Battery or alternator woes?

Just gone to leave work, jumped in the car, turned the key and nothing happened, not even any dashboard lights. I have been using the car every day for the last 6 days, doing 8-25 miles on each run. Apart from a random cut out on Saturday in heavy traffic, everything has seemed fine. Drove to work this morning, washed it and then parked it up, so 1 quick start/stop to move it after the commute.
The clock stopped at the time I turned the key, nothing has been left on.

The volt gauge has waved between 11 and 12 volts over this last week, but I never trusted that when I used the car as a daily a few years ago. I put a proper volt meter on the battery with the engine running last week and I was getting 13.98 and 13.94 with the headlights on. The battery whilst not very old (12 month old Varta), has been stood a while on the car and flattened a couple of times but I put it through a recondition cycle last week and it has been fine since, although I realise damage may have been already done.

I havent had more than 5 minutes to check things as I needed to get home, but I put the boost pack on it and she fired up straight away, a quick test with a cheapo battery/alternator kit similar to this and it showed a strong alternator reading. I left the car at work so further investigation will have to wait until tomorrow...

This might be a basic question, but if I put a volt meter on the battery when the car is running, what readings should I get I assumed around 14 would be fine? I just want to eliminate the possibility of a new alternator as I fear they will be a pig of a job to fit on an aircon car. Alternatively, is there an easy way to get a true alternator reading before it reaches the battery without taking half the front end off?

The rev counter is not working, which I understand, runs from the alternator? Could this be a sign of a failing alternator?

There hasnt been any warning lights to indicate anything wrong.

And finally, what sort of a job is the alternator replacement in the worst case scenario? And can they still be obtained or is it a refurb job?

Thanks in advance

John

Strange on this, just had the battery off the car, connected the booster pack to the terminals and then disconnected the booster and the engine continued to run with the volt meter on the car stowing a solid reading.

However, the battery reads 12.1 on the voltmeter, but will not supply the car with enough power to even run the clock. Fortunately the battery is under warranty, so I have arranged for it to be sent back for a proper test and replacement if it has failed. Just seems strange that it is reading 12.1 yet no actual supply of power when under any form of load???

Update to follow...

Wow that's brave, I never heard of running the engine without a battery, but no different I suppose to running with a dead battery after jump start. 12.1V sounds low, it should be more like 12.6-12.7V I think, when not connected, or without the engine running.

The volts when running look OK, so alternator looks to be OK. It's not that hard to replace, just need to move the A/C compressor out of the way and remove the radiator/fans. Rev counter is driven from the ECU, nothing to do with the alternator.

How did you manage to flatten the battery "a couple of times" in 1 year? I have done the same by the way, and fond that the battery will then no longer accept &/or keep charge, resulting in a replacement. Costco normally do this with no questions asked, but last time they did observe that the last one was only 6 months old perhaps (killed by a faulty/overcharging alternator).

If the battery is a regular lead/acid battery and been flattened a few times to below ~10.5 V, there is a good chance it's rather dead. Especially if it had been sitting in a flattened condition for more than a few days. A flat lead battery that doesn't get to charge ASAP will suffer from numerous internal problems finally leading to a much lower capacity and internal short circuits that can not be fixed.

If the generator warning light doesn't come on while the engine is running and you get ~13.8...14.something volts from the generator, that should be fine.

In order to check the battery: Charge outside the car until full, let it sit for a few minutes then connect voltmeter and a car bulb (55 W or so) and see what voltage you get with the bulb burning (battery under load).
A fully charged battery should read something like 13.2 - 13.8 V without load and not much less than 12 V under mild load.

On the car, you might want to check the GND connection from battery minus to chassis and gearbox. I had symptoms of a flat battery last year, even with a brand new and fully charged battery. Turned out to be the GND cable was correded away on the chassis connection except for a few copper strands. It came off by just a mild pull on the cable...

I know it was not the best idea I have ever had to run the car without a battery, but I got the results I needed - The alternator seems fine.

The car has been sat for a year or so without much attention, so the battery flattened over time on a couple of occasions.

Just taken the battery to the battery supplier and they tested it and got the same reading of 12.1, but insisted it just needs charging. I have left it with them for testing.

Since getting back to work I have nicked a battery off a sales car and everything seems fine, the volt gauge sits solid too, no fluctuation like before.

I will have a look at the GND connection shortly.

I have a Cetek MXS5 "smart" charger and with killed batteries it sometimes stops at level 4 or 5 to indicate that it won't accept charge or won't keep charge, all very clever.

In the good old days of course you could whip off the cell caps and test the density of the water/acid, or connect a "tester" which shorted out the battery taking a high drain to test capacity, and look for defective cells that would start bubbling (or maybe provoke the battery explode, I can't remember now...)

I reconditioned the battery using a Cetek 700 and it has always returned the battery to fully charged.

I have just had a quick look at the GND connection, looks like I need to remove the battery tray to inspect properly, which I will do tomorrow as it will be a good excuse to fit a reconditioned tray I have had sat at home for a couple of years. Am I right to assume the GND cable is a universal item should I need to get one quickly?

I didn't have any luck on getting one that fits as a drop in replacement. But you should get all the parts necessary to make one that fits. As far as I remember, there's the connector for battery minus on one end, a lug to be screwed to the gearbox and another lug in the middle that screws to the chassis underneath the battery tray. Might as well be two seperate cables but the principle should be the same.

Thanks for the info, I’m hoping mine is fine as the volt meter readings were taken from the terminals, but knowing my luck...

Refurbished battery tray is in the car ready to be fitted tomorrow morning, I will inspect it at the same time.

Checked the GND connection this morning and all is well.

I have also had a phone call from the battery supplier to tell me that the battery is faulty, so they are sending me a new one up later today! Panic over!

Battery fitted, volt gauge no reading steady!

The boot catch is playing up now... Just dowsed it in WD40 and seems to stay shut...

Just one full week of trouble free motoring isnt too much to ask is it?

If it doesn't open with either the key or the lever the cable may have snapped - you'll have to squeeze through the ski hatch to access it ....

It opens fine, it just doesn’t shut. I didn’t have the right size Allen key to remove the trim, but managed to get a screwdriver down to move the catch at the bottom of the mechanism and it stayed shut. I suspect the return spring is either weak or broken but I will have a better look tomorrow.

And since they happen in three’s the thermostat seems to be on the blink as it’s not getting above 70 degrees, but I did that job about 5 years ago, so I know what I’m doing with that fix!

Stat....you're lucky it lasted that long!