Gauges allow you to monitor the performance of your vehicle. The primary requirements of gauges are reliability, accuracy, and readability. Many display formats do not live up to these criteria. Panel meters are not designed to be used in vehicles. They can not function reliably for extended periods in the conditions of vibration, jostling, dust and heat that are normal in a car. LED and LCD gauges are difficult to read in the sunshine. In addition, digital gauges are harder to interpret at a glance than needle gauges. Any gauge that is not backlit will be useless at night.
The Westach gauges shown here are manufactured for electric vehicles. They feature:
- Rugged automotive quality
- Standard 2" round case
- Shielding against dust, moisture, shock, vibration, and magnetism
- Guaranteed accuracy within 2%
Notice the "upside-down" orientation of the gauge face. We had these gauges custom-built this way for better visibility when mounted below eye level, as gauges so often are in conversions.
The following are the types of gauges found in an electric car.
- This gauge gives a continuous reading of current usage. When you are coasting or sitting still, it will read zero. During full acceleration, it will peg briefly at the top of the scale, then gradually fall off as the motor achieves its optimum rpm level. When added throttle does not cause the needle to go up, you have reached the maximum potential for that gear, and it is time to shift for more power. Watching the ammeter will also help you find the most efficient gear for a particular speed, as well as the most efficient speed for a particular gear.
- This gauge measures the voltage in your battery pack and reads in percentages from full to empty. Under acceleration, it will "draw down" to a lower voltage, so it should be read when your foot is off the throttle. This gauge is more accurate than a segmented bar scale display or a sampling meter that may tend to read too low. Calibrated for 96V, 120V, or 144V systems.
High Voltage Meter
- For technophiles who want to know more detail, this gauge measures battery pack voltage and displays it in volts, to give you a running performance display.
Low Voltage Meter
- This gauge allows you to monitor the charge level of your auxiliary battery. Essential for total loss systems, it is also recommended for cars with DC/DC convertors.
- -150 - 0 - 300 amps (for Azure Dynamics AC systems with regen)
- -150 - 0 - 550 amps (for HiPer Drive AC systems with regen)
- 0 - 400 amps
- 0 - 500 amps
- 0 - 100% state-of-charge (96V, 120V, & 144v systems only)
- 75 - 125 volts
- 115 - 175 volts
- 240 - 300 volts
- 260 - 340 volts
- 6 - 16 volts
In reality, the ammeter is a millivoltmeter. This makes it possible to wire the gauge with lightweight wire instead of 2/0 cable. The shunt is calibrated to put out a specific voltage in millivolts for a specific amperage input. It is usually mounted near the controller. These Empro shunts are available to match the 300A, 400A, and 500A gauges described above.