NP993

About a month ago I returned from a 3-week work trip to a completely dead battery. I remember, in the weeks beforehand, thinking that maybe my starter was going bad, because it had been cranking very slowly. Never really considered the battery or alternator, because the battery was six months old and I'd replaced the alternator two and a half years ago (summer 2010) as preventive maintenance when I had the engine out for a clutch job (at 114K miles).

15K miles later, and after lots of battery tests and a search for a current draw found nothing wrong, it looks like the alternator is the culprit. Here's what I'm getting for charging numbers:

Idle: 13.1
Holding revs above 2K RPMs: 13.5
Idle w/ electrical load -- lights, stereo, heater blower motor: 11.66

Looking back at my receipts, the alternator I bought back in 2010 was a "Bosch OE reman 115 Amp updated version." Presumably there's no hope, over two years but only 15K miles later, for a new unit under warranty? Is it unusual for a remanufactured alternator to fail so soon? Could this be anything other than a bad alternator?

Also, if there's no hope for a warranty replacement, is there someone who could rebuild it better than Bosch so I don't have to do another crapshoot on a "reman" unit?

techman1

Would be a good idea to replace the battery cable that goes to ground. I have been told that they can generate resistance over time.

ca993twin

Take the battery out of the car and hook it to a charger. Then take it to your local auto parts store for a free battery load test. They might even be able to charge it for you if you don't have a charger. After you get this sorted out, you may want to invest in a battery maintainer if your car is left alone for more than a week at a time. Good luck.

NP993

Thanks - already did full charge and had a battry specialist do a load test. Unless the battery test was wrong it's not the battery.

Deadeye

I have a buddy who sent back 2 defective rebuilt alternators before he got a keeper. He did get very good at R and R of the damn thing.

ricks993

I had what I thought was a bad alt. it ended up being a loose wire on the back of the alt.
You might check the wires on the back of the alt, after the alt was installed they might have come loose causing your charging problem

MACH993

I've been trying to sort out a battery that drops too low to allow the starter crank the motor. I'm getting an idle reading of 13.6V from the alternator. Is that within acceptable range? I'm hoping my issue is more with infrequent driving and a trickle charger that may have come loose in the cig lighter socket, allowing the battery to drop below 12V. But after reading this thread I'm wondering if the alternator is the culprit.

IXLR8

That is low. I idle at 14.1-14.2V and that is a tad low for my liking. That is measured right at the battery.

Where did you take that voltage measurement?

Low voltages could be the regulator or a bad rectifier diode.

MACH993

I took the measurement from the battery leads.

MACH993

OK...the last couple of weeks the battery has gone below 12V and won't start the car, even having been connected to a trickle charger via the cig lighter. I thought maybe the connection had come loose and due to infrequent driving, the battery drained below 12V. Today, I jump started it and took the car for a long drive and it brought the battery up over 12V. So, I figure the altnernator is doing its job. I connected the trickle charger and started the car every hour or so. On the 4th try, or hour, it wouldn't start and the battery had gone below 12V again, even w/ the charger properly connected. Now I'm really confused trying to figure out what to try next. The battery is only a year old btw.

pp000830

Reman components are not new. Only the parts that seem to be bad are replaced. The testing of the finished reman units is minimal. Bosch like most brands probably license their name to aftermarket rebuilders to process cores (returned failed units). There are probably little or no standards for rebuilding. The warranty period for rebuilt units attests to this
Andy

IXLR8

You mean prior to the start? That is a less than half-charged battery. No wonder it won't start. A battery while parked should never go below 12.5V.

Maybe the battery has seen better days. Maybe the charger isn't working or the connection to the battery is not being made. Maybe your cigarette lighter fuse is gone, and BTW forget the cigarette lighter...go directly to the battery.


Over 12V? How much over and how did you measure it while driving?

While idling or driving...this is what it should look like...

IXLR8

Which is why I will be rebuilding my alternator myself using new components.

MACH993

The battery was at 11.6 to 11.7 while parked and after a 30 min. drive, it came up to just above 12V. I'll try connecting the charger directly to the battery and see what happens. The battery is only a year old but I guess it could still be shot and not holding a charge.

Thanks Alex. I really appreciate the help!

IXLR8

Talk about dead!

Do you have a cigarette lighter with wire ending in bare ends that you can connect the probes of a Digital Multimeter to. Twist the wire around the probe end and finish off with electrical tape.

Go for a drive. What does the voltmeter indicate now? Maybe your alternator is gone.

Of course charging up the battery by itself and when fully charged (assuming it'll take one), and then doing a simple load test will tell all.