bayite 3 Wire 0.36" DC 0~30V Digital Voltmeter Gauge Tester Blue LED Display Panel Mount Car Motorcycle Battery Monitor Volt Voltage Meter with Reverse Polarity Protection Pack of 5

Great for B&D 20v converted tools with the "power wheels adapter". B&D Batteries or tools dont have a low voltage shutoff circuit. Relies on the motor requiring 15v. So if you use those batteries in other tools with adapters. You can drain them to a point of no recharge. This lets you monitor the voltage on tools to ensure you never drop past 16.5 volts. You are the low voltage shutoff circuit :D

Good looking blue LED display with a very small footprint. Good accuracy from 0 to 30V running off of a 5V supply. These do not measure negative voltages.

Ça m'évite de sortir le voltmètre pour vérifié l'état des batteries. Un calibrage, par contre est nécessaire pour chaque voltmètre. J'aime bien.

Keeps working down to about 3 volts, which is impressive. I compared measurements with my expensive multimeter and these little displays are satisfyingly accurate.

remarkably accurate compared to my fluke. using to monitor 12 batteries in rv.