Autoelectrical dilemma

[oharv]

Hi guys, long time reader but this is my first post as a member!
My question is not specific to D22's but that's what i've got so I'll just post it here.
I've had some alternator issues over the past few weeks and as a result my fairly old starting battery has been drained to absolutely dead probably half a dozen times. Previously the alternator has been able to keep up but now I think the battery is rooted.
I recently had my alternator reconditioned so I don't THINK that's the problem, is it possible that my battery is just incapable of holding a charge?? Or is it likely that the alternator has died again... My local autoelec f@#ked me around a fair bit so unfortunately I wouldn't be surprised if that is the problem either.
Supposed to be leaving for inskip point tomorrow, any help would be much appreciated, battery is currently on a charger...

 

[Aussie Frontier]

Start the truck up and check the voltage across the battery.It should read somewhere over 14v say around 14.5 .Then after shutting down the truck check the voltages yet again , it should read just above 12 volts.Lead acid batteries should be 2 volts per cell and have 6 cells . If the voltage keeps dropping then the battery isnt holding charge.If the voltage from the alternator is below 14 then it could be thats your issue.
I cant remember the exact voltage your alternator should be putting our. I think mine sits at 14.8 volts

 

[oharv]

I'm really hoping it's not the alternator because I already forked out a heap of money for terrible service to get it repaired...
Would it also be possible for the battery to get to such a low voltage that the alternator just didn't have enough juice to charge it up to a usable level.
I've got a diesel so I assume it's quite hard to crank and the alternator is only 60A which is pretty low...

 

[Aussie Frontier]

To properly charge the battery you need to drive it maybe 30minutes. The alternator takes a while to fully charge a battery , well charge it as well as any alternator does.
in theory the alternator will run everything on the truck under normal conditions so when its running it should be able to power all the lights heater etc without an issue while maintaining a good voltage on the battery.
In the old days before computers the easiest way to test was start the car and bring the revs up , turn everything possible on and disconnect the post cable from the battery. If nothing dimmed or slowed then the alternator was driving everything.
However
Now that we are all computer controlled we cant do that as it stands a good change of killing some electronics and creating an even bigger issue .

 

[oharv]

I would have thought the alternator would take much longer than that to charge it up... Not to worry! I'm gonna see how it goes when the battery has been fully charged. If i'm up for another alternator already i'm gonna be really annoyed because I got it reconditioned like 4 weeks ago tops, and when the autoelec installed it he fried a circuit behind the dash and charged me to fix it... When I complained he became furious and essentially kicked me out of his shop and told me to never come back...

 

[Aussie Frontier]

it will all depend on the drive as to how long it takes. Lots of stop starts and idling at lights will mean a longer time. But half an hour driving at freeway speeds will put a good charge on the battery.Another thing that can lengthen the time will be what accessories you have on light headlights or A/C.Basically the more charge going to driving accessories the less charge goes to the battery.

Sounds like you wouldnt want to go back to someone like that anyway.

 

[happy john]

Strange that he "fried" a circuit did he say which one? with these mechanics ect mate you have to speak up loud otherwise they will walk all over you.

But that aside it is entirely possible the battery is rooted as said previous if your getting 14.2 plus whilst running the alternator should be fine.

Take the caps off the batt while on charge check that each cell is bubbling evenly if one is not bubbling at all not you may have a collapsed cell for peace of mind just replace the batt i do mine before they become a problem .

 

[Gonzo]

I recently had a problem with a battery . Just over 2 years old seemed ok if it was driven a fare bit but if it was a couple of days it wouldn't start . Charge her up and away we go for a week or so . But if I ran any lights ( checking camper trailer ) wouldn't start again. Auto elect did a load test , straight up said the battery roo Ted . It was starting Ok but only had about 400 CCA . New battery ! Problem solved

 

[nathand22]

After starting the car you should be able to drive around without a battery even in the car if your alternator is working correctly.
When I was a kid we use to start up our paddock basher then pull the battery out and leave it on the ground because the brackets and plate were stuffed and as long as we didn't stall it we could drive all day.

 

[oharv]

Yeah I really don't want to go back to that autoelec but if the alternator has failed already I don't particularly want to have to pay for it to get repaired again.
What happens when the battery runs dead is that all the instruments die and the check engine/airbag lights start flashing. The engine also sounds like it's running really lean and gets pretty gutless but you can still drive (I try to pull over immediately though).
This is what used to happen when the alternator was rooted...

 

[Old.Tony]

There's an easy test to see if the battery's holding a charge. When it's finished charging, take it off charge and leave it sit for 2 hours. Test the voltage - it HAS to be at least 12.8V or better.

It is entirely possible for the battery to be at fault. A discharged battery drops crystals out of the solution (this process is called "sulphation") and this shorts out the cells. The cells might take a charge and even report to the charger that it's fully charged - but removed from the charger, the sulphation makes an electrical circuit that consumes power (and sometimes rapidly).

The other thing that can go wrong is the plates themselves can deteriorate, losing substance - and therefore the ability to hold power. This is usually discovered by noticing that the battery will hold a stable voltage but can't deliver the duration of power that it used to.

Discharging lead acid batteries (like our starter batteries) below 50% capacity causes the deterioration to accelerate. Standard starter batteries can only withstand that sort of maltreatment a very few times. You need something more robust if you're going to do that to a battery frequently - like an AGM battery - and the best (most rugged) battery available is the spiral-wound battery (Optima make them, available in Australia, and they are awesome), but even they can suffer when dropped below 20% of capacity.

 

[oharv]

Yeah took the battery to marshall batteries yesterday afternoon, determined it was pretty rooted and bought a new one, probably should have done this earlier anyway because that battery was OLD! Drove around a bit last night and noticed the lights were a bit dim and they wouldn't dim when the car was turned off, a bad sign. Took the car back to marshall for a free battery test (great service by the way, nice blokes) and they read that the battery was running at 12.3V with the car on, and then 12.3V again when the car was turned off.
Not convinced that the alternator is actually burnt out but it's definitely not charging, going to take it to an autoelec ASAP and hope that it doesn't cost me an arm and a leg to get it fixed... Again...