Battery Testing

The first part of battery testing was inspecting for battery specifications. The make of our battery was a Lucas, battery number was 128HD. It has a Cold Cranking Ampere (CCA) of 400. It was a conventional battery and the electrolyte was easily accessable by removing the caps and using the tip of the hyrometer to check the level of the electrolyte.

We carried out visual checks and found that the terminals were clean and tight, there was no signs of swelling caused by overcharging.

In case of an accident, the nearest supply of water had to be identified, and was behind us about 2 meters away.

Next we had to check the electrolyte levels. To do this we dipped the hydrometer in until the tip touched the plates. We then removed it and the level can be seen on the rubber tip. The level was about 10 to 12mm above the plates. This was a bit high as the recomended level is 4 to 5mm above the plates.

The next test was to measure the open circuit voltage. With the meter range set on 20V, we got a result of 6.61v, which was due to the battery not being charged. The state of charge was recorded as under 25%.

To continue with the testing, we needed a state of charge of at least 50%, which equates to 12.4v, so our action was to put the battery on charge.

Using another battery, we got a set of hydrometer results. These results had a specific gravity variation of 100 points. The allowable specific gravity variation of a battery is between 25 and 50 points, so the result we got was a fail.

Next was to do a high rate discharge test, using a carbon pile. This was a different battery with a CCA of 310A. The load that we were to apply was 155A and the voltage that had to be held while the load was being applied is 9.5v. Our result was that the battery held a voltage of 10.6v while the loaad was being applied.

Next we used a digital battery tester to test the battery. The tester gave a reading of "PASS" which means the battery has adequate charge. The tester also said that the battery had and OCV of 13.46v. It also displayed a CCA reading of 300. The state of charge of the battery was 100%

The battery was in good condition. Although there was a surface charge on it, so putting a load on the battery for a short amount of time would have been appropriate.