'95 850GLT Battery Dead-'No' Reason-Electrical Genius Needed

[confused_al]

Here is the ALTERNATOR & REGULATOR part of the service manual, you will find the "VOLTAGE DROP TEST" procedures at the the bottom of page1. Wouldn't you ask your mechanics do the test for you?

[viper69]

Here is the ALTERNATOR & REGULATOR part of the service manual, you will find the "VOLTAGE DROP TEST" procedures at the the bottom of page1. Wouldn't you ask your mechanics do the test for you?

I will now!

Got a question about alternators..BUT not Volvo. I heard this from a friend, wondered if this is possible w/Volvo? In her car (I dont know what kind she had) her guys did some test on the alternator and such, they said "no problem", well it turns out after another battery drain for her a day later, there was indeed a problem w/her alternator which wasn't detected, a diode of some sort in the alternator was totally blown. Preventing proper charging of the battery from what she told me.

My question is, why wouldn't this have been detected by her mechanics? It just made me wonder if mechanics do their diagnostics, and perhaps the diagnostic can miss something. I'm just wondering, because that's how I felt when I brought it to my local "stealership" this was before I had located a good mechanic.

[confused_al]

why wouldn't this have been detected by her mechanics?

It should, if they do an "OUTPUT TEST" but apparently they didn't.
BTW, my ALT (95 GLT) output is around 14.4v with no load, seems to me yours is on the low side say the least.

[viper69]

why wouldn't this have been detected by her mechanics?

It should, if they do an "OUTPUT TEST" but apparently they didn't.
BTW, my ALT (95 GLT) output is around 14.4v with no load, seems to me yours is on the low side say the least.

Thanks!

Would a 1volt difference, compared to yours, cause my battery to drain as described? I wouldn't know.

With mine the change in voltage was .09Volts.


Second question, where could I find the acceptable range of voltage values for an alternator? I looked in the info provided to me above, but it's not listed.

[instarx]

When you say broken battery post, do you mean the metal terminal post itself? Wouldn't that show up as a problem already though via AAA's test?

Yes, the terminal post itself. You won't see the break because it is inside the battery. Usually caused by an overzealous or impatient mechanic trying to get the battery leads off by twisting them. Sometimes the post may be making good contact and sometimes it may not. When the AAA guy attached the clamps to the posts he may have made the connection better. It's just a possibility that your mechanic can check out in a second.

[confused_al]

Second question, where could I find the acceptable range of voltage values for an alternator? I looked in the info provided to me above, but it's not listed.

I believe the range is 13.5-14.8 (Haynes). The "output test" is the best way to determine an alt's condition, as the "voltage drop tests" will tell you the condition of the whole loop.

[viper69]

They found the problem. It's the alternator. This is the original alternator too. They said it was putting out about 20-25 amps, which is like working half the time I was told. That would explain the battery issues I've had. However why the stealership never detected this problem a few years ago I won't know.

They didn't find any draws on the battery at all.

Is this the average longevity for a stock alternator?

Second, why is the alternator so expensive WOW, I guess I'm used to replacing one on a Toyota.jeez?

[zhenya]

Well, I sure hope that is the end of your problems! Please report back after a few weeks or so to confirm.

I'm currently still fighting a long-standing issue that is similar in many ways, and that I have posted about here before. Previously we had isolated it to the diode in the alternator, which I made an appointment to have my local independent volvo specialist replace. Unfortunately the mechanic didn't agree with me and didn't want to replace the alternator. He was certain that it was the glovebox light, and wanted to remove it and install a battery cut off switch. Looking to maintain a good relationship with them, I let them do this, but unfortunately my issue remains.

The issue is two-fold - one that the battery has a constant 100mA drain such that the car will not start after 1-2 weeks of sitting. This may be the diode in the alt. - it's definitely NOT the glove light or anything else fused.

The second issue is that even if I drive the car day in and day out around town, occasionally the battery voltage will drop too low to start the car. I do a lot of > 2 mile drives - sometimes weeks at a time like this. The battery drops to about 12v when the car will no longer start, and after a full charge is at 12.8v. With the car running at idle, it reads 13.8v, and I've measured the output of the alternator at 14v at idle. This last test would seem to indicate to me that the rectifier is functioning properly - so I am at a complete loss, and a little bit hesitant to replace the alternator unless I am sure it will fix the problem.

Any other suggestions would be appreciated!

[viper69]

Well, I sure hope that is the end of your problems! Please report back after a few weeks or so to confirm.

I'm currently still fighting a long-standing issue that is similar in many ways, and that I have posted about here before. Previously we had isolated it to the diode in the alternator, which I made an appointment to have my local independent volvo specialist replace. Unfortunately the mechanic didn't agree with me and didn't want to replace the alternator. He was certain that it was the glovebox light, and wanted to remove it and install a battery cut off switch. Looking to maintain a good relationship with them, I let them do this, but unfortunately my issue remains.

The issue is two-fold - one that the battery has a constant 100mA drain such that the car will not start after 1-2 weeks of sitting. This may be the diode in the alt. - it's definitely NOT the glove light or anything else fused.

The second issue is that even if I drive the car day in and day out around town, occasionally the battery voltage will drop too low to start the car. I do a lot of > 2 mile drives - sometimes weeks at a time like this. The battery drops to about 12v when the car will no longer start, and after a full charge is at 12.8v. With the car running at idle, it reads 13.8v, and I've measured the output of the alternator at 14v at idle. This last test would seem to indicate to me that the rectifier is functioning properly - so I am at a complete loss, and a little bit hesitant to replace the alternator unless I am sure it will fix the problem.

Any other suggestions would be appreciated!

Sorry I have no advice, wish I did. You know more about electricity than I do. The people on this forum know TONS more than me, especially in this area. I've had very little problems w/electrical systems with any car, it was always the alternator. This car is the exception, and it all started in '06. So I have little to report re: help. Sorry.

If you have in your area, bring it to guys that specialize only in automotive electrical issues. As you know, the problem could be anywhere. IT could be the diode. Remember, it's your car, not the mechanics. That's exactly what happened to my friend..but this was a non-Volvo vehicle as I said before.

If you think it's the diode, take what information you know and call around see what others say. If you still have the problem, tell your mechanic.


What's the accepted range in amps for an alternator?

[instarx]

Who found the problem, the dealer? That's why it's so expensive, but after all you went through I'm sure you are just happy to have it fixed. And since it was the original 15 year old alternator that failed you're probably not feeling too bad about that either. It gave you a good run.

The alternator on my 2000 was replaced after eight years by the original owner.