I bought a cheap Chinese digital thermometer like this one
with this description Link to product
Power Type: Button Battery Model Number: Thermometer Max Measuring Temperature: 50°C - 69°C Style: Handheld Theory: Temperature Controller Display Size: 2.0 - 3.9 Inches Display Type: Digital Usage: Indoor
100% brand new and high quality. Quantity: 1 Measuring temperature range: -50Celsius~110Celsius Temperature accuracy: ±1 Celsius Temperature display resolution: 0.1 Celsius Operating voltage: 2 x 1.5V button LR44 batteries Dimension: 48×28.6×15.6mm(approx.) LCD dimension: 36×16mm(approx.) Operating Voltage: 1.5v, LR44/AG13(Include Cable length: 1m Color: Black
1X Mini Thermometer Hygrometer Temperature Meter Digital LCD Display
It does not have a Hygrometer as far as I know.
It has a probe wire length of about 1 meter. I wish to use it to find the temperature in the storage tank of a solar water heater about 20 meters away. My question is - can I just extend the wire (2-core wire) without affecting the temperature measurement? I looked up Amazon product reviews for similar products (not sure they are the same on the inside), but I didn't see any reviewers having extended the wire more than a few feet.
Also, what power supply can I use instead of LR44 cells. I cannot make out the chip inside, though some reviewers on Amazon have stated that anything upto 30 Volts would work.