Crazy Battery Charging Problem - HELP! Options

[customstarr]

Ok... heres a good one: I've had my car for about three months - most of the time it's been in storage - never once lost a charge during the cold winter - even after sitting for weeks without starting. Last week, I brought it home from storage and started some detail cleaning on it - everything was fine.

Then, while driving it, it seemed the FI was messing up - just wasn't running that great. I get home, go to restart it and the battery is DEAD.

The PO put the wrong battery in it anyway, so I went and purchased a brand new battery today. I put it in, the car fires up and runs great - for a minute - then it seems like its acting up again. I shut it down, try to restart, and the BRAND NEW BATTERY IS DEAD.

Here's the kicker: My GEN light works - comes on during key up, but does not stay illuminated while running. How could a brand new battery get immediately drained after running for just a few minutes unless the ALT is bad - but then again, why am I getting no GEN light?

PLEASE HELP! Possible Voltage Reg problem?

[Spoke]

Break out your volt meter and do some measurements. Don't have one, buy one. A volt meter is essential for working on these cars.

By the sound of it, you have some other problem besides a dead battery. Could just be a bad connection somewhere. Give us some details and we'll nail this thing down.

Try some of these tests:

1) Visually inspect all ground straps for corrosion (green color is bad), breaks, or loose connections. Check ground strap on the transmission to the chassis. Check ground strap from battery to chassis. Your alternator may even have a ground strap. Have to look under the engine for this one.

2) Ignition off, measure battery voltage from battery terminal to battery terminal. Should be 12.6 or so.

3) Ignition off, turn on headlights or just parking lights if headlights don't come on with ignition off. Measure:

a. Voltage battery terminal to battery terminal. Should still be around 12V.

b. Measure voltage from each battery terminal to its clamp. This must be 0V else you have a dirty contact between terminal and clamp. If not 0V, remove clamp and thoroughly clean terminal and clamp. A minute layer of oxidation or corrosion will cause high resistance and no start.

c. Measure ground battery terminal to chassis. Again, must be very close to zero.

A voltage drop of more than 0.1-0.2V across any connection should be considered suspect and disconnected and cleaned thoroughly. The metal should be nice and shiny on both sides (like cable and chassis or clamp and battery terminal).

4) Ignition on, car not started. First disconnect +12V to your coil to protect either points and coil or Pertronix or other electronic ignition. Repeat 3a, 3b, and 3c.

If you have a massive short to ground, the small wires on the positive battery terminal will start to heat up. The large wire on the positive terminal is for the starter and shouldn't be an issue if the starter still works.

5) Ignition on, car running. Repeat 3a, 3b, and 3c. For 3a, you should see about 13-15V on the battery terminals.

6) If the car won't start, measure battery voltage as the car is cranked. May require 2 people, one to crank, one to hold the voltmeter leads. Battery voltage should drop to 8-10V during cranking. Measure on battery terminals, not clamps. If battery voltage looks ok but no start, try measuring (during cranking) each battery terminal to its clamp. Should be near 0V. Also for ground, check battery terminal voltage to chassis ground. Again, should be less than 0.1V, 0.2V.

Good luck and happy troubleshooting,

Spoke

[Bartlett 914]

Break out your volt meter and do some measurements. Don't have one, buy one. A volt meter is essential for working on these cars.

By the sound of it, you have some other problem besides a dead battery. Could just be a bad connection somewhere. Give us some details and we'll nail this thing down.

Try some of these tests:

1) Visually inspect all ground straps for corrosion (green color is bad), breaks, or loose connections. Check ground strap on the transmission to the chassis. Check ground strap from battery to chassis. Your alternator may even have a ground strap. Have to look under the engine for this one.

2) Ignition off, measure battery voltage from battery terminal to battery terminal. Should be 12.6 or so.

3) Ignition off, turn on headlights or just parking lights if headlights don't come on with ignition off. Measure:

a. Voltage battery terminal to battery terminal. Should still be around 12V.

b. Measure voltage from each battery terminal to its clamp. This must be 0V else you have a dirty contact between terminal and clamp. If not 0V, remove clamp and thoroughly clean terminal and clamp. A minute layer of oxidation or corrosion will cause high resistance and no start.

c. Measure ground battery terminal to chassis. Again, must be very close to zero.

A voltage drop of more than 0.1-0.2V across any connection should be considered suspect and disconnected and cleaned thoroughly. The metal should be nice and shiny on both sides (like cable and chassis or clamp and battery terminal).

4) Ignition on, car not started. First disconnect +12V to your coil to protect either points and coil or Pertronix or other electronic ignition. Repeat 3a, 3b, and 3c.

If you have a massive short to ground, the small wires on the positive battery terminal will start to heat up. The large wire on the positive terminal is for the starter and shouldn't be an issue if the starter still works.

5) Ignition on, car running. Repeat 3a, 3b, and 3c. For 3a, you should see about 13-15V on the battery terminals.

6) If the car won't start, measure battery voltage as the car is cranked. May require 2 people, one to crank, one to hold the voltmeter leads. Battery voltage should drop to 8-10V during cranking. Measure on battery terminals, not clamps. If battery voltage looks ok but no start, try measuring (during cranking) each battery terminal to its clamp. Should be near 0V. Also for ground, check battery terminal voltage to chassis ground. Again, should be less than 0.1V, 0.2V.

Good luck and happy troubleshooting,

Spoke

(IMG:style_emoticons/default/agree.gif)

Top notch advise.