Review on 🔋 Innova 3721 Battery and Charging System Monitoring Device by Jamal Murph

More expensive than most but the rotating head makes reading easier. It also allows adjustment to avoid hitting the switch. depends on the car model. The readings were checked with a digital multimeter. There are 2 decimal places, but only 1 is needed to monitor the battery and charging system. Really cheap readers may not be reliable over time or are often not accurate. They're all Chinese and even expensive stuff can be crap, but I have Innova scanners and they're reasonably priced. Fit and finish are good. Clean the cigarette lighter contacts with wet/dry sandpaper on a non-metallic object or turn off the power by first pulling the fuse. Some cars have the cigarette lighter powered all the time, others only when the key is in the "on" position. or "Accessories". Corrosion, particularly if the lighter has been used by a smoker, will reduce readings. Rotate the tester cylinder in the socket several times to ensure good contact and check for changes. The higher the value, the more accurate.