The Four Range Digital Control Voltmeter provides a large easy to read digital readout of AC and DC voltages up to 500 volts - ideal for EV applications. Better, it features two control relays capable of 3 amperes and programmable to any voltage level.
The voltmeter allows reasonably accurate measurement DC voltage to 0.8% and AC voltages at accuracy of 1.0% in four voltage ranges:
- -0.1999 to + 0.9999 vdc
- -1.999 to +9.999 vdc
- -19.99 to + 99.99 vdc
- -100.0 to 500.0 vdc
We use this programmable relay funciton to energize high current contactors to cutoff charging or discharging of battery cells at a specific voltage. This prevents overcharging or overdischarging of cells during a senior moment when you walk away and become distracted while testing batteries. Strictly a theoretical problem admittedly. How would I know?
An example of this is our John Deere Electric Lawnmower. We charge this to 46 volts but it doesn't even have an onboard charger. We can use any DC source above 46 volts to charge the mower, and when it reaches 46.00v the voltmeter disengages the charge contactor, disconnecting the pack from the power source. Crude, but actually very effective.
The zero volt offset can also be adjusted to effectively "calibrate" this voltmeter against a more expensive and accurate device - a Fluke Multimeter for example. On the 10v range, we get three digits as in 3.325 volts displaying to the thousandths of a volt. With careful calibration we are actually very accurate with this meter.
Powered by 12vdc from your vehicle, it is isolated causing no pack leaks to ground.
Four Range Digital Control Voltmeter User Manual