This is the English edition of a review from my Japanese YouTube channel, iestaLife. I review gadgets from my home studio in Japan, so product links go to Amazon Japan.
Quick take
I didn’t expect much from a clip-on phone cooler, so I tested the best-selling one on Amazon Japan, the Besecou F30, with a simple before-and-after: ten minutes of the same game without it, then ten minutes with it. The hottest spot dropped from about 45°C to just under 40°C. Not dramatic, but a real difference of around 5°C.
What I tested
- Besecou F30 phone cooler (Peltier element + fan, clamp-on), ¥2,692 in a time sale at the time of recording
- iPhone 17 Pro Max in Apple’s own case, playing the game NTE at 60 fps for 10 minutes
- First without the cooler; then I let the phone cool to just under 30°C and played another 10 minutes with the cooler on
- Temperatures checked with a thermal camera; room temperature about 22–23°C
What I found
- The cold plate works fast. Within moments the Peltier plate read around 11°C, then 9.1°C. The fan side reached about 40°C, but the unit never felt hot to hold.
- Without the cooler: about 45°C at the hottest spot near the camera (where the iPhone 17 Pro Max seems to shed heat), about 42°C on the back.
- With the cooler: just under 40°C — roughly 5°C cooler.
- Fit: I couldn’t place it over the hottest area near the camera; it doesn’t sit flush there and gets in the way of the volume buttons, so it went in the middle. With a case on, the clamp arms felt slightly short, though it never came loose.
- Noise: you can hear the fan, but with game audio on it’s barely noticeable.
- Light: it glows in seven colours and the light can’t be turned off.
- Weight: 78.6g on my scale; about 360g together with the phone and case.
- Charging: about 90 minutes to charge for about 90 minutes of use, and it works while charging. It would not charge with a USB-C to USB-C cable — use the included USB-A to C cable.
| Without cooler | With cooler | |
|---|---|---|
| Hottest spot after 10 min | About 45°C | Just under 40°C |
Who it’s for
People who play long sessions, especially while charging, or who use their phone in hot weather outdoors. If you only play briefly indoors, you may not need one. For the best effect, I’d take the case off when gaming and clip this on directly.
Watch the review
The video is in Japanese. The thermal-camera comparisons are easy to follow without words — the first gaming result starts around 05:20.
Limitations
One game, one phone, two 10-minute sessions indoors at a mild room temperature. In hot weather the difference could be larger, but I didn’t test that. Coolers like this are sold under many brand names, so check the exact listing.
Products
Besecou phone cooler F30 (Peltier): on Amazon Japan
The Amazon Japan link above is an affiliate link. As an Amazon Associate, I earn from qualifying purchases. Check the listing for the exact model, current price and shipping availability in your region.
More reviews in English
