Car Charger - JEBSENS - 4in1 3.1A Fast Dual USB Car Phone Charger, Voltage Meter Monitor USB Car Charger for Smartphone with Blue LED Voltage Amps and Internal Temperature(Fahrenheit) Display - 15W

I have been using for 3 months to monitor the 12V AUX battery in my Electric Vehicle. I did extensive bench test on the accuracy and use of the functions before placing in the vehicle.The voltage read out is accurate within 1 digit compared to a .05% voltmeter. It does read low about 0.1 Volts due to contact resistance if the USB output is usedUSB charging works OK on bench test although I didn't receive the stated charging current as measured by the display current. I did not bother checking the accuracy of the current display as this function is of no interest to me as I have other better methods of charging USB devices in the vehicle.The temperature readout is a disappointment. I chose this unit from among others because I thought the cabin temp readout would be nice. I realized that having the temp sensor embedded in the electronics would have issues. On Bench test without the usb being used it appears it is calibrated about 10F low, and is reasonably close at room temperature when charging with USB at 1 amp; but other times shows 10F high. So at best it can tell if it is really cold or really hot.Another disappointment is display readability. Readability was superior and exceeded my expectations during bench test. In the vehicle it is OK at night or cloudy. Not a fault of the device is that due to position in vehicle and "old eyes" it is not usable while driving in bright sunlight.;tldr & conclusion works great for my primary purpose and needs

I’m still using this years later, but be aware that it’s not as rugged as it could be. Plastic is a bit “iffy”.

After a few days of use I very much enjoy this product. I currently have it plugged into a 12 volt automotive outlet that is powered only during key on. I would like to relocate it to higher up on the dash where I can more easily view the readout. I am also considering plugging it into a constant 12 volt source so it will keep charging my devices when I leave the vehicle and so I can read the display without having the key on.I have used the USB charger everyday for iPhone 4S and iPad 2 devices, but only one at a time. I enjoy being able to read how many amps the device is pulling during its charge. I also enjoy the thermometer. My main interest was for the volt meter display.The voltmeter has a letter at the end of the readout that looks more like a U than a V. I have checked its accuracy against my laptop connected to the vehicle via the OBDII port and the two are within a couple fractions of a volt most of the time. The blue LED readout matches many of the other gauges and chargers I have in my truck including the display on my stereo's head unit.The display cycles through the vehicle's electrical voltage, amps being drawn via the USB port, and a thermometer. It displays each readout for a few seconds before going straight to the next. It would be nice to be able to cycle through the readouts manually and to hold a single readout but for the price it's hard to complain.I like this device enough that I have shown it off to a couple people. They are amazed that it was only $10.I purchased a second device for my father. Mine is now installed in a constantly hot 12 volt socket so I have a constant reading and can charge USB powered devices all the time.

Very high quality product. LED display is excellent as are the USB charging features. Battery volt meter is also a very nice to have feature for many cars. Having all these features crammed into such a small well built device make this a very unique almost must have product. Product cycles between - car battery voltage, interior temperature, and USB charging amps.As for the USB charging - I load tested the USB ports and it does meet the specs exactly as described. This is important because many other products I've bought that are similar do not actually perform as claimed. Having the correct USB charging amps is especially important if you want to charge or use higher load devices like tablets while on the go. As others have noted the thermometer is on the inside and the electronics of its own display heat it up a little causing a slightly off reading.. Very good though for the initial reading when you first get into your hot/cold car.. Otherwise as its electronics and its LCD display heats up the thermostat usually reads about 2-3 degrees hot. Anyway this is an extremely minor complaint. If you think about it the only other alternative to this would be having the thermometer wired externally but that would be both aesthetically unpleasant and not very durable. I certainly wouldn't want any more wire zoo hanging out in my car for an external thermometer - so overall the approach taken by this product wins out compared to others I saw while shopping for this device. Anyway this minor problem is easy to work around. Just remember in practice to subtract 2-3 degrees from the actual temperature reported.Anyway - very good combination of features. Very high build quality. Build quality was higher than expected. Even the picture doesn't do justice in this regard.

It works as it should but there is no button or function to choose what it will display e.g. you will have to wait for it to cycle through voltage, temperature and amps. Not a big deal but would like to have a button to set just to display voltage all the time.

Il prodotto mi ha molto deluso. L'intensita' luminosa è troppo bassa, con la luce del giorno non si distinguono bene le cifre. La temperatura è espressa in fahrenheit e quindi completamente inutile a meno di non munirsi di un app per convertire; ridicolo!!. Le cifre ciclano in continuazione tra voltaggio temperatura e amperaggio e non c'è modo di bloccarlo sulla misura che interessa, e ogni volta che si osserva ci si trova nella misura che non interessa magari la temperatura farheneit.

in macchina sempre attaccato funziona