Head-to-head test
EcoFlow DELTA Pro vs BLUETTI AC500 + 2×B300K
The extra $2,049 buys exactly one thing: the day that runs past 3,060Wh. If your days don't, you're paying about twice the DELTA Pro's rate per watt-hour for headroom you'll never touch.
Full profiles: EcoFlow DELTA Pro → · BLUETTI AC500 + 2×B300K →
Written by Gunner GustafsonUpdated
Whole-Home Backup Tester, Station Arena Test Desk
Spec deltas
$1,899 against $3,948, and the cheaper unit takes five of the six loads we run these through. The sixth is the one that matters if you live in it: a 4,685Wh van-life day, where the DELTA Pro stops 1,625Wh short and the AC500 stack is the only box here that reaches the end of it.
What the money buys is capacity, and close to nothing else. Both packs are rated 3,500 cycles, both are specified at no worse than 20ms transfer, both cap USB-C at 100W. The $2,049 gap buys 1,930Wh, which works out to about $1.06 per extra watt-hour ($2,049 ÷ 1,930Wh), roughly double the $0.53 per Wh the DELTA Pro charges for its entire battery.
It also buys 97 more pounds. The DELTA Pro is 99 lbs in one box with wheels under it; the stack is 196.1 lbs across a head unit and two batteries, built to be installed and left. You pay that weight once, getting it into position, which is the right way to think about it. If the answer to “where does this live” is a utility room, the weight is a single afternoon. If the answer is “the back of the truck, twice a summer,” it's a reason to stop reading here.
What the Numbers Reveal
Each conclusion stated first — the numbers behind it on one line, the full analysis below.
Capacity
Identical 3,500-cycle ratings mean nothing in the longevity column repays that premium. The lifetime figures, $0.15 against $0.20 per kWh, are the sticker gap divided out over the same number of cycles rather than a separate finding. So the extra capacity has to earn its keep on the days you actually use it, and only on those days.
DELTA Pro: $1,899 for 3,600Wh, $0.53 per WhAC500 + 2×B300K: $3,948 for 5,530Wh, $0.71 per Whboth packs rated 3,500 cycles
Why it mattersIf you can't name a load that runs past 3,060Wh usable in a day, you are paying a dollar a watt-hour for capacity that sits there.
solar input
A day that empties the pack has to be refilled the next morning, and every morning after that. At its 3,000W ceiling the stack can put 5,530Wh back in under two hours of full-rated input (5,530 ÷ 3,000); the DELTA Pro's ceiling is 1,600W. So for this buyer the number that matters isn't 5,530Wh at all. It's 3,000W.
Van Life Daily needs 4,685Wh; the DELTA Pro's 3,060Wh usable leaves it 1,625Wh shortthe AC500 stack covers that same day and finishes on 16Whsolar input ceilings: 3,000W for the stack, 1,600W for the DELTA Pro
Why it mattersIf you're draining a pack every day, buy the stack and the panels in the same order — without the array to feed 3,000W, the capacity advantage decays into weight.
On a $3,948 purchase the risk isn't that the hardware is bad, it's who picks up when the box on your floor won't turn on. That turns BLUETTI's own guidance into a purchase condition: buy this stack direct, or the single most likely thing to go wrong becomes the hardest thing to fix.
multiple sources describe AC500 units arriving faulty: a battery that powers up while the inverter stays dead, and one unit shipped without the cable that links the head to the batteryB6B7BLUETTI support is email-first across a timezone gap and the least consistent in the category, and buying direct produces the better outcomesEcoFlow runs US phone, email and chat support, with a split record and a stronger return net when you buy through Costco or Amazon
Why it mattersIf you're buying the stack, buy it direct and power it up the week it lands, not the week the forecast turns.
What decides it is what the thing does in a dark bedroom at 3 a.m. The DELTA Pro at least gives you a published number to hold it to, and our own line research describes a high-pitched whine above 2,000W, on sources that may actually be describing the newer DELTA Pro 3A0A4. The stack gives you no figure, plus one hands-on report that its lights alone are reason to put it in another roomB11.
a CPAP night is about 40W for eight hours, 320Wh — 10% of the DELTA Pro's usable capacity and 7% of the stack'sthe DELTA Pro publishes 60dB; the stack publishes no noise figure at allreviewers found the AC500's indicator lights bright enough and constant enough to advise against sleeping in the same room, and its fan loud in intermittent burstsB10B11
Why it mattersAnyone buying for a bedroom should hear the stack in person first, or buy the DELTA Pro and plan on it living outside the bedroom door.
The specific dimensions that decide these two units — everything else is a tie.
Your Life, Your Pick
Selected because: Five of the six loads we model fit inside the DELTA Pro's 3,060Wh usable; the one that doesn't is a 4,685Wh van-life day, and that single row is the whole case for spending $2,049 more.
Weekend Camping and Tailgate Party are settled in the driveway, not the inverter. Both units clear those loads without breathing hard, including the 400W peak the tailgate throws, which is a rounding error against a 3,600W inverter and a 5,000W one. The DELTA Pro wins them because it's the only one of the two that can plausibly come with you.
The rows that go the other way are the ones where time is the variable. On the eight-hour outage the DELTA Pro finishes with 1,415Wh, about 86% of a second night; the stack finishes with 3,056Wh, nearly two more nights like it. That distinction is invisible during a normal evening blackout and it is the entire argument during an ice storm. Decide which of those two you're actually buying for, because the scenario table says you can't have both.
Lifetime Value
Selected because: Both packs are rated 3,500 cycles, so longevity separates them by nothing and the lifetime figures are the $1,899-versus-$3,948 sticker gap wearing a different unit.
cost / lifetime kWh
A nickel per kilowatt-hour is the whole lifetime-cost difference, and it's the least interesting number on this page. Both packs carry the same 3,500-cycle rating, so the DELTA Pro's $0.15 against the stack's $0.20 isn't telling you that one lasts longer. It's telling you what you already know from the price tag, spread thinly over a decade.
Treat the real decision as the $2,049 you spend today, not the pennies per kWh you recover later. On cost-per-watt-hour the DELTA Pro is the better buy at $0.53 against $0.71, and the only thing that overturns that arithmetic is needing watt-hours it doesn't have.
What the Specs Don't Tell You
Selected because: Two warnings here actually change a purchase: 97 lbs of difference in weight, and the fact that only one of these two units publishes a noise figure.
Neither of these is a unit you pick up and carry to the car, but they fail that test in different ways. 99 lbs is one object, a bent-knees lift, and then wheels take over. 196.1 lbs is three objects that go into place separately and then don't move again. The 97 lb gap is a one-time cost on install day, which is a far smaller problem than it first sounds — unless the unit has to change rooms, in which case it's the only problem.
The noise cards are worth reading closely, because they are asymmetric in a way that flatters our pick. The DELTA Pro publishes 60dB, conversation level on paper, and published noise figures are usually a best case rather than what you hear at full output. BLUETTI publishes nothing for this stack. That's not evidence it's louder. It means the only number on the table belongs to the unit we're recommending, and if quiet is load-bearing for you, that gap has to be closed with your ears rather than a spec sheet.
Growth Path
Selected because: Both take expansion batteries, but the stack accepts 3,000W of solar against the DELTA Pro's 1,600W, and refill rate is what decides whether a big bank is usable every day.
solar input
This is the section the stack wins, and it wins it on the number nobody shops for. Both units accept expansion batteries, so both can grow the bank. Only one can grow the input: 3,000W of solar against 1,600W. Capacity you can add later; a bigger pack behind the same 1,600W ceiling just takes longer to fill.
That matters to exactly one kind of buyer, and it's the one the van-life row already identified. If your plan is to cycle most of the pack daily off the sun, the stack's ceiling is the feature you're paying for and the expansion slots are secondary. If your plan is to sit on a full pack waiting for the grid to fail, growth path is the section you can skip.
Brand Trust
Selected because: On a $3,948 box you intend to keep for years, who answers when it arrives faulty is part of what you are buying, and these two brands answer very differently.
Buy the stack and there's a specific thing to get right: buy it direct. BLUETTI support is email-first across a timezone gap and the least consistent record in this category, third-party purchase claims are where the process gets murky, and direct buyers land on the better end of it. Set against that, our research turned up AC500 units arriving with a dead inverter and one missing the cable that links the head to its batteryB6B7, which is a failure mode that puts you in the support queue before you've powered anything.
EcoFlow's record isn't spotless either, and the fair way to put it is that it's split: prepaid-label replacements that go out without an argument, and long waits with a refurbished unit against a new claim. What you do get is a US phone number, the largest community in the space if you'd rather solve it yourself, and a stronger fallback if you buy through Costco or Amazon. On a four-figure purchase that difference in recourse is part of the product.
Strengths & trade-offs
EcoFlow DELTA Pro
Strengths
- +Costs $2,049 less
- +Lighter by 97.1 lb
- +Longer warranty
Trade-offs
- –Weaker inverter (-1,400W) limits appliance compatibility.
- –Very heavy unit that may be difficult for one person to lift.
- –Can receive complaints about fan noise under heavy load.
BLUETTI AC500 + 2×B300K
Strengths
- +Larger battery capacity
- +Higher AC output
- +Faster solar charging
Trade-offs
- –Substantially more expensive (+$2,049) than the DELTA Pro.
- –Significantly heavier (+97.1 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 Pro
2,100Wh across a weekend, peaking at all of 75W, and the DELTA Pro walks it with 960Wh still in reserve. The stack has more than twice that margin and none of it matters, because 196.1 lbs across three boxes is a thing you install, not a thing you pack. This row goes to the unit that fits in the vehicle.
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
AC500 + 2×B300K
Both units sail through the night; the question is what's left at breakfast. The stack ends at 35% used with 3,056Wh in hand, close to two more nights of the same load, while the DELTA Pro's 1,415Wh is most of a second night and not a third. If your outages are measured in days rather than hours, this is the row that justifies the stack.
Battery budget usedlower = more headroom
LOAD Fridge 150W×8h · Router + Modem 20W×8h · LED Lights (4 bulbs) 40W×6h · Phone Charger 15W×3h
SCN-03 · 8 hours · needs 320Wh
CPAP Overnight
Sleep therapy without interruption — the #1 medical use case
Either unit
A 40W CPAP for eight hours is 320Wh, so both units finish the night at single-digit or low-double-digit use and capacity settles nothing. That makes this the row where the premium is hardest to defend: you'd be paying for 5,530Wh to spend 7% of it. Noise would decide it, except only the DELTA Pro publishes a figure, so the stack has to be judged with your ears.
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
AC500 + 2×B300K
The stack clears the 910Wh workday at 19% used and banks 3,791Wh, which is the wider margin and wins the row. Worth keeping in perspective: the DELTA Pro finishes the same day with 2,150Wh left, more than two more days of identical work. Both have far more slack than a laptop, a monitor and a phone will ever ask for.
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 Pro
The 400W peak here is the biggest in the whole scenario set and neither inverter notices it, with 3,600W and 5,000W of continuous output on tap. So this comes down to logistics: 670Wh of load leaves the DELTA Pro 2,390Wh spare and, crucially, 99 lbs that rolls to the parking lot. The stack stays home.
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
AC500 + 2×B300K
This is the row that separates them, and it's brutal. A 4,685Wh day asks more than the DELTA Pro physically holds, leaving it 1,625Wh short with about 65% of the day covered. The stack covers it and finishes on 16Wh, which against a day that size is empty. Buy the stack for this life, then buy enough panel to use its 3,000W input, because a pack you drain completely is a pack you have to refill completely.
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: AC500 + 2×B300K runs 22.9h vs 14.9h.
$3,948 list · direct from BLUETTI
Planning for more than this? Describe your whole setup and get it sized →
Modeled from the spec record — same math as the tables below. Methodology
Runtime by appliance
Real-world runtime estimates for common appliances, modeled at 85% inverter efficiency.¹
Essentials
The basics you need runningscale 0–313.4hComfort & Convenience
Makes off-grid life actually enjoyablescale 0–62.7hHigh-Draw Appliances
These reveal the real limitsscale 0–4.7h¹ 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
September 13, 2026
Verdict: the EcoFlow DELTA Pro
Take the DELTA Pro at $1,899. It covers the 2,100Wh camping weekend at 69% used, the 910Wh workday, the tailgate, and an eight-hour outage with 1,415Wh still in the pack, and it comes in at $0.15 per lifetime kWh against the stack's $0.20 on identical 3,500-cycle ratings, so there is no longevity story repaying the premium. The AC500 stack is the more capable machine and our composite rates it the higher of the two; it wins the rows where the day runs long, and it wins Van Life Daily outright because the DELTA Pro doesn't finish that one at all. But 5,530Wh spread across 196.1 lbs of boxes that stay where you set them is a different product from 3,600Wh you can wheel out to a campsite. If your worst day fits inside 3,060Wh usable, the stack's advantage is $2,049 of insurance against a day you don't have.
Today the DELTA Pro is $1,799, $100 under its typical $1,899 and the AC500 + 2×B300K is $3,299, $649 under its typical $3,948. The verdict weighs typical prices, not today's. Prices checked 16 days ago.
Editor-assigned confidence, based on cited owner research and spec analysis.
List prices as of September 13, 2026. The links below open EcoFlow's and BLUETTI's current prices.
$1,799.00 · direct from EcoFlow
down from $1,899 · 5% below usual
Last checked 16 days ago. Prices move — check before you buy.
or check the AC500 + 2×B300K price$3,299.00 list
Written by Gunner Gustafson, Whole-Home Backup Tester · Station Arena Test Desk · Updated September 13, 2026
Black Friday · 38 days out
Prices to beat:DELTA Pro $1,599AC500 + 2×B300K $3,299
The lowest we have recorded for each. A Black Friday price above it is a sale that unit has already had.
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.
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 rates 3.7/5 (26th percentile of 20 Home Backup-class units), and AC500 + 2×B300K rates 4.1/5 (47th percentile of 20 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.
97 Pounds, Paid Once
99 lbs is a bent-knees, two-hands lift that rolls the moment it's upright. 196.1 lbs is a head unit and two batteries, moved separately and then left alone. The useful framing is that you pay the stack's weight one time, on install day, rather than every time you use it. So the question isn't which is heavier. It's whether this box ever has to leave the room you put it in.
DELTA Pro: 60dB Is a Claim, Not a Measurement
60dB is conversation level on paper, and paper is what it is: makers usually publish a best case for this figure, so assume more than that when the unit is pushing toward 3,600W out or charging hard. It's still the only noise number on the table here, which makes it the only one anyone can be held to.
AC500 + 2×B300K: Power Lifting to 6,000W
The AC500 + 2×B300K has BLUETTI's Power Lifting mode, which runs a resistive appliance rated up to 6,000W from its 5,000W inverter. It does that by delivering less power than the appliance asks for, not more than the inverter has: the heater still works, it just heats more slowly. Two things follow. BLUETTI scopes the mode to purely resistive loads — a heater, a kettle, an incandescent lamp — so it does nothing for a fridge compressor, a pump or a power tool; for motor loads the figure to read is the AC500 + 2×B300K's separate 10,000W surge peak, not this one. And it is not a reason to size down, because running a load that big from 5,530Wh is a short session either way. Genuinely useful if a heater or a kettle is why you're buying; beside the point otherwise. The DELTA Pro publishes no equivalent.
Warranty: 5 Years vs 4
The DELTA Pro is covered for 5 years against the AC500 + 2×B300K's 4 years. An underrated factor if you're keeping this unit for years.
AC500 + 2×B300K: No Figure to Hold It To
BLUETTI publishes no noise level for this stack, and absence isn't evidence of loudness. What it does mean is that the only published figure in this comparison belongs to the unit we're recommending, which makes the section look more one-sided than the facts are. If this is going near a bedroom, a CPAP or an apartment wall, hear it running before you buy, because no spec sheet is going to settle it.
Full record above — the Test Desk pick is the DELTA Pro.
Check DELTA Pro price →or check the AC500 + 2×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 DELTA Pro wins on both sticker price and long-term value. At $0.15/kWh over its lifetime, it's meaningfully cheaper to own. Clear value winner. One thing to know reading the table: both carry the same 3,500-cycle rating, so the lifetime rows are sticker price and capacity in disguise — the wear horizon is identical and decides nothing here.
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 and chat, with a genuinely split record: some replacements ship out on a prepaid label without an argument, others turn into long waits or a refurbished unit against a new claim. Buying through Costco or Amazon hands you a second set of rules to fall back on.
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
X-Stream fast charging and the deepest ecosystem in portable power, 12 to 15 models plus panels and smart home panels, so the accessory you want in two years probably already exists.
Worth knowing
EcoFlow tested paywalling advanced app features in early 2025 and paused the plan after the backlash. Worth knowing if the app is part of why you're buying.
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
Email-first, across a timezone gap, and the least consistent record in this category. The practical move is to buy direct from BLUETTI: third-party purchase claims are where the process gets confusing, and direct buyers land on the better end of it.
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 per dollar in the catalog and the widest range of shapes in the business, including sodium-ion cold-weather units and solar-plus-alternator vehicle hubs. The app is the category's best, 4.5 on both stores.
Worth knowing
Rated cycle life varies inside BLUETTI's own ranges rather than tracking them, so check the specific model instead of the family name. Older discontinued units can also become unrepairable, with no spare-parts policy behind some of them.
Analyst note
EcoFlow gives you a phone number and an ecosystem; BLUETTI gives you more watt-hours per dollar and a support queue in another timezone. On a four-figure box you plan to keep for a decade, which of those you'd rather have on a bad day is part of the spec sheet, not a footnote to it.
Growth path
DELTA Pro
EXPANDABLESupports EcoFlow expansion batteries, so you can add capacity later without replacing the base unit — useful if your needs may climb past 3,600Wh.
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.
AC500 + 2×B300K
EXPANDABLESupports BLUETTI expansion batteries, so you can add capacity later without replacing the base unit — useful if your needs may climb past 5,530Wh.
Accepts up to 3,000W of solar. Enough for a serious multi-panel array.
Adequate ports for most setups, but heavy users may want a power strip.
Expansion batteries are BLUETTI-specific. You're investing in the BLUETTI ecosystem.
Realistic full solar rechargeat 70% of rated panel output — see methodology
Analyst note
Both expand, but the AC500 + 2×B300K's higher solar ceiling (3,000W 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 Pro
Start with a caveat, because it's load-bearing: available coverage for this unit is badly conflated with the newer, heavier DELTA Pro 3, so specific measured figures out there may belong to a different machineA0. What carries cleanly is the line's reputation as a home-backup workhorse for high-draw appliances and large expansionA1, including one account of it serving as primary backup across repeated overnight outages over a period of months, running essentials simultaneouslyA3.
The consistent knock is fan noise under load: a noticeable high-pitched whine above roughly 2,000W that's distracting in a quiet room, while lighter loads stay civilA4. Portability reads as wheeled but conditional — integrated wheels and a telescoping handle that work on flat, smooth ground and want a cart on anything roughA2. Both of those come from sources our researcher could not pin to this exact model, so take them as character rather than measurementA0.
“Long regarded as a gold standard for home backup — designed for high-draw appliances and full-scale battery expansion, running home essentials like a fridge, lighting, and a space heater through outages.”
Sources
backuppowerhub.com · us.ecoflow.co · outdoorgearlab.com · bobvila.com · powerstationadvisor.com · robbsutton.com
BLUETTI AC500 + 2×B300K
No field report exists for this exact two-battery stack. Everything we have describes the AC500 paired with a single B300K, so the qualitative findings carry across and none of the capacity or runtime numbers doB0. The richest source is one named owner's dated install log, and his verdict on it was broadly happy, including finding it quieter than a small Pecron unit he also ownsB1; a second owner reported near-flawless operation from day one with straightforward setupB12.
The complaints are specific and mostly about living with it. The fan is loud in bursts rather than constantlyB10, the status lights stay bright enough that one reviewer advised against putting it in a bedroomB11, the app covers the basics but shows only battery percentage, with no time-remaining or voltage readoutB2B9, and there's no hard-reset button to recover from a glitchB8. One owner also had to disconnect the battery to shut the unit down, because the battery keeps the BMS awakeB4, and measured it pulling roughly 30 to 35W more from the grid than the load it was serving while it idled as a standby UPSB3B5. That last one is a single install on a single-battery buildB0, but it's worth checking if this is going to be your always-on backup.
“So far pretty darn happy, and it's much quieter than the small Pecron E1500LFP I have.”
Sources
firewoodhoardersclub.com · thesolarlab.com · freshlycharged.com · diysolarforum.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
- Established home-backup platform with wheeled portability and massive expandability; the consistent knock is fan noise under heavy load. [DELTA Pro · 3 entries]
- Multiple sources report AC500 units arriving with hardware faults — a dead inverter or a missing battery-link cable — that required contacting Bluetti support. [AC500 + 2×B300K · 2 entries]
- Fan noise is intermittent but noticeable during charging/heavy load across sources, though one owner found it quieter than a competing unit. [AC500 + 2×B300K · 2 entries]
- The app covers the basics but owners want more detail (time-remaining, battery voltage), and the unit lacks a hard-reset option to recover from glitches. [AC500 + 2×B300K · 2 entries]
- A1
“Long regarded as a gold standard for home backup — designed for high-draw appliances and full-scale battery expansion, running home essentials like a fridge, lighting, and a space heater through outages.”
backuppowerhub.com / us.ecoflow.com — EcoFlow DELTA Pro review · 2025-2026 · [positive]
- A2
“Heavy but wheeled — integrated wheels and a telescoping handle help move its considerable weight, though they work best on flat, smooth surfaces; a cart is needed for uneven ground.”
outdoorgearlab.com / bobvila.com — DELTA Pro-line review · 2025-2026 · [mixed]
- A3
“Reliable through extended outage use — served as primary backup across multiple overnight outages over months, powering essentials simultaneously; LFP battery rated for thousands of cycles and 10+ years of daily use.”
powerstationadvisor.com / robbsutton.com — DELTA Pro-line review · 2025-2026 · [positive]
- A4
“Not silent under heavy load — under 2000W-plus draws the fans emit a noticeable high-pitched whine that's distracting in a quiet room, though it runs quietly enough at lighter loads.”
outdoorgearlab.com — DELTA Pro-line noise testing · 2025-2026 · [negative]
- B1
“So far pretty darn happy, and it's much quieter than the small Pecron E1500LFP I have.”
firewoodhoardersclub.com — jtakeman, "Bluetti AC500 w/B300K battery for our home backup/supplement system install and review" · 2025-02 · [positive]
- B2
“One other odd thing — it doesn't have a time-of-charge-remaining readout like my EF or Pecron units, just battery percentage. They don't even display battery voltage.”
firewoodhoardersclub.com — jtakeman, AC500 w/B300K install and review thread · 2025-02 · [negative]
- B3
“Only thing I see so far... when it switched to grid power it was drawing approximately 35 watts more than the actual usage.”
firewoodhoardersclub.com — jtakeman, AC500 w/B300K install and review thread · 2025-02 · [negative]
- B4
“Only drawback is it needs to be disconnected to shut the Bluetti unit down, as it keeps the BMS active and won't let it shut down.”
firewoodhoardersclub.com — jtakeman, AC500 w/B300K install and review thread · 2025-03 · [negative]
- B5
“Using about 31 watts an hour as a UPS — at 85% that should last about 8+ hours. Priceless!!”
firewoodhoardersclub.com — jtakeman, AC500 w/B300K install and review thread · 2025-03 · [positive]
- B6
“Got a hold of Bluetti support — seems they forgot to ship the cable connecting the main unit to the battery.”
firewoodhoardersclub.com — jtakeman, AC500 w/B300K install and review thread · 2025-02 · [negative]
- B7
“Both the AC300 and AC500 we tested had issues where the battery would turn on but not the inverter itself — dead on arrival, essentially.”
thesolarlab.com — Bluetti AC500 Review: Pros, Cons & the Ugly Truth · unknown · [negative]
- B8
“The lack of a hard reset button on these units is also really frustrating.”
thesolarlab.com — Bluetti AC500 Review: Pros, Cons & the Ugly Truth · unknown · [negative]
- B9
“The accompanying app is decent, plainly presenting all of the basic information.”
thesolarlab.com — Bluetti AC500 Review: Pros, Cons & the Ugly Truth · unknown · [positive]
- B10
“The fan can get loud, though it's only intermittent and doesn't run constantly.”
freshlycharged.com — Powering A Room with Solar: Bluetti AC500 & B300K Review · unknown · [mixed]
- B11
“The indicator lights are quite bright and remain on all the time, so it's best not to keep the AC500 in a room where you'll be sleeping.”
freshlycharged.com — Powering A Room with Solar: Bluetti AC500 & B300K Review · unknown · [negative]
- B12
“Performed near flawlessly from day one, with easy-to-understand setup and a nice app for monitoring.”
diysolarforum.com — "Bluetti ac 500" owner thread · unknown · [positive]
Research compiled September 13, 2026.
Who Should Buy Which
Buy the DELTA Pro if you…
- →The household wiring up a fridge, lights and a modem for the evening the grid drops: 1,645Wh of load leaves 1,415Wh in the pack, and the transfer is specified at no worse than 20ms.
- →The camper or tailgater who wants one box to do both jobs — 2,100Wh weekend covered with 960Wh to spare, in 99 lbs that rolls to the site instead of staying home.
- →Anyone whose honest ceiling is under 3,060Wh a day and who would rather put the $2,049 into panels, a transfer switch, or nothing at all.
Buy the AC500 + 2×B300K if you…
- →The person whose outages come in multiples, not evenings: 3,056Wh still in the bank after the eight-hour night is nearly two more nights of the same load.
- →The off-grid daily cycler with a 4,685Wh day and the roof space to feed 3,000W of solar, which is the one buyer for whom the DELTA Pro flatly does not work.
- →The installer-minded buyer who will site 196.1 lbs across three boxes once, in a utility room, and never think about moving it again.
If neither fits
If the real job is a CPAP and a couple of phones, close both tabs. That night is about 320Wh, which is 10% of the DELTA Pro's usable capacity and 7% of the stack's, so you'd be buying a pallet to carry a grocery bag; a small LFP unit does it for a fraction of the price, and you can lift it with one hand. The same goes if your picture involves carrying power somewhere on foot, since 99 lbs is the light one here.
The Bottom Line
Buy the DELTA Pro. It covers the weekend, the workday, the tailgate and a normal night without power, it costs less than half what the stack costs, and it does all of that on the same 3,500-cycle rating as the box that charges $0.71 per Wh to do it. The AC500 stack is the stronger machine and our composite rates it higher, but stronger and worth-buying are different questions, and most people reading this page are looking at a fridge, a modem and a long evening.
One thing would change the answer: a 4,685Wh day, repeated. That's van life, a workshop, an off-grid cabin, and on that day the DELTA Pro stops well short while the stack finishes with nothing behind it. If that's your life, buy the stack, buy it direct, and buy the panels to match its 3,000W ceiling in the same order. If it isn't, the DELTA Pro is the answer, and the money you didn't spend is better off on a roof.
Frequently Asked Questions
Answers drawn from the spec record and cited owner research.
Is the BLUETTI AC500 with two B300K batteries worth $2,049 more than the EcoFlow DELTA Pro?
Only if your day is bigger than 3,060Wh, which is the DELTA Pro's usable figure after the flat 85% derate we apply to every unit on the site. Five of the six loads we model fit inside it. The price gap works out to about $1.06 per extra watt-hour ($2,049 ÷ 1,930Wh), roughly twice the $0.53 per Wh the DELTA Pro charges for its whole battery. Buy the stack when you can name the load that needs it, not as insurance.
How long will each one last in a blackout?
On the eight-hour outage we model — 1,645Wh of energy, peaking at 150W — both finish the night comfortably. The DELTA Pro ends at 54% used with 1,415Wh left, about 86% of a second night. The stack ends at 35% with 3,056Wh, close to two more nights like it. The DELTA Pro handles a normal outage; the stack handles the kind that makes the news.
Which one is quieter, the DELTA Pro or the AC500?
There's no honest way to answer that from the spec sheets. The DELTA Pro publishes 60dB, which is about conversation level and, like most published noise figures, is closer to a best case than to what you hear at full output. BLUETTI publishes no figure for this stack, so there is nothing to compare it against. If quiet is part of why you're buying, hear the stack in person before you commit.
Can one person move the AC500 + 2×B300K?
In pieces, over more than one trip. The 196.1 lbs is a head unit plus two batteries rather than a single object, and BLUETTI designs this as a stationary install. The DELTA Pro's 99 lbs is one box, still a two-hands lift, but it rolls once it's upright. If the unit has to change rooms more than once a year, that difference decides this comparison on its own.
Do both work as a UPS for a computer or a CPAP?
Both are specified at no worse than 20ms transfer, so on paper neither should let a desktop or a CPAP notice the grid dropping. Capacity isn't the question for that job either: a CPAP night is about 320Wh, 10% of the DELTA Pro's usable and 7% of the stack's. One owner's install log did measure the AC500 drawing roughly 30 to 35W more from the grid than the load it was serving while idling as a standby UPS, on a single-battery build rather than this two-battery one, which is worth verifying if it will be plugged in permanently.
Brand matchup
EcoFlow vs BLUETTI: measured across every matchup →Where to buy
EcoFlow DELTA ProPick
$1,799.00
$1,799.00 · direct from EcoFlow
down from $1,899 · 5% below usual
Last checked 16 days ago. Prices move — check before you buy.
BLUETTI AC500 + 2×B300K
$3,299.00
$3,299.00 · direct from BLUETTI
down from $3,948 · 16% below usual
Last checked 16 days ago. Prices move — check before you buy.
Prices may vary by retailer and are subject to change.