Last weekend, my car (93 Toyota Previa) wouldn’t start; I got that low-power “ticking” sound that I associate with a weak battery. It fired right up with a jump. The water level indeed appeared low, so I replenished and drove around for 30 minutes to recharge. I then cut if off, and it restarted again with seemingly no problems. The next day, things were still fine. I didn’t use that vehicle again all week. Yesterday (one week later), the vehicle wouldn’t start (I wasn’t there, but the designated re-starter said it made same lame ticking sound). I was all prepared to simply replace the battery when I said, “What the heck, just try it for myself.” Well, it started. Does this mean the battery isn’t the problem? A dear friend, with admittedly no knowledge on the subject, keeps chirping, “It’s the alternator, I tell you.” It seems to me these are my options:
(1) Assume it’s the battery on the theory that weak batteries can be intermittently ineffectual at starting cars, and get a new one–perhaps to later learn that the problem is really elsewhere (like the alternator).
(2) Fork over big $$$$ and suffer significant inconvenience next week to have someone (a “trained professional”) diagnose the problem
(3) Further troubleshoot the thing myself with the able assistance of dopers (which is, after all, much more satisfying than either of the first two options).
Many thanks in advance to all who are thoughtful enough to provide meaningful guidance.
Take it to your local “service” station and have them check your battery, they do it for free or maybe 1 or 2 bucks. Don’t buy a battery there, they will probably charge you about $30 more than you can get one for at Wal-Mart.
Just went through this and the problem was the bat on the way out. The temps were fluctuating and the bat that was right on the edge so would recover for a few days when the temp rose a few degrees. For me the car is right next to the house getting a charger out there was ease. Your case could be different.
Check all grounds and clean up the insides of the bat cable terminals.
A bat from a junkyard is about $15 bucks and will usually carry a 3-mo replacement warrantee. Easy troubleshooting.
If that does not get it then replacing the alt brushes is easy and not expensive as a brain dead eliminator.
If that fails and you have a high dc meter you can monitor charging current. You could monitor the bat voltage but that’s iffy. Sometimes you’re just reading the bat.
From the conditions you describe, I would guess that the battery is more than a couple years old. There is enough of a “silt” buildup at the bottom of the lead plates to slowly discharge the battery over a period of hours or days. You may also want to insure that the top of the battery and the terminals are clean and no corrosion is present. The presence of corrosion on the battery top and/or terminals can sometimes bleed the charge out of it.
If you possess a battery charger, you can find out pretty easily if the battery has turned into ballast. Disconnect the positive lead from the battery and make sure that there is no other secondary wire to the positive.
Connect the battery charger to the battery and start the charger. Come back in a half hour and take note of the position of the ammeter on the charger. It should be reading fairly low because the battery is probably close to being charged(if it is a good battery). If there is still a significant current being fed into the battery, come back in 15 minutes to see if the ammeter is reading any lower. If not, your battery is not going to charge fully, and will probably lose what charge it has taken. Time for new battery.
On the other hand, if the battery charges fully, come back in a few hours with the charger to see if any more can be pumped into the battery. If the battery appears to be still fully charged when you return in a few hours, bad news. It’s your alternator.
FixedBack
“When learned men begin to use their reason, then I generally discover that they haven’t got any.”~~*G.K.Chesterton 1908 *
It’s going to be tough to diagnose without the proper equipment. There are several things that can cause your problem beside the alternator and the battery. A couple of pretty common ones are a worn end bushing on the starter or a poor connection. If your car has a starter solenoid it could also be the culprit. (If the solenoid is internal to the starter, a rebuilt starter is usually the way to go.)
Since it doesn’t cost anything, the first thing I would do is remove the battery cables and clean/scrape the inside of the terminals and the sides of the battery terminals. I would also take a look at the connections to the starter and or solenoid.
If none of that works, bite the bullet and take it to a good technician.
For what it’s worth, about the only way the alternator could be at fault without the alternator warning light coming on is for:
A) The alternator light is burned out - you can check that by turning the key on without starting the car and seeing if the light comes on.
And:
B) One half of the diode bridge is out. In that case the alternator will charge the battery, but at a greatly reduced rate. That can be partially checked with a voltmeter. You should measure over 14 volts across the battery terminals when the car is running. To be sure the bridge and not the regulator is the problem you really need a ocilloscope to check the charging waveform.
C) A bad voltage regulator can also be the problem. That will show up as a low voltage like B above but the charging waveform will usually be normal. Most of the time nowadays the regulator is inside the alternator. So to replace it you will have to take the alternator apart.
Unless you are really into that sort of thing a technician might be the best way to go.
Everytime I’ve heard that clinking sound, it’s just been the battery terminals. Either they needed cleaning or the cable clamps were loose. Banging the terminals and clamps with something like a wrench is a good quick fix just to get the car started.
Look at the date on the battery!
Get a new battery, they are only like $45.00. That is the first thing I do when I buy a used car.
They are only for about 5 years anyway.
LEts see, 93 + 5 = 98. Ah, you are two years too late, no wonder 
Unless it warmed up after not starting for the other person, I would’nt say bad battery or alternator. I’d go with the selenoid going bad, or the starter wearing out.
Just have the battery tested first. That costs you nothing or almost nothing. I would say the alternator had a bad diode if when you drive without the headlights on you have no problem starting the car, but driving with the headlights on kills the battery.
Both my brother and I had a certain store’s brand of battery that the side terminals were breaking out of the batteries. Sometimes we would have a good enough connection to start, and sometimes we wouldn’t.
What everyone else said about batteries.
Most auto parts stores will test your alternator for free. Call around for prices first.
Check the Ford From Hell thread elsewhere in GQ for more diagnostic tips.
“A lot of Christians wear crosses around their necks. You think when Jesus comes back, he ever wants to see a cross?” – Bill Hicks
Many, many thanks to all who contributed. I carefully considered everyone’s suggestions and then emarked upon a course of action. I was, of course, operating under a number of rather daunting constraints; for example, not only am I woefully ignorant of virtually all things automotive, and I am also exceedingly impatiently. Accordingly, when the autoparts guy said he’d need to recharge the old battery before he could test it and that would take “about an hour,” I took my chances and just bought a new sucker. Not some $45 number, mind you, but the biggest baddest “Official NASCAR” model they had in the joint (I was assured by the sage 17 year old who sold it to me that it was worth every penny over either of the two cheaper models available) for a whopping $79.99–guaranteed to last for God only knows how long. (A little perspective here is in order: The one I replaced was the original–a Panasonic if you can believe such a thing, and contrary to my earlier report, the veheicle involved is not a '93, but a ‘91 (sorry, but I can only keep track of so many things, and with kids’ birthdays to remember, well I’m sure you all will understand my confusion). At any rate, I installed the sucker last weekend (which was, despite what all you snickering automative geniuses might think, not all that easy given that the new battery differs just enough in its dimensions from the old one that old “holding bracket” (stop all that eye-rolling right now!) no longer quite fit, and I had to improvise with some odds and ends around the garage). Now, one week later all is well. Thank you all again.