BATTERIES

BATTERIES

The purpose of the battery is to start up the engine and run the electrics of the vehicle when the engine is not running. The battery stores electricity to power up the starter.

CCA: Cold Cranking Amps ie. the current a battery can supply constantly for 10 seconds to the starter in cold conditions.

Fully Charged Battery: 12.6v

HYDROMETER TESTING:

This the specific gravity test of each of the electrolytes on the battery, if there is more than .50 OR 10% of a difference in the specific gravity reading between the highest reading obtianed and the lowest reading obtained, than the battery is close to death and its recommended to throw it away.

O.C.V TESTING:

 Open circuit voltage testing is is testing the voltage the battery supplies with the engine switched off, and no components turned on.

LOAD TESTING:

If the battery has surface charge, you have to discharge it, this is done by leaving the headlights on for 2 mins with is engine off, or cranking the engine for ten seconds after disabling its starting ability ie. by disconnecting the ignition coil.

This test is taken to check if the battery is capable of supplying the amount of current its rated at. This is done by checking if the battery is atlest at HALF charge, connect the terminals of the "High rate discharge tester" on the battery, wind the current knob to half the amps rating of the battery ie. if the battery is rated at 310, we should wind the knob to 155.

If the battery is able to deliver is rated amps within 15 seconds and without letting the VOLTS needle fall below 9.5v, than the battery has passed this test, otherwise it is recomment to dicard of this battery.

Before starting this test, the battery must be MORE then  50% CHARGE.

CONCLUSION:

The Nissan Pulsar in which I did the battery test on failed because the specific variation of two cells was more then 50.

If the specific gravity variation between two electrolyes on a battery is more than 50%, than it is recommended to throw that battery away.

4841 ELECTRICAL AND ELECTRONICS - CIRCUITS Circuits:Circuits:Circuits:(SOHEEL ALI)

Circuits:

Series Circuit: A circuit with one conducting pathway

Parallel Circuit: Circuit with two or more conducting pathways

Compound Circuit: Circuit which consists of many circuits within that has both parallel and series circuits combined.

*In a series circuit, the voltage is shared between all components, the amps remain the same throughout the circuit.

* In a parallel circuit, amps are shared between the consumers, the current however, remains the same.

* Electricity will always find the quickest and easiest way to ground, ie. if one consumer between two has greater resistance, electricity will find the alternate route, ie. the consumer with less resistance.

* High volts + low resistance = High wattage

* Low volts + high resistance = Low wattage

We assembled some circuits last week and did measuring of the voltage drop, voltage available, and the CURRENT.

VOLTAGE AVAILABLE: The volts available for a consumer to do work.

VOLTAGE DROP: The volts a consumer is using to do work.

CURRENT: The amps in the circuit.

I blew up 2 multimeters because when I was taking the amps reading, Because, I forgot to make the multimeter a COMPONET in the circuit, I accidently connected it in parallel.


EXAMPLES OF FORMULAE:

POWER = VOLTAGE x CURRENT

Ohms Law; RESISTANCE = VOLTAGE / CURRENT

eg. If the voltage in a circuit is 12V, and the current is 5A and I had to find the power output, then:

P=VxI
12x5=60W

eg. If the voltage in a circuit is 12V and the current 5A and I had to find the resistance, then:

R=V/I
12/5=3.4 Ohms