Weird battery issue

**twoqu** · 6 August 2013, 21:05

Where are you measuring the 13.47V at? If its at the battery its a bit low really. Would have thought it should be over 14V. Its possible that the vehicle is now so ancient that the + battery cable has started to degrade causing a resistance. You could measure the voltage at the alternator and a convenient earth and then at the battery to confirm whether there is any difference.
If you can access the voltage regulator check to see if the voltage is marked on it.

**Ross** · 6 August 2013, 21:22

On a side note, have you got anywhere with warranty returns? I have an 18 month old Bosch S4 dead in the garage, no joy reconditioning it, just gives an error on thr discharge test... replaced it as ECP were not very forth coming trying to return it! To be fair the car has covered about 200m in 14 months and been started just a few times... But I didn't tell them that!

I also had an S3 that went dead, but the recent purchase of a CTEK MS5.0 charger and a recondition cycle and it's working great in my Golf TDI. Have you tried a recondition on these dead batteries?

I'm keeping mine connected to the CTEK going forward as being an occasional driver does seem to kill them off quickly, I'm now on my 3rd in 3 years...

**A80Avant** · 6 August 2013, 22:00

Originally posted by twoqu

Where are you measuring the 13.47V at? If its at the battery its a bit low really. Would have thought it should be over 14V. Its possible that the vehicle is now so ancient that the + battery cable has started to degrade causing a resistance. You could measure the voltage at the alternator and a convenient earth and then at the battery to confirm whether there is any difference.
If you can access the voltage regulator check to see if the voltage is marked on it.

I'm measuring that on the battery itself. I was told that anything above 13.35 should be ok. On the clocks its reading 14V but I assume I can try to read it directly from the alternator and an earth.

**A80Avant** · 6 August 2013, 22:03

Originally posted by Ross

On a side note, have you got anywhere with warranty returns? I have an 18 month old Bosch S4 dead in the garage, no joy reconditioning it, just gives an error on thr discharge test... replaced it as ECP were not very forth coming trying to return it! To be fair the car has covered about 200m in 14 months and been started just a few times... But I didn't tell them that!

I also had an S3 that went dead, but the recent purchase of a CTEK MS5.0 charger and a recondition cycle and it's working great in my Golf TDI. Have you tried a recondition on these dead batteries?

I'm keeping mine connected to the CTEK going forward as being an occasional driver does seem to kill them off quickly, I'm now on my 3rd in 3 years...

I just got my ctek to try and recondition the battery that just went dead on me. I used a rac charger so far. Trouble is that my off street parking is nowhere near my apartment in order to plug it in so its a no go for me. It will have to be just connecting it to the second battery which I keep as a spare.

What I'd like to know is if there is anything wrong with the car that is doing that to the batteries. Both vartas have been bought online and from the same shop. So the probability of a problematic line is not off the table.

**johne** · 6 August 2013, 23:32

Your problem may be related to the discharge current. If you really are draining the battery at 0.08A which is 80mA then that's around 4 times greater than ideal.

It would be good to pull some fuses and see where your 80mA is going between the alternator, radio equipment, ECU and alarm/central locking system.

My first Bosch Silver battery lasted 7 years and my second is at 8 years. The last time I measured my battery drain it was around 15mA IIRC.

John

**A80Avant** · 6 August 2013, 23:58

Originally posted by johne

Your problem may be related to the discharge current. If you really are draining the battery at 0.08A which is 80mA then that's around 4 times greater than ideal.

It would be good to pull some fuses and see where your 80mA is going between the alternator, radio equipment, ECU and alarm/central locking system.

My first Bosch Silver battery lasted 7 years and my second is at 8 years. The last time I measured my battery drain it was around 15mA IIRC.

John

That's some good advice. At least that way I will find out what is causing the issue. True 0.08 is much more than 0.015 but when experts tell you it should be fine then you just don't question it.

My car was fine with batteries when it was in Greece. It only started to act up in the UK. Of course a few things here and there have been done with adding stuff to the electrics but only when the engine is operating or the ignition is on...

I will do some more digging... thanks

**simon20vq** · 7 August 2013, 08:15

Have you thought about fitting one of those battery isolator switches? Get them on ebay for 6 quid

**ManiacuV6** · 7 August 2013, 09:48

First you need to locate the drain. Is possible to be the alarm so is simple to disconnect the fuse for it and check again. 80mA is too much .
You should have at least 13,8V and max 14,5V with the engine running ( multimeter connected to alternator + terminal and engine ground) .

**twoqu** · 7 August 2013, 11:56

It's difficult to be precise about the amount of drain as it will depend upon what equipment the car has. The figure of above 30mA seems to be indicative of an issue.
As your vehicle is not stock in terms of equipment the comparsion figure of a stock(ish) example of 15mA may point to the different ecu, headunit or alarm etc, basically anything that is not stock! As above you can eliminate the various circuits to find the culprit.
If the alternator puts out what it should but the battery does not register it then the main battery cable is a possible issue. Even on a new cable there would be a small but measurable voltage drop. The longer the cable, the greater the drop which might have been at an acceptable level when newish, but after 15 years its not necessarily going to be in the greatest of shape!
I wonder if someone with the inferior battery location of the ABY could post a battery voltage with the engine running for comparsion. Even my ancient A6 manages at least 14V with the battery under the rear seat and a longer cable!
Guess it would be worth cleaning the actual cable terminals at the starter and of course the earth cables. Might be worthwhile adding an additional earth cable as well whilst you are at it!
The cold does seem to kill marginal batteries!

**A80Avant** · 7 August 2013, 12:19

As its an avant the battery is at the trunk making distance of cables long.

By the way the 0.08 reading was taken with the multimeter turned on the 20mA setting

**caterpillar** · 7 August 2013, 13:29

the 13,47 volt are way tooo low.... 14,4 are the lowest volt you MUST have...the battery newer got fully charged; even you drowe to the moon...if you have the acidweight meshured, you will figur out this... 1,20-1,22 arent half charged battery; when you use the starter you WILL overload the battery; and it will destruct selves....( batery cant deliver the current, the sterter needs+ petrolpump and so on...)
'full battery charge are 1,275-1,280....(strong acid)...change the regukator to 14,7 or 15 volt verson; in the end of generator
if you have a 60AH battery with 1,20 acidweight.. its only 25-30AH...

**twoqu** · 7 August 2013, 13:34

Its difficult to get trustworthy info but it looks like the voltage regulator is either 14.1V or 14.4V. So that tells us what should come out of the alternator! So if you don't get either of those then you need to at least change the regulator or examine the possibility of a decent quality replacement.
If you do get the correct output it can only be lost through the cable or at a connection. The cables are usually joined at the starter motor terminal so any corrosion there may cause some resistance.
If we can confirm that others see a higher voltage back at the battery on the same model then that should confirm you have an issue. Not much point using a 3B as a comparsion as the cable is 10ft shorter!

**A80Avant** · 7 August 2013, 15:00

Yes. First off I need.to.measure the alternator voltage. Ill do that on saturday and report back. Hopefully I will have a closer inspection of the cables and see if there is anything wrong.

**twoqu** · 7 August 2013, 15:06

Have a quick read of this

http://www.smartgauge.co.uk/controllers.html

Wade through and look at the difference voltage makes to charging the battery.

Weird battery issue

Weird battery issue

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