Battery issues?

I have a 94 Buick Skylark. It doesn't get a lot of use. I've only put

35,000 miles on it.

Sometimes when I try to turn it on it seems to kill the battery. All the lights on the dashboard will go off. Trying to turn it on again soon after will do nothing. When I test the clock it is still keeping time, thus it didn't lose a connection with the battery. If I wait a little longer the lights will come on the dashboard, but still no energy to get the car going.

If I completely disengage the battery and wait a few minutes to reconnect, it will usually turn on without problem.

I have taken the battery back to the dealer and he tested it and said it was OK. Although, it didn't seem like a very thorough test like I've seen other times.

Any thoughts on what it could be?

I appreciate the help.

BR

Reply to
Big Bubba
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The clocks are very insensible for under voltage.

Take a look at connections like pool from the battery and ground connections to the engine check for corrosions etc.

Regards,

Ralf

Reply to
Ralf Ballis

Use a voltmeter and check the battery voltage with the lights on. If it is below 12-13 volts the battery is too low.

Reply to
Woody

Classic rotten connection symptoms. If the thing will start after you've had the terminals off, you disturbed the gunk enough to get a connection. Take them apart, wire-brush them thoroughly, and reassemble with some DC-4 or some other goop to keep the oxygen and corrosive gases off them. The clock, depending on the type, will draw very, very little current, and connections would have to be bad indeed to kill it. Some older clocks had a spring-wound mechanism that had a solenoid to wind it; those clocks would clunk every few minutes. You might have one of those, though I would think that by '94 GM would have gotten with the quartz program. Those old clocks will run for some time after the battery is disconnected. Ohm's Law says that E = I x R, or Voltage is equal to Amperage times Resistance. We can use the same formula to understand voltage drop when a current is drawn. So if the clock needs ten milliamps (.

010 amps, and that's pretty liberal) and a dirty battery terminal is offering a ten-ohm resistance, the voltage drop across that dirty teminal is 0.1 volt. The clock isn't going to care much if the voltage therefore drops from 13 to 12.9, see? But the starter, which tries to draw 250 amps through that ten-ohm resistance, is theoretically going to try to cause a 2500-volt drop, which the battery of course can't accomodate. The starter doesn't get much current at all as a result. And when whatever current does flow through that dirty connection, the resistance causes heating which increases the resistance further, so your dash lights die. If we ignore the starter's resistance (which is extremely low) and just figure the battery's 13 volts across the ten-ohm dirty terminal, we will see that 1.3 amps will flow through the terminal and to the starter. Not enough to rotate the starter, never mind the engine. Connections have to be really clean and tight. Lots of auto parts outfits make a lot of money selling new batteries and starters and other stuff just because a battery cable clamp was dirty or the connections at the solenoid or starter or engine ground were loose/ oily/corroded. Sometimes the problem isn't visible; the cable can be badly oxidized inside the clamp itself. Cheaper and better to replace both battery cables when they get old. I bet that's what your car needs.

Dan

Reply to
Dan_Thomas_nospam

Should have added: Starting problems can be due to burned starter solenoid contacts, too, but that wouldn't be the case here. The dash lights wouldn't go dim.

Dan

Reply to
Dan_Thomas_nospam

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