Hello Forum users,

I have a 2001 V70 2.4T with a charging issue.
The battery has been dying repeatedly over the past two years, have changed the battery twice. Although my Volvo indy specialist did not like my battery (even though it's specified Cold Cranking Amps are ok, he says it's too small).
Had the ETM replaced about a month ago, and a few weeks ago I have been hooking it up to a trickle charger every night (which is a pain).

This week things are worse than ever. Unpluged the trickle charger, started the car and drove about 500 feet befor the battery light and El. System Service required message came on.

Was in the process of turning around, and noticed the message and light would go off when I stepped on the gas, so decided to chance it.

Pulled into a parking lot to check the serpentine belt it looked ok to me. Seemed pretty taught. Last December this same message appeared and I discovered the auto-tensioner had snapped. That was a nice easy cheap repair.

At the first red light the idle was erratic, sounded like it might stall, so I put it in neutral and lightly stepped on the gas, The light was quick and I pulled away no problem. Next light I didn't step on the gas, idle was smoother and engine was at 750rpm.

I nervously went about my business, doing about 50km (30 miles) with 4 different stops along the way (planned stops at my clients offices). I tried to stay off the highway in case I did have a problem, but eventually got on so I could gun it a little (by now the message and battery light were on full time). Made it home (total trip time was about 2hrs including client visits)
Trickle charger connected. (Nice warm dry sunny day)

Yesterday similar trip about the same distance and number of stops, was not quite so lucky, the car died about 1000feet from home So close. (all power gone, including abs, airbags etc...). Used a booster pack to start it. By the time I disconnected the booster pack closed the hood and got in the car it died again. (Cold damp rainy day)

Since I was so close to home I re connected the booster pack closed the hood and creeped home.

I charged it over night and then hit the forum looking for answers.

I am thinking it might be the alternator, voltage regulator, or the brush pack for the alternator (I don't know where I would find the brush pack though).

I'm not that comfortable with electronics, but pulled out my multimeter and did some testing. (Cold damp rainy day)

Here are the readings:

• Engine off : 12.77volts
• Engine on : Initial reading ~ 14 but never stabilized within seconds the voltage was fluctuating wildly from about 12.1 to a high of 15.something. The Battery light came on on the dash as did the El. System Service Required message.
• Engine off : 12.37volts initial reading
• Engine off : 12.61 volts about a minute later.

Test two: about 5 minutes later.

• Engine off : 12.44volts
• Engine on at idle: voltage was fluctuating wildly as it was in test 1
• Engine on at just under 2000rpm: voltage was fluctuating wildly from about 12.2 to 13.97
• Engine on at idle: turned on seat warmers, radio, wipers, flashers etc... and the voltage fluctuated from about 11.5v-12.5v
• Engine on at idle warmers,wiper,flashers etc turned off : voltage fluctuations :12v-13.8v
• Engine off : 12.3volts initial reading
• Engine off : 12.6 volts about a minute later.

So

1. With these wild voltage fluctuations would that be the Voltage regulator?
2. Does it look like the alternator is ok?
3. Could it be just the brush pack?
4. What about a dirty connection somewhere

I've had trouble with this car's ability to keep a charge for years, can't seem to find the trouble.

Any help, or experience would be appreciated greatly!

 

Disconnected the charger last night at 8pm.
With the engine off Voltage across battery terminals was 12.66v

This morning at 8:30am checked the voltage with the engine off and it was 12.44 and slowly climbed up to 12.6v.

I my auto parts store and am planning on picking up a Bosch alternator later today (w/ regulator of course). but am worried I might be wasting my time and $$.

Is there any other possible cause of unstable voltage across the battery terminals when the car is running?

 

This wont help you volvo-boy but it may help others.....my granny has a volvo that she bought new in 2001...over the last 10 months or so the battery would go flat if left for a few days...if she drove the car daily it was not a problem.....several trips to the dealer and two new batteries later the problem continued.....

The clue here is that she never drives at night.....
I happened to be at her house one night and went into the garage without turning the garage lights on as i was just grabbing a trash-bag....

I see a very faint light coming from the car....it was the reading light above the right rear door seat that someone had left in the on position....
She has never used these lights so im assuming that the car-wash guys hit it while wiping down the interior.....

All is back to normal and she has regained her trust in the volvo.


two batteries and several dealer trips for nada....amazing that her dealer mechanics did not trace this drain to the elec-system....

 

urbino,
I'm glad you were able to help your Granny, you wouldn't want her to get stranded.

I do drive at night, and often walk my dog after midnight, I'm sure I would notice a light on in the car. I'll check anyway.

I replaced the serpentine auto-tensioner last year, for a litlle while after I replace it, I could hear it slipping while parking (I guess due to the Power steering).

It stopped soon afterwards. maybe the tensioner was a little too slippery when it was brand new.

 

Could unstable voltage be caused by the ECU?
Or is it certainly the Voltage regulator on the alternator?