EV1Dash for Palm OS
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EV1Dash for Palm OS

EV1Dash is a program for Palm OS devices that will collect data from the EV1 and display it on the Palm OS device display. The intent is to provide more information to the driver so that range and performance can be optimized. Here is one of the displays. There are two other displays. One replaces the range estimates with amp hour information and the other shows the stream of bytes in a more raw format.


Release Notes

Frequently Asked Questions

Installation in the EV1


The display shows the following information:

  • Amps
    The amps currently being draw or put back into the pack is shown. Negative numbers indicate amps are being drawn from the batteries. Positive values indicate recharging is taking place. It very important to know how many amps are being drawn when trying to figure out what the maximum range.
  • State of Charge (SOC)
    The bar indicates the current state of charge of the pack. A little game I play is to see what how small I can get SOC drop to be on my commute to work. Having the SOC in 1% increments helps a lot.
  • Power Use Range Estimates
    There are 3 power use range bars; one for the instantaneous use, one for the last kilometer, and one for the whole trip. To the left, below the bar is the range the pack would contain if that power setting were maintained. The number on the right side below the bar is the range remaining in the pack based on the power setting.
  • Voltage
    Pack voltage.
  • Trip Distance
    Distance used for calculation of range and estimated battery capacity..
  • Battery Capacity
    The calculated battery capacity available to the user when fully charged. This is based on the amps drawn so far and the SOC. Optimally you should see 45Ah (53Ah * 85%) here after the batteries are broken in. If the capacity drops too low then there may be something wrong with the battery pack. Remember that capacity is effected by temperature. Please don't call GM until you are sure the numbers you are seeing are really abnormal.

Release Notes

  • Version 1.7.1 (9/9/2000)
    • Very minor change. The application now has a name.
  • Version 1.7 (8/11/2000)
    • Removed temperature. I could not figure out what GM was doing to the value which no longer seems reliable or accurate.
  • Version 1.6 (2/17/2000)
    • Added preferences form so that battery parameters can be customized.
    • Added help menu and help to forms.
    • Additional information is saved when the program is left for another application.
    • New event handling code.
    • Temperature and instantaneous range should now work on the new NiMH cars.
  • Version 1.4b3 (7/14/99)
    • Another adjustment to the charge time estimates (probably not enough)
    • Fixed some odometer display bugs
    • Fractional bar display bug fixed for values of 45% and below
  • Version 1.4b1 (5/25/99)
    • Improved charge time estimates
    • Fixed some drawing bugs
    • Added block receive indicator to raw block display mode.
  • Version 1.3.4 (5/18/99)
    • Removed the bar marks from the SOC display and added a horizontal bar indicator at the top of the SOC display.
    • Added time to charge information on the charge screen.
  • Version 1.3.3 (3/3/99)
    • Removed 3.0 OS font which caused a crash on older systems.
  • Version 1.3.2 (2/20/99)
    • Fixed a bug that caused the pilot to go to sleep if the voltage and amps did not change.
  • Version 1.3.1 (2/13/99)
    • Fixed a bug in the new block display.
  • Version 1.3 (2/10/99)
    • Added a new display option that shows all the data blocks in a tabular format.
    • Fixed a recording bug that caused to many samples to be taken.
  • Version 1.2.2 (12/1/98)
    • Fixed bug where capacity and ranges did not show the correct values after 20% change in SOC.
  • Version 1.2.1 (11/29/98)
    • The freezing problem has been fixed. (I think. Its certainly improved if nothing else.)
    • Drawing of SOC bug fixed. It now refreshes when changed.
    • New marks were added to the SOC display. They are somewhat redundant but added to match the cars display more closely.
    • Automatic trip reset is now an option.
    • Out of memory crash fix when recording has been made. This has not been tested. Please send in reports on how well it works or doesn't work.
  • Version 1.2 (11/21/98)
    • Added outside air temperature. Note that it reads high while charging due to the location of the temperature sensor.
    • Added extra digit to the power display.
    • The initialization spike is now ignored.
    • The date was added to the top of the log file.
    • Automatic reset now asks for confirmation before resetting.
    • Bar markers were added to the SOC display. These show where the real SOC bars map to the SOC display on the EV1Dash program.
    • The SOC digits are larger.
    • An optimum power diamond has been added to the instantaneous range bar. This is the range the car should get at the current speed on a flat road.
    • SOC now shows negative numbers when below 0 user SOC. Useful when below the 3 diamonds and 0 bars.
  • Version 1.1 (10/8/98)
    • Amp hours updates more frequently while charging.
    • Corrected regen and recharge effect on drain.
    • Added support for a tap on the range/numeric display to switch displays.
    • Added support for a tap on the SOC to toggle power adjusted SOC.
    • Added small 'P' in upper right corner is SOC is power adjusted.
  • Version 1.0.7 beta (10/2/98)
    • Fixed the bug related to range estimates after recharging.
    • Changes the battery capacity calculation to user capacity instead of full capacity.
    • Added options for power adjusted SOC values.
    • Added an optional display.
    • Added confirmation dialog window for removing records.
  • Version 1.0.6 beta (9/11/98)
    • Improved the calculation for the effect of regen on range and capacity.
    • Added additional triggers (odometer and SOC change) for generating a sample for recording.
  • Version 1.0.5 beta (9/6/98)
    • Fixed the amp reading on the sample data records.
  • Version 1.0.4 beta (9/4/98)
    • Removed the flicker from the values near the bottom of the screen.
    • Fixed the odometer problem that occured for odometer values over 65535 Km.
    • Reversed the direction of the amp bar.
    • Added power to charging screen.
    • Changed the recorded information to include odometer and speed. The fields were also changed.
    • The state of recording is now remembered.
    • There is still a bug that causes data to be invalid after charging.
  • Version 1.0.3 beta
    • Changed the display to show Amps in much larger font. SOC font is also larger in this version.
    • State is remembered when the program is restarted.
    • Separate display added for charging.
    • Kilometer to miles conversion is more accurate and closer to the EV1 conversion. It still might be off a little at the higher mileage.
  • Version 1.0.2 beta
    • Fixed a bug where the trip distance was incorrect after the trip reset if the Pilot was not receiving data.
  • Version 1.0.1 beta
    • Added carriage return to the data transfer for PC users (I'm a Mac user)
    • Added trip distance to the display.
    • Made an automatic trip reset when its detected that the cars SOC has changed more than 2% since the last time the PalmPilot was connected.
    • Estimated battery capacity is now saved on trip reset as well as when switch applications if the more than 30% SOC has been use on that trip.
    • Estimated SOC is now displayed after 20% change in SOC instead of 10%.
    • Battery model has been updated to use accurate test data on the EV1 batteries!
  • Version 1.0 beta
    • Initial release.
    • Peukert's constant is not accurate and needs adjusting. This effects the estimated battery capacity.
    • OC correction equation needs to be determined.
    • Range and SOC display is not correct when SOC is below 0%. I'm not sure what it should be but whatever it should be its not that way now.

Frequently Asked Questions

  • How can I avoid using so many batteries for the PalmPilot?
    Try the Nickel Metal Hydride batteries which are rechargeable. I got mine from Radio Shack. They give me 6 or more hours of continuous operation and can then be recharged. The voltage is a little different than the alkaline batteries that are expected in the PalmPilot so the capacity gauge on the pilot is off a little but other than that they last a long time and can be reused.
  • Can I plug the OBD II connector into another car?
    The plugs are the same but the pinouts are different. The plugs I provide, at least for now, have pairs of pins shorted for mechanical strength. That works out fine for the EV1 but not for most OBD II systems which use more pins than the EV1.
  • How do I get records off of the PalmPilot?
    After recording data in the EV1Dash program that data can be downloaded to another computer through the serial port of each. To download place the Palm device into its cradle which should be connected to a PC, Mac, or some other computer with a serial port. Start a terminal emulation program on the other computer and open the serial port at 19200, 1 stop bit, no parity, 8 data bits. Start a stream capture to a file. Then go to the EV1Dash program and pick the Transfer menu item. All the records will be send to the other computer and saved in the file you specified. When transferring is done close the file and quit the program. Thats it.
  • How do I run the EV1Analysis program?
    The first thing to do is download and install Java. After that run the EV1 Analysis program. Using the File:Open menu item select the file downloaded from the EV1Dash program on the Palm organizer. Depending on the speed of the computer and the length of the file it may take some time to complete the screen drawing. Be patient.
  • When does the estimated capacity change?
    The intial value of the estimated capacity is what ever the last value was or 45Ah if none have been saved yet. After a change of 20% SOC (not power adjusted SOC) the estimated capacity is calculated and displayed. After a change of 30% the value is saved as the starting value for the next trip. The value can be reset back to 45Ah using the Reset Capacity menu item.
  • Sometimes the estimated capacity changes alot while I drive?
    The estimated capacity is just that, an estimate. It is based on amps used and the SOC. Depending on a number of factors (random?) the SOC may not be completely accurate. I've seen it off by as much as 10% around the 50% SOC mark. This often causes the estimated capacity to start out low and climb to a higher value and then drop off again as the SOC drops below 50%. This error is due to the SOC calculation algorithm of the EV1. Maybe someday I'll figure out what it is and correct the error but for now its something we'll have to live with.
  • In the numeric display what does "drain" mean?
    The "drain" is the same as the "Net Ah" except that the amps are scaled according to the effect they have on the charge (Peukert like). If you hold a steady 25 Amps the net Ah and the drain will be exactly the same. If you pull more than 25 Amps the drain starts to become larger than the net Ah. If you get real aggressive the difference gets even larger. The drain is more indicative of how much you are really effecting the battery capacity. If you are moderately careful you should be able to keep the drain within 15% of the net amps. If you are really pressing for a record you want to be under 10%. That's a lot harder to do though.
  • What is the "SOC Power Adjustment" option under the Display menu?
    The "SOC Power Adjustment" corrects for the drop in voltage as the SOC changes. It used to be on all the time but I made it an option so you can see what the EV1 thinks the SOC is. If you don't compensate for the voltage sag of the batteries as the charge runs out you find that the second half of the battery charge does not get you as far as the first half. The effect is about 6% overall. If you want a more accurate picture of the SOC by how far you can go then leave the "SOC Power Adjustment" on. That's with the little dot next to it.