U.S. Battery Evaluation Report

1. The batteries were installed on May 29, 1988 with a Total Kwh Meter reading of 7735, Total Hour Meter reading of 1974.1, and Odometer Reading of 101,090.
2. Events and facts that may affect the overall efficiency:
   1. Rear tires replacement at cycle # 394 (5/30/90).
   2. Out of service dates (with batteries not cycled):
      1. 12/23/89 - 1/5/90 (vacation)
      2. 9/1/90 - 9/13/90 (injury)
      3. 12/27/90 - 1/7/91 (vacation)
   3. Power for an electric heater is derived entirely from the propulsion batteries when operated during the period from November through April each year. The current drawn is usually only about 6.5 amperes (700 watts at 108 volts).
   4. Replacement of batteries - see below.
3. Total miles has been corrected to exclude a total of 11.5 miles during which the car was towed with the odometer connected.
4. The fact that the very last cycle was made and recorded on April Fool's Day is purely coincidental!
5. The batteries were removed on April 6, 1991 with a Total Kwh Meter reading of 16,024, Total Hour Meter reading of 2935.6, and Odometer Reading of 118,644.

The table below summarizes how the overall efficiency changed during the life of the batteries. Values are shown once for each 50 cycles. Note the overall trend of efficiency decrease (i.e., increase in Kwh per Mile) following the break-in period after cycle # 150.

Watering was performed when the electrolyte level (distance above the top of the plates) fell below about 1 inch. Each cell was filled to a level about 1.5 inches above the top of the plates.

Detection of an impending failure or weakness was made first by noticing failure of terminal voltage of suspect battery to rise as high as other batteries at end of charge (i.e., most batteries greater than 7.35 volts at approximately 3 amperes - suspect about 7.00 volts at 2 amperes). As the batteries aged (i.e., beyond 250 cycles) the terminal voltage decreased (to about 7.00 volts) and current increased (to about 6 amperes) for acceptable batteries, with the voltage of suspect defective and/or worn-out batteries considerably less (like < 6.6 volts). In all cases the final decision for replacement was made by measuring specific gravity after a full equalization charge for over 24 hours. Replacement data is as follows:

Delta S.G. is the difference in specific gravity between the highest (usually 1250-1275) and lowest cell. Important Note: A major extension of battery life may be noted by comparing this evaluation with the Alco evaluation which I conducted between October 1985 and May 1988. I believe the reason for this improvement was due to physical separation of batteries which are located inside the battery box (numbers 5 - 16), thereby reducing heat build-up. I used 3/8" hard rubber sections between adjacent batteries, thus increasing the conduction of heat away from batteries. All other conditions were identical!

Eighteen (type 2200) U. S. Batteries were connected in a series configuration per the diagram below. Twelve of the batteries (5 - 16) were enclosed in a battery box and separated from each other with 1/4 inch hard rubber. The battery box was constructed from 1/4 inch plywood, and did not include insulation. Batteries 1 - 4 were located on the floor behind the driver and rider front seats. Batteries 17 and 18 were located adjacent to, yet outside of, the battery box.

The remaining 11 pages of this report present the data which was recorded during this evaluation on a cycle by cycle basis. The following notes serve to clarify the data entries made:

1. Odometer Reading is in error. It is corrected by the following formula to compute actual Cycle Miles:
   Cycle Miles = (Odometer Difference) x 1.126

2. Total Hours is the total time that the propulsion battery voltage has been applied since car was converted. This meter is therefore running while sitting at a stop light.
3. Total Kwh is the current reading of the meter from which the honda is charged. Nothing else is connected to this meter's output.
4. Cycle Kwh/Mile has been computed for each cycle. These efficiency values fluctuate because I do not fully charge after each cycle, usually every other weekend. An average over many values will however be fairly accurate. Values greater than .6 are recorded as ____ to indicate either that battery equalization was performed or the efficiency was lower (particularly toward the end of battery life - above 400 cycles). Values less than .2 are recorded as ____ to indicate that efficiency was higher than normal because adequate charging time was not available before the car had to be once again placed into operation.

[Because of the length of the table, EV Online has divided it into sections by year to make it easier to read on the Web. -- Ed.]