Battery Testing Optimizes Savings on Government and City Fleet Vehicles
12/01/2021

Save time, money, and downtime with consistently accurate battery testing and maintenance.

Today’s commercial vehicles, such as government and city fleets, have more complex electrical systems that must support various onboard systems, such as fuel control, GPS, ABS, surrounding traffic surveillance, and climate control.

Because the battery systems of commercial vehicles use multiple 12-volt (V) batteries connected together in parallel, this increases the Amp-hour (Ah) capacity and CCA for more cranking power and energy. This volume of energy is needed to meet the amplified power demands of onboard accessories that power much larger engines.

Government and city fleet vehicle batteries must withstand harsh operating conditions, while being ready to start high-compression diesel engines and provide power for very large loads. On a daily basis, batteries used for these purposes experience substantial charge/discharge cycles yearly.

To adequately maintain fleet performance and profitability, battery systems must be properly tested. Here are some helpful tips to maximize your fleet’s battery systems.

Know the Battery Type

There are three types of lead acid batteries commonly used in government and city fleet vehicle applications today: the maintenance-free flooded electrolyte battery, the Absorbed Glass Mat (AGM) battery and the Thin Plate Pure Lead (TPPL) AGM battery. An AGM battery contains fiberglass mat separators to absorb the electrolyte, making the battery spill-proof so no additional water is ever needed.

Plates made of pure lead that are found in premium TPPL AGM batteries can be thinner. More plates can be used when they are thinner to increase the surface area exposed to the electrolyte. This generates more power in the same amount of space as a comparable flooded or AGM battery.

Identify the Proper Battery State of Charge

When a government or city fleet vehicle comes in off the road for regular maintenance, each battery should be tested. Spotting a deficient battery avoids a no-start situation for the driver while on the road.

A voltmeter on the battery terminals indicates State of Charge (SOC). Battery charging is done by the alternator which should provide a regulated charge no lower than 14.00V and no higher than 14.70V to prevent premature failure.

Charging systems on all vehicles usually operate at 14.20V; the charging system output amperage is what differs. Output amperage on small vehicles can be less than 100 amps and go up to 300 amps on large HD trucks. Some applications like transit buses can have more than 500 amps of output.

Battery Testing

The testing methods for different types of batteries are identical. It is important that the battery be at least 75% SOC, which for TPPL batteries is 12.60V, before testing for the most reliable results. If the battery voltage is below 12.60V, complete the following steps.

  • One of the most common service mistakes is using the incorrect method of charging for the battery type. Modern, “smart” battery chargers have the ability to determine the battery condition and adjust the charging rate accordingly. They also have been programmed with a charging algorithm to adjust the charge voltage and amperage during the charging process.
  • Be sure to choose the proper battery type charge setting for the battery being charged (Flooded vs. AGM). Charge the battery until the charger indicates the charge is complete. Unplug the charger and disconnect the battery from the charger.

For best results on AGM/TPPL batteries, let the battery sit 10-12 hours to let the surface charge dissipate to obtain a proper voltage reading.  For flooded batteries let the battery sit 30 minutes. If the voltage is ≥12.60V, then proceed to the testing below; otherwise, reject the battery.

One-Half CCA Load Test Procedure

This procedure should help determine whether the battery has sufficient cranking power or is reaching end of life. The load test should be performed on each battery separately.

  • Connect the load tester cables and the voltage leads of a separate digital voltmeter (if the tester does not have a built-in digital voltmeter) to the battery terminals.
  • Adjust the tester load current to load the battery to half its rated CCA and apply the load for 15 seconds.
  • At the end of 15 seconds note the battery voltage on the voltmeter and discontinue the test. If the temperature is 70°F (21°C) or higher, the battery voltage should be at or above 9.60V. If so, the battery can be returned to service. If below 9.60V, the battery should be rejected.

Avoiding Failure with Premium AGM Batteries

The most effective defense against high cycling with deep discharging is to incorporate large amperage alternators. This provides the fastest recharge to fully charge. Take rested voltage values of each individual battery to look for voltage value consistency. This will help identify any battery with a lower voltage value that might be failing.

Government and city fleet vehicle managers increasingly rely on TPPL AGM batteries because they last longer. TPPL AGM batteries also help reduce costs associated with an unexpected failure to start and offer 30-60 months longer service life. The use of pure lead significantly reduces plate corrosion, while a TPPL battery with tin-plated brass terminals requires no terminal maintenance.

Battery Maintenance Tips

  • Keep batteries at 100% state of charge and the depth of discharge no greater than 30%.
  • Examine the entire starting/charging system to ensure the alternator is correctly sized for the battery technology used.
  • Test the batteries individually to ensure they are properly charged.
  • Conduct voltage drop testing of the starting/charging system as part of the regular maintenance to identify potential issues.
  • Charge batteries regularly and ensure they are mounted securely and safely.
  • Keep batteries level at all times to avoid dangerous acid spills.
  • When removing a battery from a vehicle, always remove the ground (negative) cable first.
  • Batteries should be stored in a cool dry place, avoiding areas where freezing temperatures are expected and away from direct exposure to heat sources.
  • Don’t leave batteries uncharged for long periods of time.
  • Don’t add water or equalize AGM batteries.

Continental Battery carries a full range of commercial fleet batteries. With the expertise and proficiency of working with the commercial fleet and trucking industry for many years, Continental offers not only top quality products, but also award-winning customer service and support.

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