Foton Series Light Bus. Instruction — part 16

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Chapter 11 Structure, Application and Service of

Electrical Devices & Instrument

11.1 Electrical System Overview

The rated voltage for electrical devices on BJ6536 series of light bus is 12V. Single wire system is adopted

for the circuit of electrical devicess, with negative grounding. The circuit for the complete vehicle is composed of

three major harnesses. Front panel harness is wired inside the cab; body harness is located inside engine

compartment; and chassis harness is arranged inside the frame. The insertings of front panel instrument harness

and chassis harness must be dismantled before cab is to be disassembled.

Most electrical fittings and harnesses are connected with plug connector except very few of them jointed with

bolts, which is beneficial to inspection and maintenance. It is not allowed to randomly change the positions of

plug during use, so as to ensure the reliability and safety of the circuit. All the circuits are fitted with fuses. The

fusible link is designed to protect the vehicle circuit, it breaks when circuit current becomes high. Fusible link

should be replaced after a fault has been removd. It is not allowed to use other metal conductor as fuse.

Refer to the diagram for connection of vehicle electrical devices (See the electrical wiring diagram attached

to this book).

11.2 Fuse Box

Fuse box integrates multiple electrical connections in one place to facilitate easy check and service on

vehicle electrical devices. Refer to the indication diagram and parameters on fuse box cover to locate the wiring of

each device and perform service. Use of other electrical fittings beyond specfication is not allowed..

11.3 Troubleshooting

If faults are noticed during driving and sevice check, operator can pinpoint fault locations according to

electrical diagram, performs service or replacement. Never change connector location at random or connect wrong

wire. Fault check starts with the most convenient place, and places where faults frequently happen such as

bulb/fuse, and plug-in connectors..

11.3.1 Gasoline Engine Failure Startup

Use elementary diagram to remove gasoline engine fault. Here are some typical faults during startup:

(1) While ignition switch is set to START, cannot hear starter electro-meganetic switch clicking and starter

rolling..

(2) Electo-magenetic clicking is heard, but starter does not run.

(3) Starter begins to roll, but engine does not start up.

(4) Hear continious clicking sound.

Analysis:

1. No starter switch clicks when ignition switch is set to “START”. Check if battery is connected. If battery

is connected, test ignition switch and start relay power outputs. Repair or replace ignition switch or relay if there

is power, otherwise test starter power connector. If the connector is hot, it indicates that starter switch attracts coil.

Repair the starter.

2. When ignition switch is set to “Start”, starter electro-magnetic switch clicks but starter does not run. This

indicates there is no continuity at starter due to burntout or dirty main contacts. Adjust starter switch travel and

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remove dirt on main contact.

3. When ignition switch is set to “START”, starter begins to run but engine does not start up. One cause

may be that starter small gear runs at high speed earlier before it meshes with flywheel gear ring due to wrong

switch travel. Adjust switch travel. Another cause may be that starter non-return clutch is damaged. Repair or

replace starter.

4. When ignition switch is set to “START”, starter clicks continiously. The cause may be

a)Starter rotator is short circuit. Repair or replace rotator;

b)Battery is low.

To test above two symptoms, press horn while key is at “Start”:

a)If horn works well or sound a little bit lower than usual, it indicats that battery is full, click sound is due to

rotator short circuit.

b)If horn does not work or its sound is much low, it indicates that battery is low. Recharge battery.

11.3.2 Faults -- alternator, regulator and indicator

Refer to elementary diagram to check faults on alternator, regulator and indicator..

Analysis:

Check failure alternator. While power supply to whole vehicle is normal and ignition switch is set to “ON”

position, check the indicator light first. Turn indicator light bracket behind the instrument panel by 90º to remove

it. If the bulb is in good condition, re-mount it to proceed to further check. Open the fuse box and check the fuse

for power supply. If the fuses look good, use a multimeter to test resistance. If the circuit connection of indicator

light in here is good, the indicator light should be on. If an open circuit is found, turn to check harness at vehicle

body or on front panel and alternator. Perform service if any bad contact or open circuit if found. When ignition

switch is on “ON” position, the alternator indicator light should be on. But if the indicator light keeps on after

starter has been started and alternator has been running at 100r/min or above, it indicates that the alternato is in

trouble or the built-in voltage regulator has been damaged. In this case, alternator should be repaired or replaced.

11.3.3 Headlight faults diagnosis

Refer to the elementary diagram analyze headlight faults.

Analysis:

1. Low beam faults

Set headlight switch to Hi-beam, toggle Dim switch. Hi-beam is on while Lo- beam is off, Probe test Lo-

beam output at combined DIM switch, if it is not hot, it indicates poor contact at DIM switch or wire dewelded. If

the switch is hot, it indicates no continuity at headlight plug-in connector, Lo-beam fuse burntout or bulb failure.

Repair or replace.

2. High beam faults

When headlight switch is set to Hi-beam, no high beam when toggling switch dim switch. To test this, first

set headlight switch to “0” position, slowly lift combined switch handle, turn on “flash to pass” switch to see if

high beam is on:
→(yes)→no continuity at DIM switch→repair or replace dim switch
→(no, and hi-beam indicator on dashboard is also off)→hi-beam output wire de-welded, cut off or poor contact
→(no, but hi-beam indicator on dashboard is on)→check fuse on fuse panel

→(fuse is ok but fuse post is not hot)→light relay damaged→repair or replace.

3. Check PASS light switch

While headlight switch is off, toggle PASS light switch, hi-beam is off. To test this, set headlight switch to

Hi-beam, lift combined switch handle to trun on DIM switch. If hi-beam is off, control circuit and light relays may

be the cause. If hi-beam is on, PASS light switch may be failure.

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11.3.4 Faults diagnosis -- corner light, taillight and fog light

Please refer to the elementary diagram for analysis of faults of front corner light, taillight, and fog light.

Analysis:

A.

While switch is set to “Lo-beam”, corner light is off, probe test the continuity of corner light ouput:

→(not hot)→repair or replace switch
→(hot)→broken bulb, poor contact

B.

While switch is set to “Lo-beam”, corner light is on but taillight is off. Check harness connection at

ceiling and taillight plug. If they are all ok, failure bulbs or poor contact may be the cause.

C.

While switch is set to “Lo-beam”, fog light is off. Probe test fog light switch:

→(not hot)→fog light poor contact
→(hot)check bulb and two plug connectors
→remove faults

11.3.5 Faults diagnosis --

Please refer to elementary diagram for diagnosis of faults.

Analysis:

Set ignition switch to “ON”, toggle switch to “LEFT”

If : LF- light is off→check bulb and plug

LF-light is on but LR light is off→check bulb for de-welding, wrie cutoff.

LF/LR light are off→turn on emergency switch

→if lights are all on→L-switch failure

→if lights are all off→emergency switch poor contact or flash relay failure

and if: Left is on but indicator on dashboard is off→check indicator and dashboard plugs

Same measures are applied to RF, RR s.

11.3.6 Faults diagnosis – windshield wiper circuit

According to diagram to check windshile wiper circuit. While vehicle power supply is normal, turn on wiper

switch. If wiper does not move, check if wiper fuses are burnt out or wiper motor 4-lead plug is connected. If all

works well, turn to check wiper switch output line. Locate faults and remove them. If motor does not run after

ciruit faults have been removed, the cause must be on motor. Repair or replace motor.

11.3.7 Fault diagnosis – i

nstrument panel indicator circuit

Refer to the elementary diagram to diagnose instrument panel indicator circuit

Analysis:

a) Oil pressure indicator keeps off

Check bulb for damage →(ok)→bulb socket continuity→(ok)→ground short oil pressure sensor lead:

if: indicator lits→sensor damaged

indicator is still off →check continuity between harness at chassis behind front fender and engine

compartment harness.

It can also probe to test continuity at indicator’s positive side, if there is no power supply, meter’s print

circuit or plug may be the cause.

b) Oil pressure indicator keeps on

If pressure indicator keeps on after engine has started. Disconnect sensor lead:

if: indicator is till on→indicator’s circuit grounds

indicator turns off→check oil pump performance and any restriction in oil pipe

c) Coolant temperature meter faults

According to elementary diagram to analyze faults. Follow circuit to check if sensor or meter head causes the

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fault. Typical faults in this case are: damaged sensor, meter head is stuck or lead is disconnected. Their solutions

see “Coolant temperature meter and sensor” in 18.5 (“Complex meters and auxiliary electrical devices3①”.)

d) Fuel meter faults

Solutions see “Fuel meter &sensors” in 18.5 (“Complex meters and auxiliary electrical devices” 3②.)

During the process, never scratch on fuel tank to check after sensor’s float has been removed.

11.3.8

Troubleshooting for other e

lectrical devices and curcuits

BJ6536 series light buses also equip with other assemblies such as CD/Radio/Cassette player, central lock,

back-up radar, washer, horn, brake lights, top lights, back-up lights buzzer, heating unit&A/C. By refering to their

elementary diagrame, opeartor can locate their connector positions, find fault one by one and remove them.

Only professional or trained technician can repair CD/Radio/Cassette player and A/C system

Back up radar is a kind of vehicle back-up assisting device. It contains sensor, display, controls and circuit. It

is used to detect any obstacles within the range of 0.9-0.3m right behind vehicle. At the moment obstacle is less

than 0.3m to vehicle, it triggers system is to alarm. Display shows approaching distance (cm), obstacle’s position,

alarm sound frequence change etc.

Summery: Fault checks stated in this section are only regular check procedures. Things are more complicated

in real world. Pratically, operator should watch how and when faults happen, then carefully makes reference to

diagram and knowledges on devices controlling relations. Check should start with the simplest one. This will

make fault-removing much quicker.

11.4 Electrical devices

11.4.1 Battery

BJ6536 series light bus uses dry load battery. In emergent case, it could fill formulated electrolyte into

battery after the electrolyte has been laid for 30 minutes, but battery normally has to be charged for 3~5 hours

before use. Battery has been charged for 4 hours before delivery from factory.

1. Structure, Parameters and Performance

S/N

Description

Parameter

1

Model

Negative ground

2

Number of batterie cell

6

3

Rated Voltage (V)

12

4

Rated Capacity (V/A-h)

12/60 (BJ491EQ1)80(4D22)

5

Fluid level height above pole plate (mm)

10~15

6

Exterior dimensions (L × W× H) (mm)

254.4×164×220

7

Specific Gravity of Electrolyte

Table 11-1 Specific Gravity of Electrolyte for Different Regions and Temperature (g/cm

3

)

Specific Gravity of Electrolyte at 15

for Fully

℃

Charged Battery

Climatic Condition

Winter

Summer

Region where temperature is lower than -40℃ in winter

1.31

1.27

Region where temperature is above -40℃ in winter

1.29

1.25

Region where temperature is above -30℃ in winter

1.28

1.25

Region where temperature is above -20℃ in winter

1.27

1.24

Region where temperature is above 0℃ in winter

1.24

1.24

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Table 11-2 Corrected Values of Temperature and Specific Gravity of Electrolyte

Measured Temperature of Electrolyte

+45

+30

+15

0

-15

-30

-45

Corrected Value of Readings from Gravimeter

+0.02

+0.01

0

-0.01

-0.02

-0.03

-0.04

2. Use of battery

(1) Preparation of electrolyte: Standard sulfuric acid and distlled water are to be used.
① Lead-acid battery electrolyte is made up of distalled water and concentrated sulfuric acid, and the density

of electrolyte in a battery that is used for starting up a vehicle is 1.280±0.005g/cm

3

(25℃).

② The container used to prepare electrolyte must be glazed ceramic, glass fibre reinforced plastic, plastic

tank, or lead-lined wood tank that have higher acid and temperature tolerance. Operator must wear protective

articles during the process.

③ Rinse and clean the container prior to preparation with clean water.
④ Pour purified water into the container first, then fill slowly concentrated sulfuric acid into purified water

while keep stiring. Never do this other way round avoid explosive splashes.

The conversion formula is d25=dt＋0.0007(t-25)

d25 : Density of electrolyte at 25℃ dt: Density of electrolyte when temperature is t

0.0007 : Temperature Coefficient t: Actually Measured Temperature of Electrolyte

The proportion of purified water (or distilled water) and sulfuric acid in electrolyte is shown in the following

table.

Table 11-3 Proportion of Purified Water (or Distilled Water) and Sulfuric Acid in Electrolyte

Specific Gravity of Electrolyte at

0℃ (g/cm3)

Volume Ratio of Purified Water (or

Distilled Water) and Sulfuric Acid

Weight Ratio of Purified Water (or

Distilled Water) and Sulfuric Acid

1.10

9.80:1

6.28:1

1.11

8.80:1

5.84:1

1.12

8.00:1

5.40:1

1.13

7.28:1

4.40:1

1.14

6.68:1

3.98:1

1.15

6.15:1

3.63:1

1.16

5.70:1

3.35:1

1.17

5.30:1

3.11:1

1.18

4.95:1

2.90:1

1.19

4.63:1

2.52:1

1.20

4.33:1

2.36:1

1.21

4.07:1

2.22:1

1.22

3.84:1

2.09:1

1.23

3.60:1

1.97:1

1.24

3.40:1

1.86:1

1.25

3.22:1

1.76:1

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Specific Gravity of Electrolyte at

0℃ (g/cm3)

Volume Ratio of Purified Water (or

Distilled Water) and Sulfuric Acid

Weight Ratio of Purified Water (or

Distilled Water) and Sulfuric Acid

1.26

3.05:1

1.60:1

1.27

2.80:1

1.57:1

1.28

2.75:1

1.49:1

1.29

2.60:1

1.41:1

1.30

2.47:1

1.34:1

Remark: This table is calculated based on a 1.83 specific gravity of pure sulfuric acid at 20

.

℃

(2) Fill fluid
① Exhaust bolt, make sure to penetrate the riser vent on the exhaust bolt, as there is gasket and sealing paper

underneath it, to be removed after acid has been filled.

② Electrolyte must be cooled down to below 30℃ before filling.
③ Fluid level for plastic case battery aligns with “MAX” line, and that for electrolyte in rubber case is higher

than partition board by 10~15mm.

④ Tighten vent plug to prevent fluid leak.

3. Charge a battery

(1) Charging device

DC power supply must be used to charge a battery. AC must be converted into DC before charging.
① Rectifier

Solid rectifiers such as cupric oxide rectifier, selen rectifier, and silicon rectifier, as well as gas filled valve

rectifier (tungsten rectifier) and mercury rectifier are commonly used. Their input AC voltage is generally 110V or

220V, and the nominal voltage of output is 6V, 12V, and 24V. Solid rectifiers have been widely applied as they are

easy to use and no service is needed during charging.

② Controllable silicon voltage regulating charger

As the number of batteries in serial is varied, voltage is to be changed during charging process to control the

charging current. Therefore, it is required to use DC power source as its voltage can be regulated. Though silicon

rectifier is comparatively light and easy to move, it still needs rather cumbersome voltage transformer.

Controllable silicon voltage regulating charger can be adopted to overcome the above-mentioned shortage. One

kind of 8kw controllable silicon voltage regulating transformer in the market uses a power supply of 220V AC, to

be converted into DC through the controllable silicon rectifier, and charge the battery from its output end, with a

0~220V DC output voltage and a 0~40A current.

(2) Detecting Instrument

Densimeter, thermometer, voltmeter, and ammeter, as well as other testing instruments and necessary tools

are generally required for battery charging and routine maintenance.

(3) Battery charging
① Preparation prior to charging

Check and measure if electrolyte or purified water complies with regulations. Remove vent plug on battery,

and add fluid or replenish water to the maximum level line.

② Connection for charging

The charger positive is to be connected with battery positive, and negative to negative. Make sure not to

connect them reversely. Charging connections must be secured.

③ Charging Mode

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There are normally three kinds of charging types as constant current, constant voltage and quick charging..

Constant current charging: including initial charging, supplementary charging, general charging and

equalizing charging.

▲ Initial charging: Initial charging is the first-time charging on a new non-dry load battery. After non-dry

load battery has been filled with electrolyte, it is to be laid for 1~6 hours. Start charging when fluid temperature

has cooled down to below 35℃. The current for initial charging is generally 0.07C20A, and when single frame

voltage has charged to 2.4V, go on charging with half of the current.

▲ Supplementary charging: Supplementary charging is applied to the dry-load battery that has been

stored for a long time with rather poor dry-load electrical performance, or the battery that has been laid for about

one month after it was filled with acid and charged. The current for supplementary charging is 0.1C20A, and the

time duration for supplementary charging is 5 hours or so, or the charging duration is to be determined based on

the length of storage.

▲ General charging

General charging means the charging after the battery has been used after initial charging. 0.1C20A is applied

for the 1

st

stage of general charging, it charges the battery for 8~12 hours until the voltage has risen to more than

2.4V/single frame, then go on chargingd for another 10 hours at halved current. The charging power rate is

generally more than 1.5 times that of the discharging rate, or 1.3~1.5 times that of the rated charging capacity.

▲ Equalizing charging

It is to fully charge the battery with general charging method, and then to charge it with 0.035 C20A current.

When battery emits uniform air bubble and temperature has risen, stop charging for one hour. Repeat it for 3~4

times the same way, so that each single battery can give out large amounts of air bubble. Finish charging when

voltage of battery and density of electrolyte have tended to be stable.

▲ Constant voltage charging:

Constant voltage charging is to charge the battery with a constant voltage. At beginning the charging current

is relatively larger, and then it is reduced gradually. The voltage for constant voltage charge generally remains

during 2.3~2.4V. Very few evaporation occurs with such a method, and therefore, the constant voltaging charge is

often applied to maintenance-free sealed lead-acid batteries.

▲ Quick charging:

Large current and impulse are applied for quick charging. It uses intermittent charging method with short

period discharging to charge a battery. 1~2 times C20A large current is used for quick charging. Quick charging

proceeds with tailor-made quick charger.

▲ Signs of a fully charged battery

Large amounts of air bubbles are generated in battery single frame. Battery individual voltage ranges during

2.6~2.8v, and the value can remain unchanged for more than two hours.

▲ Notes to battery charging

Fluid temperature shall not exceed 45℃, otherwise cooling measures should be taken (to reduce charging

current or stop charging or cool down in water tank), for ventilation to be nice and fire source to be forbidden.

▲Check and assess a faulty lead-acid battery

Table 11-4 Specific Gravity Measurement

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S.G. Value (25℃)

Assessment

Treatment

More than 1.300

Concentration of electrolyte is too

high, incorrect fluid filling.

Use ion wate to adjust.r

1.250~1.280

Good

1.250~1.220

Not fully charged

Supplementary charging

Lower than 1.220~1.100

Overdischarging, concentration is too

low

Check after charging

More than 0.04 difference in specific

gravity among frames

Certain single frame is faulty

Check after charging

Table 11-5 Voltage Measurement

Voltage

Assessment

Treatment

More than 12.5V

Normal

12.5~11.5V

Not fully charged

Supplementary charging

Lower than 11.5V

Over dischargeing or internal failure

Check after charging

Table 11-6 Capacity Measurement

Display on Volume Meter

Assessment

Treatment

White Zone

Fully charged

Green Zone

Normal

Yellow Zone

Re-charging

Supplementary charging

Red Zone

Fully discharged

Check after supplementary charging

4. Common failures, cause analysis, and failure removal for lead battery

(1)

Why does a full battery lose its power after being laid for long?

A full battery will lose its power after being shelf-stored for long. This is called “self-discharging” process.

Battery material purity is the main cause of self-discharging. There are impurities in battery plates and electrolyte,

they makes potential difference (PD) among impurities itselves or between impurities and plates. This could form

a “partial current” loop that makes battery discharging.

As perfectly pure material will never be available, and battery plate/metal seperator also constitutes battery

cell, slight self-discharging is inevitable. But use battery wrongly will accelerate self-discharging. When

electrolyte iron content is over 1%, battery will be discharged completely overnight. Electrolyte splashes on

battery cover will also trigger self-discharging once they connect battery terminals. Longer shelf-stored battery

will let acid sink to bottom, creating PD between plate top and bottom that makes battery self-discharging.

To correct a seriously self-discharged battery, one can let it discharge completely. That is to encourage

impurities to enter electrolyte. Then remove electrolyte, wash battery with distilled water. After being filled with

new electrolyte and recharged, the battery can work again.

(2) What is sulfuration of battery? And what is the cause?

Battery sulfurization refers to coarse crystals (lead sulphate) layer on battery plate. These coarse crystals

block seriously cavities on plate to reduce battery capacity. Crystals have very low conductivity, they increases

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battery internal resistance, making battery unable to provide enough current to starter to crank engine. Besides,

crystals cannot dissolve in electrolyte even in normal recharging process. Serious sulfurization kills a battery.

The main causes of sulfurization lay to: A.repeated short recharging for longer time and longer battery

shelf-storing time after being discharged. In these two cases, lead sulphate will re-crystalized due to temperature

change. B. Battery level is too low, larger plate area is exposed to air to make oxidization happening (especially

for negative plate); C. during vehicle’s driving, electrolyte contacts oxidized section on plate, creating hard layer

of lead sulphate that sulfurizes upper part of the plate. Besides, much higher electrolyte gravity, impure electrolyte

and abrupt temperature change are also the causes.

To cure these, one should always keep battery full; recharge drained battery within 24 hours; keep proper

fluid gravity and level. Slightly sulfurized battery can be recharged with over-charging method, and serious one

with de-sulfurizing charging method.

(3)

What will happen after battery plate has sulfurized?

There are several abnormal symptoms such as: single cell end voltage drops sharply (testing with high

sensitive discharger); early “boiling” during recharging while electrolyte gravity increases slowly (even no

change); electrolyte temperature increases sharply.

(4) How to prevent plate from sulfuration ?
① Do not lay a half –discharged battery too long, and keep battery full all the time.
② Maintain fluid level is 10-15mm above plate, add distilled water if necessary
③ Do not over discharge a battery.

(5) How to fix a sulfurated battery?
① Prolonged recharging with low current can cure slightly sulfurized plate. That is to recharge continuously

by second stage current after first recharging till bubbles are seen in electrolyte and electrolyte gravity reaches

around 1.280.

② Seriously sulfurized plate can be cured by “water treatment”. When a battery’s discharge capacity reaches

80% of its rated capacity, the treatment is basically done. Otherwise repeat above process till battery restores its

performance.

(6)

Why are there short-circuit happening inside battery?

How to fix it?

①Inferior or or defected separator plate. They let battery paste (active media) penetrate the plate to connect

two (+ -) poles.

②There are heavy sheddings on the bottom. It conducts plate lower edge to make short circuit.
③Higher charging or discharging current makes plate warped, or conductive objects drop into battery to

make short circuit.

Open battery to check once there is short circuit inside. Change plate if it is defect or has cavities; remove

battery paste sediments; and press warped plate into flat.

(7)

What is it like when plate short circuit happens?

The main symptom is: low voltage in open loop with small capacity. Single cell end voltage drops to zero

quickly by testing with high sensitive discharger. And end voltage and electrolyte gravity raise very slow during

charging process. There are few or even no bubbles at later charging stage.

(8)

Why does battery plate become warped?

The main symptom is: low voltage in open loop with small capacity. Single frame end voltage drops to zero

quickly by testing with high sensitive discharger. And end voltage and electrolyte gravity raise very slow during

charging process. There are few or even no bubbles at later charging stage.

①Poor quality. At the time a battery is made, the manufacturer did not Lead-galvanize plate evenly, paste

grown on plate also distributes unevenly. Therefore, chemical reactions happen on plate vary on each section, and

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plate expensing and shrinking rate also differ. All these make plate warped or even cracking.

②Frequent high voltage discharging; different current density on each section of plate; and paste’s different

expansion rate make plate warped.

③Excessive discharging makes lead sulphate growing in the depth of plate, recharging cannot help to restore.

The internal expansion occurred also makes plate warped.

(9)

Why are there so much plate shadding?

Shadding happens mainly on positive plate. Paste’s size keeps changing during charging and discharging. It

is normal and inevitable to see they peel off from plate. But use battery wrongly will accelerate this process, these

wrong doings include:

① Higher recharging voltage increases electrolyte temperature; paste expands and softens to peel off.
② Over charge battery frequently. Great amount of air escapes from plate cavities to form pressure to press

paste to peel off.

③ Higher discharging current, prolonged connection to starter and warped plate also accelerate paste to peel

off.

④ Unable to charge battery timely in winter, electrolyte gravity becomes low and electrolyte freezes.
⑤ Battery has subjected to strong shock while vehicle is driving.

(10)

What is the cause of polar reverse in a centain frame?

The causes: the capacity of this frame reduces due to fault or other reasons. While discharge is in progress,

low capacity cell discharges to zero first, discharge current from other cells will come to charge this cell. This will

reverse this frame’s poles (+ ←→ ―).In a battery with 3 frames, if one of them reverses its pole, battery’s end

voltage value will be 2V rather than 6V (tested with voltmeter).

To prevent this from happening, one should maintain battery carefully, and keep watching closely all the time

to notice faults early. For any low capacity charge or discharge separately any frame of low capacity or replace

frame plate until its capacity approaches or equal to other normal cell’s capacity.

(11) Why will battery blow up?

Battery blow-up mainly happens when a battery is over-charged, during which water in electrolyte

decomposes into hydrogen and oxygen with great amount of bubbles. Other causes include: internal short-circuit,

extrem sulfurization. When a battery is being recharged, electrolyte temperature will increase sharply, the process

evaporates humidity in great amount. In the case battery fluid filler hole is restricted to block excessive gas to

escape, battery will blow up when internal pressure reaches to centain level (or ignited by spark). Precautions

include:

① Always keep vent hole on filler cover cleared;
② Keep connections on terminals tighten to avoid spark;
③ Open filler cover first when tested with high sensitive discharger;
④ Do not charge battery excessively to reduce gas production. There should be no lighted fire around

charging chamber and be sure to keep good ventilation.

(12)

Why will battery fluid level lower quickly?

Water evaporation and electrolysis process during recharging can lower the fluid level. One should check

fluid level every 5-6 days in summer and 10-15 days in winter. If fluid level lowers too quickly, the cause may be

higher charging current, one should adjust charging system.

(13)

What is the cause to make fluid level in a frame lowering quickly?

Cracked case or damaged sealing may be the causes. In the event case and seal are all well, the cause may lay

to short circuit or sulfulrization in this cell. While there is short circuit or sulfurization happening, temperature

will go up quickly during recharging. This process overheats electrolyte to prompt water evaporation. When a

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plate has sulfurized, the early “boiling” during recharging will also lower fluid level.

(14)

What should be added when fluid level lewers, distilled water or electrolyte?

Add distilled water when fluid level lowers. It is water evaporation and water electrolysis (happened when

discharging is almost finished) that lowers the level. Add electrolyte will increase fluid gravity, shortening

battery’s life span. In the case broken battery case makes fluid leaking, one should repair the case before adding

formulated electrolyte.

(15)

How to test battery’s remaining capacity?

There are two methods in general:
①Test eletrolyte gravity with hydrometer, as gravity in charged battery increases and reduces in discharged

battery. Gravity will help to judge how much power remained in a battery. Experience tells that 6% discharing rate

equals to every 0.01g/cm gravity reduction. When a full battery’s gravity is known, one can caculate roughly

discharging rate according to electrolyte gravity measured. For example, a full battery’s gravity is 1.28, measured

value is 1.20, and therefore 48% of battery’s capacity has been discharged.

② Use a high-rate discharger to measure voltage of single-frame.

High-rate discharger is also called discharge tongs that is composed of one 3V DC voltmeter and one load

resistor, as indicated in Figure 11-1.

Figure 11-1 High-rate Discharger

During measurement, Press firmly tong tips on (+,―)posts of measured cell for 5 seconds, read battery end

voltage value under heavy load discharging process. This will help to decide correctly the discharging rate and

starting capacity.

There are different dischargers supplied by different manufacturers, one should measure and read

current/voltage values according to discharger manual. A good battery’s single cell voltage should be over 5V, and

the value keeps stable during 5 seconds. If in a certain cell, voltage drops quickly in 5 seconds or its read is over

0.1V lower than that of other celles, this cell is failure and should be repaired.

(16)

When to formulate electrolyte, why can only pour sulphate acid into water, not the

other way round?

Blending sulphate acid with water will creat great amount of heat. Water’s specific heat is quite different

from that of sulphate acid, it is 1C/g/℃while concentrate sulphate acid specific heat is 0.33C/g/℃. Pouring water

into concentrate sulphate acid will produce drastic sectional heating and even explosive splashes. But this will not

happen when one pours acid into water because water has higher specific heat. This way is much safer.

(17) How to use and maintain a battery in the winter?

In order to keep battary in good condition to prolong its service life, follwing rules should be observed:
①Always keep battery full to aviod freezing due to low electrolyte gravity. Ice would make case broken,

plate warped and sheddings.

Table 11-7 Discharging / Specific Gravity /

Chapter 11 Structure, Application and Service of Electrical Devices & Instrument

·243·

Temperature at Freezing Point of Battery

Discharging

Degree

Fully Charged

25％

50％

75％

100％

S.G.

15℃

Freezing

Point

0℃

S.G

15℃

Freezing

Point

0℃

S.G.

15℃

Freezing

Point

0℃

S.G.

15℃

Freezing

Point

0℃

S.G.

15℃

Freezing

Point

0℃

1.310

－76

1.270

－58

1.230

－36

1.190

－22

1.150

－14

1.290

－70

1.250

－50

1.210

－28

1.170

－18

1.13.0

－10

S.G and

Freezing

Point of

Electrolyte

1.280

－69

1.240

－42

1.200

－25

1.160

－16

1.12.

－9

1.270

－58

1.230

－36

1.190

－22

1.150

－14

1.110

－8

1.250

－50

1.210

－28

1.170

－18

1.130

－10

1.09

－6

1.240

－42

1.20

－25

1.160

－16

1.120

－9

1.08

－5

② In winter, it is suggested to add electrolyte with gravity of 1.40 as per chart 11-3 for adjustment..
③ In winter, adding distilled water only at the moment when engine is running (engine is recharging battery)

to avoid icing due to uneven mixing water with electrolyte.

④ In winter a battery’s capacity decreases. Cranking a cold engine at this time should give it enough time to

preheat. When it is hard to start the engine, do not activate starter more than 15 seconds each time, and there

should be 2-3 minutes interval between two consecutive crankings. If engine still cannot startup after three

attempts, one should turn to check engine for fault before next try.

(18)

Why are there yellow or white pastes on battery cover? How to get rid of it?

Pastes on battery cover and around terminals are the results that sulphrate splashes corrode posts, cable

clamp and bracket. White paste is mainly of lead sulphrate, and yellow one is of iron sulphrate. These two types of

pastes have very high electrical resistance, they forms very high contact resistance if they are present at

connectors. To get rid of them, one can use rag soaked with 10% soda solution to clean electrolyte splashes on

battery cover and case, then clean with water and dry them up with clean cloth. Also clean battery terminals and

cables with soda solution. If there are low conductive oxidants, one can use knife to scrape them away. It is better

to apply vasiline or grease on fastened terminals and cable clamps.

(19)

How to cure iced battery?

Frozen battery are mainly caused by:
① Factory battery has very low electrolyte gravity, it freezes when it is used in cold climate;
② Battery has not been recharged timely after being used. Its electrolyte gravity becomes low;
③ Distilled water added has not mixed evenly with electrolyte. Upper and lower part of fluid in battery has

different gravity. (Start up and run engine for some time can help to mix them evenly).

Remove a frozen battery to warm room to let it melt slowly, recharge it slowly with low current. One should

keep watching each cell’s voltage and electrolyte temperature. Electrolyte gravity in a charged battery should

reach rated value. Otherwise one should use distlled water or sulphrate (gravity: 1.400) to make adjustment.

Replace new plate to fix a seriously frozen battery.

Battery typical defect analysis and liabilities

Table 11-8 △ Liabilities of battery supplier ● Liabilities of vehicle user and dealer

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·244·

Defect

Defect Analysis

Symptoms

Defect Treatment Liability

Insufficient

Charging

1. Vehicle voltage regulator’s

setting is low

2. Vehicle power consumption is

higher than charged capacity

3. Frequent

start-up,

short

driving distance

4. Alternator failure or circuit

faults

5. Terminals or cable corrosion

1． Voltage

is

around

12V

1. Electrolyte gravity is

lower than 1.220

2. Hard to start-up

3. To

check

with

capacity

analyzer

(yellow or red area)

1.Adjust

regulator

2. Recharge

battery

3. Customer

replaces new

battery

●

Overchargeing

1.Vehicle

voltage

regulator’s

setting is higher

2. Prolonged charging

3. Prolonged and longer distance

driving

4. Higher recharge voltage

1. Battery sump or vent

plug turn black or yellow

2.

Separator

plate

carbonated

3.Positive

post

is

corroded, broken, floated

4.Wet

acid

on

sump

surface

5.Electrolyte level always

lowers or fluid turns

muddy

6.Plate

shedding

falls

evenly

1. Adjust charger

2. Customre

replaces new

battery

●

Over Discharging

1. Use short-charged battery

2. Electrical device short circuit

3. Electrical device is kept on

1. Voltage is below 10V

2. Specific gravity of

electrolyte is below 1.100

3. Low specific gravity

after supplementary

charging

1. Adjust charger

2. Supplementary

charging

3. Customre

replace a new

battery

●

Short Circuit

1. Weld lead enters when a

battery is assembled.

2. Plate is warped to short circuit

3. Separator is missed or broken

during assembling

1. Voltage is around 10V

2. First frame gravity is

the lowest among the six.

3. Tested voltage drops to

lower than 8V, with
“boiling” symptom in

faulty frame.

3. After supplementary

charging, faulty frame’s

gravity is still lower

with less gas generation

Manufacturer

replaces new

battery for

customer

△

Chapter 11 Structure, Application and Service of Electrical Devices & Instrument

·245·

Defect

Defect Analysis

Symptoms

Defect Treatment Liability

4. Brown or white shedding,

higher charging current;

over-charging; over discharging;

impure electrolyte

4. Large self discharging Customer

replaces new

battery

●

Open Circuit

1.

Poor

welding

at

battery

assembling — terminals and plates

2. Outside short circuit

3. High current discharging

1.Voltage’s

extremely

unstable

2.Terminal melted

3.Voltage is less than 0V

at

discharging,

faulty

frame cell smokes

4.Unable to input current

at

recharging,

battery

smokes or its fluid level

goes up

Customer

replaces new

battery or

manufacturer

repairs

△

●

Incorrect fluid

adding

1. Too high or too low specific

gravity at initial fluid filling

2. Fluid level drops, or wrong fluid

adding (impure water)

While gravity is higher:

1. Gravity after adding≥

300

While gravity is lower

after

separator

is

carbonated:

2. Gravity after adding ≤

1.200

3..Separator plate color is

light

4.Lower battery capacity,

fluid is muddy or with

abnormal color due to

impure fluid

Change

electrolyte,

customer replaces

new battery if it

is seriously

failure.

●

Plate Sulphation

1. Insufficient initial charge

2.

Longer shelf-storing time

3. Under charged for long

4. High specific gravity of

electrolyte

5. Fluid level drops, upper plate is

exposed to air

6. Impure electrolyte

1.Capacity reduced during

normal

dischaging

process

2.Gravity is lower than

normal value

3.Voltage drops quickly at

discharing

4.Bubble production at

charing

5. PbS04 coarse crystals

1.Use

over-charging

method

2.Charging

repeatedly

3.Water treatment

method

4.Customer

replaces

new

battery

●

Excessive

Shedding

1. Brown sediment due to too large

charging current

2. White sediment due to over-

discharging

1. Sediments are found in

fluid, brown

materials

goes up from bottom

2. Battery capacity

1. For plastic case

battery,

repalce

plates

and

remove

●

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·246·

Defect

Defect Analysis

Symptoms

Defect Treatment Liability

3. Impurities presence inside

battery

4. Paste shedding due to prolonged

higher gravity and temperature

5. Larger shedding due to poor

plate quality

reduced

sediments

2.Charge

with

low

current,

adjust

fluid

concentration

and

level

at

later stage

3.

Customer

replace

new

battery

4.Mmanufacturer

replaces

new

battery

to

customer

1. Battery separator is perforated

during manufacturing

2. Poor thermal sealing

1. Lower voltage

2.Fluid gravities among

crossed

frames

are

similar, separator is light

in color

3.Fluid

among

frames

flow to each other when

battery is turned down

Manufacturer

replaces new

battery to

customer

△

Cross-frame

electrolyte

leakage

3. Impact of outside force

4. Test cross-flowing fluid

(with analyzer) will creat

gassing, fluid is muddy

Customer replace

a new battery

●

Reversed Polarity

during assembly

1. Reversed polarity during

assembly

2. Reversed polarity during battery

cover mounting

1. 8V for one reversed

frame, and 4V for two

reversed frames

2. 12V for reversed cover

Manufacturer

replaces new

battery to

customer

△

Polarity reversal

at charging

Wrong connection of positve and

negative terminals during charging

1. Negative voltage value

2. Electrolyte specific

gravity is lower than

1.200

3. Colors of +/- plates

are reversed

Customer

reversed charging

or manufacutuer

replace new

battery for

costomer.

△

1.Poor battery cover thermal

sealing.

2. Poor connection between

terminals and cover

1. Leakage—filler hole

2. Leakage at case and

cover junction

3.Tilt battery over 60,

fluid flows out

Manufacturer

replaces new

battery to

customer

△

Fluid Leak

3. Fluid leak dut to impact

4. Impact damage on case Customer replace

a new battery

●

Chapter 11 Structure, Application and Service of Electrical Devices & Instrument

·247·

Defect

Defect Analysis

Symptoms

Defect Treatment Liability

1. Bad welding or in short circuit

1. Check welding quality

or short circuit

Manufacturer to

make a

replacement

△

2.Vent plug is restricted

2. Vent plug failure due to

obstruction

●

3. Bad contact in terminal

3. Terminal is melted and

damaged

●

4. Spark presence during charging

or operating

4. Case broken, crack

goes from up all the way

down

Manufacturer

assists to repair

or customer

replaces new

battery

●

5. External terminal is in short

circuit

Abrupt cracking

of Battery

6. Circuit failure

5. Check terminals for

possible poor contact

Customer

replaces new

battery

●