308 battery problems wasn’t the alternator. Now what?

Sorry if I misunderstood but a receipt does not rule out the problem being the battery

 

Agree that a recently replaced battery isn't "good" just because it was recently replaced (especially if it's been deep-cycled a lot because the car actually had a different problem) -- any Auto Parts store should be able to load test it.

Better to "test" the alternator when it is in place in the car (i.e., measure the voltage at the battery at various engine RPMs and measure the current draw from the battery with the key "off"). For example, if you have a wiring problem in the car that's not supplying the excitation to the alternator, the alternator will test fine on the bench (because the excitation will be supplied by the tester). On the 308, the excitation is supplied via the alternator warning light IIRC (on later models, they got smarter, and supplied the excitation via a separate circuit so a burned out, or disconnected, alternator warning light wouldn't disable the alternator) so the first question (if both the battery and alternator test OK on the bench) would be: "Does your alternator warning light correctly illuminate with the key "on" and the engine not running (when the battery and alternator are in place)?".

 

Since you have the alternator out, might as well have it recondition/rebuild or at least put new voltage regulator with new carbon brushes.

 

Will the battery hold a charge overnight when it is disconnected from the car?

 

If the battery does hold a charge overnight when disconnected you probably have a short somewhere or maybe a relay that is sticking. Best way I have found to track this down is to put a small light in series with the battery. If there is current flow the light will illuminate. Go to your fuse block and pull one fuse at a time until the light goes out. This will at least give you a starting point as to what circuit is causing the problem.

 

Purchased a battery earlier last year and damn thing wouldn’t hold a charge for more than two days. Replaced it with another and no problem again.

You should get the red alternator light illuminated upon start up. Simply blip the throttle and it should go out. ( if charging correctly).

 

It is also normal on 308s to have the Alt. light stay on until you give it some RPM. Just a blip of throttle will usually get the light out and the Alt. genning like it should.

 

If not charging correctly the first thing I would look at it is if your alternator belt is too loose? After that I would look at every item the guys mentioned above.

Steve Magusson has helped me out more times than I can count.

 

Yes, that's the one.

 

Not sure what exactly the symptom is. Won’t start or won’t crank? What year 308?

Won’t start is not necessarily battery.

 

Charge up the battery. Stick it back in the car. Key up, but do not start. Make sure battery light is illuminated. Start the car
Blip the throttle until the light goes out. Using a multi meter, check the voltage at the battery. You should see 14.5 volts. Turn on lights, fans, a/c etc. The voyage at the battery should not drop below 13 volts if the alternator is in good shape.

If all is well, start looking for a draw. Disconnect the negative battery terminal. Put in series a test light. If a strong draw is present, the test light will be very bright. Start pulling fuses and relays until it goes out. Now you have found your circuit the issue is on. Start isolating the issue from there.

 

Step One should have been actually testing the battery.

 

Glad that you got it sorted out, and all is working well. I'll comment again here that when a warning light comes "on" at the wrong time that's something a human easily notices and immediately recognizes as a problem, but when a warning light stays "off", when it should be "on", that rarely gets noted (even though it also is a strong indication of a problem). Every Owner should understand from their OM what the various warning lights should be doing -- both going "on" or being "off", and watch them to make sure they are doing the right thing. Your early 308 doesn't have too many warning lights to worry about, but the dash on a US TR looks like a flashing Christmas tree during the starting process