Roper ZAP PK Xero Existence Log for August 2007


L. David Roper

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Steppin' Out, solar-panel ammeter, replacement axle

1 August 2007

  • In full sun the solar panel puts out about 1 ampere at about 100 volts, for power of about 100 watts.
  • Ordered a 3-amperes panel meter to hook onto the solar panel.
  • A question: since the solar panel is hooked directly to the battery pack, is there a danger that this arrangement will overcharge the batteries? Should I install a switch between the panel and the battery so that I can turn off the panel when the batteries have just been charged by the power company?
  • The man who runs the local company, Solar Connexion, that installs solar panels on buildings stopped me today at a local electric company to talk about Sun Roper. He said that he had been studying ZAP cars for some time. He drove it for about 1/8 mile.
  • Recorded operating data using the PakTrakr, its current sensor and the ES1R automatic logging serial interface. Starting analyzing the data. The first analyses are available .

2 August 2007

Sun Roper was on exhibit outside in near 90° heat at the YMCA of VT 134th anniversary celebration. About 10 people talked to me about it with great interest. Several thanked me for pioneering this vehicle in Blacksburg.

3 & 4 August 2007

  • Sun Roper was on exhibit at Steppin' Out in Blacksburg. I talked to at least 100 people about electric and hybrid vehicles in each of the two days in hot weather. Much interest was shown.
  • I have been invited to give a talk on hybrid vehicles at a service club in Floyd VA soon.

7 August 2007

  • Sun Roper hauled three 4'x8'x1/4" bead boards 10 miles back to Lowes today. They did not quite fit in between the back solar-panel posts because I did not push the posts all the way to the bed walls when I drilled the holes in the bed for them; they lack about 1/8" being right against the walls. So, I had to slightly angle the panels with a thin pad between the upper edge and the post.
  • Changed the oil in the gear box at slightly over ZAP 2000 miles. This time I planned to use all Lucas Heavy Duty Oil Stabilizer, but it ran so slowly out of the funnel that I mixed about 10% or more Lucas 80/90 weight oil to make it flow better. I will see if the pronounced whine when driving is now reduced.
  • Because of the solar-panel back posts I had to reposition the two chains to hold the tailgate horizontal; see pictures below.

8 August 2007

10 August 2007

I got the revised ES1R data logger for PakTrakr, but it is too hot to download data from it today.

11 August 2007

I would like to figure out how the solar panel is wired. There are large rectangles and small rectangles inside the large ones. There are 26 across and 14 down of the large rectangles for a total of 364 large rectangles. Within each large rectangle there are 29 small rectangles, which must be the actual photovoltaic cells (I assume multi-crystalline). If that is correct, there are 10,556 small photovoltaic cells in the panel.
According to ZAP, the panel is rated at 150 watts. To charge the 72-volts battery pack, the panel must put out more voltage than that. In full sun I measure 93-97 volts output for the panel. Using a clamp-on ammeter I get 1.0 to 1.3 amperes going into the batteries  in full sun.
My questions are:

  • What is the open-circuit voltage and what is the maximum current output of each of the 10,556 cells?
  • How many of the large rectangles are wired is series to yield about 100 volts
  • How many parallel sets of large rectangles are there to yield about 150 watts or about 1.5 amperes?

12 August 2007

13 August 2007

  • Drove a 16.5 round trip to Whitethorn VA, up and down many steep hills, where there is a wide spot on the New River for flat-water canoeing/Kayaking. Tried to download the trip data using PakTrakr/ES1R, but failed.
  • Drove a short route in the neighborhood of our house recording the data with PakTrakr/ES1R and plotted the results.

14 August 2007

Drove the trip to Whitehorn again, downloaded the data and plotted it. There was still some data corruption. It apparently is due to the wires running close to the battery.

15 August 2007

  • The picture below shows how I rerouted the PakTrakr Remote and wires and the current sensor wires this morning. I will take a long trip today to see if the corruption of data has been solved.
    • I attached the Remote on the outside of a metal bar beside the battery.
    • I moved the current-sensor wire outside the metal bar beside the battery.
    • I moved the Remote wire outside the same metal bar.
  • Was stopped by a Blacksburg police officer this morning because I do not have the state inspection sticker on the windshield. When he walked around the driver's side of Sun Roper he saw it on the left small window behind the driver. We had a long discussion about where it should be. He old me that I am not required to wear a helmet in Virginia because SR is enclosed. He later called my home and left a message that I have the safety-inspection sticker displayed correctly.
  • Drove 34.5 miles today with a two-hour charge in the mid-afternoon. On my way home after dark on the hilly and curvy Merrimac Road the low-battery light came on while going up a steep hill. I then realized that I did not have enough charge to make it up one more steep hill and a few smaller ones. On previous trips I had noticed a country garage (Jerry's Garage) that was over the hill. It was open, so I stopped and asked Jerry if I could charge up for an hour or less. He readily agreed. I spent the next hour and 15 minutes discussing cars, including his race car on which he was working, with Jerry and his dad Carl. They told me to stop by anytime, whether or not they were open, to charge Sun Roper using an outside plug. I told Jerry about my ideas for a bed lift, and he said to bring SR and the lift parts by some time for him to see if he could do the job. There are many of these country garages on the back roads of Virginia. They serve important social functions of providing affordable transportation for folks, recycling autos and as neighborhood-chat places.

16 August 2007

Tightened the parking brake, which was very easy to do.

17 August 2007

Drove to New River Glass in Christiansburg to see if I could get a sliding window put in the rear window to increase the air flow by the driver in hot weather. They cannot make it. They called around companies that make such windows, but none of them ever heard of a ZAP Xebra. They called ZAP and were told that ZAP would consider such an option if enough owners asked for it.

18 August 2007

  • Took Sun Roper to the big summer-end classic car show at K-Mart in Christiansburg where I talked to many people about it.
  • It sounds like the right-rear wheel bearing is whining, which is the one with the leaking CV boot. Mark Higley is sending me a complete axle. I will have South Main Auto do the replacement; but they would like to have explicit instructions, which Mark is trying to get from ZAP.

20 August 2007

  • Mayor Ron Rordam of Blacksburg drove Sun Roper for a few blocks today. He said that it was a fun ride.
  • Started attaching a small 3-amperes ammeter to the line coming out of the solar panel. Used Star Brite liquid electrical tape purchased at Advance Auto to seal the edges that connect the clear plastic front to the black back. Will get small lugs for connecting the wires to it tomorrow at Radio Shack. Then I will attach it to the back right post with blue duct tape after putting a strip of electrical tape over the zero-adjustment screw to keep water from entering the meter there.

21 August 2007

The ammeter is now attached to the wire leading from the solar panel; see pictures below.


It reads 1 ampere in full Sun.

22 August 2007

Installed an Acu-Rite outdoor window thermometer on the inside of the back window, so that it can be seen in the center rearview mirror:

It is designed to go on the outside of windows, but putting it on the inside of the back window makes the view correct when viewed through the center mirror. It showed 114 degrees when I got in Sun Roper to drive home from a trip downtown today, but was down to 91 degrees when I got home.

24 August 2007

Took the trip to Whitehorn again so that I could download the data for it using PakTrakr. The analysis is on-line. There still are errors in the download. Soon I will rewire PakTrakr and the current sensor to get the wires farther away from the batteries and battery cables and shielded by the body frame.

27 August 2007

Got a replacement axle from ZAP through Mark Higley to replace the right rear axle whose CV boot is leaking grease:

John Gipson has given me explicit instruction about how to replace the axle to give to South Main Auto to do the job.

31 August 2007

Left Sun Roper at South Main Auto to get the right rear axle replace while we are on a trip to Atlanta.

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