EVisionTM

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METRIC MIND ENGINEERING PRESENTS

EVision^{^TM} is very versatile and sophisticated instrument which allows monitoring, accurately measure and record many parameters related to an EV traction battery. It is designed mainly for use in pure electric vehicles, but since it is primarily a battery performance instrument (not a vehicle performance), it can be used in electric boats, buses, motorcycles, any type of hybrid vehicles, or in general in any application (including stationary) where its battery parameters have to be monitored.

MMC is releasing second generation of EVision. Similar to the first generation, it meant to replace older e-meter type of gadget and thus provides many more functions and flexible user configurable display options while getting rid of numerous e-meter shortcomings. EVision^{^TM} 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 viewed at once on bright multicolor LED display - two parameters using digital readout (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, creating custom "page". 20 such combinations (pages) are stored in memory and can be recalled and selected by either touching an HMI rotary encoder switch, or optional push buttons mounted remotely. Communication between main controller, HMI and Display modules is implemented via CAN bus. Communication between shunt measurement board and main controller is via fiber optic link.

EVision^{^TM} is equipped with vehicle's stock analog fuel gauge driver allowing using existing fuel gauge on the dash as traction battery SOC monitor. The instrument is powered solely from the traction battery pack via integrated isolated DC-DC converter handling 60VDC...900VDC traction battery voltage span and does not require any other external power to function. It will also monitor and display status of auxiliary onboard 12V battery, but does not use it as power source. Power consumption is about 3 W in running mode and about 300 mW in sleep mode.

EVision^{^TM} is also equipped with galvanically isolated standard RS232C serial interface suitable for capturing continuously streaming data, configuring unit and updating its firmware. All streaming values are date/time stamped and always outputted (in readable NMEA ASCII format) whether acknowledged/captured or not. Corresponding PC software with GUI is included, but data capturing can be performed using any serial comm software such as Z-terminal for Mac or similar software for Linux.

EVision^{^TM} consists of 4 sub-blocks: main controller, HMI (remote user interface via rotary encoder) shunt measurement PCB and external or in-dash multi-color LED display. Optional speed sensor is required for computing driving efficiency as well as speed and distance. PCBs are sold either without enclosures (to be installed in the battery or contactor box compartment and under dash) or with optional machined enclosure.

Here is the testimonial of the first beta tester John Wayland who installed and evaluated EVision^{^TM} in his White Zombie - first world's quickest street legal electric drag racing vehicle.

Specifications for production units are listed below.

Measured and displayed parameters:

Traction battery

Instantaneous traction pack voltage, V
Instantaneous driving current in or out, A
Instantaneous charging current, A
Instantaneous power in or out, kW
Running Coulomb capacity Ah
Running energy, kWh
Running State Of Charge (SOC), %
Temperature (highest of 2 zones), °F or °C
Indication of direction of battery current, OUT (drive) or IN (regen or charging)
Battery Cycle counter, full cycles
Traction battery imbalance detection and measurement
TTF (Time to Full) estimation in charging mode
Indication of charging status
Automatic drive/charge/idle mode detection

Auxiliary 12V battery:

Instantaneous voltage (V)

Vehicle:

Current vehicle speed^¹
Energy consumption, Wh/mile and/or miles/kWh
Odometer and Trip Odometer function
DTE (Distance to empty) estimation
Night time display dimming and HMI illumination
Sleep with wake up on ignition or charge
No power consumed from onboard auxiliary 12V battery, no such battery is required for full functionality.
Power steering pump programmable drive

Instrument

Streaming running data out from the serial port
Download and Upload instrument configuration parameters, user preference, battery and vehicle parameters
Long retention of internal RTC setup for correct time stamping without power applied (~ 1 week).

External controls:

Stock analog fuel gauge drive
Charger disconnect Itimer) after predefined charge is completed

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).

Main improvements of new production EVision-2 include:
- New brighter LED display appearance - now user can request any RGB color display with standard being blue and white. Here is example of randomly applied colors - any feature on a display can have its own individual color per request.
- Dual shunt measurement circuitry improving accuracy of tracking relatively low charging current (0...40 A and 0...100 A ranges) while extending accurate measurement range of drive/regen current up to 4,000A.
- Widest in industry traction battery working voltage span - 65...900 VDC is handled.
- Electrical noise immune fiber optic link between shunt measurement unit and main controller/display improves safety and robustness, especially for high power applications (sport performance or drag racing EVs, trucks/buses, etc).
- Addition of "favorite" buttons allowing quickly get to the home page and increment/decrement pages thus eliminating need to use rotary encoder. Now either (or both) control methods can be used.
- Addition of opto-isolated charger control output (charger enable).
- Addition of opto-isolated programmable power steering control output (OEM option).
- Measurement board and Main controller units now can optionally be placed into machined enclosure.
- User-upgradable firmware via secure bootloaders.

Display color	Specified by user at the time of purchase. Standard colors are White, Yellow, Red, Green Blue, Purple. Any other RGB color - on request.
Measured battery current (drive/regen)	+/- 0.1 A...4,000 A (ranges 200, 500, 1000, 2000, 4000 A). Accuracy is 1% of top scale.
Measured battery current (charging)	- 0.1 A...100 A (ranges 40A, 100 A). Accuracy is 1% of top scale.
Measured traction battery voltage	60...800 VDC continuous, 900 VDC peak.
Measured aux. 12V battery voltage	0...16 VDC
Measured traction battery capacity	0...999 Ah
Measured traction battery energy storage	0...999 kWh
Measured traction battery relative SOC	0...100%
Measured traction battery power	+/- 0...2000 kW
Measured temperature	-35°C...+99°C
Full charge cycles counter	0...65535 cycles
Vehicle speed displayed	0...450 MPH (US), 0...600 km/h (EU)
Trip odometer max value	999 miles (US), 0...999 km (EU)
Power supply current (from traction pack)	9 mA @ 350VDC, 30 mA @100 VDC (running mode)