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See the 13 tests

1. In the box
2. Fan modes & speeds
3. Noise level
4. Power source #1 – D batteries
5. Run times
6. Power source #2 – AC
7. Airflow distance
8. Base stability
9. Handle & groove
10. Waterproofing
11. Portability
12. Fan & blade size
13. Materials
14. Pros, cons, recommendations
15. Bonus – MUST read!

In the Box

I picked up this O2Cool Treva fan from Amazon, and here’s what it looks like still in its packaging:

And here’s everything I got out of the box:

• O2Cool Treva fan
• Supplied adapter (AC)

Fan Modes & Speeds

The Treva has a simple two-speed operation – high and low. I measured both with a mini anemometer:

• High 2.6-3 m/s (8.5-9.9 ft/s)
• Low 2.2 m/s (7.4 ft/s)

Noise Level

I also measured each mode with a sound meter:

• Off 40.5 dBA
• Low 53 dBA
• High 57 dBA

Not the quietest, but a relatively quiet operation.

Power Source #1 – D Batteries

This Treva has 2 power sources, and the first is via six D-cell batteries.

The battery door is at the back and held together with screws, so you’d need a multi-tool or screwdriver to get it open.

Run Times

I couldn’t find any run-time info anywhere, so I ran my own tests on the 6 D batteries:

• High 60 hrsplus about 5 hrs of very light airflow afterwards
• Low 85 hrs

Note I use Energizer Max batteries. If you use different ones, the run time will differ.

Power Source #2 – AC

The second power source is via the AC adapter that came in the box.

The other end plugs into the fan’s outlet (marked ‘9V-DC, 700mA’). Plug it in and the batteries automatically disconnect from the circuit, and the fan runs off mains power.

Airflow Distance

Using the same mini anemometer, here’s how far the airflow reached on each mode:

• High 11.5 ft
• Low 7.8 ft

That said, on high the usable airflow only reached about 6.7 feet – roughly the size of a 4-person tent. I wouldn’t recommend it in anything bigger.

Base Stability

The base isn’t the biggest – it’s actually kind of narrow, and when I bring this camping it’ll sometimes just fall over on its own, which isn’t great.

The fan on the right (yellow) is my Geek Aire Camping Fan, which is much more stable thanks to its wider base.

Handle & Groove

At the back of the Treva there’s a finger groove to place your hand and pick up the fan. Not much of a handle, but it works fine:

Waterproofing

The Treva doesn’t have an IP rating, so I tested it in 30 minutes of heavy rain, and it held up fine:

However, the battery compartment had water all around the rims, so I definitely don’t think this is built to take much rain.

Portability

Here’s how the Treva weighs in, and how small it packs down:

• Weight, with 6 D batteries 64.4 oz
• Weight, fan only 34.5 oz
• Packed size 12 x 12.75 x 2.8 in

Fan & Blade Size

• Fan face 10.25 in
• Blade diameter 9.25 in

Materials

The entire fan is plastic. It felt fine mostly, but the safety-cage grills are a little flimsy – you can press them in with a bit of force. It’s supposed to have a ‘patented fan blade design’ and ‘sturdy plastic construction’, but I think that’s just marketing.

Pros, Cons, Recommendations

Now, what are the pros and cons, and would I recommend the O2Cool Treva fan?

Low upfront cost

The number-one pro of this Treva is price, and that’s the main reason I bought it.

Note Do a quick search on Amazon for a 10-inch portable fan and this is going to be one of the cheapest ones (last checked – 2025).

Big 10-inch fan face

Even on the low mode it moves a good amount of cool air, because the face is so big – it cooled me down nicely. And the high mode delivers genuinely refreshing airflow.

Good battery life

Run-times are strong on battery power, between 60 and 85 hours depending on mode. That’s almost an entire week of camping, which is great.

Dual power sources

This is my only personal fan with two power sources:

• AC power
• D batteries × 6

Not stable on uneven ground

The base is really narrow, so a gust of wind can blow it over easily – not the best for tent camping.

D batteries are expensive

I typically pay $1 to $2 per D-battery, so this 6-battery fan costs $6 to $12 every time you power it up on batteries.

Lacks a lot of features

This fan doesn’t have many extras:

• No sleep timer
• No battery lights
• No lighting / adjustable LED lights
• No mobile charging or power bank function
• No rotation / adjustable tilt
• No warranty

Note Some fans come with lanterns or flashlights. For example, the Coleman OneSource Fan has a neat little flashlight at the bottom.

Bonus – MUST Read!

Every figure above is from my own testing — measured by hand, bought with my own money.