Quote:
Originally Posted by Bob Carriere
We always hear about how important it is to have a good grounding connection particularly on 6 volts system........ well it also applies top 12 volts.
Everytime I used the tester it showed 12.88 volts.... so I assumed that power was getting to the starter.......
Decided to remove the bolt holding the ground wire..... installed two new star shaped washers one on each side of the cable ferrule..... bingo started right away.
Don't think that faulty connections can only happened on 6 volts system.
I have concluded that although the ground wire was conducting enough voltage at the low amps generated by the tester the connection was bad enough that on a high load for the starter it failed to carry the amperage.
Lesson learned.
Bob C.
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Bob,
Good information. I have also seen this on 12/24 VDC systems. Just because the meter shows appropriate voltage, does not mean that the circuit is capable of drawing sufficent current to start a vehicle. Case in point, last year I had some issues with my Jeep Grand Cherokee on the North Shore of Lake Superior, on a Sunday. I dropped into a gargage, where the mechanic was not around, but someone offered to take off the battery cables and clean the terminals. The terminals were pried off, and the terminals were cleaned, and re-installed. The vehicle started but continued to act up intermittently. I would measure the voltage on the battery, and all seemed good. I ended up replacing the 12 VDC battery. When taking the terminals off, it became apparent that the lead connector on the battery was cracked at the plates of the battery. So at times it worked well, and other times it was unable to provide enough current because of the break.
Now I have purchased a battery terminal puller, which is very low cost, compared to the cost of replacement of a battery. I try to use the battery termninal puller now on all my vehicles, rather than just using some random tool to pry off the connectors.
In Ottawa, one fellow was having problems setting the voltage regulator on the alternator after assembling the system back up. The battery voltage kept on getting lower, and adjusting the voltage regulator was of no use. Voltage regulators need a reference to ground to work. It ended up the large ground wire from the engine to the body was not connected up. As soon as that was done, the voltage regulator was functional and could be adjusted. Then the batteries could accept a charge and their voltage increased.
Lots of little things to look at with batteries and starter/alternator circuits when they do not work properly.
Cheers!
Stuart