Possible bad battery or connections?

[jpb2222]

Seems as though the drop is between the starter and the alternator. The b+ output on alternator gets really quite hot-- ive just nwo burned my thumb testing it.
Could this still be battery pos cable from term to starter? or from starter to alternator?
If so are there any write ups or ideas for how to replace the wire from starter to alternator?

Thanks!

[jreed]

You could have high resistance connections at the battery, starter and alternator. I like your approach of checking for excessive voltage drop and/or heat at each one.
I have an 850, which is different, so I'm not familiar with the resources available, but a search shows that one good spot to read up more about the cables is available here:
viewtopic.php?t=59119&p=300796

[yanga001]

Seems as though the drop is between the starter and the alternator. The b+ output on alternator gets really quite hot-- ive just nwo burned my thumb testing it.
Could this still be battery pos cable from term to starter? or from starter to alternator?
If so are there any write ups or ideas for how to replace the wire from starter to alternator?

Thanks!

There are a few writeups and i heard marine battery connectors are the way to go. I would replace the battery pos from alternator to battery as your starter only sees high current on startup as it cranks using the battery. I would not suspect as much corrosion on it but a good litmus test would be to get an infared heat gun or thermometer and stick it against the connections you want to test. You are less likely to have a failure within the insulation then you are to have a failure at the exposed terminal ends. Also, welding wire is what i hear most people use for the home made replacement cables.

I have a v70 1998 and am looking at doing this project soon, although i am replacing the voltage regulator first as i rebuilt an alternator in every way but the regulator.

[jpb2222]

Car has been starting and running fine now outside of other previous issues. I had been charging and then disconnecting the battery whenever I left the car, and after work broke the pos terminal nut. Got home with locking jaw pliers. Replaced the terminal bolts with brass bolts, temporarily until I install the cables I just received.
The interesting aspect is that the drop is not between the battery and the starter, but between the alternator and the starter. I picked up cables for both, and a new universal marine terminal. Nut on alternator seems tight enough, but gets very hot while running-- enough to where I burned my thumb when touching it. Starter nut does not get hot, however.
So wondering if it's just the cable? Will replace both, and hopefully my temporarily gone problem goes away for good.
After that it's time to replace the front brakes and fix my p0242 code / turbo.

Thanks for all the help my friends

[MrAl]

1998 Volvo V70 T5.
Replaced alternator after diodes went bad, 3 months ago. At the same time I also replaced the battery (everstart from walmart) as it similarly was no good. Drove 1500 miles no problems. Then recently I was unable to start the car at work parking lot. No crank no start. Single click.
Tested battery with multimeter I had on hand, and the battery read above 12volts. Assumed that it should be enough to at least crank the starter, so assumed the starter was bad.
I came back later and pulled the starter and battery and had them tested at Autozone. Both were fine, but battery needed a charge.
Came back to car and she started right up.
(note; at this time, something odd happened. I had gone to junkyard and grabbed a starter and starter relay. I switched relays before first pulling the starter, and the noise went from a single click to rapid clicking. I'm not sure if that is of note, here.
Also strange: when I was measuring the voltage of the battery pre-starter removal, I had first measured it at 12.4v. Later, I measured and it was 10v. Then later, perhaps the next day, it returned to 12v. I cannot remember if I had measured them all while the battery was connected, or if one of the measurements were while the car was unplugged.)
I drove her home, then sat it overnight. The next day I drove to the store, assuming all was fine, and when I went to leave I encountered the same problem. Started with a jump and made it home.

So obviously, in my mind, something is wrong with the battery or the connections inside the car. Perhaps the Autozone test missed something, and the battery is in fact no good? Or I have a loose connection somewhere, or a parasitic draw?

If anyone can recommend any ideas or courses of action I'd be very thankful.

- Justin

Hello,

Did not read all the other posts yet in a bit of a rush right now but i did spot this thread so thought i would throw in a little info about batteries.

The measurement of batteries is a little harder than we might think at first because batteries respond very differently depending on their state of charge and how they were discharged previously to the measurement.

If the battery is working sometimes you can get some idea how it is doing, but it could be wrong. The right way to do it is to load it with a sizable load so that it draws significant current from the battery. For small battery like 9v and AA and AAA sizes you can use a small load current maybe 50ma, but for a car battery you need to draw significantly more like 100 amps or more.
When the load is applied, you check the voltage and watch it drop. If the battery was just charged and the voltage drops too fast then the battery almost always bad. Non reversible chemical changes inside the battery make it impossible to charge. When this happens you have to buy new battery.
The main point though is that you have to measure the voltage under load which can actually be while cranking the engine over in the morning. If you monitor the voltage as it is cranking, you will see the voltage drop. When the battery is new it drops a little, when the battery is old it drops a lot. By connecting a meter to the battery before each start, you can test every time you start the car and that way you get some idea when the battery is getting old.
You can use a switch to turn the meter on if you like, or find a line that turns on only when the key is turned to either 'on' or 'start' so you can measure the voltage each time.

If you look at a good spice model of a battery you can get some idea how complex it is. There are at least two storage members not just one and some low value resistors and inductors. The heavy load test is still a good one though it tests the ability of the battery to hold a charge.

[abscate]

Car has been starting and running fine now outside of other previous issues. I had been charging and then disconnecting the battery whenever I left the car, and after work broke the pos terminal nut. Got home with locking jaw pliers. Replaced the terminal bolts with brass bolts, temporarily until I install the cables I just received.
The interesting aspect is that the drop is not between the battery and the starter, but between the alternator and the starter. I picked up cables for both, and a new universal marine terminal. Nut on alternator seems tight enough, but gets very hot while running-- enough to where I burned my thumb when touching it. Starter nut does not get hot, however.
So wondering if it's just the cable? Will replace both, and hopefully my temporarily gone problem goes away for good.
After that it's time to replace the front brakes and fix my p0242 code / turbo.

Thanks for all the help my friends

Bad positive cables are a known failure on these cars. I’ve had two go bad and am looking at a third, all on high mileage 1999s.

I tried the aftermarket one from FCP which lasted one year. Go Volvo part here for longevity

[jpb2222]

The issue is now fixed. The b+ nut on the alternator connection was slightly loose. I failed to check previously as when I had attempted the nut was burning hot and I could hardly touch it. I picked up a cable at a parts store and when i went to check the connections to see if the cable was the right length, I realized it was loose. Tightened it up now, and now the voltage drop is around 1 volt. Still not very good and I will replace the b+ battery cable in the future, but as of yet (around a week since I tightened) the car is charging fine and starting well.

RESOLVED

thank you all for the info and help

[scot850]

Glad it turned out to be fairly cheap to fix!

Neil.

[MrAl]

The issue is now fixed. The b+ nut on the alternator connection was slightly loose. I failed to check previously as when I had attempted the nut was burning hot and I could hardly touch it. I picked up a cable at a parts store and when i went to check the connections to see if the cable was the right length, I realized it was loose. Tightened it up now, and now the voltage drop is around 1 volt. Still not very good and I will replace the b+ battery cable in the future, but as of yet (around a week since I tightened) the car is charging fine and starting well.

RESOLVED

thank you all for the info and help

Oh that's nice glad you got it going now. It's always nice when it is something simple.

On my old Hyundai i had trouble with the ground connection on the alternator. That nut was both for the mechanical mount and the electrical connection for the ground to the alternator. The nut had to be super super tight or it would not charge the battery right.

Good luck with it in the future.

[abscate]

Car has been starting and running fine now outside of other previous issues. I had been charging and then disconnecting the battery whenever I left the car, and after work broke the pos terminal nut. Got home with locking jaw pliers. Replaced the terminal bolts with brass bolts, temporarily until I install the cables I just received.
The interesting aspect is that the drop is not between the battery and the starter, but between the alternator and the starter. I picked up cables for both, and a new universal marine terminal. Nut on alternator seems tight enough, but gets very hot while running-- enough to where I burned my thumb when touching it. Starter nut does not get hot, however.
So wondering if it's just the cable? Will replace both, and hopefully my temporarily gone problem goes away for good.
After that it's time to replace the front brakes and fix my p0242 code / turbo.

Thanks for all the help my friends

Update June 2022

New and service alternate cables no longer made for our cars, even from Volvo

Thread on building your own here, with updated parts/pricing coming

viewtopic.php?t=100379

Bad positive cables are a known failure on these cars. I’ve had two go bad and am looking at a third, all on high mileage 1999s.

I tried the aftermarket one from FCP which lasted one year. Go Volvo part here for longevity