Specifications checked against manufacturer pages on 2026-08-23.
EcoFlow DELTA 3: 1,024 Wh of LiFePO4 cells behind a 1,800 W continuous inverter, in the 1 kWh-class size. Checked against the maker’s page on 2026-08-23: every published figure, the runtimes those figures imply, and the specifications EcoFlow does not publish at all. Nothing here is a bench result, and each calculated number says so on its own row.
In short. 1,024 Wh in the 1 kWh-class band: $0.68/Wh at the list price we recorded; 37.1 Wh per pound; 4,000 rated cycles to 80%+. On our assumptions a full-size refrigerator calculates to 16–17 hr, and a 40 W CPAP calculates to 18–21 hr. The runtime figures are calculated, not measured.
Check the current price
That link points at the base unit we transcribed, not a kit with panels. Amazon prices change daily.
Who it is for, and who should skip it
The published figures answer this before any opinion does.
It fits if
- A refrigerator is what you are saving. It clears a 12-hour outage on our assumptions with about 4 hours to spare, and the stated 3,600 W surge covers a roughly 900 W start.
- One night of uninterrupted medical equipment. A 40 W machine without a humidifier runs the night with margin, and the maker states under 10 ms on the grid handover. A heated humidifier changes that arithmetic.
- The unit has to move. 27.6 lb is a two-hands lift rather than a cart job, so car to porch to basement is realistic.
Skip it if
- You want resistive heat. A 1,500 W heater empties this unit in about 0.6 hr. That is physics, not a flaw in this model.
- You own a large array already. It takes at most 500 W of solar; panels past that ceiling idle rather than charge it faster.
- Your plan involves house wiring. Nothing portable connects to a panel safely without a transfer switch installed by a licensed electrician. Settle that before buying.
Every published specification
Numbered notes give the source location or a caveat where a figure needs one. “Manufacturer does not state” marks an absence on the maker’s page; “Not yet verified by CalmWatt” marks one of ours.
| Specification | EcoFlow DELTA 3 |
|---|---|
| Rated capacity | 1,024 Wh1 |
| Usable capacity (calculated)* | 870–922 Wh |
| Continuous AC output | 1,800 W2 |
| Surge output | 3,600 W3 |
| Full recharge from wall | 56 min4 |
| Cell chemistry | LiFePO45 |
| Rated cycle life | 4,000 cycles to 80%+6 |
| UPS switchover | <10 ms7 |
| Expandable | Yes, up to 5,000 Wh8 |
| Max solar input | 500 W9 |
| Max AC charging input | 1,500 W10 |
| AC outlets | 611 |
| Highest USB-C port | 100 W12 |
| App control | Yes13 |
| Stated noise | <30 dB14 |
| Warranty | 5 years15 |
| Weight | about 27.6 lb16 |
| Manufacturer list price when checked | $69917 |
* Rated capacity × an assumed 85–90% conversion efficiency. Ours, because nobody publishes one.
Notes on the figures
- DELTA 3, rated capacity: 1024 Wh
- DELTA 3, continuous output: 1800W total
- DELTA 3, surge: Surge 3600W
- DELTA 3, full recharge: With the 1,500 W AC input setting.
- DELTA 3, cell chemistry: LFP (LiFePO4 battery)
- DELTA 3, cycle life: 4000 cycles to 80+% capacity
- DELTA 3, UPS switchover: Stated as under 10 ms; an upper bound.
- DELTA 3, expandable: Up to 5kWh
- DELTA 3, solar input: DC Charge Input, 11V-60V 500W Max
- DELTA 3, AC input: 1500W
- DELTA 3, AC outlets: 6 outlets, 1800W total (Surge 3600W)
- DELTA 3, USB-C: 2 ports, 100W Max
- DELTA 3, app: APP (TOU / Storm Warning Alert)
- DELTA 3, noise: Stated as under 30 dB at 600 W output and under 40 dB at 1,200 W; an upper bound at a stated load.
- DELTA 3, warranty: 5 years
- DELTA 3, weight: Manufacturer states ‘approx.’
- DELTA 3, price: Manufacturer list price when checked; on sale at $569 that day.
What no maker states
What a maker leaves out is a fact about the product too. What remains unanswered is a category-wide blank rather than this maker’s. That is unusual: 29 of the 34 units we have transcribed omit at least one figure, and this one omits none.
- Usable capacity. Nobody states this, here or elsewhere. The rating describes the cells, not the outlet, and the difference depends on what you plug in.
It is the one number every spec sheet in this category leaves out, and the one a buyer most wants. We show our arithmetic instead of pretending the figure is published.
What it runs, and for how long
The appliance set is fixed across the site, which is what makes these hours comparable with any other page here.
| Appliance | DELTA 3 |
|---|---|
| Full-size refrigerator 150 W, 900 W start, 35% duty · eff. 80%–87% |
16–17 hr |
| Mini fridge 70 W, 400 W start, 30% duty · eff. 70%–82% |
34–40 hr |
| CPAP without humidifier 40 W · eff. 70%–82% |
18–21 hr |
| CPAP with heated humidifier 95 W · eff. 80%–87% |
8.6–9.4 hr |
| Gas furnace blower 400 W, 1600 W start, 40% duty · eff. 85%–90% |
5.4–5.8 hr |
| 1/3 hp sump pump 500 W, 1800 W start, 15% duty · eff. 85%–90% |
about 12 hr |
| Router and modem 20 W · eff. 70%–82% |
36–42 hr |
| Laptop 60 W · eff. 70%–82% |
12–14 hr |
| 1500W space heater 1500 W · eff. 82%–88% |
about 0.6 hr |
Calculated, not measured: hours = rated Wh × efficiency ÷ (appliance W × duty). Assumptions: How we verify. “Unlikely to start” means the start-up surge exceeds the stated surge rating.
The same specs, normalized
| Measure | DELTA 3 |
|---|---|
| Cost per watt-hour | $0.68/Wh |
| Watt-hours per pound | 37.1 Wh/lb |
| Surge headroom | 2.00× |
| Recharge rate | 18.3 Wh/min |
| Rated cycle life | 4,000 cycles to 80%+ |
| Continuous watts per dollar | 2.58 W/$ |
A ratio means something only against another unit’s, so pair these with the head-to-head pages below. Definitions: How we verify.
What those figures actually mean
Cost per watt-hour: $0.68/Wh. The $699 list price we recorded over 1,024 Wh of rated capacity. Capacity alone tells you nothing about value. This does, and it moves every time the price does.
Watt-hours per pound: 37.1 Wh/lb. 1,024 Wh in 27.6 lb makes this a two-hands lift. These cells are heavier per watt-hour than the ones they replaced, and last far longer. That is the trade the cycle rating prices.
Surge headroom: 2.00×. A stated 3,600 W surge over a 1,800 W continuous rating, which covers the roughly 900 W a full-size refrigerator needs to start. A unit with hours to spare and no headroom fails in the first second.
Recharge rate: 18.3 Wh/min. A full wall charge in 56 minutes. Over a long outage, refill speed decides how long an engine runs or a cord stays borrowed.
Rated cycle life: 4,000 cycles to 80%+ capacity. At one cycle a week that is roughly 77 years away, which is another way of saying something else will retire this unit first unless you cycle it daily. The percentage matters as much as the count: two ratings only compare when they name the same remaining capacity.
Continuous watts per dollar: 2.58 W/$. This one moves opposite to cost per watt-hour on most units, so a unit can look good on exactly one of them.
Where it sits in our database
Read against our own database rather than against the maker’s marketing, the figures place like this.
| Measure | DELTA 3 | Among verified units |
|---|---|---|
| Rated capacity | 1,024 Wh | 23rd largest of 34 |
| Continuous AC output | 1,800 W | 22nd highest of 34 |
| Cost per watt-hour | $0.68/Wh | 18th cheapest of 32 |
| Watt-hours per pound | 37.1 Wh/lb | 17th densest of 34 |
| Weight | 27.6 lb | 15th lightest of 34 |
These positions describe size and price, not fitness for your outage. The row built on price uses the manufacturer list price recorded on 2026-08-23; the retail price behind our link moves independently, so recompute that row against what you are shown.
Three outages, and the figure that decides each
- One night, one CPAP. A 40 W CPAP without a humidifier calculates to 18–21 hr. The stated under 10 ms handover is what decides whether the machine notices the outage.
- Twelve hours, one refrigerator. A typical full-size refrigerator calculates to 16–17 hr, and the stated 3,600 W surge covers its roughly 900 W start.
- The loads people forget. A gas furnace blower calculates to 5.4–5.8 hr and a one-third horsepower sump pump calculates to about 12 hr. Both are hard-wired in most houses, which makes this an electrician’s question before it is a battery one. A router and modem, meanwhile, calculates to 36–42 hr.
- Three days, with something to recharge from. A full wall recharge takes 56 minutes, and it accepts up to 500 W of solar, so day two turns on your panels and your sky.
The DELTA 3 against other units
A single unit’s ratios mean little alone. These 8 head-to-head pages put the DELTA 3 against another unit on the same figures.
- Anker SOLIX C1000 Gen 2 vs EcoFlow DELTA 3
- Anker SOLIX C1000 vs EcoFlow DELTA 3
- Bluetti AC180 vs EcoFlow DELTA 3
- Bluetti Elite 100 V2 vs EcoFlow DELTA 3
- EcoFlow DELTA 2 vs EcoFlow DELTA 3
- EcoFlow DELTA 3 vs EcoFlow DELTA 3 Plus
- EcoFlow DELTA 3 vs EcoFlow RIVER 2 Pro
- EcoFlow DELTA 3 vs Jackery Explorer 1000 v2
Questions people ask about the DELTA 3
Every answer below comes from the tables above.
How long will the DELTA 3 run a refrigerator?
16–17 hr on our assumptions for a typical full-size unit at 150 W running and a 35% duty cycle. The stated surge covers the roughly 900 W start. Substitute the wattage from the label inside your door.
Can the DELTA 3 run a CPAP all night?
Yes on capacity: a 40 W machine without a humidifier calculates to 18–21 hr against the eight hours a night usually needs. The maker states under 10 ms on the handover. Add a heated humidifier and the hours roughly halve.
How long does the DELTA 3 take to recharge?
56 minutes from a wall outlet on the maker’s figure, with up to 500 W accepted from solar. That is the figure that matters once the outage passes a day.
How much does the DELTA 3 weigh?
27.6 lb on the maker’s figure, or 37.1 Wh of rated capacity carried per pound. That is a two-hands lift, which is why units this size tend to stay where you put them.
How many cycles is the DELTA 3 rated for?
4,000 cycles to 80%+ of original capacity, on LiFePO4 cells, which is roughly 77 years at one cycle a week. A figure quoted to a different retention level is a different promise, not a better one.
Can you expand the DELTA 3’s capacity?
Yes, to a stated 5,000 Wh with the maker’s expansion battery, up from 1,024 Wh alone. Expansion batteries are announced earlier than they ship; check availability.
Check the current price
That link points at the base unit we transcribed, not a kit with panels. Amazon prices change daily.
Related reading
The honest comparison is not with a bigger battery but with an engine: a 1,500 W space heater empties it in about 0.6 hr, yet nothing here vents carbon monoxide into a garage. How often gasoline generators kill indoors — and how the official count keeps being revised — is documented in our CPSC revision matrix, while our refrigerator hub ranks every unit we have verified on the same twelve hours.
Ordering before a storm? Check the arrival date at checkout — a unit that ships tomorrow can beat a better one that ships next week. Amazon Prime includes fast delivery on eligible items and starts with a free trial; we earn a commission if you join.
Sources and method
- EcoFlow DELTA 3: manufacturer product page, checked 2026-08-23.
Every quoted number comes from the maker’s page with its source sentence recorded. Every calculated number is marked as such and uses the formula above. Method: How we verify. More: Comparisons.