1. What is Electro-chemistry?
Electro-Chemistry is a branch of chemistry which deals
with the chemical changes which occur due to the effect
of Electric Current.
2. Types of Electro-Chemical Cell?
There are 2 types of Electro-chemical Cells
1. Which requires energy to be supplied to the system.
Ex: Electroplating Baths
2. Which can generate electricity. Which is also called
as Galvanic / Voltaic Cell.
Ex: Dry Cells, Lead acid Cells
3. Galvanic Cells
There are three types of galvanic cell.
i. Primary galvanic cell (Irreversible)
ii. Secondary galvanic cell (Reversible)
iii. Fuel cell (It needs external fuel)
4. What are the Components of an electrochemical cell?
1 Positive (+ve)
5. What is the Current flow pattern during charging
During charging, current flows from negative electrode
to positive electrode. (-ve to +ve).
During discharging, current flows from positive electrode
to negative electrode. (+ve to –ve)
6. What is lead acid Battery?
Lead Acid Battery has Positive Electrode made up of
Lead Peroxide (PbO2) and Negative Electrode made
up of Spongy Lead (Pb). The electrolyte is Sulphuric
7. What is the overall reaction in an lead acid Battery?
8. What are the different types of batteries available?
a. Tubular Batteries.
b. Valve Regulated lead Acid Batteries (VRLA)
c. Automotive Batteries.
d. Stationary Cells.
e. Air Craft Batteries.
f. Traction Batteries
g. Train Lighting Batteries.
9. How does a Lead Acid Battery operate?
When two electrodes of dissimilar metals are placed
in an electrolyte, there will be a measurable potential
difference at their terminals. In the lead acid system,
one electrode of highly – oxidized lead (positive
plates) and another of pure, spongy lead (negative
plate) are immersed in the electrolyte (solution
of distilled water and sulphuric acid).
The lead acid battery does not store electricity. It
produces DC current and voltage through a chemical
reaction within the cell. On discharge, the positive
and negative plates change to lead sulphate. As a result,
there is little flow and the cell is considered discharged.
In actual practice, the discharge is stopped when the
specific gravity of the electrolyte has decreased to
about 1.100 at 270C or a terminal voltage of 10.5 for
a 12V battery.
To recharge the battery, DC current is passed through
it in the opposite direction, reversing the chemical
action in the cells. This removes the sulphate from
the positive and negative plates.
The charging returns the plates to their original state
of charge and the electrolyte to its full value 1.240
specific gravity at 270C.
10. What is Ampere Hour Capacity?
It is the measure of electrochemical reaction in a
cell. i.e. the quantity of electricity the battery
11. What is the rating of a Battery?
The Battery is rated as various types say: 10Hr rate,
5 Hr Rate etc. i.e. For ex: if we take an 100Ah battery
at 10 Hr rate it means that you can discharge 10Amps
of current continuously for 10 Hrs and not 100Amps
for 1 Hour. If we discharge at any current higher than
10Amps the efficiency of the battery reduces.
The rating for different types of batteries are:
Automotive – 20Hr Rate
b. Tubular / Stationary – 10Hr Rate
c. Traction – 5Hr Rate
d. SMF – 20Hr Rate
12. How to Check the Condition of the Battery?
State of charge of any Battery can be understood by
Checking Total Voltage, Cell Voltage
and Cell Specific Gravity.
The Total voltage of a fully charged battery on open
circuit is > 12.3V for a 12V Battery
• The Specific Gravity of a fully charged cell is 1.240.
13. What is specific gravity?
Specific Gravity is the Weight of the given liquid
with respect to the weight of water.
• Hydrometer is the instrument used to measure Specific
• Unit of measurement is g/cc
14. HOW TO USE HYDROMETER?
Insert the rubber tube of the hydrometer in the cell
you want to check
Press the rubber bulb at the top of the hydrometer
to suck the acid form the cell.
The hydrometer float inside the glass barrel starts
The float should be free floating and should not touch
the walls of glass barrel.
Now read the reading on the hydrometer float which
is corresponding to the acid level.
The reading gives the direct specific gravity value
of the acid.
15. How to INSTAL A BATTERY?
battery should be placed in a cool dry place.
• The battery should be placed on a wooden stand or a
• The transit plugs shipped with the battery should be
removed and replaced with Aqua Trap Vent Plugs (Supplied).
• During connection care should be taken not to Short
the Battery Terminals.
• The terminals should be covered with the Plastic Terminal
Caps to avoid shorting due to external objects.
• Keep the battery top open. Do not cover with Plastic
• Apply Petroleum Jelly on the terminals.
Keep the Bolt & Nuts tight.
• Check the Electrolyte level in all the cells, Cell
voltage, Total Voltage.
16. What are AQUA TRAP VENT PLUGS?
minimize the evaporation of water the batteries are
fitted with Aqua trap vent plugs made of Ceramic.
• These plugs trap the gases released during the normal
charge / discharge cycle and enables condensation.
• If the pressure inside the cell rises above a prescribed
limit it passes through the ceramic portion of the
• To enable free movement of these gases the plugs should
be kept clean, free from dust and other particles.
• The Plugs can be cleaned with free flowing water and
17. How to STORE CHARGED BATTERIES?
A fully charged battery can be stored up to 30 – 40
During storage see that the battery is stored in a
Keep the top and the sides clean.
After the specified storage period give the battery
a freshening charge of about 5 – 6 Hrs at a rate
of 10% of the battery Capacity.
18. What is TOPPING UP OF THE BATTERY?
The batteries which are fitted with the float level
indicators should be topped up when the indicator level
drops down below Red mark and to be filled with D.M.
Water up to the green mark.
For the batteries with out float level indicators,
the acid level should be up to 1- 1½ inch above
the protector (White mesh) level.
Care should be taken that the water level should not
be less than the protector level and not more than
1½ inch above the protector.
Always USE D.M. WATER. Never use Acid or Mineral water
for topping up.
19. What is BOOST CHARGE?
Some times the battery may be over discharged or will
be left in the state of discharge for a long time.
Such batteries will be difficult to charge with the
solar panel or with small current.
To bring the battery back to the normal condition Boost
charge / Bench Charge should be done.
20. How is PERIODIC MAINTENANCE done?
Check Total Voltage, Cell Voltages and Cell Specific
Check the electrolyte level and top up with D.M. Water
Clean the top and sides of the battery.
Clean the vent plugs.
Apply petroleum jelly to the terminals and connectors.
21. HOW TO KNOW WEATHER THE BATTERY IS FULLY CHARGED?
During charging Hourly readings of Battery Voltages,
Cell voltages and Cell Specific Gravities have to be
The battery is fully charged when we get the same 3
Consecutive readings of Cell voltages and Cell Specific
22. Which type of Battery should I use for my UPS
You can either use UPS / Tubular Batteries or VRLA Batteries (SMF). Tubular
Batteries are preferred as its life is more and it can take up any type of
abuses like over charge, deep discharge etc. This Battery comes fitted with
aqua trap vent plugs which reduces the water loss. The main advantages of SMF
Batteries are, there is no need of maintenance like topping up with D.M Water.
23. Should the Battery be topped up with Acid / Water
The Battery should be topped only with D.M Water. The acid should never be
24. How much of water should I add to the Battery?
The water should be added up to a level of 1" above the top plate surface.
25. What is IFC?
IFC means Initial Filling & Charging. Our Batteries normally comes in charged
26. How is IFC done?
a. Wash all dirt from the battery and clean its terminals
before placing it on charge. Do not allow dirt to
get into the cells.
b. Fill the cells with battery grade sulphuric acid
of 1.220 specific gravity at 270C.
c. Ensure that the level of acid is 6mm above the top of the protector.
d. Allow the cells to rest for 12 to 15 hrs after filling. After this, if topping
is required, it should be done with some initial filling acid (i.e. 1.220)
e. Use direct current from a charging source suitably controlled, so that the
current rate to the battery will not be excessive. The positive terminal of
a battery is usually marked with a ‘+’ or a ‘P’.
f. Connect the positive lead from the charger to the positive terminal of the
battery and the negative lead to the negative terminal. If several batteries
are to be charged in series, they should be connected from the positive terminals
of one to the negative terminals of another so that when the row of batteries
is connected, there will be a positive and a negative terminal free for connecting
the positive and negative charger leads respectively. Adjust the charging current
according to the battery type.
g. The charging current should be about 5% of the rated capacity of the battery.
h. While charging, watch the temperature of the batteries carefully. If the
temperature of any one of them reaches 450C reduce the rate of charging (i.e.,
half the rate of charging), or suspend charging till the temperature falls
below the specific limit.
i. The usual duration of charging is around 80 – 100 hours. Charging
should be continued till the voltage and specific gravity of each cell remains
constant for three consecutive hourly readings and all cells gas freely.
j. If the specific gravity of all cells is not within five points of the desired
value (1.230 to 1.235) at the end of full charge, remove some of the electrolyte
with the hydrometer. Add distilled water to reduce the specific gravity if
it is too high, or add 1.400 specific gravity acid to raise the gravity if
it is too low. Continue charging so as to give the electrolyte a chance to
mix. Note the specific gravity reading after another hour to note the effect
of the addition. Continue this procedure till the specific gravity is brought
to the desired value by charging for one hour after each adjustment.
k. Never adjust the specific gravity of a cell that does not gas freely on
charge. Unless the electrolyte has been lost through spilling or leakage, it
will not be necessary to add acid to a battery during its life.
(Please Note that warm electrolyte will have a low
27. Can I keep the Battery in discharged condition?
No, the Battery should never be kept in the discharged
condition. If left in the discharge condition for
long time it will lead to sulphation of Battery
plates which will be difficult to remove.
28. How do you prepare an electrolyte?
The electrolyte used for a lead acid battery is prepared
with distilled water and sulphuric acid. The water
used to prepare the electrolyte or to top up the
battery should be free from chlorine and iron. The
pH value of distilled water should be between 6.5
and 7. Do not use tap water or other contaminated
29. What is electrolyte Specific Gravity of a fully
The electrolyte in completely charged battery usually
has a specific gravity of 1.24 i.e. 1.24 times heavier
than water at the same temperature.
30. How do you determine the Specific gravity of electrolyte?
The normal method for measuring the specific gravity
in a battery is by using a syringe hydrometer. By
pressing the rubber bulb, the electrolyte is drawn
into the barrel and readings are taken at the lower
point of meniscus. While taking the readings one
must be sure that the hydrometer is floating freely
in the electrolyte inside the barrel. The readings
can be misleading if the temperature fluctuations
are high. Since specific gravity is measured at a
temperature of 270C, the electrolyte must be adjusted
to this degree if temperature variations are high.
31. What is temperature correction of electrolyte?
The temperature correction of the electrolyte is 0.0007
for every degree rise or fall from 270C. For temperatures
below 270C, the difference is multiplied by 0.0007
and subtracted from the specific gravity value. For
temperatures above 270C, the difference is multiplied
by 0.0007 and added to the specific gravity value.
32. How do you prepare an electrolyte of certain
specific gravity – Procedure?
33. Acid mixing Chart ?
The electrolyte for the battery is prepared in a clean
vessel made of porcelain, plastic or lead – lined
tanks. No other metal vessel should be used. It is
advisable not to use glass vessels, as they may break
due to high temperature generated. While mixing the
electrolyte, the acid should be poured into water and
NEVER water into acid. Do this slowly and continuously,
stirring with a wooden stick. Final adjustments should
be made after the acid has cooled to room temperature.
34. HOW TO CLAIM WARRANTY?
mixing by volume using 1.840 acid.
specific gravity at
27 deg C
mixing by volume using 1.400 acid.
Water required to one part acid
Water required to one part acid
The battery should be returned to the manufacturer
or the nearest dealer within 15 days of the failure
of the battery, in unopened condition with electrolyte
along with the complaint details. The company reserves
right to repair or replace the defective product.
35. Replacement of one or more units in a string
If more than 10% of the batteries in a single string
are observed to be under-performing, then it is most
possibly a case of:
- Incorrect sizing of battery
- Incorrect charge parameter
Whilst replacing one or two units in a string, care
must be taken of the following points:
a. Do not replace one or two units in bank which
has already performed for more than 18 months.
b. Replaced units will age fast and will not deliver
the same life as it would have, if it was used in a
36. Parallel String:
Care must be taken of the following
* UPS must have charging current available to charge
* Not more than three parallel strings are recommended
for a set
* Paralleling of units of different makes is not recommended.
* Paralleling of different Ah capacities is not recommended.
* Paralleling of unequal age is acceptable with the
caution that the new unit shall age faster and will
not deliver the full service life.
37. What is an U.P.S?
U.P.S denotes Un-Interrupted Power Supply. This is
small electronic equipment which supplies AC when
there is power and when there is no power it converts
DC supply from the Battery to AC & supply to
all the items / gadgets connected to it.
38. What is a Domestic Inverter?
Domestic Inverter are used for lighting. It can power any general electrical
39. What is an Off-Line U.P.S?
Off-Line UPS is mainly for low end computer applications.
UPS is designed mainly for computers. The change
over time from mains to UPS supply is only few milli-seconds.
40. What is an On-Line U.P.S?
In On-Line UPS the supply is always from the inverter & there
will be no change over from mains to UPS or from UPS
to mains. This UPS is used for high end computer application,
CNC Machines and other precise instruments.
41. For a general computer use, which UPS should I
For a general computer use you can go in for Off-Line UPS. There are different
models according to the customer’s requirements.
42. How do I choose the UPS capacity?
First write down your requirement (the points you need to be powered with the
Calculate the wattage of each point,
Tube light – 40 to 60 Watts.
Fan – 60 to 80 Watts.
Now add all the load and you will arrive at the total wattage required by you.
43. What is the difference between VA and Watts?
VA denotes Volt Amperes. 80% of VA is Watts. All our UPS are designed in terms
of VA. To arrive at VA divide the load in Watts by 0.8 (Approx.)