk financial commitment: $1,499 up front and $300 a year of warranty coverage, versus more than double either number for the Apex 300 + B500K.
Buy the Apex 300 + B500K if you…
- →Your heaviest day genuinely approaches or exceeds 4,685Wh — daily van life, a home leaning on it as primary backup, or running power tools and appliances for hours at a stretch. This is the one unit here built for that day.
- →You want the better per-watt-hour price on raw capacity, $0.42 against $0.49, and a higher, 2,400W solar ceiling if you plan to keep expanding.
- →You have a fixed place for it to live — a van's power bay, a utility room — because 183 lbs isn't something you relocate casually, and you're not chasing the lowest sticker price.
If neither fits
If your heaviest draw is genuinely small — a CPAP, a few devices, an occasional short outage — both of these are far more battery than you need at prices that reflect it. Look at a smaller, cheaper power station instead and put the savings toward panels or a second battery later.
The Bottom Line
Buy the Apex 300 + B500K if your heaviest real day tops 4,685Wh — it's the only one of these two that gets through that load without running dry, it's the better price per watt-hour of capacity ($0.42 against $0.49), and its solar ceiling gives it more room to keep growing. Buy the DELTA 3 Ultra Plus if it doesn't: you'll pocket $1,800, carry 105.8 fewer pounds, and still cover camping, blackouts, CPAP nights, workdays, and tailgates without noticing the difference.
Both are already big; only one of them is sized for daily van-life math. Match the battery to your actual heaviest day, not to whichever spec sheet looks more impressive.
Frequently Asked Questions
Answers drawn from the spec record and cited owner research.
Is the BLUETTI Apex 300 + B500K worth more than double the price of the EcoFlow DELTA 3 Ultra Plus?
Only if you'll use the extra capacity. The Apex 300 + B500K holds 7,884.8Wh against the DELTA 3 Ultra Plus's 3,072Wh and is the only one of the two that finishes a 4,685Wh van-life day without running dry. If your heaviest day looks more like camping or a blackout, you're paying $1,800 more for headroom both units already have.
Which one is quieter?
The DELTA 3 Ultra Plus, on paper and in practice — it's rated at 30dB against the Apex 300 + B500K's 45dB, a 15dB gap, and professional reviewers describe it as unusually quiet even under heavy load. The Apex 300's fans are also described as tame for the category, but that's evidence from the smaller base unit, not confirmed on this exact stacked configuration.
Can I actually move either of these by myself?
The DELTA 3 Ultra Plus, yes — 77.2 lbs is a real lift but a one-person job. The Apex 300 + B500K, not easily: at 183 lbs, one reviewer said they could barely carry it a few feet and never got it onto a table. Plan on a fixed spot for the Apex 300 + B500K rather than moving it often.
Which one is actually cheaper to own?
By the numbers, the DELTA 3 Ultra Plus: $300 a year of its 5-year warranty against $660 a year for the Apex 300 + B500K, because you're committing less than half the money up front. Per watt-hour of capacity the Apex 300 + B500K is actually the better price, at $0.42 against $0.49 — the two numbers answer different questions, and cost-to-own is the one that matters if you won't use the extra capacity.
Do both of these expand further?
Yes — both support add-on batteries beyond what's tested here, so neither is a dead end if your needs grow. The Apex 300 + B500K has the edge for continued growth, with a 2,400W solar ceiling against the DELTA 3 Ultra Plus's 1,600W, which matters more as the bank gets bigger and takes longer to refill.
Brand matchup
EcoFlow vs BLUETTI: measured across every matchup →Where to buy
EcoFlow DELTA 3 Ultra Plus
$1,599.00
$1,599.00 · direct from EcoFlow
Last checked 3 days ago. Prices move — check before you buy.
BLUETTI Apex 300 + B500KPick
$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.