Which extra battery fits the EcoFlow DELTA 2 and DELTA 2 Max?
Buy the DELTA 2 Max Extra Battery (2,048 Wh, $899). It fits both. On a DELTA 2 it takes a typical fridge from about 9.1 to 27 hours. A DELTA 2 Max takes two: about 18 to 53 hours.
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Price checked October 18, 2026; Amazon shows today’s price. This is the listing for the pack on its own, not a bundle with a station.
Hours count the power the station uses just to stay on. A pack adds hours, not watts: a DELTA 2 still gives 1,800 W and a DELTA 2 Max 2,400 W. Which pack fits which unit.
Which pack fits which unit
- DELTA 2: one pack (EcoFlow). Any of the three below fits.
- DELTA 2 Max: up to two packs (EcoFlow manual). The DELTA 2 Max Extra Battery or the older DELTA Max Extra Battery fits. The small DELTA 2 Extra Battery does not: EcoFlow lists it for the DELTA 2 only (EcoFlow).
| Pack | Battery | Cells | Weight | Fits | Amazon |
|---|---|---|---|---|---|
| DELTA 2 Extra Battery | 1,024 Wh | LFP, 3,000 cycles to 80+% | 21 lb | DELTA 2 | Amazon had no listing for it on its own when we checked (October 1, 2026) |
| DELTA Max Extra Battery | 2,016 Wh | NCM, 800 cycles to 80% | 40 lb | DELTA 2 and DELTA 2 Max | Older pack; we did not price it |
| DELTA 2 Max Extra Battery | 2,048 Wh | LFP, 3,000 cycles to 80+% | 42 lb | DELTA 2 and DELTA 2 Max | $899, checked October 18, 2026 |
From EcoFlow’s Smart Extra Batteries page. LFP cells last far longer than the older NCM cells: 3,000 cycles against 800. That is why we name the DELTA 2 Max Extra Battery.
How many hours each setup adds
One full charge, one appliance at a time. A typical full-size fridge averages about 83 W, because its compressor turns on and off. The CPAP is a ResMed AirSense 10 with the humidifier on, 22 W (ResMed), 8 hours a night.
EcoFlow DELTA 2
| Setup | Battery | Typical fridge | CPAP, humidifier on | Pack cost |
|---|---|---|---|---|
| DELTA 2 alone | 1,024 Wh 855 Wh usable | about 9.1 h | 3.0 nights | — |
| DELTA 2 + one DELTA 2 Extra Battery | 2,048 Wh 1,709 Wh usable | about 18 h | 6.0 nights | no Amazon price |
| DELTA 2 + one DELTA Max Extra Battery | 3,040 Wh 2,537 Wh usable | about 27 h | 8.9 nights | older pack, not priced |
| DELTA 2 + one DELTA 2 Max Extra Battery | 3,072 Wh 2,564 Wh usable | about 27 h | 9.0 nights | $899 $526 per added usable kWh |
EcoFlow DELTA 2 Max
| Setup | Battery | Typical fridge | CPAP, humidifier on | Pack cost |
|---|---|---|---|---|
| DELTA 2 Max alone | 2,048 Wh 1,727 Wh usable | about 18 h | 5.4 nights | — |
| DELTA 2 Max + one DELTA 2 Max Extra Battery | 4,096 Wh 3,453 Wh usable | about 36 h | 10 nights | $899 $521 per added usable kWh |
| DELTA 2 Max + two DELTA 2 Max Extra Batteries | 6,144 Wh 5,180 Wh usable | about 53 h | 16 nights | $1,798 $521 per added usable kWh |
Hours count the inverter’s loss and the power each station uses just to stay on (our one runtime rule). The same rule gives the hours on our DELTA 2 and DELTA 2 Max pages. Per added usable kWh is the pack price divided by the usable energy it adds. Pack price checked October 18, 2026.
A pack or a second station?
The DELTA 2 Max Extra Battery costs $521 per usable kWh it adds. A second DELTA 2 Max costs $1,029 on Amazon (checked October 18, 2026): $596 per usable kWh. So the pack is the cheaper way to add hours. A second station also gives you a second set of outlets, but it does not join the first one: you plug each appliance into one or the other.
Buy a pack when your station already starts and runs what you need and only runs out of hours. A pack will not help a fridge or pump that the station cannot start.
Questions people ask
Which extra battery works with the EcoFlow DELTA 2?
EcoFlow names three: the DELTA 2 Extra Battery (1,024 Wh), the older DELTA Max Extra Battery (2,016 Wh) and the DELTA 2 Max Extra Battery (2,048 Wh). The DELTA 2 takes one at a time. The DELTA 2 Max Extra Battery adds the most and lasts 3,000 cycles; with it a typical fridge runs about 27 hours.
How many extra batteries can the DELTA 2 Max use?
Up to two, for 6,144 Wh in all. With two DELTA 2 Max Extra Batteries a typical fridge runs about 53 hours, against 18 hours on the DELTA 2 Max alone.
How much does the DELTA 2 Max Extra Battery cost?
$899 on Amazon when we checked on October 18, 2026. That is about $521 per usable kWh it adds to a DELTA 2 Max, and $526 on a DELTA 2.
Does the DELTA 2 Extra Battery fit the DELTA 2 Max?
No. EcoFlow lists the 1,024 Wh DELTA 2 Extra Battery for the DELTA 2 only. The DELTA 2 Max takes the DELTA 2 Max Extra Battery or the older DELTA Max Extra Battery.
How long will a DELTA 2 with an extra battery run a fridge?
About 27 hours for a typical full-size fridge with the DELTA 2 Max Extra Battery, and about 18 hours with the smaller DELTA 2 Extra Battery. The DELTA 2 alone runs it about 9.1 hours.
Does an extra battery let the station run bigger appliances?
No. It adds stored energy, not output. The DELTA 2 still gives 1,800 W and the DELTA 2 Max 2,400 W with a pack attached.
Sources
- EcoFlow Smart Extra Batteries page (fit table, capacity, cells, cycles, weight; read October 18, 2026)
- EcoFlow DELTA 2 Max user manual (PDF) (up to two extra batteries)
- EcoFlow DELTA 2 Max Smart Extra Battery page
- ResMed, Power consumption of Air10 devices (1018673/1) (CPAP watts)
- Amazon listing and price for the pack checked October 18, 2026.
We did not test these stations or packs ourselves. Every maker figure names its source. Hours use our one runtime rule.