For our last week in Electrical we did "on car" battery testing

• The very 1st thing we did was a Visual inspection.
• Then  we did an open circuit voltage test to determine the condition of the battery
• Checked the electrolyte levels to make sure the battery is not low on acid
• We also did a parasitic draw on the battery to check how many amps the battery was putting out with the Ignition switched off
• We checked for Corrosion around the battery terminals, made sure they are tight, checked for any damage to the Positive and Negative wires, checked that the battery was locked down in place, made sure there was no acid leakage and no damage to the battery itself
• Since the battery in the car was on charge, we removed the charger and turned on the headlights to remove the surface charge to get an accurate Voltage reading. Then using a Voltmeter we measure the Voltage between each battery terminal, our result was 12.7v which means the battery has a 100% state of charge
• Using a Hyrdometer we unscrewed the caps at the top off the battery and check the Electrolyte levels in each cell. Our result was 1.240 in each cell which indicates a 100% state of charge
• With the parasitic draw test we had to connect an Ammeter in series with the battery (and everything switched off) and using a jumper wire to keep the battery grounded and not loose connection we recorded the amount of Amps being drawn from the battery with everything turned off. Our Result was 0.02mA. Anything over 0.08mA is a high current draw and it will mean that your car will have trouble starting up after being parked for a small period of time and all your battery power is being used.

For our third week in Electrical we did charging system testing

• The 1st thing we did was a visual inspection. Checking for leakage, corossion around termainals, loose connections and any other damage to the battery. The Wiring was checked for losse connections, cracks, splits, and any other damage. The Alternator was inspected for any physical damage to it and poor connections from the wiring.
  During our Visual inspection we noted down some corossion around the battery termainals and some acid sitting on top of the battery (leakage)
• Then we tested the condition of the battery. With the Multimeter we did a OCV test which we got 12.6V. Then a hydrometer test checking the Electrolite levels in each cell of the battery which we got 12.10 for each cell except the last cell where our result was 12.50
• After that we checked the condidion of the drive belt. Rotating the engine by hand and checking for signs of uneven wear, cracks, splits and any other damage to the belt which would cause failare
• After that we tested the Alternator with no Load on the car. Using a Voltage meter we had the engine running and connected to the + of the Alternator and - off the battery. We made the engine run at 2000 rpm and recorded our Voltage result.
• This time we did the same, testing the output of the Alternator but with load on the engine. So with it running we stiched on interior and exterior lights aswell as the stero and heater. Anything to draw power from the battery.

For our second week in Electrical we made Logic probe testers.

A Logic probe tester is a very basic and easy to use tool. There are two loads comeing off the probe one negative and one postive. You connect poitive to positive on the battery and negative to negative. There are two L.E.Ds on the probe, one red and one green. With power connected to it both L.E.Ds should light up. Once you touch the postive terminal on the battery the red L.E.D will go out leaving the green lit. When you touch the negative terminal on the battery the Green L.E.D will go out leaving the red lit. When the Green L.E.D is let it means you have positive voltage at the point your touching and when the Red L.E.D is let it means you have negative volatage.

For our first week in Electrical we worked on circuit boards

1/ With the circuit boards we made a Parallel and Series circuit using a 12v power supply and two identical light bulbs for each circuit and of couse a fuse and switch

2/ Using a Multimeter we then tested Voltage, Resistance and Amperage and compared the diffrence in circuits.
Some of the reading we got was:
36.3 ohms resistance in bulb one and two.
Series circuit with one bulb was using 4.4 Watts

3/ We noticed in the Parallel circuit each bulb was recciving a full 12v from the power supply but in the Series circuit each bulb was only receiving 6v.

4/ This ment the bulbs in the Parallel circuit were a lot brighter compared to the series dull bulbs.

After taking some Amperage readings we notcied in the Parallel circuit Amps slpit in half and Amperage in the Series circuit stayed the same through out. We measured 0.51Amps through out our series circuit with two bulbs connected.

Some other important readings that we took note off was Voltage drop across diffrent points.
The switch in the circuit used .008V
We did this by talking a Voltage reading accross the switch, so negative on the Voltmeter went before the switch and the positive went after the swtich so we could see how many Volts was being used up at the switch.



The Safety gear we had to have was overalls and steel caps boots.