METRIC MIND ENGINEERING PRESENTS |
| EVisionTM is sophisticated instrument which allows to monitor, accurately
measure and record many parameters related to a traction battery. It is designed primarily
for use in electric vehicles, but since it is primarily a battery performance
instrument, it can be used in an electric boat, bus, motorcycle, any type of hybrid
vehicle, or in general in any application (including stationary) where its battery
parameters have to be monitored. As a vehicle instrument, it meant to replace e-meter type of gadget and thus provide many more functions and flexible user configurable display options while getting rid of numerous e-meter shortcomings. EVisionTM not only acts as a "fuel gauge" of an EV or HEV, but also tracks (and logs with external PC) about 15 different parameters. Any three parameters can be displayed at once - two using digital readout (two 3 digit 7-segment LED displays) and one - using 25 segments analog bar. User can assign any 3 of about 15 parameters to any of 3 displays (where respective unit identifiers are available) to be displayed at once, creating custom "page". 20 such combinations (pages) are stored in memory and can be selected at the touch of remote rotary encoder switch. In addition, EVisionTM is equipped with vehicle's stock analog fuel gauge driver allowing using for instance existing fuel gauge on the dash as traction battery SOC monitor. The instrument is powered solely from the traction battery pack via internal isolated DC-DC converter and does not require any other external power to function. It will monitor and display status of auxiliary onboard 12V battery, but does not require it as a power source. EVisionTM is equipped with galvanically isolated standard RS232C serial interface for capturing streaming data, configuring unit and update the firmware. All parameters and values are date/time stamped and continuously streamed out in NMEA ASCII format whether acknowledged/captured or not. Corresponding software with GUI for a PC is included, however because it is only an interface for serial comm routines and actually Windows HyperTerminal handles communication, identical job can be performed using any serial terminal software such as Z-terminal for Mac or any serial comm. pack for Linux. Here is the testimonial of the first beta tester John Wayland who installed and evaluated EVisionTM in his White Zombie - first world's quickest street legal electric drag racing vehicle. Specification for pilot pre-production units is listed below. Measured and displayed parameters: Traction battery
Auxiliary 12V battery:
Vehicle:
Instrument
External controls:
EVisionTM consists of at least 4 sub-blocks - main controller, HMI (remote user interface via rotary encoder) shunt measurement PCB and external or in-dash display. Optional speed sensor is required for efficiency and distance estimation calculations. Inter-component communication is implemented via CAN bus. Front end measurement hardware is based on BRUSA Ah counter shunt and measurement PCB to maintain backward compatibility with legacy BRUSA Ah counters. Thus existing BRUSA Ah counter owners can keep their measurement board with shunt and upgrade only EVisionTM display and main controller. Display comes in 2 flavors: external in a spherical enclosure and internal - without enclosure (for in-dash integration). 12V auxiliary battery voltage is monitored, but not used to power EVisionTM. In fact 12V power doesn't have to be present for proper instrument operation. The power is supplied directly from the main traction pack and the power consumed is about 2 W in running mode and about 300 mW in sleep mode. On this example of external display, vehicle efficiency (Wh/mile - US version) is configured for upper display, battery power (kW) - for lower display and battery relative state of charge (%SOC) - for the analog bar, acting as a fuel gauge. Relative SOC level is also outputted through the analog gauge driver as PWM signal. 1 US models display Imperial units (distance - miles, speed - MPH, temperature - °F) while EU models display metric units (distance - kilometers, speed - km/h, temperature - °C). 2 Speed sensor required (included with all M3 models). |
