I recently read the following extract below which explains how to test a car battery by putting stiff wires right into the cells and measuring the voltage.
I'm attracted by this method because I do not have a hydrometer to test the individual cells. Could someone answer these questions about this method.
(1) Is the method described below a sensible approach?
(2) Is the method a good indicator of the cell's health?
(3) Is he advocating pushing the coat hanger wire right down between the plates of a cell or only pressing down on the top of the plates?
(4) Does the method damage the cells either physically or chemically?
John
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The Charging System. Part 1: The Battery
The individual cells can also be tested with a voltmeter.
Take a coat hanger and make two lead extensions about six inches long and attach them to the meters test leads.
Touch the positive lead to the positive terminal and stick the negative lead inside the cell next to it.
It should read about 2.1 to 2.3 volts.
Now insert the positive lead in the first cell and the negative lead in the second cell.
Proceed down the line until you get to the last cell. Here you will put the positive lead in the last cell and the negative lead on the negative terminal.
All the cells should read the same, or within 0.2 volts.
If one reads 4.0 or more, you have a shorted cell and the battery is no good.
If you get a very low reading or a zero reading, the cell is open and again the battery is no good.
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