EVanagon - Data

EVanagon - Conversion Details

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Data
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Pack Capacity (Ahr, kWhr)
    C20 Rate
    C1 Rate

Battery Info
    Model No.
    Expected life cycles
    Actual life cycles experienced (cycles at replacement, cycles so far with X performance)

Vehicle Efficiency
    Wall-to-wheel (e.g., KillaWatt meter)
    60 mph draw at calm steady conditions
    Battery-to-wheel
    Battery In/Out

Driving Miles
    Typical drive (e.g. daily commute, chg at work?)
    Max miles driven

Vehicle Info
    Make/Model
    Weight (front/back)
    Tire specs

Journal

5-20-08
I now have about 4000 miles on the electrified vehicle and have not done much to it since January. Toasted the transmission sometime in the fall '07 timeframe, but was traveling for two months for work, so little was accomplished. After the returning from work in early Dec '07, and spending time with family, I worked hard and got her going again with a new tranny and a few other upgrades (new wheels/tires, springs, shocks). Most of my miles are freeway commute to work, 12 miles one way.

8-5-07
Golly, the past few months have not been productive in EVanagon land (work and vacation). After the 5-10-07 update, I was able to drive to work 3 times using surface streets. I was in 3rd gear the whole way and on a long straight flat section I was able to just barely achieve 40 mph. During this time it was discovered by me, and told by tech support that my motor was in Wye configuration, which gives high torque but only to low rpms (falls off rapidly after 1100 rpm or so). They sent out the hardware to change the wires around, as well as the software. After driving the vehicle around a bit, I realized that the rear batteries had been mounted too low for functionality and asthetics. I decided that this was not acceptable and thus built a fully different motor mount mechanism and put the four rear batteries inside the vehicle.

Yesterday I spent 8 hrs putting the vehicle back together and was able to drive over to a friends BBQ. What a difference Delta makes! I was in 2nd gear the full way, got up to 55 mph at some spots (phew, no ticket). Now I need to get my gear shift mechanism working, this will allow me to get to freeway speeds, and 1st gear as needed.

There is however a big problem at low rpms - if I try to accelerate quickly by putting down the pot box, the motor cuts out abruptly sending my tranny/motor mount into some gnarly vibrations (not good). Once I get above 20 mph or so I can floor it with no problem. Hopefully just some software parameter tweek.

5-10-07
Pull Test:
I was not able to determine the gear ratios for my transmission (stock) yet, but I was able to hook up my load cell and attempt to pull/drag my other vehicle. I performed three trials, each in a different gear. The first gear I was in was 4th, and was able to pull a dead weight of about 500 lbs (via the load cell). In third I got ~1000 lbs, and in 2nd I got about 1500 lbs, and was starting to drag my 1998 Outback (in gear with the e-brake pulled hard). So, changing gears had a big effect on available torque, and subsequent acceleration. However, in none of the gears was I able to get above about 35 mph. And when I did get to 35, it was on a down hill or long flat. Also, my vehicle should weigh about 4500 lbs (I weighed it at 2300 lbs empty, + 2200 lbs for batteries, motor, controller, charger, etc), quite average for this size EV.

Pics: Pull_1.jpg Pull_2.jpg

Battery Load Test:
For each battery, I again monitored the voltage while I floored the vehicle up the same stretch of road. All of the batteries had a very similar response, except for one of which it dropped to a few volts upon load. This bad battery was removed from the pack, and the battery limitation parameters in the DMOC software were adjusted (see the attached parameter file with pertinent values). Now that the bad battery was extracted, I was able to give the pack a proper charge.

Real Drive Tests:
The good news is that I have driven to work the past two days (18 miles each way). However, I am restricted to surface streets due to my ~35 mph limitation. I am in 3rd gear. As noted above, the pack now sags less but yet the power limiting issue remains. If I floor the pot box, I accelerate to a point where the motor begins to lurch pretty violently, even though the battery limits are not being impinged upon. This is shown as the big neg pulse in the plot, before max rpms. I have to let up on the throttle a lot to get rid of the lurches. Once I have passed the "bad" rpm, I can then floor it again and request all she's willing to give, which isn't a lot. Again, the batteries in this test are good, limits are not being hit.

Another thing that I noticed was that although the regen works quite well for low rpm's, it enters into a positive feedback loop at high rpms, to the point where I have to quickly turn off regen to not break my car. I have verified this performance on smooth steady roads, where I have been able to work the pedal slowly out to not start an oscillation - however, the oscillation comes on like a classic exponentially increasing envelope. I suspect that the PID gains need to be changed - or better yet would be to add in a max slew rate limitation since one doesn't need regen to react quickly.

Another observation is that after I get to work (and home), I notice that the motor is almost too hot to touch, while the controller is barely luke warm. During the drive, I can hear the controller fans turn on after each of the 3 or 4 minor hills I go over. Now, even though the contrroller should be 98% efficient while the motor is only 93%, I think the motor is getting disproportionately hotter than the controller. The motor generates about 3 times as much heat as the controller (per quoted efficiency), but the thermal mass (and total mass) of the motor is much more than three times that of the controller. With this observation and the funny IqF and IdF traces, I think there is something going on with the motor, or the control of the motor. Finally, the cables goinig to the motor also seemed pretty warm.

RunData_051007.xls
Lessonebattery_ParamFile-051007.ccp

4-30-07
This other software parameter that was supposedly wrong was the DecoderPulses parameter. Not sure what the number was previously, but a value of 60 changed how the vehicle performed. Now, I am not certain that this was the only parameter changed since I uploaded a whole new configuration file that Azure representitive sent me, so it might have had different settings.

With this change (new parameter and ...), there was a little bit more power, but most significantly now the regen braking works! Previously when I tried to apply the regen the motor would lurch semi-violently. But now they work quite nice, offering up to 25 amps of regen current.

Third Drive Data: Run_Data_042807.xls

So, even though these two software parameter tweeks have made driving the car possible and better, there still is a fundamental lack of power. For instance, I am only able to pull 50 amps or so when I should be able to pull 250 amps, a factor of 5 too low. I still don't have enough power to drive on arterials - I can only hit 30 mph in a slight downhill.

Below are hints that hopefully will isolate the problem.

1) Amount of power available is dependent on speed. When I floor the accelerator, I slowly begin to accelerate. During this initial acceleration the current is low (~10-20 amps) and the voltage drop is minimal. As the speed picks up, the current slowly rises and the voltage sags more and more. By the time I get to my max speed (separate issue described below), I am getting the most power, and thereforer the most current (~45 amps). This all happens over about 5 seconds. This motor should not have this characteristic - it should have full torque at zero RPM. I read through all of the speed ramps and other drivability settings, and none of them has a power limitation ramp with speed (it does with time, with battery voltage, etc).   Obviously there is some parameter that is limiting the power. To illustrate the low power at low speeds, I almost got stuck in my backyard trying to drive over a pretty small clump of grass.

2) When I get to my max speed (which is about 30 mph), the motor begins to lurch a bit and sound whinny. Further holding of the accelerator produces unhealthy sounding lurches and sounds.   From the data it looks like I am only getting up to 1600 rpm, which is on the low side of its capability, not even to the max power RPM.

3) I have played with the power adjust knob to make certain that was not the cause. Although I don't have confidence that its working correctly, I have put it in all three positions and no change was sensed.   I believe open for the two wires should give the most power. Lastly, I am not even getting the power I should for the minimal setting.

4) Is one of the parameters that is recorded battery current?   There are   three (maybe more ) currents recorded, IqF, IdF, IsLimit.   What are these and what do they scale to (Amps?)? How does the DMOC calculate power draw?

5) The data also show that the torque that I am requesting, and recieving, is 300 Nm!!! I am certainly not recieving this torque - loud noises, fast moving objects, or smoke will happen if this much power is delivered.

4-24-07
Found a partial solution to the power issue. The encoder direction bit was set to "-1" where it should have been "1", apparently this was supposed to have been changed when I switched two of the three motor terminals to reverse the direction of the motor. The car was able to get up to 20 - 25 mph!!! It also looks like there is another software parameter that is likely wrong and will hopefully give me full power.

Second Drive Data: Run_Data_042307-B.xls

TroubleShooting 4-22-07:
The below files are information captured in attempts to solve my problem of almost zero power. I was able to perform an initial drive (see the movie on the root page of this site). During the drive I had sufficient power to make it up and down the street a few times and get up to 20 mph. I did notice a pretty good drop in the already low power during these first few drives (total was less than 0.5 mile). The power was pretty severly low even for this case. Then, after the car sat for a day or so, I attempted to drive it again. No go. The best I could do is creep forward in my flat driveway - my 15 month old daughter was passing me up. Something was very wrong. So I went about charging the batteries to check that box off - no change. Then (a few weeks later) I tested the individual batteries to ensure that they were in good health. The battery no-load and under-load voltages are described in the Excel file listed below, they all seem to check out well. The DMOC data is data recorded while the car was in full throttle. Lastly, I took a movie while doing this full throttle event (but didn't get my daughter in the movie unfortunately), so that the motor noise could be heard. There is a noise that comes from the motor or something that doesn't sound right (the old laptop is unfortunately pretty noisy itself). There is also more vibration than I think there should be. I'm quite certain that the clutch isn't slipping - I'd be happy if that was the problem. Unfortunately this "troubleshooting" data is the first to be put on this site.

Excel File: Battery_load_test-042107.xls
DMOC CC Shell File: Troubleshoot_Data_042107.txt
Movie: Motor_Noise_042207.mov

Contact: insolation@mac.com