Hi Guys...new to the forum having acquired a Mk2 S40 very recently.

My first issue today was Power system - urgent service.

I'm wondering if this is just a blip as I was stuck in gridlocked traffic with heated seats, heated windscreen, rear screen and heater all on full...thats a lot of load on a cold engine and zero degree weather.

Once out of the traffic, the light went off and car seemed happy again. Battery is new and no reason to suspect a faulty alternator yet.

So, is this likely a blip or a future problem?

Thanks guys.

 

Check battery voltage while the car is idling to make sure the alternator is charging properly. Should get around 14-14.5V

If you are getting lower, might be time for an alternator/ voltage regulator.

 

I understand. I'm hoping it was just too much for it on a cold morning. Roads are gridlocked here but will give it a run when they're cleared...see what happens.

 

the alternator should be able to support all your accessories. As Dingus1 noted, you should test battery voltage 1) engine off across the battery terminals you should read 12.6 to 12.8V depending on how fully charged the battery is 2) engine on at idle, no accessories should read 14 to 14.5 or so. Now turn on all accessories, rear defrost, heater blower, high beams, seat heaters etc. Volts should remain above 13 even at idle.

If you are seeing less, it may be the cables - so clean/retighen the cables to the battery terminals, check/clean/tighten the battery ground connection at the chassis, check/clean connections to the alternator, and inspect the main positive battery cable for any corrosion or salt deposits (like that stuff on the battery terminals). If you feel or see any swelling it means its heating up (or if you feel it heat up while idling) it means there's corrosion inside the cable and its time to replace before it fries.

Last thought - you didn't mention which year but some Volvos as sensitive to the battery size/model. The newer model's voltage regulators are designed to avoid over charging the battery so if you mess with that side of the equation by installing an incorrect battery, you may get odd behaviors.

 

My bad, its a 2005.

I decided to charge the battery up for 6 hours and do a couple of local journeys. I had all sorts of errors and intermittent battery lights.

At the end of the second journey, I lost all power and car died completely...fortunately close to home.

Checked battery and got 0.1v so its seems as if the cold weather (-7 some nights) destroyed this seemingly very new battery (and maybe me turning all the heating to the max at the same time).

When I get a new battery, I will check the alternator output just in case.

Will let you know what happens.

 

If your battery went dead while the car was running - the alternator is not recharging it. Either due to a bad alternator, missing/slipping belt, bad connection ----

A battery can freeze and self destruct - (ice forms and expands inside the battery) But only if the battery is completely discharged. A charged battery will not freeze (in temps most humans live in/near)

 

Agree with hoonk (as usual). There's almost no chance that the problem is only the battery. This is where you really NEED a multimeter, or if having to connect test leads to points under the hood throws you off, at least get something like this:


Yes, that one's unavailable, but it was well under $10 delivered when I bought it a year or so ago, and a nice USB power source to boot.

 

I borrowed a battery (440 CCA )to get the car home...but, car would not start. After a minute battery went from 12v to 3v whilst on the car.

Disconnected alternator cable and car started with borrowed battery and got 1/4 mile back to my driveway where it died completely again.

However, battery still had just about enough power to start its donor car.

So, my friend and I are a little stumped but car is safe while we figure it out.

Presumably a new alternator will be needed. I will scour the forum for recommended alternator options. And, how bad a job is it to do on a driveway?

Thanks guys...

p.s. I do have a meter but it was too cold and I thought I'd be ok with a full charge...didn't expect complete failure. Learning the hard way!

 

update. Charged the battery overnight to 12.8v. All fine. Battery in car and steady.

Re-connected the alternator cable and noticed a few wisps of smoke around the alternator cable area...and a funny smell.

Thinking that cable maybe shorting/overheating...currently waiting for assistance.

Is there anything in the alternator itself that might fry?

All these things happening before attempting to start engine and no key

 

I have replaced many alternators on that model Volvo - What seems to happen is they overheat and fry. So hot it melts the belt sometimes. Have not research what goes wrong with them to make them overheat - I just replace them (with the OEM alternator only) when they are fried and no longer charging.

 

Thanks Hoonk. I guess I will have to take the plunge.

Is the OEM the Denso? Its a minefield finding which one to buy....(UK)

 

Denso is OEM, correct. Some models have different Amp ratings, verify you are getting correct Amperage on the new one if more than 1 option is listed.

 

Thanks guys. Part ordered and fitting at the weekend all being well.

 

ordered a DAN930. Hoping to fit at the weekend. Found the instructions on the forum. Looks do-able.

 

To potentially save you from the headache I ran into on my old 850. Make sure the alternators match before putting the new one in. I put my new one in without checking and didn't notice the pulley was different. It was offset from the engine about 3/8" so it made my belt almost walk off and I needed to do the alternator job all over again and swap the pulleys. I don't remember what brand I put it in back then (probably super cheap one because I was much younger.)

 

Thanks Dingus, I'll update here any problems or sucesses

 

FWIW, the wisp of smoke and odd smell could be nothing more than the high-amperage flow of power across the connection as you made it (meaning the old alternator MIGHT have been OK). That said, I doubt it, given the scenario you described... almost certainly a bad alternator, and the borrowed battery was probably nearly discharged when you put it in.

Yes, it's always (always, always, always) easier to do a little diagnostics instead of hoisting batteries, towing cars or getting stuck in the middle of nowhere. ;-)

 

so, after a 24 hour battery charge I got the car started and measured battery voltage under 12v. So, nothing from the alternator.

Whether battery is fully ok remains to be seen...the status light shows nothing at all. not red or green. But, it didn't have any trouble starting the car twice.

 

All sounds just like a garden variety alternator failure.

Coincidentally I just swapped out the alternator on my 1996 Jeep XJ Cherokee. Funny enough, the initial symptom wasn't low voltage but a serious misfire that created a crank position sensor failure. Turns out that the dirty voltage from the failing alternator (probably bad diodes) put enough noise on the electrical system to glitch the engine computer (and my AM radio).

 

I got this message, once, when my factory ordered 2020 V90 Inscription T6 was only about 2 weeks old, with less than 300 miles. When my message displayed, I also felt a tug on the steering wheel (I was driving in pilot assist at the time). When I restarted the car, the message disappeared and the car drove fine. Regardless, I took it to the dealership, where they had to do a software update to correct it.