Roper ZAP PK Xero Existence Log for April 2007

L. David Roper

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2 April 2007

Arrived from NYC just before 6 PM and backed the PK out of the garage and washed the travel dust off of it. Attached the SUNRPR license plate to it and put on the "It's Electric" applique of Dale Gunter on the front and back windows, the ELECTRIC labels on all for sides and the "Want one?" signs on all four sides. Drove about 5 odometer miles around the Stoubles Mill subdivision.

It takes a large force to get the bed started up to dump; then it takes some significant force to keep it from hitting hard at the end of the lift. I wonder how much more force will be required when the solar panel and its frame are installed. I think that a 12-volts electric lift is needed.

Had an occasion in my driveway in which the forward motion did not occur when I shifted from R to F. Am I shifting too quickly? Should I let it sit in N for a second or so when shifting from R to F?

I received a solar fan to put at the top of a side window:

My 2005 Prius has to live in the driveway now. Our 2006 Highlander Hybrid gets to share the garage with the PK. After the solar panel is put on the PK, I will probably keep the PK in the driveway.

3 April 2007

Drove to the Post Office to send off my new motorcycle helmet for a larger size. Drove to South Main Auto Service to see about putting the Gottlieb shock/spring on the front wheel and to adjust the steering wheel 1/4 turn to the right; appointment is next Tuesday morning. (Later Richard Weaver of ZAP sent me the instructions for taking the steering wheel off.)Got dielectric grease at Advance Auto to put on the charge prongs to make it easier to attach and remove the charge cord. Drove 19.6 odometer miles up and down several moderate hills. Showed the PK to the State Farm people who insured it; they were thrilled to see it. A man at the Post Office was looking all around it, so I gave him a sheet about it. Several drivers and pedestrians honked at me and gave me a thumbs up, including one of the clerks at Advance Auto. I charged it for a few hours after this trip.

Had another occasion in a Blacksburg parking lot when it would not go forward after shifting from R to F. I tried it again stopping the switch in N until I heard the click and then shifted into F and it worked.

I put the Dale Gunter "Sun Roper" appliques on after retrieving parts of them from the paper backing:

The other one is near the bottom of the cab below the charging plug. I think that they look great!

I unpacked the solar panel. It is well constructed with neat plug ins on the back:

Its dimensions are 34" x 47 3/4" x 2" (frame depth; the panel is much thinner). It weighs 29+ lbs. There are 26 cells across and 14 cells down for a total of 364 cells. Can someone figure out how they are connected to yield more than 74 volts and 150 watts? The voltage was only 2.2 volts, so something was wrong. Richard Weaver figured out quickly that the diodes in the black box on the back of the panel were put in backwards. Two days later: At Richard's instructions and instructions on the two sides of the black box, I opened the black box with a narrow screwdriver, used pliers to remove the 3 diodes and turned the diodes around. Then the voltage in partial Sun was 97 volts, quite sufficient to charge the 74-volts battery pack.

I drove to a nearby cardboard recycle bin to deposit the cardboard packing for the solar panel and charged the PK some more after that.

In the evening I drove to a meeting with an adult passenger and back for a total of 32.5 odometer miles for the day, or 28.6 miles when the 0.86 odometer correction (supplied by Richard Weaver of ZAP) is applied. (See Mileage Record.)When I plugged it in to charge the battery pack at the end of the day, the garage circuit breaker tripped off. I think that it was because the small garage refrigerator was on. It worked ok after I turned the breaker back on. The total energy put into the battery today was 11.05 kWh for a total of 2.5 miles/kWh. Since I now pay about $0.075/kWh, the fuel cost was about $0.83.

I tried the ZAP cover today:

It is designed for the SD. I will cut off the back of it to make it fit the PK cab better.

4 April 2007

Had 5 people come by at 11 AM to look at and drive Sun Roper; two were a reporter and a photographer from The Roanoke Times to get information for an article in the New River Current section of The Roanoke Times tomorrow morning.

Drove 8.4x0.86=7.2 miles today and put 2.71 kWh of energy into the batteries. (See Mileage Record.)

Put a bicycle cable lock on the left side of the bed to be able to lock it down:

5 April 2007

An article about my Sun Roper PK was in the New River Valley Current section of The Roanoke Times this morning:

Drove 36.4 odometer miles in 3 different trips from home and used 10.69 kWh. (See Mileage Record.) I used a seat heater much of the time and the heater a little. Several people drove the PK, including the Director of Public Works for the Town of Blacksburg.

Showed the PK to a class of 25 aeronautical students, 9 from Loughborough University in England, of Professor James Marchman at Virginia Tech. They are designing a flying 3-wheel hybrid (uses gasoline in the air and has gas-alternator-electric motors in the two back wheels on the ground) motorcycle. I will attend a seminar about their project tomorrow. One of the students drove the PK and was impressed with the linearity of the steering.

The black box on the back of the solar panel shows, on each side of the cover, a screwdriver with graphical instruction: 1. insert screwdriver. 2. turn clockwise. After a little finagling I did that and got the box to open. I reversed the diodes in the solar panel black box on the back (see above) and it then yielded 97 volts in partial Sun. Here is the inside of the black box with the 3 diodes installed in the proper direction:

Still having intermittent problem of F not working after using R. Is there a loose connection?

6 April 2007

A neighbor, my granddaughter, Eva, and my daughter, Tamra, drove the PK in the morning. My stepson, Chris, drove it in the evening. Many people tell me that they like the PK as I drive around.

Drove about 18 miles to run some errands and then another short afternoon trip for a total of 27.1 odometer miles; charging was 9.38 kWh. (See Mileage Record.)

The window crank has been gouging me left leg, so I used a needle-nosed pliers to remove the latch pin and turned the crank handle 180 degrees. I got the latch pin back in but have not been able to push it all the way in.

The odometer LCD is hard to read, especially at night when the purple back light is on. Is there a better LCD to replace it?

7 April 2007

Drove downtown Blacksburg to pick up some extension 14-gauge wires and butt connectors for installing the Powercheqs at Advance Auto and some metric wing nuts to replace the regular nuts that hold the metal plate in place over the batteries just behind the cab, to make it easier to take it off. Several people stopped me to talk about the PK; several had seen the article in The Roanoke Times. Two congratulated me for "building" the vehicle!

(See Mileage Record.)

The plug at the back two red lights keeps falling out. I used duct tape to hold them in place.

9 April 2007

Drove to the New River Valley mall for the first time (20.2 miles round trip). Then drove to Blacksburg to be interviewed by a reporter for the Collegiate Times for a total of 30.1 miles for the day. An article about the PK is to be in the Wednesday Collegiate Times. (See the picture of Sun Roper on the front page of the Collegiate Times.) Many people stopped to talk about the PK with me. Several commented on it being the electric car that they saw in the newspaper.

10 April 2007

Drove 8.1 miles to Virginia Tech and back. Gave a ride to an 88-year-old friend who used to be a pilot for many years.

11 April 2007

Left the PK at South Main Auto (American Car Center) to have the Gottlieb adjustable shock/spring put on the front and to have the steering wheel aligned with the front wheel. Also, I asked them to fix the left turn signal so that it would cancel when the wheel is turned forward.

12 April 2007

Bought American Auto Accessories heavy-duty bumper guards at Pep Boys Auto in Richmond, Virginia. Must wait until 65 degrees weather to put them on the front and back of my PK. Put them on 17 April:

Decided to leave them silver instead of painting them blue to give an accent look and reflect more light at night.

13 April 2007

Picked up the PK at South Main Auto. Had a long talk with the mechanic who replaced the shock. SMA will be my main mechanical place for working on my PK. They drove it about 20 miles and adjusted the Gottlieb front shock/spring for the best ride. The steering wheel is now straight, but the left turn signal still does not cancel. They also did the Virginia motorcycle safety inspection, which is required when I take my motorcycle skills test.

Drove to the VT YMCA Thrift Shop to prepare for the Step It Up Rally tomorrow. By the time I got it home it had 27.9 miles on it and the battery symbol was blinking red, but it still had quite a bit of power left. I like the better ride in the front end. Now I would like to have better suspension in the back; the most disconcerting aspect is the rocking when the PK is driven across a depression or a bump at an angle.

Drove to Virginia Tech for an energy talk.

14 April 2007

Drove to the Step It Up Rally at the Virginia Tech YMCA Thrift Shop, 28.6 miles total; I almost ran out of juice. The hill going north on North Main Street in Blacksburg really taxes the motor.

We had the rally inside because of cold weather and a little rain. Many people looked over the PK with many questions and comments. See for pictures of Sun Roper at the Step It Up Rally.

I like the way the front end rides in my PK with the Gottlieb shock/spring, and it seems to steer easier at low speed.

15 April 2007

Drove to the Unitarian Church to participate in a discussion with a Blacksburg Town Council member on Global Warming and Cool Cities for Blacksburg.

Installed a net for holding items to the front of the bed:

Also notice the two bungee cords for further securing heavy items.

16 April 2007

Drove downtown to replace the 16" windshield wiper with a 20" Bosch wiper. The old one did not clear the screen high enough for me. The new one is quieter. While I was on my way someone shot several people on the Virginia Tech campus; many police cars and rescue vehicles, and even a fire truck, passed me. I had planned to drive across the campus on my way home. At my 3rd stop I was given information about the first shooting and was advised not to drive across campus. If I had I would have driven right by the building where the second shooting occurred. Since I retired in 1996, I do not know any students or professors that were involved. It is a horrible tragedy.

The steady rating for the generator is 750 watts. If the vehicle will go 3 miles for every kWh, then running the generator for 1 hour will produce 0.750 kWh or enough to travel 2.25 miles.

The web page says that, with energy loss accounted, one gallon of gasoline releases about 8.8 kWh. So, one gallon of gasoline would provide enough charge to the batteries to drive about 26.5 miles @ 3 miles per kWh, but it would take about 12 hours to charge.

A power outage caused the Kill-a-Watt meter to zero out, so I cannot record energy usage for today.

17 April 2007

Measured some parameters of the PK:

  • Wheel base: 8'
  • Tread width (center to center): 4'
  • Center of gravity (assumed at center of the batteries): 1.33' for a static stability factor of 1.50, about the same as a Chevrolet Camaro. (See p.1 of for the formula.)
  • Minimum turning diameter for my PK (measured at edge of front wheel, not the body):


The turning diameters are larger than for the Toyota Prius : 25.2'

Friend Professor J. D. Stahl brought his wife and two small sons over to ride in the PK.

Drove the PK to the candlelight vigil at Virginia Tech.

18 April 2007

Drove downtown to get a hair cut. Then drove to Christiansburg and tried to drive the motorcycle course behind the DMV; it is impossible for the PK to do the course and it has nothing to do with the skill of the driver. I am worried as to what the DMV agent will do when she/he finds this out. I may go ahead and take the Motorcycle Safety Course at New River Community College, which automatically gets one the motorcycle endorsement on a driver's license. It costs $82.20. I have until March 2008 to get the endorsement.

I bought a helmet for $40 and started wearing it.

I went to B & K Truck to check on getting the bed and sides of the bed lined; they do Xtreme Liner and it will cost $350 plus $100 for a blue color. The places where the sides touch the bed and each other will not be lined; there is not enough room. It is going to be done next week.

I went to the Habitat for Humanity of the New River Valley ReStore to work as a volunteer for 3 hours; I plugged the PK in and it received a charge of 3.23 kWh for a charge rate of 1.07 kWh/hour. The odometer read 18.7 miles since I left home. By the time I got back home it read 34.2 miles. There were several challenging hills on the route.

Problem of shifting from F to R has not occurred for many days. I think I was trying to shift too fast.

19 April 2007

Drove downtown to run a few errands and get a Blacksburg motorcycle decal for the PK: $13.85 for a year.

At the request of a Yahoo/Xebra-EV person, I made the following measurements of the PK:
Length: about 10' 10" (difficult to measure because of curvature of front)
Width: 5' 7" (including 1" "fenders" on each side)
Mirror extension: 7" for a total width of 6' 9"
Open door: about 2' 7" (difficult to measure because of curvature of door edge) for a total width with both doors open of 10' 9"

I put graphs of voltage versus SOC for charging and discharging on Yahoo/Xebra-EV :

Plot of data from Deep Cycle Battery FAQ for Solar Electric Systems:

Plotted from data at How to Size and Use Your Data Bank:

It appears that the most energy can be gotten out of a battery by only discharging it to 40% most of the time, although 30% to 100% is not too bad.

Comparison of different batteries used in ZAP Xebras:

Taken from .

Drove downtown with my wife, Jeanne, her first ride in the PK, to scoop free ice cream at Ben & Jerry's for Virginia Tech students and other Blacksburg residents. She said that it is noisy and rough riding and that my black helmet needs a propeller on top.

20 April 2007

Drove to recycle cardboard, slick magazines and white paper. Later drove to the memorial ceremony at the Virginia Tech Drill Field and bought a VT T-shirt and car decals.

In between Dale Schutt came to help me put on the Powercheqs. The separate batteries' voltages before putting them on were:

Battery 1: 12.92; Battery 2: 12.96; Battery 3: 12.95; Battery 4: 12.97; Battery 5: 12.97; Battery 6: 12.96

Maximum difference = 0.05 volts.

We found that the easiest way to remember how to attach the 3 Powercheqs leads to the battery terminals is:

  • Battery 1 has only the yellow wire attached to the + terminal.
  • All 5 other batteries have yellow and white wires attached to the positive terminal. Therefore, one should prepare the yellow wire of the next PowerCheq to install before attaching the white wire of the PowerCheq to which the white wire is attached. The instruction specify that the white wire is the last of the 3 wires to attach for a given PowerCheq.
  • Only the purple wire is attached to the negative terminals of all 6 batteries.

The five white labels on small black boxes identify the Powercheqs.

For batteries 1 & 2, the purple and white wires had to be extended.

21 April 2007

Drove to Blacksburg recreational center to participate in tree planting for a town nursery. Then drove to Farmers' Market to buy food. Then drove to Market Place Shopping Center to get dog food at The Tractor Store; several people gathered and asked questions about the PK. Then went to Lowe's to get 10 sacks of 2-ft^3 pine-bark mulch (about 40 wet pounds per bag); could have hauled twice as much.

In afternoon the brake relay arrived from Mark Higley. I removed the jumper (3rd down slot and bottom slot connection) on the brake relay plug in the fuse box under the front hood and plugged in the brake relay; then I cut the bottom connection of the brake diode:

The first picture above shows the arrangement for both foot brake and emergency brake not stopping PK movement. The second picture above shows the arrangement for only the foot brake not stopping PK movement; note the cut diode connection. That is, now the vehicle will not move if the emergency brake is on. The label on the cover of the fuse box under the hood is:

22 April 2007

Took an old friend for a ride to lunch today. He was enthused about the PK.

Canvas Works sent me paper to draw the pattern of the windshield in order to make a heatshield for it. I have used heatshields on my last four vehicles; I think that heatshield is the best sunscreen.

I attached my mp3 player to the CD input plug on the right front of the radio and it worked.

I noticed that the accessories battery has much space around it in its container, so I put some wood and cardboard chocks on two sides of it to hold it more firmly.

A graph showing the batteries conditioning (miles/kWh vs days driven) is below.

24 April 2007

Drove 24.5 odometer miles to the New River Valley Mall area. The voltage-SOC curve indicated about 25% SOC at the end. Two men stopped me to talk about the PK; one sounded very interested in it.

I put small rubber bumpers between the bed and the two bed latches to keep them from rattling.

25 April 2007

I fitted a hyperbolic tangent to the miles/kWh versus days driven to yield an asymptote of 3.16 miles/kWh. This clearly shows batteries conditioning. I will update this almost daily as more data are collected.

In the evening I drove to three meetings. A man at one of the meetings expressed great interest in the PK, so we put his bicycle in the back and he drove it to his home in downtown Blacksburg. At his home I had the old trouble of getting the vehicle to move. I will check for loose connections tomorrow.

26 April 2007

Drove Sun Roper to Christiansburg to get the inside of the bed and the sides Xtreme lined with a dark blue color while I worked at the Habitat for Humanity of the New River Valley ReStore.

The liner turned out very nice, as shown in the three pictures above. It cost $350 + $125 for the blue color.

After I parked at the liner company and went in to make the arrangements, I went outside to check the liner color against the PK color and the PK was not in the parking lot! I looked across the street and saw it with its back end in a ditch about 200 feet away across a grass field. I had forgotten to put the emergency brake on in the "level" parking lot! It had crossed a small street and went between a large tree and a metal post. I went back in to get help. When we got back outside a policeman and several other men from a nearby lube shop came over and helped push it out of the ditch. Then the PK made it fine up a slight hill in high wet grass. Whew!!! I asked the policeman if I needed to file an accident report, and he said that no damage had been done, so I did not. I could not detect any damage underneath. The tall grass in the field must have slowed it down so that it did not hit the ditch very hard.

I drove to Blacksburg Community Band practice. Several band members gathered around the PK to ask questions. The fold-down side was very handy for putting the heavy bass trombone and gig bag in the bed. I used a bicycle cable lock to lock it to one of the front pillars.

The brake light has been randomly coming on. On the way to Christiansburg it came on more often. On my way home it was on dim most of the way. I must get it looked at soon. How high does the brake fluid have to be for the brake light not to shine?

27 April 2007

The brake fluid was a little low, so I bought Valvolene SynPower Full Synthetic High Performance brake Fluid (Exceed DOT 3 & 4). After filling it with a long-neck funnel I had trouble getting the cap back on; I could only get it to latch on one side. It seems tight enough latching on one side only, but it bothers me. I am going to have South Main Auto look at it on Monday and also try to get the turn signals to cancel properly and figure out why the brake dash light is on dimly.

Several people commented about the PK as I drove by them today. One guy on a bicycle said "That is the coolest car I have ever seen!"

28 April 2007

Drove to the Green-Homes conference at the VT YMCA and later to the NRV Mall through a back road with steep hills. Many people gathered around the PK after the conference and a few at the Mall.

The brake light gradually went off. Sean Rarey of Grants Pass EV (Oregon) says that the brake-light circuit has a bleed.

I did a check of the speedometer and the odometer with a GPS and concluded:

  • The speedometer is very close; perhaps slow by 1 mph at 40 mph
  • The odometer is high by a 0.86 factor, the same factor as determined by Richard Weaver for his PK. In the mileage record below I multiply the odometer reading by 0.86 to get actual miles driven.

29 April 2007

Drove to Advance Auto and bought a new rear-view mirror to attach to the windshield:

I cut the old one off with a hack saw. It now does not vibrate nearly so much. The new one has a night lever.

I bought Lucas Heavy Duty Oil Stabilizer and Lucas 80/90W gear oil and changed the oil in the gear box with half of each. (The Xebra manual recommends all LHDOS, but others on Yahoo/Xebra-EV recommend 75% 80/90W and 25% LHDOS, so I compromised with 50% of each.) Here is what the old gear oil looked like at 425 actual miles.(Mark Higley had changed it previously at about 100 miles.):

Mark Higley said that he had the shop that drilled out and replaced the old oil plugs to also change the gear oil. He instructed them to do a mix of 75% 80/90W and 25%  Lucas Heavy Duty Oil Stabilizer.

Took the steering wheel off and tried to align it better so that the turn signals will cancel in both directions. Finally got the brake-reservoir lid to close tightly.

30 April 2007

Drove to DMV in Christiansburg to take the Virginia motorcycle skills test. 2.5 hours after I entered the DMV I emerged with the Class-M designation on my driver's license for $8. I had to wait behind two others who took the regular driver's skill test. The examiner saw my PK while she was doing those tests. She realized that it was not capable of doing the first two (sharp turns and cone weaving) of the four exercises. After several phone calls to Richmond she finally got the person in charge of motorcycle licensing and he said that they are working on a test for the Xebra-type vehicle, but to just have me do the last two exercises (fast stop and fast swerve). I slid the tires when braking for the first time while passing the test. Half way through the wait I offered to just go to the New River Valley Community College and take the motorcycle course for an automatic motorcycle license, but the DMV manager said that they would work something out, and they did. Despite the long wait I am pleased with the result. Now I can tell others interested in getting a Xebra in Virginia that it can be registered and the driver can get a license to drive it.

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