- 170W
- while running
- 1,918Wh
- used over a full day
- 15 of 15
- models we track can run it
- Best on a budgetBluetti AC708.2 hr$359Check price
- Best for a small tankEcoFlow River 3 Plus3.0 hr$299Check price
- Best for outages that last daysEcoFlow Delta 3 Plus10.9 hr$669Check price
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Runtime for every model
| Model | Runtime | Capacity | Output | Weight | Price | Per Wh |
|---|---|---|---|---|---|---|
| EcoFlow River 3 | 2.6 hr | 245Wh | 300W | 7.8 lb | $239 | $0.98 |
| Jackery Explorer 300 v2 | 3.1 hr | 288Wh | 300W | 8.2 lb | $299 | $1.04 |
| Anker Solix C300 | 3.1 hr | 288Wh | 300W | 9.1 lb | $249 | $0.86 |
| EcoFlow River 3 Plus | 3.0 hr | 286Wh | 600W | 10.4 lb | $299 | $1.05 |
| Bluetti AC70 | 8.2 hr | 768Wh | 1,000W | 22.5 lb | $359 | $0.47 |
| EcoFlow Delta 3 Plus | 10.9 hr | 1,024Wh | 1,800W | 27.6 lb | $669 | $0.65 |
| Jackery Explorer 1000 v2 | 11.4 hr | 1,070Wh | 1,500W | 23.8 lb | $499 | $0.47 |
| Anker Solix C1000 Gen 2 | 10.9 hr | 1,024Wh | 2,000W | 24.9 lb | $499.99 | $0.49 |
| Bluetti Elite 100 V2 | 10.9 hr | 1,024Wh | 1,800W | 25 lb | $489 | $0.48 |
| EcoFlow Delta 3 Max | 21.8 hr | 2,048Wh | 2,400W | 44.8 lb | $879 | $0.43 |
| Jackery Explorer 2000 v2 | 21.7 hr | 2,042Wh | 2,200W | 39.5 lb | $899 | $0.44 |
| Anker Solix C2000 Gen 2 | 21.8 hr | 2,048Wh | 2,400W | 41.7 lb | $899.99 | $0.44 |
| Bluetti Elite 200 V2 | 22.1 hr | 2,073Wh | 2,600W | 53.4 lb | $899 | $0.43 |
| EcoFlow Delta Pro 3 | 43.6 hr | 4,096Wh | 4,000W | 113.5 lb | $2,799 | $0.68 |
| Anker Solix F3800 | 40.9 hr | 3,840Wh | 6,000W | 132.3 lb | $1,979.99 | $0.52 |
Shaded rows are our picks. Assumed load: A 55-gallon tank with a 20W filter running nonstop and a 150W heater on about 40% of the time, which averages 80W.
What a tank draws
Two things in a heated tank need power around the clock. The filter pump runs all the time, at about 20W for a 55-gallon tank in our numbers. The heater is the big one at 150W, but it has a thermostat and only switches on when the water drops below its set temperature. We assume that is about 40% of the time.
20W plus 40% of 150W averages 80W. Over a day that is 1,920 watt-hours at the tank. A watt-hour is a unit of energy: one watt used for one hour. The lights are not counted. Leave them off during an outage.
Your tank will differ. The heater’s watts are printed on it, and the filter’s are on the pump label.
The heater decides the runtime
How often the heater runs depends on the gap between the room and the water. In summer it may barely switch on, and the runtime climbs toward the filter-only figure. In a winter outage the room cools and the heater works harder. If it runs 80% of the time, the average climbs to 140W, and the 10.9 hours from a 1,000Wh unit falls to about 6.2.
Tank size matters too. A larger tank holds its temperature longer than a small one, the way a big pot of soup stays hot longer than a cup. A small tank cools quickly, so it needs help sooner.
The filter-only plan
This is the biggest lever, and it costs nothing. In an outage, unplug the heater and run only the filter or an air pump, about 20W. Then wrap the tank in blankets to hold the heat in.
That cuts the draw from 80W to 20W, so any battery lasts about four times as long:
- Bluetti AC70: 32.6 hours, up from 8.2
- 1,000Wh class: about 43.5 hours, up from about 10.9
- 2,000Wh class: about 87 hours, up from about 21.8
Moving water is what the fish need first. It carries oxygen to them and to the helpful bacteria that live in the filter. Heat is the slower problem. Keep a thermometer on the tank and plug the heater back in for a while if the water gets too cool. How cool is too cool depends on the species, so check a care guide for your fish.
Why UPS mode matters here
Outages do not wait until you are home. UPS stands for uninterruptible power supply. The station plugs into the wall, the filter and heater plug into the station, and the battery takes over when the grid drops. The gap is listed in milliseconds, thousandths of a second.
Three of the picks list 10 ms and the Bluetti AC70 lists 20 ms. The Jackery Explorer 1000 v2 runs the tank for 11.4 hours, but Jackery lists no switchover time for it, so it is not a pick.
One limit to plan around: nobody is there to unplug the heater. Until you get home, the battery carries the full 80W. Size for the hours you are usually away, then switch to filter only.
Where to put it
Set the power station where a spill or a leak cannot reach it, not on the floor beside the stand. Let each cord hang in a low loop before it rises to the outlet, so water running down the cord drips off at the bottom.
The picks in detail
Anker Solix C1000 Gen 2
- 10.9 hr
- Aquarium filter and heater
- $499.99
- $0.49 per Wh
- 24.9 lb
- Weight
Left plugged in between the wall and the tank, this takes over in 10 ms when the power fails, whether or not anyone is home. It runs the filter and heater for 10.9 hours, which covers an overnight outage. Switch to filter only and it lasts 43.5 hours. A full wall recharge takes 49 minutes. The Bluetti Elite 100 V2 matches its runtime and switchover for about $11 less.
What fits
- 10 ms UPS switchover
- 10.9 hours with the heater, 43.5 hours filter only
- Full wall recharge in 49 minutes
What does not
- About $11 more than the Bluetti Elite 100 V2 for the same runtime
- Cannot be expanded with extra batteries
Anker's list price is $599.99. It has sold for under $430 at other retailers.
Bluetti AC70
- 8.2 hr
- Aquarium filter and heater
- $359
- $0.47 per Wh
- 22.5 lb
- Weight
8.2 hours with the filter and heater covers a workday or a night for $359, which is $0.47 per watt-hour. On filter only it runs 32.6 hours. It has a UPS mode, with a 20 ms switchover against 10 ms on the other picks. The trade is 2.7 fewer hours than a 1,000Wh unit, for $130 less than the cheapest one.
What fits
- $359, the lowest price that covers a night
- 32.6 hours on filter only
What does not
- 20 ms UPS switchover
- 8.2 hours with the heater, 2.7 fewer than a 1,000Wh unit
Coupon deals well under this price have appeared.
EcoFlow River 3 Plus
- 3.0 hr
- Aquarium filter and heater
- $299
- $1.05 per Wh
- 10.4 lb
- Weight
A small tank has a smaller heater and filter than the 55-gallon setup in our table, so this 286Wh unit goes further than its 3.0 hours suggests. On a 20W filter alone it runs 12.2 hours. It lists a 10 ms switchover and weighs 10.4 lb. Add-on batteries take it up to 858Wh if you want more later. At $299, or $1.05 per watt-hour, you pay a lot for each hour of runtime.
What fits
- 10 ms UPS switchover
- Expandable up to 858Wh with add-on batteries
What does not
- 3.0 hours with a 55-gallon tank's filter and heater
- $1.05 per watt-hour, the highest rate in the table
This is EcoFlow's regular price. It has sold for far less during sales.
EcoFlow Delta 3 Plus
- 10.9 hr
- Aquarium filter and heater
- $669
- $0.65 per Wh
- 27.6 lb
- Weight
On its own this gives the same 10.9 hours and 10 ms switchover as the Anker. The reason to pay more is that add-on batteries take it up to 5kWh. By the same math, 5kWh runs the filter and heater for about 53 hours, which is what a winter storm calls for when the room is getting cold. $669 is $0.65 per watt-hour, and $180 more than the Bluetti Elite 100 V2 before you buy any add-on.
What fits
- Expandable up to 5kWh with add-on batteries
- 10 ms UPS switchover
What does not
- $180 more than the Bluetti Elite 100 V2 for the same 10.9 hours
- 27.6 lb, the heaviest of the 1,000Wh units
EcoFlow's list price is $799.
Verdict
Buy the Anker Solix C1000 Gen 2, or the near-identical Bluetti Elite 100 V2 for about $11 less, to cover a 55-gallon tank through a night with nobody home. The Bluetti AC70 does a shorter version of the same job for $359. For a small tank, the EcoFlow River 3 Plus is enough. If your outages run for days, start with the EcoFlow Delta 3 Plus and add batteries. In every case, the filter-only plan matters more than the model you pick.
How these numbers were worked out. Runtime = battery capacity × efficiency ÷ average watts. We use 85% efficiency for AC outlets and 90% for DC and USB ports, because some energy is lost as heat on the way out. A model is marked "can't run it" when the device needs more watts than the outlet gives, or a bigger startup surge than the unit is rated for. Your own device may draw more or less than our assumed load, so treat these as estimates. Prices were checked on 2026-10-04 and change often. Full method
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