CLARK FORKLIFT ET102 Batteries and Chargers TECHNICAL TRAINING MANUAL

ET102

Batteries and Chargers

TECHNICAL TRAINING Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

Contents About this class .......................................................................

About safety ................................................................................

Section 1. Construction and Function of Batteries ................

Objectives .....................................................................

Construction of Batteries .................................................

Function of Batteries ... ...................... ........................

Specific Gravity ............................................................

Summary .......................................................................

Section 2. Rating Batteries ..... .............................................

Objectives ........................................................................

Terms for Rating Batteries .......................................

Comparing Battery Power Requirements ........................

Summary ......................................................................

Section 3. Chargers ...........................................................

Objectives ........... ...........................................................

Safety.................................................................................

Types of Charges .... .......................................................

Types of Chargers ...........................................................

A Properly Charged Battery ......................................

Summary ......................................................................

Section 4. Safety ......................................................................

Objectives .................... ..................................................

Hazards ......................................................................

Precautions ................... ........ .... .......................................

Summary ......................................................................

Section 5. Testing and Troubleshooting ...........................

Objectives ........... ...........................................................

Testing ......................................................................

Visual Inspections ....................... .....................................

Hydrometer Reading for Specific Gravity .......... ......

Load Tests .......................... ..............................................

Troubleshooting .............. .................... ...........................

Summary .......................................................................

Section 6. Battery Maintenance..................................................

Objectives ............................ ...........................................

Maintenance .... ................................................. ......

Some DOs and DON'Ts .................. ............................................ .

A Quick Reference for Battery Maintenance ................

Summary ......................................................................

2 3 4 4 4 7 8 8 9 9 9 11 12 13 13 13 15 16 17 18 19 19 19 21 22 23 23 23 23 24 25 26 28 29 29 29 31 31 32

©Copyright Clark Material Handling Company1990.

Revised 1998.

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Batteries and Charger page l

About This Class In this class you will learn basic concepts and service procedures related to the use of batteries in fork lift trucks. The objective of the class is to help you learn basic terminology, tests, and procedures that will help you to service and maintain batteries. You will learn:

• How batteries work • How chargers work • Safety guideli.nes • Service and troubleshooting steps • Maintenance procedures.

The material describes basic concepts common to two types of batteries, Ignition batteries, used to start trucks powered by internal combustion engines (IC trucks) and Motive-Power batteries, used as the power source for electric trucks.

This class consists of six sections:

1. Construction and Function of Batteries 2. Rating Batteries 3. Chargers 4. Safety 5. Service and Troubleshooting 6. Maintenance At the beginning of each section you will be given an explanation of the objectives to achieve for that section. The material and explanations you find will help you reach the objectives.

You will be tested at the end of the day to determine if you have reached the objectives.

Batteries and Chargers page 2

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About safety The following messages may be used to emphasize important information: Note: This message is used when special information, instructions or identification is required relating to procedures, equipment, tools, pressures, capacities and other special data.

Important: This message is used whenspecialprecautions should be taken to ensure a correct action or to avoid damage to or malfunction of the truck or a component.

CAUTION: This message is used as a reminder of safety practices which can result in personal injm-y if proper precautions are not taken.

WARNING: This message is used when a hazard exists which can result in injury or death if proper precautions are not taken.

DANGER: This message is used when an extreme hazard exists which will result in death or serious injury if proper precautions are not taken.

When checkin_g electrical com�nents on an electric truck, always raise tlie drive wheels off the floor and ..Put blocks under the truck, disconnect the battery, and discharge the capacitor. These actions prevent injury to yourself and damage to the truck.

AIW.1!YS familiarize yourself with the safety information in the Operator's and Service Manuals before you operate or repair the truck.

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Batteries and Charger page 3

Section 1. Construction and Function of Batteries This section explains the basic construction of batteries and how they work. These general explanations will be useful for understanding the material in the rest of the manual.

Objectives In this section, you will learn how batteries are constructed and how they work. After reading the material, you will be able to identify the parts of a battery and describe how they use electro-chemical action to produce electricity.

Construction of Batteries This section describes how batteries are made and two different types of lead-acid batteries.

The Battery A battery is a series of cells which accept electrical energy, a charge, by chemical action.The cells of a battery contain a series of alternating positive and negatively charged plates. These plates are grids with a lead compound pasted in place and have a tab, or lug, at the top.

The lead of the positive plates is lead peroxide, plates is sponge lead.

the lead of negative

The lead peroxide of the positive plates is held in place by a wrapping of porous glass and fiberglass materials. The plate is surrounded by a perforated plastic envelope. The wrapping and envelope are intended to keep the lead from shedding while allowing the battery acid to flow freely around the plate. The sponge lead of the negative plates is not affected by the acid in the battery and so does not require a wrap to prevent shedding.

The positive and negative plates are interleaved alternately in the cell.

Every cell has one negative plate added so the sequence always begins and ends with a negative plate. Between each plate is a porous, non­ conducting separator that insulates the plates from one another. The lugs, offset to opposite sides of the cell, are connected in series to a strap that forms the positive and negative terminals, or posts, of the battery. An element is a group of interleaved positive and negative plates with separators inserted. A perforated protector is positioned at the top of the Batteries and Chargers page 4

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element and a sediment bridge is fixed at the bottom. The protector is a slotted, plastic card that holds the plates in position and protects them once the element is inserted into the container. The sediment bridge supports the element at its base and holds the plates and separators in place. When all of the pieces are fitted together the element is inserted into a high-impact, acid-proof container called a jar. Once the element is inserted into the jar, it is fitted with a hard rubber cover that is cemented into place. The cover has lead inserts molded into it that fit around the posts from the positive and negative straps. Lead is use to build up the posts, bond the posts to the cover inserts, and seal the inserts.

A sulfuric-acid and water mixture called the electrolyte is poured into the cell once it is sealed. The cell is now ready for the forming charge.

Battery Cell Reservoir

�+---

Negative Plate

-+---Positive Plate

Separator

Sediment The forming charge is a timed, low amperage-rate charge conducted when the battery is at a specific temperature. These characteristics of the forming charge produce the positive and negative polarities of the plates and develops the Amp-Hour Capacity (AHC) of the battery cell. (Amp­ Hour Capacity is described fully in "Rating Batteries".) The cells are now ready for use, either individually or connected to other cells for added voltage (and AHC). Each cell has a nominal voltage of 2 volts (2V). A 12V battery is therefore six connected cells, a 36V battery is 18 connected cells.

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Batteries and Charger page 5

Types of Batteries There are two types of lead-acid batteries, the Flat Plate battery, described above, and the Tubular Plate battery. The names refer to the construction of the positive plate; negative plates are the same in both varieties.

Flat Plate batteries have the lead peroxide bonded to a flat grid and are wi·apped to protect the lead compound and prevent shedding.

Flat Plate

In Tubular batteries, the positive plates consist of a series of splines or rods connected at the top to the lug portion of the plate. Each spline is covered by the active material (the lead peroxide), held firmly in place by porous wrapping. This is inserted into a perforated tube of polyvinyl chloride (PVC) lined with spun fiberglass. A molded plastic boot at the base of the tube assures retention of displaced, or shed active material.

The charge produced by the chemical effects of the electrolyte is routed to the positive terminal more effectively because of the direct path introduced by the tubular design.

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Tubular plate

Function of Batteries A battery releases power by the chemical action of the electrolyte with the active material of the positive and negative plates. When a battery is connected to an electrical load, the chemical energy is converted to usable electrical energy by this action.

Voltage and electrical potential develops because of the dissimilar metal composition of the positive and negative plates when immersed in the electrolyte. The dissimilarity of lead peroxide and sponge lead causes the sulfuric acid in the electrolyte to bond temporarily to the plates. The resulting chemical reaction changes both the positive plate lead peroxide and the negative plate sponge lead to a lead sulfate composition. As the plates approach the lead sulfate composition, their ability to attract the sulfuric acid, and thus induce chemical reaction, is weakened. No chemical reaction means no electrical potential and so the battery is "discharged", its chemically induced electrical potential is used up.

Charging the battery reverses this process. Once current is conducted into the battery, the water, sulfuric acid, and lead sulfate react. The sulfuric acid returns to the water, the electrolyte mixture approaches its former composition, and the plates return to their lead peroxide and sponge lead composition.

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Batteries and Charger page 7

Specific Gravity Electrolyte is measw·ed in specific gravity. Specific gravity is a measure of the amount of water and sulfuric acid mixed. Water has a specific gravity, or weight of 1.000 and sulfuric acid has a specific gravity of 1.400.

The sulfuric acid is then mixed into the water to form electrolyte. The higher the sulfuric acid content, the higher the electrolyte specific gravity will be. Generally, the specific gravity of electrolyte would be in the range of 1.280 to 1.320.

Important: Discharge should never draw the electrolyte below a specific

gravity of 1.160 in most types of batteries.

There are a number of conditions determining specific gravity, including duty cycle (work loads) and temperatures. Manufacturer's specifications contain full details on specific gravity levels based on charge, discharge and other performance conditions.

Note: See Section 5, "Service and Troubleshooting'' for details on checking

the specific gravity of electrolyte.

Summary In this section, you learned how batteries are constructed and the two types of batteries generally used. You also learned how batteries work and were given a definition of specific gravity for use in measwmg the sulfuric acid and water mix of the battery's electrolyte.

Batteries and Chargers page 8

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