Battery Technical Manual

Battery Technical Manual for Motorcycles/ATVs/Snowmobiles The information contained in this manual is based on materials from GS Yuasa Corporation and Yuasa Battery, Inc. in the USA. 1/46

Table of Contents 1. Role and Functions of Motorcycle Batteries 2. A Practical Understanding of Lead Acid Batteries 3. Battery Construction 4. Battery Components 5. Types of Motorcycle Batteries 6. Basic Battery Characteristics 7. Handling New Batteries 8. Handling and Storage Before Sales 9. Recharging Batteries 2/46

1. Role and Functions of Motorcycle Batteries Motorcycles use lead acid batteries, which supply electricity to the ignition and lighting systems. Unlike automobile drivers, motorcycle riders can start the engine by kick-starting the engine or pushing the vehicle when the battery is discharged. However, if the battery is not working properly, it may cause a bulb or fuse to blow. Therefore, it is important to understand how a battery functions and follow the correct maintenance procedures to avoid these problems. Battery functions and requirement loads are listed in the following table. Battery Function Supply electricity for starting Small voltage drop Supply high current Power for continuous cranking Supply constant and stable electricity while engine is running Supply electricity for lighting system Maintain stable voltage supply Supply electricity when the load exceeds generator capacity Maintain stable voltage supply Requirement Load Starter motor High torque High current High revolution speed High voltage Cranking time Constant power Ignition system Ignition High voltage Electrical component Lighting Stable voltage Stable operation Absorb voltage fluctuations Proper capacity Backup for electrical load 1.1 Starting Batteries must be able to supply high current and voltage to the starter motor when the starter switch is operated. The power supplied must be sufficient for the starter motor to rotate with enough torque to start the engine even on cold mornings. 1.2 Lighting While a vehicle is being ridden, the battery directly provides a sufficient and stable electricity supply to the lighting and signal components. The battery also stabilizes the electricity supply and acts as a protective buffer in the case of a power surge. 1.3 Ignition Whilst the engine is running, the spark plug ignites the air-fuel mixture in the combustion chamber. To generate the spark at the spark plug, the ignition system requires a stable electricity supply with enough voltage to induce high voltage in the ignition coil. 1.4 Charging Electricity, which is generated by the vehicle, is controlled at a constant voltage by the rectifier regulator and it is used to charge the battery. Because a malfunction may occur if the generated electricity exceeds the proper charging value, the battery absorbs any electricity fluctuations to maintain the correct voltage and protect electrical components. 2. A Practical Understanding of Lead Acid Batteries 3/46

* This chapter comes from the Yuasa Technical Manual, which is available on the Yuasa Battery, Inc. home page. Lead acid batteries are relatively simple in design. Dissimilar metal plates are immersed in an electrolyte solution consisting of sulfuric acid and water. These are then insulated from each other with a permeable, non-conductive material, which allows the transfer of ions. The transfer of ions occurs during the discharge and recharge of the battery. Also occurring is the change in specific gravity or density of the electrolyte. During the discharge period, sulfuric acid is drawn from the electrolyte into the pores of the plates. This reduces the specific gravity of the electrolyte and increases the concentration of water. During the recharge, this action is reversed and the sulfuric acid is driven from the plates, back into the electrolyte, increasing the specific gravity. During the discharge, lead sulfate is being formed on the battery plates. Although this is the normal activity within the battery during discharge, a timely recharge is required to drive out the sulfuric acid into the electrolyte. Without this recharge, the lead sulfate will continue to develop and become difficult if not impossible to break down during recharge. Once this advanced sulfation develops, permanent capacity loss or total failure of the battery is likely. Besides the sulfation concerns, many other detrimental actions are taking place inside the battery while in a discharged condition. The corrosive effect on the lead plates and connections within the battery is greatly increased due to the reduced specific gravity of the electrolyte. The corrosion of the plates will typically result in a gradual reduction in performance followed by battery failure. The corrosion associated with the inter cell connectors and the connecting welds will in many instances result in a sudden battery failure. The corroded connector may have sufficient integrity to support low drain accessories such as lights and instruments, but lack the necessary strength to provide the high discharge current required to start the vehicle. This corrosive effect can also dissolve the lead into solution, which in turn may compromise the plate insulators and result in micro shorts. Another condition that frequently occurs in a discharged battery is freezing. In a deeply discharged battery, the electrolyte has a reduced specific gravity and becomes a higher percentage of water than sulfuric acid. During this condition, the battery may freeze at temperatures as high as 0 C (32 F). The electrolyte in a fully charged battery will not freeze in temperatures down to around 50 C ( 65 F). Deep discharge can be created by a multitude of conditions, but the predominant reason is neglect. During long periods of storage, the battery state of charge must be checked and maintained per the battery manufacturer s recommendations. Other conditions that can drain the battery are inoperative or inadequate charging systems on vehicles, parasitic or key off drains, loose or dirty terminal connections, etc. Although many of these conditions can be corrected, often the problems you cannot correct may be overcome by a periodic charging schedule. You can establish a routine by which you check and charge the customer s battery or recommend permanently attaching a backup charger while the vehicle is not in use. 4/46

When charging the customer s battery, always refer to the instructions on both the battery and the charger. While maintaining the customer s battery at a full state of charge will insure optimum life, overcharging may significantly reduce it. With a conventional type battery that offers access to the cell compartments, the periodic addition of distilled water may be required. Water loss is normal in these batteries through the process of electrolysis and evaporation. Low electrolyte levels that expose the lead plates to the air will result in permanent damage to the battery. Maintain the electrolyte levels above the minimum fill line on the battery and at or below the maximum line. A sealed (Valve Regulated Lead Acid) battery should be maintained with the same care as a conventional type battery with the exception of the addition of distilled water. Sealed VRLA batteries have a predetermined quantity of electrolyte added at the factory or in the field using the acid bottle specified for the battery. Once activated, the battery is permanently sealed and must never be opened. 3. Battery Construction 5/46

Motorcycle batteries are divided into two types by construction. One is the normal vented lead acid battery type and the other is the VRLA (Valve Regulated Lead Acid) battery type. The battery size and shape are different for each type and the batteries are classified as follows. 3-1 Vented Lead Acid Battery Small motorcycles use this type of battery. Batteries are comprised of multiple battery cells that are connected in series. A single cell generates about 2 V of electricity. Accordingly, a 6 V battery consists of 3 cells and a 12 V battery consists of 6 cells. Electrolyte plug Exhaust elbow joint Terminal Negative plate Separator Positive plate 3-2 VRLA (Valve Regulated Lead Acid) Battery 6/46

This type of battery is sometimes called a sealed battery or MF (maintenance free) battery. Recently, however, battery manufacturers call these batteries VRLA, because this term properly expresses the construction compared to other terms. The term VRLA is also written on the battery case. VRLA batteries were developed for the following reasons: a) Demands for modern motorcycles are for vehicles that are lighter and smaller than automobiles. As a result, the installation space for the battery is smaller and locations where the battery can be installed are limited. b) Off-road motorcycles operate under harsh conditions with significant movement. Therefore, these motorcycles require batteries that do not spill electrolyte. c) Scooters require a large helmet storage space. Therefore, the space for the battery is reduced to accommodate this larger storage space. d) During long storage periods, such as during the winter season, batteries need to have less self-discharge. For the above-mentioned reasons, VRLA batteries were developed and constructed as follows: a) Due to the battery construction, no inspection of the electrolyte level and no refilling of the distilled water are required. As a result, the battery does not have a refilling plug and is completely sealed. This is why a VRLA battery is sometimes called a sealed battery. b) A special separator holds the electrolyte itself; therefore, the electrolyte does not move in the battery case. c) A pressure regulator rubber valve (control valve) and safety valve with filter are used. d) Recently developed VRLA batteries are approximately half the size of vented type batteries. Some VRLA batteries are filled with electrolyte and charged at the factory. Cover body (P.P.) Seal cap Safety valve with filter Terminal (leadcalcium alloy) Pressure regulator rubber valve (control valve) Negative plate Battery case Special separator 4. Battery Components Positive plate 7/46

4-1 Plate The plate is made from a lead alloy grid and filled with an active material. The active material of the positive plate is lead dioxide and it has a chocolate brown color. The active material of the negative plate is sponge lead and has a lead gray color. Vented type batteries use a lead-antimony alloy for the grid and VRLA type batteries and highperformance batteries use a lead-calcium alloy. Batteries that use a lead-calcium alloy have less self-discharge and a smaller decrease in the electrolyte. Grid Positive plate Negative plate 4-2 Separator and Glass Mat The board, which is inserted between the positive plate and negative plate, is called the separator. The function of the separator is to prevent a short circuit between the plates. The separator is made of a glass or synthetic fiber, which is highly resistant to acid, and has many pores to facilitate an electrochemical reaction. 4-2-1 Separator for Vented Type Batteries The separator is made of a porous synthetic fiber with good permeability for ions. 4-2-2 Glass Mat The glass mat for vented type batteries is made from crossed glass fibers and it exerts pressure on the positive plate. The pressure keeps the active material on the positive plate. Because motorcycles are subject to more vibration than automobiles during operation, it is necessary for the glass mat to exert more pressure to prevent deterioration of the plate. 4-2-3 Separator for VRLA Batteries A special fine glass fiber separator is used, which holds the electrolyte itself. The separator transports the oxygen gas from the positive plate to the negative plate. 4-3 Electrolyte 8/46

The electrolyte of the battery is dilute sulfuric acid and is a colorless clear liquid. It plays an important role in charging and discharging. Generally, the standard specific gravity of electrolyte is 1.280 at 20 C. The specific gravity of the electrolyte for VRLA batteries is 1.320 at 20 C, which is higher than the specific gravity for vented type batteries. VRLA batteries require a precise amount of electrolyte to be held in the separator. If there is too much electrolyte, it will overflow and if there is too little electrolyte, performance will decrease. Therefore, the precise amount of electrolyte for each cell is contained in the bottle that comes with new VRLA batteries. Always use the correct amount of electrolyte for each battery. 4-4 Case and Cover The battery case and cover are made of polypropylene or ABS resin. The battery case is divided into 3 cells for 6 V batteries and 6 cells for 12 V batteries. Vented type batteries have a separate filling plug for each cell, but the gas exhaust system is centralized. VRLA batteries are sealed after being filled with electrolyte and they have no ventilation during normal operation. However, if the internal pressure increases significantly, such as due to overcharging, a rubber safety valve (regulator valve) opens to release the pressure. The safety valve is equipped with a ceramic filter to prevent ignition of the vented gases due to an external spark. 4-5 Terminal Types 4-5-1 Bolt and Nut Terminal A bolt and nut are used to secure the motorcycle wire harness to the battery. Typically, the bolt size is 5 mm or 6 mm and an additional bracket is sometimes used to accommodate alternate tightening directions on some motorcycles. 4-5-2 Quick Fastener Terminal A flat plate type terminal is used for small capacity batteries. The motorcycle wire harness has a quick coupler. 4-5-3 Lead Wire Terminal Small 6 V batteries have lead wires, which are used to connect to the wire harness. The positive lead has a male terminal and the negative lead has a round female terminal. To insure good conductivity, battery terminals should always be clean and tightened securely. 9/46

4-6 Exhaust Tube When a battery is charging, oxygen gas and hydrogen gas are generated. To release these gases from inside the battery, the battery has an internal central exhaust passage, which leads to the exhaust elbow joint. Because these gases contain acid, they will corrode motorcycle parts. Therefore, an exhaust tube is fitted onto the exhaust elbow joint and routed carefully so that the gases will be vented at a location that will not damage the vehicle. Never pinch or kink the exhaust tube that is used to release the gases. If the exhaust gases are not released, high pressure will build up in the battery, possibly causing the battery case to deform or even cause the case to rupture. The exhaust tube has a slit in the battery end of the tube to release gases in case the exhaust tube is pinched or kinked. If you use a new normal tube as a substitute for the exhaust tube, be sure to keep same length then cut. Make a slit in the end of the tube that is connected to the battery. Also, make sure that the length of the tube is sufficient to release the gases in a safe location that will not damage the vehicle. The exhaust elbow joint of a new vented type battery is plugged using a rubber plug. The rubber plug prevents oxidization of the negative plates. Do not remove this plug until the battery will be used. After filling the battery with electrolyte and installing it onto the motorcycle, be sure to remove the rubber plug and install the exhaust tube. If the rubber plug is accidentally left installed, pressure will build up in the battery, possibly causing the battery case to deform or even cause the case to rupture. Slit Exhaust tube routing Do not pinch or kink Outlet position Never place near chain or frame parts 10/46

5. Types of Motorcycle Batteries The battery model code is classified into 3 types. The naming for each type is different. The naming is as follows. 5-1 Normal Motorcycle Battery 12 N 9-4B - 1 1 2 3 4 5 1 Indicates voltage 6 = 6 V 12 = 12 V 2 Indicates normal motorcycle battery 3 Indicates type of battery case (external dimensions) 4 Indicates terminal shape and position of exhaust elbow joint 5 Indicates terminal pattern if shape is different 5-2 High-Performance Motorcycle Battery YB 10 L - A2 1 1 2 3 Indicates high-performance 4 battery 2 Indicates type of battery case (external dimensions) 3 Indicates battery polarity 4 Indicates terminal shape and position of exhaust elbow joint 5-3 VRLA Battery YTX 7 L - BS 1 2 3 4 1 Indicates VRLA battery Codes YT, YTR, YTZ, and GT are used in addition to YTX 2 Indicates starting performance of normal battery that corresponds to VRLA battery A = Downsized 3 Indicates battery polarity 4 Indicates readiness type 6. Basic Battery Characteristics As already mentioned, motorcycle batteries are classified into 2 types: vented lead acid type and VRLA type. 11/46

Lead sulfate Lead dioxide Lead sulfate S e p ar at or Lead sulfate Lead Lead sulfate The characteristics of each battery are as follows. 6-1 Chemical Reaction of Battery 6-1-1 Vented Type Batteries a) Electrochemical Reaction during Discharging During discharging, accumulated chemical energy at the positive plate and negative plate is converted into electric energy. Due to an electron transfer, both the lead dioxide of the positive plate and the lead of the negative plate are converted into lead sulfate. During this electrochemical reaction, water is generated, which dilutes the electrolyte. As a result, the specific gravity of the electrolyte lowers. Therefore, the specific gravity of the electrolyte indicates the battery condition. As the electrolyte is diluted by water during discharging, it may freeze more easily than the electrolyte in a fully charged battery. Load Light, Ignition + + Negative plate Positive plate Lead Lead sulfate Lead dioxide Lead sulfate Electrolyte Sulfuric acid Diluted by water Formula 1: Electrochemical Reaction during Discharging Positive plate: PbO 2 + 4H + 2- + SO 4 + 2e - PbSO 4 + 2H 2 O 2- Negative plate: Pb + SO 4 PbSO 4 + 2e - Pb : Lead 2- SO 4 : Sulfate Ion PbO 2 : Lead dioxide 2e - : Electrons PbSO 4 : Lead sulfate H + : Hydrogen Ion b) Electrochemical Reaction during Charging During charging, electrical energy accumulates in the positive plate and negative plate as chemical energy. The lead sulfate of the positive plate is converted back to lead dioxide and the 12/46

Le ad sulf ate Lead dioxide Le ad sulf ate S e p ar at or Le ad sulf ate Lead Le ad sulf ate lead sulfate of the negative plate is converted back to lead. The sulfur that is released from the positive plate and negative plate returns to the electrolyte. Charger Generator + + Negative plate Positive plate Lead sulfate Lead Lead sulfate Lead dioxide Electrolyte Dilute sulfuric acid Former specific gravity electrolyte Formula 2: Electrochemical Reaction during Charging Positive plate: PbSO 4 + 2H 2 O PbO 2 + 4H + + SO 4 2- + 2e - Negative plate: PbSO 4 + 2e - Pb + SO 4 2- c) Electrochemical Reaction during Charging and Discharging Formula 1 (electrochemical reaction during discharging) and formula 2 (electrochemical reaction during charging) can be expressed as a single formula as follows. Positive plate Electrolyte Negative plate Positive plate Electrolyte Negative plate PbO 2 + 2H 2 SO 4 + Pb PbSO 4 + 2H 2 O + PbSO 4 Charged condition Discharged condition d) Electrochemical Reaction at Terminal State during Charging When the battery is fully charged, the active materials of the positive plate and negative plate have almost fully been converted back lead dioxide and lead respectively. If charging continues, 13/46

Lead dioxide S e p ar at or Lead the charging current will decompose the water in the electrolyte into its elements, hydrogen and oxygen. These generated gases are vented into the atmosphere through the exhaust system of the battery. During charging, the battery must be kept away from sparks and flames because hydrogen is highly flammable. If the electrolyte level decreases due to this electrochemical reaction during charging and if water is not supplied during maintenance, the positive and negative plates will be exposed to the air. If the positive and negative plates are exposed to the air, they will oxidize, forming lead sulfate. The lead sulfate prevents the electrochemical reaction and reduces the battery performance. In addition, a low electrolyte level also causes other problems. Concentrated electrolyte causes corrosion of the plates. Therefore, to insure a long battery life, do not allow the electrolyte to decrease to a low level. Hydroge n Charger Generator + Oxyge n + Exhaust elbow joint Hydroge n Oxygen Electrolyte Formula 3: Electrolysis of Water at Terminal State during Charging Electrolysis of water: H 2 O 1/2 O 2 + H 2 (Electrolyte decrease) decrease) Formula 4: Gas Generation by Electrolysis of Water Positive plate: H 2 O 1/2 O 2 + 2H + + 2e - Negative plate: 2H + + 2e - H 2 Although the gases are generated as indicated in the above formulas, they are not generated at the same time. Oxygen is generated during the middle and at the end of the charging period while hydrogen is generated during the final period. 6-1-2 VRLA Batteries a) Construction and Electrochemical Reaction during Discharging The electrochemical reaction in VRLA batteries is the same as in normal vented type 14/46

Le ad sulf ate Le ad Le ad Lead sulf sulf dioxide ate ate L ead Le ad sulf ate batteries. The difference is the battery construction. In VRLA batteries, the battery case is sealed using the pressure regulator rubber valve (control valve) and flow of the electrolyte is very low compared to that in vented type batteries. The electrolyte is impregnated into the separator and the negative plate has a larger capacity to absorb oxygen from the positive plate when the battery is close to fully charged. - - Load Light, Ignition + + Pressure regulator rubber valve (control valve) Lead for absorbing oxygen Positive plate Negative plate Lead dioxide Lead sulfate Lead Lead sulfate Electrolyte-impregnated separator b) Electrochemical Reaction during Charging During charging of a VRLA battery, the lead sulfate of the positive plate is converted into lead dioxide and the lead sulfate of the negative plate is converted into lead. This is the same as in 15/46

Le ad sulf ate Lead dioxide Le ad sulf ate Le ad sulf ate ead L Le ad sulf ate a vented type battery. However, the negative plate has a larger capacity to absorb oxygen, which is generated at the positive plate. The cycle is repeated at the negative plate. lead lead sulfate + water lead Water is not decomposed by current. This is the reason that the water level does not decrease and there is no need to supply water. However, the lead capacity of the negative plate is limited and if the charging exceeds the capacity, the negative plate will not be able to absorb the oxygen and the pressure will increase. As a result, the pressure valve opens to release gas, which causes the electrolyte level to decrease. Whenever charging a VRLA battery, overcharging must be avoided. To prevent damage due to overcharging, VRLA batteries require a dedicated VRLA battery charger. To absorb oxygen from the positive plate, the construction of a VRLA battery is different from that of a vented type battery and the components of the battery function differently. 1. Quick generated Gas (O 2 ) Movement Oxygen gas has to move quickly from the positive plate to the negative plate. Therefore, electrolyte is completely impregnated into the special porous glass mat separator and controlled so that there is no flow of electrolyte in the battery. 2. Sealing from Air Air (O 2 ) from the atmosphere must not contact the negative plate. The pressure regulator rubber valve (control valve) is used to prevent the intake of air when the pressure inside the battery is negative. However, the valve functions to release the positive gas pressure when the battery is overcharged. - 3. Less Self-Discharge Pressure regulator Self-discharge generates a small amount of water. The positive and negative rubber valve grids are (control valve) Lead made of lead-calcium alloy, not lead-antimony alloy. The lead-calcium alloy grid provides less self-discharge. - Charger Generator + + Discharging Lead sulfate + Water Lead for absorbing oxygen 1/2 oxygen Lead Water Positive plate Lead sulfate Lead dioxide Negative plate Lead sulfate Lead Electrolyte-impregnated separator 16/46

c) Electrochemical Reaction during Charging and Discharging The discharging and charging electrochemical reaction is the same as in vented type batteries. The difference is that the negative plate absorbs oxygen from the positive plate and produces water. The water returns to the separator and is not released from the sealed battery case except during overcharging. d) VRLA Battery Electrochemical Reaction Oxygen is converted back into water at the negative plate. Negative plate Oxygen generated at positive plate Electrolyte Negative plate (partial discharging) Water generated at negative plate Pb + 1/2 O 2 + H 2 SO 4 PbSO 4 + H 2 O cf. Gas generation is the same as in vented type batteries. Positive plate: H 2 O 1/2 O 2 + 2H + + 2e - Negative plate: 2H + + 2e - H 2 Although the gases are generated as indicated in the above formulas, they are not generated at the same time. Oxygen is generated during the middle and at the end of the charging period while hydrogen is generated during the final period. 6-2 Relationship between Specific Gravity and Discharge Amount 6-2-1 Specific Gravity 17/46

The specific gravity is proportional to the charging state of the battery. Therefore, you can measure the specific gravity to check the battery charge. However, the specific gravity does not increase linearly during charging due to a dispersion delay. Therefore, the battery charge cannot be checked by measuring the specific gravity during charging. Relationship between Electrolyte Specific Gravity and Discharging Rate of Vented Type Batteries Open Circuit Voltage 12.72 V Specific Gravity 1.280 12.48 V 1.260 1.240 Good 1.220 12.24 V 12.00 V 1.200 1.180 1.160 1.140 Need charging 11.76 V 1.120 100% Charge 50% Discharge Fully Discharged Discharging Ratio % 6-2-2 Open Circuit Voltage Because the battery case is sealed, you cannot check the specific gravity of VRLA batteries. 18/46

Therefore, you have to check the open circuit voltage to check the battery charge. Note: The relationship between the open circuit voltage and the charging state of VRLA batteries is not the same as with vented type batteries. Relationship between Open Circuit Voltage and Discharge Rate of VRLA Type Batteries Open Circuit Voltage 13.0 V 12.8 V 12.6 V Good 12.4 V 12.2 V 12.0 V 11.8 V 11.6 V 11.4 V Need charging 11.2 V 100% Charge 50% Discharge Fully Discharged Discharging Ratio % 6-3 Open Circuit Voltage of VRLA Batteries after Filling with Electrolyte Dry type VRLA batteries have to be filled with electrolyte before use. After the battery is filled with electrolyte, the open circuit voltage will be 12.6 12.8 V even without charging. This is because simply filling the battery with electrolyte will give the battery a charge of around 80%. In addition, the concentration of the electrolyte near the plates temporarily decreases while the electrolyte is being added. The electrolyte is not stable immediately after filling the battery; therefore, you must wait more than 20 minutes before sealing the battery then installing the seal cap. Following condition battery needs charging as instructed battery case. a) Removed seal cap battery before filling electrolyte b) Hard to start engine due to winter cold temperature and long stocked battery after manufacturing. Note: You cannot accurately check the battery during charging or immediately after charging has finished. Wait around 30 minutes until the battery state has stabilized before checking the specific gravity or voltage for both vented type batteries and VRLA batteries. 6-4 Open Circuit Voltage Changes after Charging is Finished After charging, the battery voltage changes as shown in the following graph. 19/46

Wait around 30 minutes until the battery state has stabilized before checking. Charging Stop Charging (Ambient Temperature: 25 ー C) Terminal Voltage 18.0 V 17.0 V 16.0 V 15.0 V 14.0 V 13.0 V 12.0 V 11.0 V 10.0 V 6-5 Temperature Conversion Formula for Electrolyte 0 10 20 30 40 50 60 Elapsed Time (Minutes) The specific gravity of electrolyte changes according to the temperature. If the temperature is extremely high or low, you have to adjust the hydrometer reading. This is because the electrolyte volume increases or decreases according to the temperature although the mass does not change. Use the following formula to convert the specific gravity according to the temperature. D 20 = D t + 0.0007 (t-20) D 20 : Specific gravity after conversion according to temperature D t : Measured specific gravity at temperature t* t : electrolyte temperature when it is measured. * Temperature in degrees Celsius 6-6 Final Discharge Voltage When the battery is discharging at a constant current, the voltage drops gradually, then it drops 20/46

more quickly past a certain limit point. If the battery is discharged to 0 V, it cannot recover to its former state even if it is recharged. Therefore, to keep the battery in good condition, the voltage should not decrease to lower than this minimum voltage. This minimum voltage is called the final discharge voltage. The discharging characteristic and final discharge voltage are shown in the following graph and table. Discharging Characteristic Curve Terminal Voltage (V) 12.6 V 12.0 V 11.4 V 10.8 V 10.5 V 10.2 V Final Discharge Voltage 9.6 V 0 1 5 10 Discharging Time (Hours) Final Discharge Voltage Discharging Rate Final Discharge Voltage/Cell 12 V Battery 5 10 hours 1.75 V 10.5 V 1 hour 1.60 V 9.6 V High-rate discharge 1.0 V 6.0 V 21/46

6-7 Battery Capacity 6-7-1Motorcycle Batteries The battery capacity means the amount of electricity that can be obtained from a battery. It is expressed as a product of the discharge current in amperes (A) and the discharge time in hours (h). The actual capacity is measured as the number of hours required for a 100% charged battery to reach the discharge final voltage using a constant discharge rate and it is expressed using the following formula. Capacity (Ah) = Discharge current (A) x Discharging time to final discharge voltage (h) Discharging is an electrochemical reaction between the active materials of the electrodes and sulfuric acid. If the discharging current is too large, the dispersion of the sulfuric acid cannot match the discharging speed. As a result, the quantity of sulfuric acid decreases around the electrodes and the voltage decreases much more than with a small discharge current. Therefore, the battery capacity is small for a high-rate discharge. A motorcycle s battery capacity is expressed at a 10-hour discharge rate. For example, if 11.2 Ah is indicated on the battery case, the battery can supply 11.2 A in the 10 hours. The following graph shows the discharge characteristics according to the discharge rate. In the case of an 11.2 Ah/10 hour battery, 0.1C equals 1.12 A and the blue line shows a discharge characteristic of 1.12 A per hour. 1C equals 11.2 A per hour and the red line shows the discharge characteristic. Therefore, in the case of 11.2 A, the battery is completely discharged within an hour and the final discharge voltage is around 9.5 V or less. Discharge Characteristics of a VRLA Battery C = 10-Hour Rate Capacity (Ambient Temperature: 25 ー C) Terminal Voltage (V) 13.0 V 12.0 V 11.0 V 10.0 V 9.0 V 0.4C 0.6C 1C 0.2C 10-hour discharge rate 0.1C 8.0 V 2C 0 1 5 Discharging Time (Hours) 22/46 10

Battery capacity 6-7-2 Automobile Batteries Automobile batteries use different discharge capacity standards. One standard uses a discharge rate, which is the same as motorcycles, but the time and current are different. DIN: 20-hour discharge rate to reach final discharge voltage of 10.5 V SAE: Reserve capacity (RC): Time to reach final discharge voltage of 10.5 V RC is one of the indications for battery capacity. Battery condition: Fully charged Discharge current: 25 A current drain* * A typical automobile consumes around 25 A under an average electrical load and the vehicle can supply power to necessary electrical components using 10.5 V. JIS: 5-hour discharge rate to reach final discharge voltage of 10.5 V Another standard to test battery capacity is Cold Cranking Ampere (CCA). DIN, SAE, and JIS used different methods for CCA. But recently it is unified and now EN=IEC=SAE=JIS The details are as follows. Battery condition: Fully charged Temperature: 18 C Under the above conditions, CCA is the amount of current the battery can supply for 30 seconds while maintaining at least 7.2 V. 7.2 V is the minimum voltage required for the ignition system to operate and the maximum cranking time is considered to be 30 seconds. CCA means the starting ability of the engine using the battery capacity under cold conditions. Therefore, the larger the CCA value, the higher the starting ability. 23/46

12.0 V 11.0 V 10.0 V Fully charged battery 8 ー C 7.2 V after 30 seconds 9.0 V 8.0 V 7.0 V 7.2 V 0 V 0 CCA Value (A) 6-7-3 Correspondence for EU regulation From 2010 model, new battery will have EU standards indication. EU battery capacity is indicated by 20HR rate compare to JIS 10HR rate. Even battery is the same, indication is little different by discharging hours. For example, YTZ12S capacity is 11Ah by 10 hours discharging and 11.6Ah by 20 hours discharging. Also CCA value is also following EU standards. VRLA battery positive plate and negative is close compare to vented battery and CCA value (high rate discharge ability) is higher than vented battery. Capacity is proportional to size of plate. So CCA difference is smaller than capacity difference compare to VRLA battery and automobile vented battery. EU standards indication for capacity EU standards CCA JIS indication (Japanese industrial standards) 24/46

6-8 Temperature and Battery Capacity The battery capacity changes according to the electrolyte temperature. As a result, it is more difficult to start an engine under cold conditions. The reason is that the battery cannot discharge due to the low electrolyte temperature. In addition, the engine requires more cranking power under cold conditions because the oil becomes more viscous, which creates higher resistance. The motorcycle battery capacity is measured at 25 C using a 10-hour discharge rate. 120 110 Capacity (%) 100 90 80 70 60 50 40 0 10 10 20 30 40 Electrolyte Temperature The relationship between the temperature and the starting requirements is shown in the following table. Engine Starting Torque Battery Power Battery Fatigue 25 C 100% 100% 100% 0 C 160% 80% 200% 18 C 250% 50% 500% For vehicles, such as snowmobiles and ATVs, which are used and stored in very cold conditions, the battery and engine require heating by an external power source. This is because the engine requires a lot of power for cranking due to the large oil resistance and the starter motor needs more electricity. 25/46

6-9 Electrolyte Freezing Point During discharge, the specific gravity of the electrolyte decreases and the concentration of water, which freezes at 0 C, increases. Accordingly, if the battery is discharged completely and the electrolyte specific gravity is low, the electrolyte may freeze. This will seriously damage the plates, separator, and battery case. If the battery will be stored under cold conditions, the battery should be charged fully before storage. Freezing area 26/46

6-10 Discharge 6-10-1 Self-Discharge Battery electricity is consumed inside the battery over time regardless of whether the battery is connected to any electrical components. This is called a battery self-discharge. The battery electricity decreases day by day while the motorcycle is stocked and both vented type batteries and VRLA batteries require periodic maintenance. Some foreign metals (impurities), which exist in the battery, separate out on the plate and create a local battery. Current flows from the foreign metal to part of the plate, which consumes electricity. This phenomenon occurs more if the battery is filled with dirty water that includes impurities. In addition, self-discharge is higher for battery grids that contain antimony, such as those in vented type batteries. Current Foreign metal Local battery creation Examples of Foreign Metal Platinum (Pt) Gold (Au) Silver (Ag) Nickel (Ni) Copper (Cu) Antimony (Sb) Negative plate 6-10-2 Amount of Self-Discharge The amount of self-discharge is affected by several factors. 1. Time after Charging The amount of self-discharge is large immediately after charging, then it decreases proportionate to the elapsed time. 2. Temperature Self-discharge is proportionate to the temperature. When the electrolyte temperature is high, self-discharge increases. As a result, self-discharge increases during the summer time and the battery discharges more quickly. 3. Polar Grid Material VRLA batteries, which use a lead-calcium alloy grid, have less self-discharge than vented type batteries, which use a lead-antimony alloy grid. In general, a VRLA battery discharges 2.5 4% per month and a vented type battery discharges 5 8% per month although this varies according to the actual state of the battery. 27/46

The relationship between the storage time and the remaining capacity according to the temperature is shown in the following graph. Battery type: VRLA battery YT4L-BS Vented type battery YBN4L-B 100 Remaining Capacity (%) 90 80 70 60 50 40 ー C 25 ー C 0 ー C 0 ー C 25 ー C 40 ー C 40 0 1 2 3 4 5 6 7 Storage Time (Months) 28/46

6-10-3 Dark Current (Current Drain) Motorcycle electrical systems consume a small amount of electricity even when the main switch is turned to the off position because the Immobilizer, clock, computer memory, and other components require a constant supply of electricity to function properly. This is called dark current or current drain. In addition, if the customer installs additional electrical accessories onto the motorcycle, the battery voltage will decrease even more and the battery will discharge quickly. Therefore, if the motorcycle is stored for a long time, the battery requires periodic maintenance regardless of whether it is a vented type battery or VRLA battery. Example of Discharge by Dark Current Dark current: Storage time: Battery capacity: 0.002 amperes 90 days 11.2 Ah 0.002 x 24 hours = 0.048 Ah 0.048 x 90 = 4.32 Ah 4.32 11.2 = 0.385 x 100 = 38.5% 38.5% of the electricity is lost by the dark current in 90 days. Checking the Dark Current To check the dark current, a multimeter is required that can measure the current in mma units while the main switch is turned to the off position. Do not turn the main switch to the on position. If the main switch is turned to the on position, a large current will flow, which could cause the fuse of the multimeter to blow. Battery Multimeter Negative battery lead To wire harness 29/46

6-10-4 Total Discharge When vehicle is stored, the battery discharges by self-discharge and the dark current. The following examples show the amount of discharge during 3 months of storage. Example of Vented Type Battery Model: YBR125 Battery capacity: 5.0 Ah Self-discharge at 25 C: 7% per month Dark current: 0.001 A Self-discharge: 5 Ah x 0.07 x 3 months = 1.05 Ah Dark current: 0.001 A x 24 hours x 90 days = 2.16 Ah Total discharge: 1.05 Ah + 2.16 Ah = 3.21 Ah 3.21 5.0 = 0.628 x 100 = 62.8% Example of VRLA Battery Model: Battery capacity: Self-discharge at 25 C: Dark current: FZ1 11.2 Ah 4% per month 0.002 A Self-discharge: 11.2 Ah x 0.04 x 3 months = 1.34 Ah Dark current: 0.002 A x 24 hours x 90 days = 4.32 Ah Total discharge: 1.34 Ah + 4.32 Ah = 5.66 Ah 5.66 11.2 = 0.505 x 100 = 50.5% Battery discharges naturally day by day. Therefore, if the vehicle is stored for a long time, periodic charging is necessary. Lead sulfate, which is created on the plates during discharging, will crystallize. Once the lead sulfate crystallizes, it will be very difficult to remove from the surface of the plate and battery performance will decrease. Therefore, periodic charging is very important during long-term storage to insure long battery life. 30/46

6-11 Charging Methods and Characteristics 6-11-1 Charging Vented Type Batteries When a discharged vented type battery is charged using a constant current, the standard current is 10% of the battery capacity. When the charging of a discharged battery using a constant current begins, the voltage and specific gravity will initially increase at a slow rate. Once the battery voltage reaches around 14.1 14.4 V (2.35 2.4 V per cell), gassing starts. After the gassing starts, the voltage will increase quickly. At the end of the charging and past the gassing starting point, voltage increases quickly and reaches the maximum voltage. Accordingly, once the gassing starts, the charging is nearly complete. Terminal Voltage Vented Type Battery Charging Characteristics 18.0 V 1.30 17.0 V 16.0 V Gassing point 1.20 15.0 V 1.10 14.0 V Electrolyte Electrolyte Specific Gravity 13.0 V 12.0 V Temperature 30 11.0 V 20 2 4 6 8 10 12 14 Charging Time (Hours) 16 31/46

6-11-2 Charging VRLA Batteries When the charging begins, the battery voltage increases, which is the same as with a vented type battery. However, when the gassing starts, the oxygen is absorbed by the negative plate, which causes the voltage to be unstable. In addition, the amount of electrolyte that flows is low compared to a vented type battery. Therefore, overcharging, which reduces the amount of electrolyte, must be avoided. Once the electrolyte is lost, battery performance will be lost. Less flowable electrolyte can lead to higher battery temperatures and cause increased self-discharge and overcharging. The charging current should be kept under 10% of the battery capacity and the voltage should be kept under 15 V. The charging current when the battery is at a fully charged state should be kept under 5% of the battery capacity. If a VRLA battery is deeply discharged, it will be difficult to recover the battery capacity compared to a vented type battery. Therefore, charging a deeply discharged VRLA battery requires a higher voltage to break down the sulfation (lead sulfate) of the plates. For the above-mentioned reasons, a VRLA battery needs a special charger for optimum charging that controls the current and voltage as shown in the following graph. Charging Current (A) Terminal Voltage (V) VRLA Battery Charging Characteristics by constant voltage charger 2.5 20 V 2.0 16 V 1.5 12 V 1.0 8 V 0.5 4 V Charging current 0 2 4 6 8 10 12 14 Charging Time (Hours) 32/46

7. Handling New Batteries 7-1 Removing Old batteries 1. Turn the main switch to the off position to stop the engine. Do not stop the engine by disconnecting the negative lead. Otherwise, electrical components could be damaged and the electrical system could malfunction. 2. Always disconnect the battery lead from the negative battery terminal to prevent short circuits. Then, disconnect the positive lead. 3. Remove the exhaust tube from the exhaust elbow joint. Then, remove the battery. 4. If the terminals are corroded, clean them. 7-2 Preparing New Batteries Always wear rubber gloves and protective eye wear when handling electrolyte. 1. There are many battery sizes and capacities. Therefore, choose the battery that is suitable for the vehicle from the compatibility list. 2. Fill the battery with the correct electrolyte. * Vented type batteries and VRLA batteries use electrolyte with a different specific gravity, which must never be mixed. Vented type battery electrolyte specific gravity: 1.280 VRLA battery electrolyte specific gravity: 1.320 Also, VRLA batteries require the correct amount of electrolyte to obtain their full performance. Always use the electrolyte bottle that comes with the battery. * If the battery is filled with electrolyte at the factory, it does not have to be refilled. 33/46

7-3 Activating Vented Type Batteries and Filling with Electrolyte 1. Remove the filling plugs and cap from the exhaust elbow joint. * Never reinstall this cap onto the exhaust elbow joint. Otherwise, the battery could explode. 2. Prepare the electrolyte. 3. Place the battery on a level surface and fill it with electrolyte up to UPPER LEVEL indicated on the battery. 4. Wait until the electrolyte level has stabilized. Once the level goes down, add electrolyte up to UPPER LEVEL again. 5. Let the battery stand for 20 30 minutes after filling it with electrolyte. The electrolyte needs time to disperse through the separator. 6. After the battery is filled with electrolyte, it is able to supply electricity. However, the battery is only able to provide around 80% of its full capacity. After the battery is filled with electrolyte, initial charging is recommended. Initial charging will insure a longer battery life. Charge the battery for 2 3 hours at a current equivalent to 10% of its rated capacity, which is indicated on the battery case. * During charging, electrolyte may spill out of the open battery filling holes. Be sure to loosely refit the filling plugs before charging the battery. 7. After the initial charging, if the electrolyte level has decreased, add electrolyte up to UPPER LEVEL. 8. After the charging is complete, tighten the filling plugs firmly. However, do not over-tighten the filling plugs. 9. Wash off any spilled electrolyte from the battery using plenty of water. Pay particular attention that any electrolyte is washed off of the terminals. Then, dry the battery completely. Electrolyte 5 30 C UPPER LEVEL LOWER LEVEL Remove cap 34/46

7-4 Activating VRLA Batteries and Filling with Electrolyte When activating the battery, check the following points: * Always use the electrolyte bottle that is packed with the new battery. VRLA batteries need electrolyte with a different specific gravity than that for vented type batteries. In addition, VRLA batteries require an accurate volume of electrolyte for each cell. * Do not remove the foil sheet covering the filling holes before activation. 1. Place the battery on a level surface and remove the foil sheet completely. 2. Keep the electrolyte bottle at a temperature of 5-30 C. 3. Remove the strip cap from the electrolyte bottle. Place the strip cap aside you will use this strip cap as the sealing plug of the electrolyte filling holes of the battery. * Do not open or break the seals of the electrolyte bottle. 4. Place the electrolyte bottle, with the sealed tops of the cells down, into the filling holes of the battery. Hold the bottle level and push down to break the seals. After the seals have broken, air bubbles will appear in the electrolyte as the electrolyte flows into each cell. Do not tilt the electrolyte bottle. 35/46

5. To confirm that the electrolyte is flowing into the cells, check that bubbles have appeared in the electrolyte or that the level of the electrolyte in the bottle goes down gradually. If bubbles do not appear, lightly tap the affected bottle cells with your finger. 6. Let the battery stand for more than 20 minutes to 1 hour under the above condition. 7. After checking that all of the bottle cells are completely empty or that you cannot see any electrolyte in the bottle, remove the electrolyte bottle from the battery and wipe off any spilled electrolyte. 8. After filling the battery with electrolyte, wait 20 60 minutes, and then equally and firmly install the strip cap with both hands. Do not pound the strip cap or use a hammer. 9. After electrolyte has been added, a new VRLA battery is approximately 80% charged and the battery voltage is around 12.5 12.6 V. After filling electrolyte and battery voltage is under 12.4V, recharge battery. 10. Charge the battery using a VRLA battery charger. 11. Following condition battery needs charging as instructed battery case. a) Removed seal cap battery before filling electrolyte b) Hard to start engine due to winter cold temperature and long stocked battery after Handling Points for New Batteries 1. After activation, a new battery is approximately 80% charged. 2. An initial charge is recommended for vented battery. Never quick charge the battery. 3. Charge a new vented battery at a rate of 10% of its rated capacity. 4. The battery temperature must not exceed 50 C. 36/46

8. Handling and Storage before Sales 8-1 Checking before Storage After receiving a new battery from the supplier, check its condition before storage. 1. Check for any packing damage or leaking of electrolyte. 2. For vented type batteries, check that the filling plugs and exhaust tube are securely fitted. 3. For VRLA batteries, check that the proper electrolyte bottle is attached. 4. For VRLA batteries filled with electrolyte at the factory, check the open circuit voltage and recharge the battery if the voltage is below 12.4 V. 8-2 Storage 1. Choose a cool place ( 5 to 15 C). 2. Keep the battery out of direct sunlight and do not store the battery in wet or very humid locations. 3. Avoid long-term storage as much as possible and use proper stock management to sell longer stocked batteries first. 8-3 Recharging during Storage 1. Recharge the battery if 6 months has passed since the battery was manufactured. 2. Recharging every month is recommended for batteries in stock. 3. Recharge batteries using the suitable charging method. 9. Recharging Batteries A battery must be recharged immediately if it is discharged by overuse or from being stored for a long time. If the battery is left with low voltage or in a discharged condition, it may lead to sulfation of the plates and freezing of the electrolyte at low temperatures. Battery recharging is required under the following conditions: Vented type battery: Specific gravity is lower than 1.240 VRLA battery: Open circuit voltage is lower than 12.4 V 9-1 Battery Charger Use a battery charger that is suitable for the small-capacity batteries for motorcycles, ATVs, and snowmobiles. To prevent overcharging, an automobile battery charger is not recommended. VRLA batteries need a dedicated VRLA battery charger. Otherwise, the battery could be overcharged, which could cause a decrease in the electrolyte level, reducing the battery performance. If you do not use a proper battery charger, you cannot expect a full charge and the battery could be damaged. 37/46

9-2 Connecting the Battery and Battery Charger 1. Remove the battery from the vehicle. Do not charge the battery while it is still installed on the vehicle. 2. Remove the battery charger plug from the power outlet to prevent sparking when the battery charger leads are connected to the battery terminals. 3. When connecting the battery charger leads to the battery, make sure to connect the positive and negative leads to the correct terminals. Never reverse the lead connections. Otherwise, the electrical components of the vehicle and the battery could be damaged. 4. Do not connect 2 or more batteries in parallel for charging. It disarranges the charging current. 9-3 Charging Current and Time Different ampere-hour batteries have a different charge rate. For most motorcycle batteries, charge them at 10% of the rated ampere-hour value, which is indicated on the battery case. For quick charges, also follow the value indicated on the battery. Always check the ampere-hour value of the battery and do not overcharge or over quick charge a battery. For Yamaha batteries, see the charts in the Appendix for the charging currents. 9-4 Estimated Charging Times Open Circuit Voltage Estimated Charging Time 12.4 V Within 4 hours 12.3 V Within 6 hours 12.2 V Within 8 hours 12.1 V Within 10 hours 12.0 V Within 12 hours 11.8 V Within 15 20 hours 9-5 Precautions for Charging 1. During charging, the battery temperature will increase. Always keep the battery temperature under 50 C. 2. Charging generates hydrogen gas, which is highly flammable. Do not disconnect the battery charger leads during charging. Otherwise, a spark may be produced. Also, keep any fire or flame away from the battery during charging. Charging Precautions for Vented Type Batteries 1. Remove the filling plugs and exhaust elbow joint cap. 2. Choose a well-ventilated place so that hydrogen gas does not collect. 3. Once the battery starts gassing, charging is almost finished. 4. Check the specific gravity of the electrolyte. When the specific gravity is over 1.270, charging is completed. 5. After finishing charging, disconnect the battery charger plug from the power outlet. 6. Disconnect the battery charger leads from the battery terminals. 7. Tighten the filling plugs and wash off any electrolyte from the battery using plenty of water. Charging Precautions for VRLA Batteries 38/46

1. Never remove the sealing strip cap. 2. Use a VRLA battery charger. 3. When using a normal battery charger, charge the battery using the current and time indicated on the battery case. If the battery temperature rises quickly, stop charging immediately. 4. Always keep the battery temperature under 50 C. 9-6 Finishing Charging Vented type batteries Gassing starts and the specific gravity is 1.270 1.290. VRLA batteries Open circuit voltage is over 12.8 V. 9-7 Measuring the Specific Gravity Using a Hydrometer 9-8 Installing the Batteries 1. Make sure that the positions of the positive and negative terminals are the same as the terminal positions of the removed battery. 2. Hold the battery securely and place it in the battery box. 3. Install the battery holder and tighten the fasteners. 4. First, connect the positive lead. 5. Next, connect the negative lead. 6. Apply a small amount of grease to the terminals to prevent rust. 7. Install the terminal covers. 8. Install the exhaust tube. Make sure that there are no kinks in the tube and that the end of the tube is located in the correct location. 9-9 Check Points for Installation 39/46

Exterior is clean and dry Terminal is clean - Exhaust tube is securely fitted to exhaust elbow joint No kinks or clogs Routing is OK Tube end is located in correct location + Electrolyte level is OK Connect positive lead first Battery holder is securely tightened Appendix 40/46