Battery/Charging issues...still...

[zhenya]

As pointed out, one of those B+ wires goes into the fusebox and will be obvious...It is very important that his wire is in solid condition...Another of those B+ wires goes to the B+ terminal on the alternator...This one is VERY important because if it is not solid the alternator cannot fully charge the battery, even if the alternator is good...You can check it's condition by measuring it's voltage drop...Do this by connecting the multimeter negative lead to the postive battery terminal and the multimeter positive lead to the B+ terminal on the alternator...Voltage drop with the engine running should be fractions of a volt...

Jerry

I measured this voltage drop on the first page. I measured 214mV, ever so slightly above the spec of .2v, so seems ok, despite the mess that wire was in at the battery terminal (since cleaned). Wires at the starter and the alternator look very good and are tight.

[Retired MVS Contributor]

[100 ohms is 100 ohms and .01 ohms is 10 one hundreds of an ohm...That is still greater than zero ohms...No cable or wire can ever be zero ohms, it will always be greater than zero...Resistance cannot go negative...

Most spark plug wires today are resistance wires and the resistance will vary depending on it's length...Many spark plug wires are not wires at all...They have a carbon trace core, and pulling on the wire can stretch it and break the trace...

Jerry

Good point Jerry, My memory served me badly in this case so .001 is the corrct way of expressing it in a formula. For example 1Kohm or 1,000ohms would be expressed in the formula V = I x R as 0.0001
Many meters are not sensistve enough to show that a cable is in fact 0.00015 ohms for example. Gold plated cables get as close to dammit to the ideal zero ohms, that's why they're used in audio applications. They just show 0.00 on the scale if they are digital. If they are analogue meters it's a guessing game. But we are getting way off the beaten track, now.[/quote]

Very low resistances (below one ohm, but not zero ohms, which does not exist) is a laboratory measurement done with a Wheatstone bridge...Even in the world of super conductors and cryogenics, zero ohms dos not exist...For our purposes, we have no need to be concerned with it...

Jerry

[takane2]

For small values of resistance you can use milliohms, so 0.01ohms could be 10mOhms

[jackwatch]

Hi all
just logged on to continue/update my education in Volvo's newest quality control strategies and saw the battery issue. I have a 1999 V70 that until this year needed a new battery every 2 years, second week of February ,I believe. This was first noticed and mentioned to me by the AAA guy who we call for a boost when it happens. There is a low voltage leak somewhere or bad ground. I first noticed this when the car was 2 years old when the AM radio would pick up RF interference during damp/wet weather. This would go away temporarily when you lock /unlock the doors with the driver's door master lock. By the way, this switch burned out ( smoke and melting wire) 5 years ago too!! I always suspected a weak generator in this model as, even when new, all lights would dim a bit when putting on pretty much anything. I suspect since these batteries are not the deep cycle type, it cannot survive this problem. Well this just graduated into a yearly plan, as I'm going to sears this morning to get a new battery(10 months old). The fact that the battery goes bad in a short service life indicates that it never recovers 100% from general usage, and when it passes its (say 75% cycle level) it begins to loose its recovery capability. Naturally Volvo cannot find this out and after the first battery replacement ( the warranty ran out on the second occurrence) I've been going to Sears. I do not need to pay for an electrical harness replacement, after the warranty expires.
Life goes on. I actually logged on tho get advice on the mass air flow sensor, after having replaced the throttle body last year (warranty extended to 10 years in lieu of a class action suit/recall, but no owner notification was ever done) when the unit was 10 years and 4 months old, they mentioned that the mass air flow sensor may need replacement soon. Can this be done by the owner? it looks simple enough, is there any calibration procedures required after installation?
Later

[Retired MVS Contributor]

Log onto www.batterystuff.com for a ton of information about lead-acid batteries...It will dispell a lot of misunderstanding and misinformation about batteries...

I am amazed at how few folks own and use a battery hydrometer...Yes, it is 100 year old technology, but it is still the best test tool available for batteries and will tell you more about your battery in ten minutes than all the digital and anolog tools combined...And it is inexpensive...I know, I've got them all...It will pin-point weak cells, dead cells, and shorted cells...After a re-charge, it will tell you if the charge was successful or not...Due to a factor called "surface charge", even if the voltage measures up to snuff with a voltmeter, it does not mean that it is fully charged and the hydrometer will spot that...Cells in a charging battery do not charge up evenly...It will often be found that the first cell is up to a full charge, but as you move from cell to cell across the battery with the hydrometer, the further you move to toward the sixth cell, the weaker each cell is...

Deep cycle batteries are not recommended for automotive service...They are outstanding for long term service, but are woefully lacking for instant starting power, especially in cold climes...They have thicker plates that resist warping, but not enough of them for high energy output when needed...

Jerry

[zhenya]

Ok, here is where I stand today.

I checked my parasitic draw again today, to see if it revealed anything new. It is drawing ~120mA total current - a bit more than when I checked this last year. This time I disconnected the three separate + cables that come together at the battery - this allowed me to isolate the various components to check the parasitic draw. I found that the B+ cable going to the fuse box had a draw of about 55mA - that seems to be in the normal expected range for this car. The main + cable going to the alternator had 65mA, and the third small cable about 1.5mA. At this point I was ready to change the alternator immediately as it has a 65mA draw even when disconnected from the rest of the vehicle electronics!

However, I had some more time to think about the problem, and if the diodes are failing or failed, I should be seeing AC ripple voltage at the battery, or at the very least, at the output of the alternator. Documentation I can find says that more than 0.5v AC current is a problem. However, I'm only seeing 0.05 volts of AC!

Lastly, I took the car to Autozone to have them do their basic alternator test, since it's free, and it passed all tests - output, diode, and regulator.

I'm still totally stumped here, and despite my love for this car, and all the money I've put into modding it to my liking with the intention of keeping it for 10 years, I'm about ready to get rid of it!

[BEJinFbk]

Hi all
just logged on to continue/update my education in Volvo's newest quality control strategies and saw the battery issue. I have a 1999 V70 that until this year needed a new battery every 2 years, second week of February ,I believe. This was first noticed and mentioned to me by the AAA guy who we call for a boost when it happens. There is a low voltage leak somewhere or bad ground. I first noticed this when the car was 2 years old when the AM radio would pick up RF interference during damp/wet weather. This would go away temporarily when you lock /unlock the doors with the driver's door master lock. By the way, this switch burned out ( smoke and melting wire) 5 years ago too!! I always suspected a weak generator in this model as, even when new, all lights would dim a bit when putting on pretty much anything. I suspect since these batteries are not the deep cycle type, it cannot survive this problem. Well this just graduated into a yearly plan, as I'm going to sears this morning to get a new battery(10 months old). The fact that the battery goes bad in a short service life indicates that it never recovers 100% from general usage, and when it passes its (say 75% cycle level) it begins to loose its recovery capability. Naturally Volvo cannot find this out and after the first battery replacement ( the warranty ran out on the second occurrence) I've been going to Sears. I do not need to pay for an electrical harness replacement, after the warranty expires.
Life goes on. I actually logged on tho get advice on the mass air flow sensor, after having replaced the throttle body last year (warranty extended to 10 years in lieu of a class action suit/recall, but no owner notification was ever done) when the unit was 10 years and 4 months old, they mentioned that the mass air flow sensor may need replacement soon. Can this be done by the owner? it looks simple enough, is there any calibration procedures required after installation?
Later

You have a problem that a good tech who's comfortable with electrical troubleshooting should be able to solve.
At this point, you're just changing the bandage on a wound that won't heal. Find the right guy and get it solved.
And +1 on No Deep Cycle battery. That's not your answer either. Find a good indy shop that knows Volvos!

[Retired MVS Contributor]

Ok, here is where I stand today.

I checked my parasitic draw again today, to see if it revealed anything new. It is drawing ~120mA total current - a bit more than when I checked this last year. This time I disconnected the three separate + cables that come together at the battery - this allowed me to isolate the various components to check the parasitic draw. I found that the B+ cable going to the fuse box had a draw of about 55mA - that seems to be in the normal expected range for this car. The main + cable going to the alternator had 65mA, and the third small cable about 1.5mA. At this point I was ready to change the alternator immediately as it has a 65mA draw even when disconnected from the rest of the vehicle electronics!

However, I had some more time to think about the problem, and if the diodes are failing or failed, I should be seeing AC ripple voltage at the battery, or at the very least, at the output of the alternator. Documentation I can find says that more than 0.5v AC current is a problem. However, I'm only seeing 0.05 volts of AC!

Lastly, I took the car to Autozone to have them do their basic alternator test, since it's free, and it passed all tests - output, diode, and regulator.

I'm still totally stumped here, and despite my love for this car, and all the money I've put into modding it to my liking with the intention of keeping it for 10 years, I'm about ready to get rid of it!

No, you will never see ripple voltage at the battery with anything except an oscilloscope, the storage battery is a tremendous ripple filter...It is a giant capacitor doing what capacitors do, storing energy and returning it when needed...If you measure the open-circuit voltage of a run-of-the-mill battery charger you will see about 35 volts with at least that much ripple... Connect it to a battery and the voltage will drop to 14 volts and the ripple will disappear.

If you are seeing a 65ma drain on the alternator B+ there is a bad diode in there and I am surprised, I have not seen an alternator diode go in years...It is not the regulator, the regulator only controls field current...The six stator diodes are connected directly to the B+ and the is a leaky one in there for sure...

You still have another problem though...55ma drain on the fuse box is about double the normal parasitic drain...

jerry

[zhenya]

Thanks Jerry. I understand that the battery would certainly filter the AC, but wouldn't I see it when measuring directly off the alternator?

Is there any other explanation for the 65mA on the Alternator side of things? The fuses and relays were completely out of the loop during that measurement.

[Retired MVS Contributor]

Thanks Jerry. I understand that the battery would certainly filter the AC, but wouldn't I see it when measuring directly off the alternator?

Is there any other explanation for the 65mA on the Alternator side of things? The fuses and relays were completely out of the loop during that measurement.

You would only see ripple directly off the alternator if the alternator B+ wire were disconnected....You would not see a sine wave, you would see the aggragate 3 phase output of the diode bridge...It would be DC with heavy ripple and the ripple frequency would vary with engine speed...

I am assuming that you connected your milliameter between the battery and the disconnected B+ wire going to the alternator and that there are no other wires in parallel...If so, the only explanation for the 65ma draw is a leaking diode...The diodes are in series/parallel so there is no way to determine which one of the 6 diodes it is without disconnecting them all at the internal soldered joints...You need special dies to press out the diodes and press in new ones...It isn't worth it and I would replace the alternator if it were mine...

Jerry