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``` 本製品は高性能ペルチェ素子(24W/40*40㎜TEC)を内蔵されたiPhonePromax,Plusやタブレットクーラーです。電源を入れて3秒ほど驚異的な冷却効果を発揮します。 対応機種:タブレット/iPad/iPhone12以降型番Promax,Plus/Switch/Kindle 冷却効果:本機40℃降下 冷却方式:ペルチェ素子 冷却モード:三段階(静音16W;4000RPM/冷却20W;6000RPM/極冷24W;8000RPM) 固定方式:ゴムベルト/磁気吸着式 寸法質量:約109g、約幅72×奥行72×高さ32mm(伸縮ゴムベルトを除く) ``` Moss in a terrarium apparently does poorly above 30°C, although the species makes a big difference.Related product listings: Search Amazon for small 3.5L tanks (Ad)
 The cooler was an unfamiliar Chinese brand sold on Amazon. These products seem to be made entirely in China.  I cut a hole in the tank's included cardboard and fitted the cooler. I attached four small aluminum fins to its cold side. Within a few minutes, it became very cold and condensation formed. That could also supply moisture.Related product listings: Search Amazon for small aluminum heat sinks (Ad)
 I placed temperature/humidity meters inside and outside to compare the readings.Related product listings: Search Amazon for temperature/humidity meters (Ad)
 Glass has relatively low thermal conductivity and the lid was cardboard, but I hoped the small tank would cool to some extent. **Test 1: one hour** - **Inside the tank:** - Start: 26.1°C at 15:00 - After one hour: 24.1°C at 16:00 - **Outside the tank:** - Start: 26.5°C at 15:00 - After one hour: 27.0°C at 16:00 After an hour, it was 27.0°C outside and 24.1°C inside, apparently a difference of nearly 3°C. The meters differed by 0.5°C at the start; treating that as measurement error and subtracting it gives about 2.5°C. The USB cooler starts automatically when powered on, in its low mode at 15W. The button increases cooling to medium at 20W or high at 25W. A smart adapter can turn power on and off but cannot press the button, so I tested at 15W. The result seemed questionable, so I tried again another day. **Test 2: four hours** - **Inside the tank:** - Start: 26.0°C at 12:00 - After four hours: 24.8°C at 16:00 - **Outside the tank:** - Start: 27.7°C at 12:00 - After four hours: 28.5°C at 16:00 The temperature inside stopped falling after about an hour. My impression was that it cooled by roughly 1–1.5°C. I could not tell whether this was the Peltier unit's limit or the tank's poor insulation limiting the inside/outside difference. That is probably about what to expect. It is a Peltier cooler, after all. Considering how simple a USB unit is, the result was reasonably good. It can cool the tank a little, if only for peace of mind. There also seemed to be a time lag between the inside and outside temperatures. At about 07:30, both read 23°C. The inside appeared to warm about an hour later than the outside. **Test 3: four hours** - **Inside the tank:** - Start: 24.0°C at 12:00 - After four hours: 23.7°C at 16:00 - **Outside the tank:** - Start: 24.5°C at 12:00 - After four hours: 26.6°C at 16:00 I still could not tell how much was error, but perhaps the cooler kept it about 2°C below where it would otherwise be. Assuming electricity at ¥27 per kWh, the calculation gives roughly ¥0.4 per hour, or ¥4 for ten hours a day. Very cheap, but was that right? The adapter became extremely hot, which made me wonder.Tablet USB Peltier cooler listingsBrowse listings on Amazon Ad · Amazon Associates link