Two Volvo alternator questions

K

Kira

Joined
Aug 19, 2010
Messages
16,189
Location
Champlain/Hudson Valley
I replaced my growling alternator with a "new" example from a long established rebuild shop.
Even with a new battery, I get a red 'battery warning light' and corresponding text message in a dash window.
It puts out 14.7 volts at idle, so it works.

A post I found on a Volvo board said this was common.
Does anybody know what causes this?

Also, the rebuilder said he'd keep my original Volvo alternator aside in case I needed it rebuilt.
Does anybody know if rebuilding the OE alternator is even possible?
 
It is on the "backside" (opposite the pulley side) of the alternator.

I thought of that and asked the rebuilder if I could have it. If I get no further info (Swedespeed appears to be frozen up), he will rebuild my OE using the same regulator.

Anybody else?
 
Does your Volvo require any kind of reset or something? I know some Euro requires require special procedures with batteries and electrical stuff :sneaky:
 
Does the voltage go even higher when you rev it? If so the regulator is not working.

On older cars the light is attached to the regulator system and generally indicates the alternator is not making output. No computer is involved.
 
SC Maintenance said:
14.7 V is pretty high for a lead acid battery. That’s more than 2 volts over nominal. Is the light on because it’s too high?
Click to expand...

Agreed. 14.7 is usually short term voltage when cold right after starting and should taper down. Rev the motor. If the voltage goes up, it’s putting out too much which points to a regulator or wiring problem.
 
Kira said:
I replaced my growling alternator with a "new" example from a long established rebuild shop.
Even with a new battery, I get a red 'battery warning light' and corresponding text message in a dash window.
It puts out 14.7 volts at idle, so it works.

A post I found on a Volvo board said this was common.
Does anybody know what causes this?

Also, the rebuilder said he'd keep my original Volvo alternator aside in case I needed it rebuilt.
Does anybody know if rebuilding the OE alternator is even possible?
Click to expand...
What model/year Volvo.

Can you post a photo of the alternator. The warning light requires equal voltage on both sides of the warning light to go off. Perhaps this is a wiring issue, 14.7 volts is what should be expected some older generators produced between 14.8 to 15.4volts without any battery issues.
 
14.8v will not cause a battery to boil, all batteries gas of during charging but 14,8v will increase the amount of gassing. Back in the day batteries had removal tops to allow the corrosive gas to escape thus increasing rust in the surrounding area.

We now have (so called) maintenance free batteries that have reduced gassing.

Boiling of a battery is caused by internal short or by incorrect use of battery booster chargers. Some people create a problem by incorrectly tightening the battery terminals causing hairline cracks around the terminals allowing corrosive fumes to escape.

If a battery boils the casing of the battery will be very hot to touch and will have a very strong smell, at this stage the battery is an explosion waiting to happen.

As a side note my expensive 9 stage charger operates at 15.8 volts in equalization/recondition mode (calcium battery).
 
You have a 2001-2007 V70,right?

It should be closer to 13.5-14.0 volts when charging - so, I would suspect the voltage regulator.

A new Bosch 120 amp from FCP Euro is a drop in affair that should work perfectly. The optional 140 and 160 amp that FCP offers are slightly larger and don’t drop in.

There is no reset or other work required other than bolting in the alternator in a Volvo of that vintage.
 
This may help with the alternator voltage reading as it depends on temperature, for example Vidi Volvo software states a voltage of 14.95 volts at 10 degrees centigrade and the workshop manual states 13.6 to 14.8.
 
If this is the Volvo I remember, then it has the battery in the rear of the car, under the cargo area. The battery is vented via a tube to the outside. The temperature of the battery is generally reasonable, as it’s protected/insulated by the car, so you don’t see a lot of wild voltage swings based on temperature.

The only time I have had a “battery” warning light on the dashboard is when the alternator was not charging correctly (low battery voltage). It is usually preceded by “elec sys service” message that is caused by under/over voltage from the alternator.

I would test the battery, too, as part of the troubleshooting. It may be that the alternator is fine, but the battery is not, even though this warning didn’t exist prior to the alternator rebuild.

Batteries on this car generally last at least 10 years, because of their protected location. A genuine Volvo battery is about $200, and has the vent tube fitting included.
 
I can't believe I failed to provide year, mileage, etc.

It's a 2007 V70 2.4 (base, non-turbo) w 149k.
A fellow on Swedespeed mentioned the charging system revision of ~2004 in which the LIN system is involved.
Bosch #8697015 is the correct regulator.

Link to a great response:
/www.swedespeed.com/threads/replaced-your-alternator-with-a-cheap-one-and-now-your-battery-light-is-on-and-youre-getting-a-service-power-system-urgent-message.662156/?post_id=8032595#post-8032595

When we installed it -and the light consistently comes on 15 seconds after startup- we checked the voltage (14.7).

Since my Volvo battery was 7 yr + 1 mo. old, I was advised to change it. Both the dealer fitted one and the replacement from AutoZone were black and from Mexico. The oldie was lead acid so I stuck with that...after a minor drama I'll describe later.

I too am aware of the longer life often seen by our rear mounted batteries. An H6 is called for.
The tray has an additional bolt hole for an H8.

I must go to the alternator shop (where they're rebuilding my old one) and give them the part number.

I'll be back in an hour (ha-ha)
NOTE of POSSIBLE INTEREST: Google Rayelco in Lodi, NJ to see the finest starter/alternator shop in all the land.
 
4329 said:
14.8v will not cause a battery to boil, all batteries gas of during charging but 14,8v will increase the amount of gassing. Back in the day batteries had removal tops to allow the corrosive gas to escape thus increasing rust in the surrounding area.

We now have (so called) maintenance free batteries that have reduced gassing.

Boiling of a battery is caused by internal short or by incorrect use of battery booster chargers. Some people create a problem by incorrectly tightening the battery terminals causing hairline cracks around the terminals allowing corrosive fumes to escape.

If a battery boils the casing of the battery will be very hot to touch and will have a very strong smell, at this stage the battery is an explosion waiting to happen.

As a side note my expensive 9 stage charger operates at 15.8 volts in equalization/recondition mode (calcium battery).
Click to expand...
14.8 Maybe an the high side of marginal but you said up to 15.4V is OK. Definitely not for lead acid.

Every lead acid battery has a vent. It must - the charging process creates hydrogen. Not venting would create a explosive hazard. Just because it doesn't have a service port does not mean its sealed. It has a vent still. It must. You just can't add water.

Your equalization/recondition recharger uses high voltage at very low current in short pulses - which is done specifically to break down sulfate in the battery. Its not sustained and is only done in burst short enough to not incur much charge. Very different.

Boiling off is the term everyone uses for lowering vapor pressure causing more off gas. Every old mechanic used this term.
 
1. The fellow at the alternator shop got the same info and had acquired the correct regulator. I'll be picking it up on Monday.
2. Then we talked about his 2 new puppies and I showed him our young Shiba Inu. Dog People Unite. Good stuff.
3. The drama I referred to above came with possible education:

I went to Walmart for a replacement battery. They had a $70 battery and a $200 4-year battery.
Without thinking I grabbed the 4 year one which turned out to be an AGM.
The car came with lead acid and that was my preference. I failed to read to the details on the label.
However, I must say I was surprised that the print, including the words AGM, were quite small. I'm used to the AGM being featured in larger type.

Turns out the small, hold-down clamp didn't have a lip to grab on. Do AGM batteries have a different case bottom?
This one sure did.
In fact, just using a longer bolt would've worked but would've pushed into the battery's side....NOT GOOD.

So it was a bother and a blessing to shoot back to Walmart, get a full refund (all I said was that I bought the wrong one), and went to AutoZone because I had a $30 Merch Credit and got a 2-year lead acid which fit the clamp perfectly.

Please no commentary on how much better some other battery would've been. I just wanted this phase of the operation done.

So BITOGers, read labels carefully. I had no inkling I bought an ill-fitting AGM.

I'll let you know 'when the light goes out'.
 
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