This document provides a checklist of key process points and potential faults in the manufacture of dry charge lead acid batteries. It lists process steps such as grid casting, paste mixing, pasting, plate formation, drying, assembly, storage and their associated faults. Faults can cause issues like reduced battery capacity and life, poor performance, plate damage and contamination. The document describes the effects of faults such as incomplete drying, moisture, oxidation and contamination on battery plates and performance.

1. Positive Plate Negative Plate D.C Battery
DRY CHARGE BATTERY MANUFACTURE - CHECK LIST OF KEY PROCESS POINT
Process Detail Fault
EFFECT ON
Build up of resistance layer between
grid/active material.
a) Problems in casting - incomplete grids.
b) Problems in processing - soft grids
Too little
Too much
Alloy - Tin contentGrid Casting Nil
a) Prolems in casting - short runs,
feather
Reduction of capacity initially and
progressively during storage.
Paste Mixing Additives - L.S.A Too little
Too much
Poor disribution
N / A
Plates absorb moisture easily
Plates stick to platens on drying
Uneven wetting.
Low initial performance and posibly some
Asembly difficulties
Deterioration during storage.
Poor initial performance due to non-wetting of
negative.
Reducetion in initial performance.
Paste plate density High
a) Reduces wettability - access of acid to
active material
b) Buckled plates.
Reduces wettability - but no to
such an extent as positive.
a) Poor initial performance.
b) Reduction in high rate performance.
Assembly difficulties
Pasting
Pasted Plate Uneven finish Uneven plate thickness
Possibly prevents close contact of plate
during drying leading to high
oxidation of dried formed plates.
Low initial capacity.
Reduction of battery life.
a) Deteriotion during storage.
B) Reduction of battery life.
Ageing
High moisture
content of aged plate.
High Residual lead.
Shedding of active material during
life and possibly in formation.
a) Poor formation.
b) Buckled plates.
N / A
Reduction of battery life.
a) Reduction of capacity.
b) Assembly difficulties.
Formating
Underformation.
Overformation
High specific gravity acid.
The colour of the plate is either very
pale brown or having white patches.
Colour - very dark brown, with active material
brittle leading to high scrap.
Incomplete drying necessary to wash plates
before drying.
Colour - Whitish Grey.
Nil
a) Plates sticking together during
drying.
B) Acid attack of equipment
leading to iron contamination
of plates
N / A
Low initial performance.
Deterioration during storage
Reduction of initial performance.
Reduction of initial performance.
Drying Positive Plate Incomplete
drying
Drying at high temp
(i.e. greater than 85°C)
Extended drying periods
(i.e. greater than 24 hrs)
High moisture.
Increasing rate of formation of high
resistance layer between active
material/grid.
Build up of high resistance layer

2. Positive Plate Negative Plate D.C Battery
Reference :
Chloride Group PLC UK
Compiled by
Imran Shahnawaz
Manager Quality Assurance
Exide Pakistan Ltd.
Process Detail Fault
EFFECT ON
Low initial volts.
Possible low capacity.
Possible low battery life.
a) Deterioration during storage.
b) Possible poor initial performance.
D/C Plates Moisture.
a) High oxidation level of plates.
B) Possible melting of plates on removal
from drying equipment or final air
cooling
a) High oxidation level of plates.
B) Possible melting of plates.
Drying Cont.2 Negative Plate Incomplete drying
Oxygen access to plates
before completion of
drying
N / A
Low initial performance.
Low initial performance.
Assembly Positive plate lug dirty
Excessive use of water to
cool bars.
Poor burn pos bar
Wet plates in assembled battery
Wet plates in assembled battery
Storage
a) Poor initial performance.
b) Deterioration during storageSeparators Moisture. Wet plates in assembled battery
Wet / Oxidised plates in
assembled battery
D.C. Batteries Moisture. Wet plates. Wet / Oxidised plates.
Wet plates in assembled battery
Wet / Oxidised plates in
assembled battery
Container/Lid Moisture. Wet plates in assembled battery
Wet / Oxidised plates in
assembled battery