When installing or commissioning NEW batteries

Discover gives every EV Traction Dry Cell and EV700 Dry Cell battery an individual serial number. This serial number is in addition to the production and shipping codes that can also be found on the battery. Documentation is the first step to installing and maintaining batteries. Upon receiving your electric vehicle or prior to the commissioning of the batteries you have purchased, a service record should be prepared. This record will serve to track the batteries performance and service history until removed from service.

• Date: record the commissioning date.
• Temperature: record the temperature at the test site.
• Serial number: record each batteries serial number that can be found on the part number label. If you have trouble finding it use a non-erasable marker and give each battery an individual number..
• Battery Production Code: record the production code that will be laser burnt into the cover..
• Appearance and condition: record your observations of the batteries appearance
• OCV: record each batteries Open Circuit Voltage reading using a digital volt meter making sure to record the reading and the temperature compensated reading using the guide below.
• Hydrometer reading: if your using FLOODED or WET accessible batteries record the S.G. reading and the temperature compensated reading using the guide below

How do I temperature compensate my hydrometer readings?”

Temperature Compensation Guide.

If you are using a non-temperature compensated hydrometer, make the adjustments shown in the table above. For example, at 30°F (-1.1° C), the specific gravity reading would be 1.245 for a 100% State-of-Charge. At 100° F (37.8° C), the specific gravity would be 1.273 for 100% State-of- Charge. This is why using a temperature compensated hydrometers are highly recommended and more accurate than other means when testing flooded battery types. For non-sealed batteries, check the specific gravity in each cell with a hydrometer and average the reading

• IR Value: if you have or intend to use an internal resistance or conductance meter for future evaluation you must use the same meter now and record its readings. Future readings are meaningless without a reference base line reading. Also you must make sure to use the same meter as different meters will give different readings. Even the same meter will change calibrations over time.
• Load test:  load test each battery using a carbon pile tester and record the voltage at 15 seconds. This is the voltage reading at 15 seconds while discharging the battery at 3.5 times the 20HR rating (350 amps on a 100AH battery). It must maintain 1.75 volts per cell when commissioned and may move to1.6 volts per cell with age. The key is to watch that the voltage does not continue to drop but “holds the load” steady at or above the minimum voltages during the test.
• Install and connect all of the batteries:
• Check that all battery cables are the same size and of proper current carrying capacity
• Check to make sure that all cable ends are clean
• Check to make sure that all cable ends are connected directly to the battery terminal bushing WITHOUT ANY washer in between the terminal bushing and the cable end
• Install and torque the terminal nut using the torque data given on the battery label
• Total Pack Voltage: record the total battery pack voltage
• Voltage Drops: cable lengths should be kept short and cabling must be sized large enough to prevent significant voltage drops. While the voltage drop should be “0”, there should be a maximum drop of 0.2 volts (200 milli-volts) between batteries. Electric vehicle applications where batteries may be installed in separate areas must pay special attention to voltage drop as battery performance and life will be affected.
• Battery Tapping: tapping out one or two batteries from a string of batteries to power lower voltage accessories is NOT acceptable and will void the batteries warranty. Tapping increases the level of service and attention you will need to give to your battery bank to keep it in balance and working properly. You will need to periodically break the battery bank and charge each battery individually to get them back into balance. A DC to DC converter should be used instead of tapping.
• Charging Time: after discharging the batteries to an average of 1.75 volts per cell (10.5 volts per 12 volt battery, 5.25 volts per 6 volt battery) engage the charger and record the time to charge the bank from 100% discharged to 100% charged. Let the batteries rest for at least 8hrs, preferably 24 hrs. As the battery bank ages charge time may change.

  How can you tell if a battery is fully charged?

  The only true way to tell if a VRLA battery is fully charged is by using a good voltmeter to determine the open circuit voltage (OCV). Accessible flooded type batteries can use a hydrometer as well. Remember to temperature compensate readings.

  Digital Voltmeter Open Circuit Voltage (OCV at rest)

  State of Charge	Discover	Discover
  SOC %	Flooded	EV Dry Cell
  100%	12.80-12.60	12.90-12.80
  75%	12.40	12.60
  50%	12.20	12.30
  25%	12.00	12.00
  0%	11.80	11.80

  Divide the above values in half for 6 volt batteries or by six to determine cell voltage. The TRUE OCV can ONLY be measured after the battery has been removed from the charge or discharge load for 24 hours.

Different types of batteries use test procedures that allow different end of life criteria. For example an electric vehicle or standard deep cycle product would be considered to be at its end of life when it was not able to deliver 50% of its rated capacity while a golf cart battery would not be determined to be at its end of life until it was not able to produce at least 1.75 volts per cell during 40 minutes of discharge at 75 amperes.

By establishing and recording the base line performance of the battery or battery bank at time of installation, you will be able to track the health of the batteries over time by performing the same tests at regular intervals and comparing the results to the original results and eventually predicting end of life status. Understanding these base line criteria and the affects temperature has on all aspects of performance and charging will help to quickly and professionally diagnose performance related issues that might arise.

NOTE: In the interest of safety and performance multi battery systems must be engineered and installed properly! An excellent and easy to understand free booklet on multi-battery applications, “Introduction to Batteries and Charging Systems”, can be downloaded from www.surepower.com