Cells And Batteries

Question 1

3 types of lead acid battery

Answer 1

Flooded cell, gelled electrolyte, absorbative glass mat (AGM)

Question 2

Open circuit voltage of a lalanche cell

Answer 2

1.5v

Question 3

What is the open circuit voltage of a lead acid battery?

Answer 3

2.1v

Question 4

What happens to effiency of a lead battery when it gets cold? Why?

Answer 4

Its efficiency decreases. Because the water inside the battery begins to freeze.

Question 5

State advantages to gelled electrolyte over flooded cell lead batteries.

Answer 5

They are sealed
They cant leak
Can use jn any orientation
Almost maintenance free
Corrosion resistant

Question 6

Which of the 3 lead acid battery types has the lowest internal resistance

Answer 6

AGM Absorptive glass mat

Question 7

What does VRLA stand for, and what are the two types of them?

Answer 7

Valve regulated lead acid.
Gelled electrolyte
AGM

Question 8

Open circuit voltage of a nicad battery

Answer 8

1.2v

Question 9

Advantages to nicad vs lead acid batteries

Answer 9

Higher energy to weight ratio
Low internal resistance
Faster recharge rates
Long storage life no need for mait charging
Not subject to freezing or over heating
Can completely discharge/recharge without damage
Barely have to add water so lower maintenance.

Question 10

Are nicad batteries sealed or vented

Answer 10

Both

Question 11

How much power can a 1kg lithium battery store

Answer 11

150 watt hours

Question 12

Advantages to lithium batteries

Answer 12

Lightweight
Highly reactive
Hold charge well
No memory effect
Can go through hundreds of charge cycles

Question 13

How much enerygy does a lithium battery lose a month

Answer 13

5%

Question 14

Disadvantages of lithium batteries

Answer 14

Start degrading as soon as manufactured
Sensitive to hight tempreture
Comete discharge destroys it
Must be internally monitored which increases cost
They can be a fire hazard
Expensive

Question 15

Lithium cells produce _x the volagge of an alkaline cell

Answer 15

2

Question 16

What does the ptc do in a lithium battery

Answer 16

Prevents over heating

Question 17

What does amp hours represent

Answer 17

The total energy capacity of a battery

Question 18

How do you calculate amp hours

Answer 18

Amps x time

Question 19

How do you calculate current from amp hours

Answer 19

A-H / time

Question 20

How do you calculate terminal volatge of a battery

Answer 20

Battery voltage X 91%

Question 21

What is cranking amps

Answer 21

Current drawn from a charged battery for 30 seconds at a temp of 0 celcius without cell voltage dropping below 1.2v per cell

Question 22

What is cold cranking amps

Answer 22

Current drawn from a charged battery for 30 seconds at 0 farenhite without cell vtage dropping under 1.2v

Question 23

Why do we need to know cca

Answer 23

Because not all starters are the same

Question 24

What is reserve capacity rating

Answer 24

The number of minutes a lead acid battery can deliver 25A at 25 celcius before comgage drops below 1.75v per cell

Question 25

With a 10 hour rate a 12v battery has a capacity of 56 AH.
What current was used to obtain this result?
What is the minimum allowable terminal voltage for emergency power after this test.

Answer 25

1)current= AH/time = 56/10=5.6A
2) Terminal voltage= 91% of 12v = 10.92V

Question 26

Reserve capacity is quoted in?

Answer 26

Minutes

Question 27

What steps do you take to calculate internal resistance of a battery

Answer 27

Take the terminal voltage with no load and subtract the voltage when a load is attached, this is you volt drop from internal resistance

Then use ohms law with the load amperage and voltdrop from internal resistance to calculate resistance.

Question 28

What is the formula to calculate internal volt drop due to internal resistance in a battery

Answer 28

Vnoload - Vwithload = volt drop from internal resistance

Question 29

What formula calculates internal battery resistance?

Answer 29

R=Vvoltdrop from resistance/current of load