Because I drive a lot in the short haul winter and therefore the fear have my battery would falter I bought this chic voltmeter for the cigarette lighter. Although very cheap the accuracy of the voltmeter is (compared with newly calibrated voltmeter) better than 0.1V (as konreter value 12.08V be as 12.0 V 12.09V but already as 12.1V as shown). The accuracy which is more than sufficient to detect a weak battery. The temperature display I could not test against a calibrated measuring device, but it should be noted that the temperature sensor is externally attached to a short cable and you therefore do not measure the internal temperature of the cigarette lighter but actually an air temperature when abspreizt the cable slightly. For well under ten euros each incl. Shipping costs I have it equal again 2 ordered as a small gift for two friends. Subsequent note: after I ordered 2 pieces, I can say that all 3 devices at the voltage having a very good accuracy. all 3 devices have an accuracy of better 0.1V at 12.1 V. Device 1: 12.1 V appears in fact from 12.09V Unit 2: 12.1 V appears in fact from 12.08V Unit 3: 12.1 V appears in fact from 12.12V Temperatures I have now compared to a temperature sensor with a nominal + -2 ° C accuracy. All 3 were in a range from + 1 ° C within this comparison device. The model that I myself use shows after a long time about 1 to 2 ° C more than I set in my regulated air conditioning in the car. Ie I am for the price very zufrienden with my purchases.
