Battery on my '03 Fabia 1.4 16v 100hp decided it wasn't going to turn over the engine last week - when I turned the ignition key most of the lights on the instrument binnacle went out and it managed half a turn of the crankshaft and then slumped. After that the central locking decided it wasn't going to play. So I decided to take it out and recharge it. Measuring the voltage between the posts using a Fluke multimeter it showed 11 volts out-of-the-car. The car is parked outside and hadn't been used for about a week and a half.

 

I was a bit dubious as to whether recharging would work as the battery is a 6.5 year old sealed Varta calcium and it has been on the way out for the last 18 months (I reckon at least one cell had gone) and it had lost its charge once or twice before in cold weather, but not as much as this time. Usually its managed a few revolutions before conking out and then I was able to jump start it - I think I've been able to keep it going so long because, at 63 Amp hour, it was slightly oversized for the twin cam engine.

 

So over the weekend I've recharged it on and off, leaving the leads off on two successive nights to see if it holds its charge. And it did, maintaining a no-load voltage across the posts of 12.6Volts, which according to wiki means its 100% charged. So Sunday evening I re-installed it in the car (Without starting it) and then PM today and took a voltage reading - 12.3 Volts (Now wiki says that's 75% charged). So going from a 20C heated room to 10C outside temperature had knocked a good 20% off the capacity ? That sort of sensitivity is not normal for a "Good" battery, is it ?

 

Anyway, the readings still seemed to indicate that there was sufficient power to turn-over the engine so decided to attempt to start it. I turned the ignition to the first position and on completion of the power steering pump initialisation voltage measured (Plug-in digital display) at the cigarette lighter  socket was 11.8 volts and then recovered slightly to 12.1.  After that the engine fired up OK and operated without problems. .Whilst the engine was idling, voltage measured at the cigarette lighter socket was 13.8 -13.9 volts - In the zone ?

 

So I took it for a 20 mile run up the motorway and during the run the displayed voltage fell slightly so that by the time I  got home it was reading 13.7.  With the engine off it read 12.1 again.

 

It is difficult to know whether this battery should be replaced. Apart from once a year in a cold snap when it seems to loose all its charge, the rest of the time its fine. But because its sealed you just don't know what the state of the cells is with regard to coverage or specific gravity - in the old days before sealed for life batteries, SG was a sure-fire indicator of whether a battery c ell had gone or not.

 

This is academic, as I've ordered a replacement, but I'd be interested to see what other people think.

 

Does, for instance, running a battery with lower than normal charge state/voltages  more likely to damage sensitive electronics in today's cars ?

 

Nick

Edited 17 February, 201412 yr by Clunkclick

Not likely to damage stuff, but it will trigger various faults to appear / get logged on VCDS - typically things like power steering go first due to voltage demanded, and then other little things will crop up.

I did a VCDS scan on return from the run and it did show a lot of faults, but I can't be certain how many of those originated from just disconnecting and re-connecting the battery. Anyway, they got deleted and on a second scan, after a static engine re-run, all looks fine.

 

Unofficially can you top-up sealed for life batteries ?

 

Nick

This seems like a good guide:-

 

http://www.diy-nos.freeserve.co.uk/testing-battery.htm

 

Reading from this, I'd say my old battery has definitely had its day.

I.e. After a 2 day recharge, magic-eye showing black and resting voltage @12.1 volts .

After re-install of battery it shows 11.8 volts once power steering pump powers-up.

 

That's totally discharged. So the battery can't hold a charge.

 

Nick

Edited 22 February, 201412 yr by Clunkclick

Last week got  a new Varta battery of the same spec installed (D15) - £55 delivered from one of those online battery suppliers -BMS. Not bad. Bosch equivalent £20 more !

 

As this was the first time I'd purchased a battery on-line, I proceeded a bit cautiously.

 

 

 

Shortly after delivery, the new battery voltage across the posts measured 12.77 volts.

 

I let it stand for 24 hours to get to room temperature and then charged it.

 

After a five hour recharge using one of those CTEK devices (5 amp version) and being left standing at room temperature for 15 hours, voltage was 13.25.

 

After a further overnight rest it measured 12.90 volts. During  a second CTEK charge of 4 hours it read 14.65 volts and, after completion of the charge, 13.1 volts.

 

At that point, the after charge voltages weren't improving, in actual fact the opposite. That indicated to me that it wasn't going to take anymore, so I, let it stand for 4 hours, then installed it in the car

 

Been using the car without problems for the last few days.

 

Hopefully, that will be good for the next 6 years.

 

 

Nick