97 small turbo did not start today after sitting 2 days in very cold conditions. Battery could not turn it over aside from a little bit when I first tuned the key.
Boosted it with a good battery and away I went.
I have been monitoring the battery voltage at the cigarette lighter for some time and it it ranges from 13.6 to 14.1 after about 6 seconds after starting.
The battery is relatively new.
So why is it not holding a full charge?
So either something is draining it overnight(s) or i am not getting sufficient amps back to the battery to bring to a full charge while driving even though I have good voltage. (if that is possible).
The car is used for relatively short trips 15-20 minutes 2 time a day and I have the headlamps on, the heater fan, and the seat heaters often.

Theories??? debugging procedures??? Any help would be appreciated. right now I have disconnected the positive terminal and i am giving it a good charge with an external charger.
Txs
Jim

 

My car use to charge between 12.2 and 13.1 (usually around 12.4-12.8). Now it charges between 13.5 - 14.1. You may have a bad cell or 2 in your battery. An auto parts store can check it for you.

 

The battery is good. I am 99% sure of that. I externally charged it last night and I have a nice voltage of 12.8V at the battery. I never see this kind of voltage at the battery unless I externally charge.
I am putting out between 13.6 and 14.1 volts while driving.
Jim

 

Up here in Canada we have daytime running lights. Most cars have their lights on all the time but at reduced power.
To me my volvo has its daytime running lights on all the time at full power.
In cold weather and short trips I don't think i am getting enough power back to the battery to maintain it.
Is there any easy way to switch off the headligts during the day?
txs Jim

 

 

I think if you turn the switch manually to parking lights you cut out the daytime running lights.
I've messed with that little **** on the headlight switch but I can't get mine to shut off no matter where I place it. I'm thinking that part on mine is shot but not worth buying a new switch for.

"I never see this kind of voltage at the battery unless I externally charge."
And you won't otherwise the cars system would be boiling your battery.
That's because a plug in external battery charger will charge a battery more than the cars internal system. But it's just the voltage. The battery likely has nearly the same starting power (amps) either way. The external charger will cram a few more in but not much.

And once again people are talking about voltage like it's really telling them something. You need to have the battery tested with a load to see if it has the amps it should. If it's starting the engine it likely does but since so many places will test it free, have it tested and KNOW it's good or bad. Why chase a ghost because you "thought" something was this or that.
Same with the alternator. If it's charging at 14.2 volts you think it's good, right ?? Maybe, maybe not because it can be charging at 14.2 volts and almost no amps. No amps to the battery and the battery can't start the car no matter how good it is. Testing the starting and charging system with volts is just slightly more useful than wetting your finger and trying to figure out which way the wind is blowing.

 

Thanks that was helpful. I will bring the battery in for testing (even though I am 99% certain it is good).
I am very interested to know how an alternator can produce 14v but not deliver amperage. Are you thinking a failed diode? What other failure modes can produce proper voltage but less than adequate amperage.
Txs
Jim

 

It can be due to a badly corroded connection/loose connection anywhere between the alt and battery or a failure in the regulator. If it's part of the diode trio you will lose 33 or 66 percent of the alternators ability to charge or backwards you're only getting 33 or 66 percent of it's possible output. But the voltage on that same alternator will test perfect. It will show up more in winter as summer you can get away with 2/3 and maybe even 1/3 of the alternators output (amps) but in winter with the heater on high, headlights on and maybe the seat heaters, rear window defogger, heated mirrors and wipers too you'll suck all the power off the alternator and start draining the battery too. AND, if it's the diode trio that's bad and it's still making that 13 or 14 volts it's likely you'll never get a battery/alternator idiot light because the light is an idiot and only "sees" that the alt is charging. It can't differentiate if the charge is enough the way a physical ammeter would swing left of center to warn you that you're not getting enough juice to the battery.

If all you have is a voltmeter there isn't a problem with using it and it's a quick easy test but if the voltage is good you still need to go further to make sure the amps are there. If the voltage is low or you're only reading battery voltage in the circuit then you know it's not charging. Voltage is better than nothing and it can show you a problem it just can't tell you for sure the system is functioning properly.

 

Not sure if you're in the "states" but in the U.S. most auto parts stores, tire stores and others have hand held testers and can come out to the parking lot and test your battery, starter and alternator in the car while you watch for free.
Don't need to pull the battery and walk it in.

 

Thank you!
Yes I am up here in Canada and love my seat heaters but have not been using them lately.
I have been searching for the information you have provided here on alternator failure modes. I plan to do "power management" until winter is over and then pull the alternator and have the diodes and regulator checked as well as resistance checks on all connecting wiring.
I feel like I am only getting 66% of the power I should...
Thanks again. Extremely helpful.
J.

 

Check to make sure the light in the glove compartment is shutting off properly. That on top of cold temps will kill your battery in short order.

 

I was working on my other car today and found that the water level in some of the battery cells was low even though the battery is 6 to 8 months old. You might check water level just to be sure you are getting everything you can. What are the CA and CCA ratings on your battery?
I have a general battery question for anyone. I always use distilled water in batteries but what would the effect be if I used tap water?

 

Corrosion.

 

Makes sense, thank you sir.
On my Mercedes yesterday I had an issue similar to this thread and I found that I had a bad voltage regulator that was putting out less than peak voltage and when the car was off it was draining the battery.

 

I know the guy at the auto parts store, so he gave me a new battery. I asked for a group 48 and it was a $4.00 upgrade. YES!!!!
When i received the battery it measured 12.4 volts.
I installed it with no problem . YES!!!! Just sits right in there and will give me 770 cold cranking amps. sweet.
I drove around for 30 minutes. Checked voltage after 20 minutes and it measured 12.7, so my alternator is definitely charging.
I will let it sit overnight and do a voltage check first thing tomorrow. I also disabled the light in the glove box. That little bugger could be on and u would never know it, especially since i had a lot of stuff shoved in there.
I will let u know results but I have my fingers crossed in hopes of seeing some nice morning voltages...Will let everyone know...
J.

 

I highly recommend looking for dome light activity when it gets dark. Today's the shortest day of the year, so you don't have to be all that selective to experience dark.

These problems are a lamp most of the time.

 

https://volvoforums.com/forum/volvo-...g-101-a-42655/

 

It was a cold night here. just went out and checked the voltage. 12.33V
pretty disappointing. I checked the draw with everything off and it is only 30 milli amps. Totally acceptable.
This will get me started , but sitting 2 days in a row and I'm going to be looking for a boost....

I'm thinking of hooking up a battery on/off switch until I can do further debugging. I need to find out the condition of the alternator diodes....

 

Update.
-20 c or -5F here today.
I needed to run a few short errands. Started the car no problem with a battery voltage of 12.33.
2km trip, stop car.
1km trip stop car.
2km trip stop car.

All the time the voltage as measured at the cigaretter lighter was 13.8 to 14.1 volts.

Checked battery voltage when i got home. It was 12.2V with car off. WTF
so now my working theory is the car has barley enough power to run the car, but not enough to bring the battery to full charge. Good voltage but no amps.
So darn cold here to be working on a car.
Not sure of next move or how I can limb along to the spring. Is it OK to connect a battery charger in the car without disconnecting the battery?
Txs

 

No, that is not it. You should not be driving 1 km and then making judgements about this anyway, but my point is the good voltage with no amps idea is wrong, unless the no amps is caused by a bad connection to the battery.

The battery works by simple electrochemistry. It has to absorb electricity if the system is operating above 12.3 volts in your case. It has to discharge electricity at a voltage below 12.3 in your case. electrochemistry doesn't allow any disobedience. So when the voltage is 14.1, if that voltage was across the battery terminals, the battery has to be absorbing electricity at a very good rate. It is the battery itself that determines what the charging rate will be at 14.1 volts. In the battery, voltage and amps are connected by fundamental chemistry that cannot be controlled. The alternator, on the other hand, is designed to vary amps all over the place. It's the part that can adjust. 14.1 is pretty much perfect.

So, if the battery is not soaking up juice when it's available at 14.1 volts, usually you'd have a bad batter, but I am assuming that is not hte case here. YOu could have a bad connection between the point at which power is available and the battery itself. But I don't think that is your problem. I think the problem is that you didn't drive far enough.