[Q] Alternator about to crap out?

[terrabytetango]

tl;dr - The charging voltage is around 13.8 without any ancillaries switched on, but when the A/C, lights and fog lights are switched on, my trust Fluke shows just 12.4V. Is it time to get the alternator rebuilt?

So the Shitbox's battery died on me this evening, as I was about to leave the office. Thankfully some good Samaritans first helped me push start the car, and when that failed, a set of jumper cables and a volunteer came along to give me a boost. The battery is only about 2 months old, having been replaced by the previous owner shortly before I took ownership of the car. The lights dim whenever the windows and/or the A/C is operated, but I attributed that as normal since the Vios displayed such tendencies as well. HOWEVER, this morning, the driver's window got stuck in the down position, how it had miraculously come up by the time I had finished closing the gate (it's got auto power on driver's side, and i yanked it hard a few times before getting out). Then at the office, I tried to lower the window to speak to the security uncle, but the window wouldn't go down, although I felt it struggle. I attributed to it finally have jumped a rail, and thought I'd fix it during the weekend. So imagine my surprise when I jump in, twist the key and nothing happens except for the start solenoid struggling. I immediately attributed it to the window, BECAUSE, my mum found an easter egg (which is also there in the Axio, but that car's like 2 decades newer and has more complex electronics than the first moon mission); the windows remain operable once the key is pulled out either on a timer or until the doors are opened. I attribute the sticky window and this feature (?) to the draining of the battery. So this evening, I decided to check on the battery (after driving home with no A/C and only fogs), and the battery is at 12.45v. I then proceeded to test how well the thing was charging, and 13.8v with everything shut off except for radio, 13v with A/C, and only 12.4v with everything switched on. So might this be normal for a 90's car, or is the alternator on it's last legs?

 Long, and pretty much useless details. but it's been a while since I've typed out a proper forum post (wife is in Mannar, so jobless till Friday).

[The Stig]

What is the battery 12v30a or 12v40a ? 

[Kavvz]

9 hours ago, terrabytetango said:

So the Shitbox's battery died on me this evening, as I was about to leave the office...

Okay so I've missed this purchase, must have happened when I was away? So do me a favour and humour me: What are you referring when you reference this 'Shitbox' of a car and also why are you driving the aforementioned Shitbox? I thought you had a fancy new Axio Hybrid to impress the Perera's and the Peiris's ? 

[terrabytetango]

The Shitbox is a 1993 Toyota Starlet. Still have the Axio as well. All the Pereras, Pieris' and even the De Sarams are wholly impressed by it.

Edited August 4, 2016 by terrabytetango

[PreseaLover]

26 minutes ago, terrabytetango said:

The Shitbox is a 1993 Toyota Starlet. Still have the Axio as well. All the Pereras, Pieris' and even the De Sarams are wholly impressed by it.

de saram's hahahaha  you missed the fernando's

[Rumesh88]

Readings are not normal even for a 90's car. Looks like your alternator needs rebuilding. If the luck is with you, be prepared to replace brushes and bearings. But to me with the readings given for a 2 month old battery it can be your diode set or the regulator (comes built into the diode plate). BTW just to be sure if you can safely reach the alternator output terminal (which is always live!) take a reading with load and compare with that above. If they are not the same it could be some corroded terminal somewhere in between.

[terrabytetango]

34 minutes ago, The Stig said:

What is the battery 12v30a or 12v40a ? 

12v45a, don't remember the battery make, it's got a red top with white sides.

 

1 hour ago, Rumesh88 said:

Readings are not normal even for a 90's car. Looks like your alternator needs rebuilding. If the luck is with you, be prepared to replace brushes and bearings. But to me with the readings given for a 2 month old battery it can be your diode set or the regulator (comes built into the diode plate). BTW just to be sure if you can safely reach the alternator output terminal (which is always live!) take a reading with load and compare with that above. If they are not the same it could be some corroded terminal somewhere in between.

That's a good idea! Never thought the issue would be between the alternator and battery. I brought my multimeter along today, I'll check it out during lunch time.

[Kavvz]

On 2016-08-03 at 10:09 PM, terrabytetango said:

The Shitbox is a 1993 Toyota Starlet. Still have the Axio as well. All the Pereras, Pieris' and even the De Sarams are wholly impressed by it.

lol !! We used a have a Starlet in the extended family. Pretty dependable ole thing it was too, I don't think it needed any major repairs outside of the normal maintenance while it was around. And you're keeping it all in the Toyota family I see...Well no WONDER all the neighbors are impressed at the fleet of Toyotas!

[terrabytetango]

21 hours ago, Kavvz said:

lol !! We used a have a Starlet in the extended family. Pretty dependable ole thing it was too, I don't think it needed any major repairs outside of the normal maintenance while it was around. And you're keeping it all in the Toyota family I see...Well no WONDER all the neighbors are impressed at the fleet of Toyotas!

Plus it's a pretty fun drive too, runs out of steam when approaching 100km/h but man I still enjoy rowing the gearbox. Plus, clutch balance on a petrol isn't as bad as I thought it would be. Only problem is the fuel consumption, given my "spirited" driving behaviour.