DEOK Digital Car Voltmeter LED Red 12/24V Generator/Battery Voltage Monitor Cigarette Lighter Plug DC 8-30V

I bought this nifty little device a couple of days ago. It came well packaged so there was no chance of it breaking and was pretty descent quality for something less than a tenner. The device was fused which i thought was fantastic as electrical protection is paramount for modern vehicles these days. Nothing was wrong with my battery or alternator it was recommended by my Mechanics teacher as this can be very helpful for checking your battery voltage and alternator charge rate. When you plug in this device you should expect to see 12.1 Volts to 12.4 Volts with the car turned off, and when turned on you should expect to see 13.2 Volts to 14.8 Volts which is a healthy charge rate and maybe a bit more like 14 Volts.

Sometimes it works . . sometime not (hence 2 stars rather than 1). Normally you can tell - the car does not generate 44 volts or 66 volts and a simple unplug / replug works at the moment. Not sure how much longer before it fails completely - for me when it does I will throw it and use a wired in meter next time - but others may prefer a power socket mounted meter in which case I do not recommend this one.

Works great, smaller than expected (didn't really check the size properly beforehand) so doesn't block extra sockets in a multi 12V extension when oriented sideways. Provides a nice clear readout of car battery voltage, enabling monitoring during ignition, while stored etc. and checking for variation in voltage due to cold weather, diagnosing battery drain problems etc. A multimeter would be more versatile, but this can be constantly left in the vehicle.

plug it in and tell you the voltage on the car while it off and while it on idling it it said as what it meant to say as you can quickly check on what happening and useful for sub woofers to :D

Enabled me to diagnose a faulty alternator although no fault was indicated on the car instruments

It does what it is designed to do

good value, very easy to use and you don't have to go under the bonnet.

Excellent price and does what it says on the tin, super quick delivery too!