Did I kill my battery / charging system?

[bobdotorg]

This past weekend my car would not start - turned over about three or four times, and then rapid clicking / flashing dash lights. Since then, it's been hit and miss, but it's clear that the battery is not getting / holding much of a charge.

Once the car is started (I've been parking on an incline and letting out the clutch) I can run all accessories with no problem, so I don't think I killed the alternator.

All the symptoms of a battery that won't take / hold a charge, but I'm not sure for two reasons:

1. the battery is 18 months old

2. I replaced my thermostat the previous evening, and had about a liter of coolant drain from the thermostat housing down the back of the engine. I also mucked around with the three cable attachments above the housing.

3. No symptoms before replacing the thermostat.

To try to remedy, I cleaned and sealed the cables and terminals at the battery, and sanded the negative cable where it connects to the transmission. Still no go. I've not yet tried to get to the connection at the alternator.

Another thing of note - I did not tighten the intake hose next to the battery enough, and it popped of at full boost. Loud and scary to lose power like that, but no cloud of smoke, so no tears.

It took 5 or so minutes to re-attach the intake, and then I had the first non-start. Could the concussion from the intake hose popping off have killed the battery, voltage regulator, or other component?

Unfortunately I'm out of town for another week and don't have a charger or multimeter to do any real testing.

Any insights would be appreciated, as I'd really hate to buy a battery and have that not be the source of the problems.

[Kimberly]

As a first quess, I would isolate the source of problem to either the alternator or battery. Since you do not have any way of checking, see if an Advance Auto is nearby and they check it. If your alternator is working it should be putting close to 14V to your 12 volt battery. If it is, then you may have a battery shorted out internally provided all your connections are good and you have a good frame ground. A voltmeter would really help you isolate the problem more quickly. Did you look at the alternator connections as well for a possible problem??

[bobdotorg]

Thanks for the reply. Checking / cleaning the alternator connections is my next step. I'll have a jack and stands tomorrow. If that doesn't work, I'll yank it out of the car and take it to Checker.

I also dug up a voltmeter in my friend's garage, but it's an analog relic with 10V and 50V scales, so not much help there, as it's about 1mm between 11 and 14V.

Anyone know what the correct resistance is for a battery?

[Kimberly]

I do not know -- but another check that should be done first is to check the water level in the battery. If the top of the plates are showing then you could be low on water, due to battery leaking, alternator overcharging, or evaporation loss. Also look in each cell to see if one is showing discoloration versus the others.

[Saaboheme]

And get yourself a hydrometer to check the specific gravity of the electrolyte in each cell. They can all be full and yet you can have a cell or two failing.

[Kimberly]

Another method to check for a battery for an internal short (although I use it as a last resort if the hydrometer readings are not conclusive and I suspect that it is the battery) is to disconnect both the positive and negative cables from the battery, then hook a set of jumper cables to the battery and then connect the other end of the jumper cable together (which will arc especially if battery is good) & read with a voltmeter quickly. The battery if good should still read above 11 volts and hold it and go down slowly ---if battery has a short it will drop down below 10V right away. The reason I use this as a last resort is that I am afraid the battery could explode (although I never had it happen). I cover the battery with plastic except for the terminals in case it does.