BOLT 8T8920 - Caterpillar

Several factors are important to the selection of a battery for use in diagnostic tools. Some of these are capacity, discharge rate, storage life, price and temperature range where the battery will be used. These factors, and others shown in the chart that follows, will give the user the technical information needed to make the best selection for the application.
The illustrations that follow show the typical voltage discharge curve for the three most common types of batteries. 1.5 volt, "AA" size batteries are shown for illustration purposes. The load is equal (same) and constant for the three batteries.
As seen in Illustration 3, the mercuric oxide (mercury) battery gives a longer life at a more constant voltage. Intermittent (not constant) use will give even longer life. The mercuric oxide battery is used in the 9S9102 Thermistor Thermometer Group, 9S2000 Hydraulic Flowmeter and 1P5500 Tachometer Group.
Because of the more constant voltage output characteristics of the mercuric oxide battery in comparison to the zinc-carbon battery, the "V-adj" setting on these diagnostic tools will need fewer adjustments during use of the tool.
In a flashlight application, constant voltage is not needed and mercuric oxide has a high cost. Carbon-zinc is satisfactory in this application; however, alkaline-manganese dioxide will give a longer service life and is more cost effective.
General Information
For best results, put batteries in a cool, dry storage location. Prevent fluctuations (changes) in the temperature at the storage location. When a large number of batteries are kept in storage, make sure the older batteries are used first.
Remember, a measurement of no-load voltage will not give the correct indication of the battery condition. Battery voltage must be measured under normal operating conditions. If the battery voltage is low and there is more than one battery in the piece of equipment, a replacement of all batteries at the same time is necessary.
Illustration 1. Voltage discharge curve for carbon-zinc battery.
Illustration 2. Voltage discharge curve for alkaline-manganese dioxide battery.
Illustration 3. Voltage discharge curve for mercuric oxide battery.