battery/alternator troubleshooting
 

So my battery died without warning, last Friday afternoon. The car started on the first lick when I left work and when I went to re-start it at a service station 20 minutes later, it was as dead as could be. I put in a new battery that evening and drove it about 20 miles without trouble. Put a charger on it the next day and it almost immediately indicated a full charge.

My mechanic gave the car a once-over yesterday and declared the charging system healthy, but I didn't like the expression on his face. Said what I described seems odd, and I agree. No reluctant starts, no lights brightening with throttle, no warning light, nothing. "Sounds like a bad connection," he said, seconding the opinion of the guy who sold me the battery. A similar thing happened to me with a Legacy a few years ago: Stuck in standstill traffic, I shut-off engine to save fuel, turned the key five minutes later and got not even a click. No light that time, either, but the alternator was deemed toast by the same fellow who checked the car yesterday.

My mechanic knows his stuff and has never steered me wrong, so when he seems a bit troubled, I'm troubled. What do y'all think?

dcb

Me thinks..... Alternator wiring upgrade and call it a day.

When you say "dead as can be" do you mean you had no lights, radio, etc? Or just that it wouldn't crank?

Nothing. Not enough juice to honk the horn. Pressing the horn button caused the barely-lit dome light to go out. I had to depress the shift lock button to move the gear selector to neutral. Tried jump-starting, but even after several minutes the engine would barely turn over. The "donor" battery's terminals were pretty grungy, but still. This after a 20-minute drive and a couple of minutes at idle (AC and stereo blasting), waiting for a space at the gas pumps. With the new battery she fired on the first hit, as always. It's as if the battery (the age of which I did not know) suffered some bolt-from-the-blue, catastrophic failure while I was inside settling-up at the cash register.

No warning light nor any other hint of batt/alt troubles before or since.

dcb

I agree, it sounds like a bad connection or battery. Any problem since?

None. (BTW, the old battery terminals were clean and corrosion-free.) What would cause a battery to fail this way?

I actually have 4 gauge cable, solder, and gold plated ring lugs for the alternator wiring upgrade; just one of 101 things I've never gotten around to doing. Seems I read it's wise to include a fusible link in the positive lead. Opinions?

Oh, and thanks for the feedback.

dcb

Cracked plate(s), connectors, etc. or it was just its time, who knows without an autopsy. Battery forensics?

Circuit protection is rarely a bad idea but there are millions and millions of cars with longer, unprotected runs. One fact is that each connection present is a potential point of resistance/voltage drop. Like Trevor said, the wire from the factory will carry the load. However at high output some output can be given up to just heating the wire. In that respect a heavier wire is a bit safer and a bit more likely to deliver the full output to the battery.

Get yourself a voltmeter you can plug in the lighter while driving. Make sure it's one that displays voltage. You can monitor the battery/charging system yourself.

Similar thing happened to me yesterday. The battery was old enough for this to be about time. I think the recent higher afternoon temperatures finally killed it.

I was running around, and had already made four stops. When I went to leave the 4th store, I turned the key to ACC, got the radio, but when I turned to ON everything went out -- even the clock reset. With the door open, back at ACC I got the "key in with door open" chime.

Water was down a little in three of the cells. I filled them back up. We'll see what happens today, but I'm planning to shop for a new battery. Any recommendations?

I bought a mid-priced Brand-X at my local O'Reilly Auto Parts, thankful they were still open and that they had one on the shelf. In 30+ years of driving, I doubt I've ever bought a particular brand of battery more than once.

dcb

Optima red top is one Ive seen th most in various lockers and such, but its a rather expensive one i think

Now that I thought about it, the last day or two before the battery was a little bit sluggish starting the car. Old battery was a Sears "Weatherhandler" from almost 6 years ago. So I suppose I got my money's worth.

The battery prior to that was the factory original, which didn't even last 3 years. The car had been on the new car lot just over five months, so that might have shortened its life a little. That one took a little longer to die -- over quite a few days, when the car wouldn't start on the first try I was able to let it sit for a little while and the battery would revive enough to work.

I was ready to buy another DieHard, but Sears pissed me off -- they wanted $13 to do the test and installation (it was free last time), and their price on the shelf was $5 more than the price shown online.

Did what I should have done first -- went and looked at the review in Consumer Reports (November 2004). They rated the "Autocraft Silver" at Advance Auto Parts ahead of the Weatherhandler for the size needed for the SVX (group 24), with a better warranty (24/72 months vs. Sears' 18/72). And at $50 it was $10 less than Sears'. And Advance did the test and installation for no extra charge.

I was so happy I bought two oil filters from them too (second will be nearly free after rebate :)).

The wide band I'm using in my car displays the battery voltage as it is heating up the sensors after starting the car--this lets me see my voltage on a regular basis. The alternator relies on it's bolting to the engine for the ground connection. I can't speak for how good or poor this is in the factory location but after relocating the alternator for our supercharger system (alternator brackets bolt to block and exhaust manifold covers) it was necessary to run a ground directly to the battery.

I've previously done some upgrading of the positive wiring after noting the voltage is depressingly low on the acc line. Using my true rms fluke multimeter and the factory service manual wiring schematics I started upgrading the circuit starting at the alternator and battery wiring. I determined that at least in my case the poor voltage was caused by the ignition switch. If this is the case for everyone else then either our ignition switches are all just worn/corroded or they are the weak link to begin with--in either case no wiring mod will fix our voltage woes unless it's a new ignition switch or a big fat relay with the switch controling the circuit instead of making the circuit.

Another thing to consider is assuming my case is also the general case then none of the electronics running the engine are effected. Unfortunately pretty much everything else is. I'm curious to see if a new ignition switch makes a good connection or not but to date have not been motivated to pull apart EVERYthing necessary to do the R&R.

The lighter plug is the worst voltage in the car....makes me want to cry, how very inconvenient.

I hope you were pithy. Did they bloviate while you were there?