How long should the battery last ?

[andyg plym]

So not using the s2 as a daily anymore as I bought an a4 TDI which runs on thin air!

I have occasionally been using at weekends but if I leave it a week sometimes I have a flat battery, I recently bought a new one which has helped but I noticed the other day whilst giving it a good run it was only charging at 14 volts according to the on board volt meter.

Knowing this is unreliable I got my multimeter out and from the battery its 13.9 volts and dead on 14 at the alternator.

I recently read this was bang on even though I thought it needs to be more like 14.6-8 ? Whilst purchasing the battery we did a quick test using an amp clamp and it was only drawing 0.01 volts which is very good.

How long should the battery last ? I would of thought 2 weeks?

[UrS4boy]

How old is the battery? If it is new(ish) it should hold a good starting charge for a month or so in warm weather. If it is old, not so long.

Typically a battery is done after 4 or 5 years.

BTW, your voltages are fine. 13.7V with the engine running is quite normal in my experience with 3 C4 Audis.

[andyg plym]

Battery was bought brand new about 2 months ago, I charged it up overnight and was surprised to see the inspection indicator not green for charged but actually still black indicating it needed further charging.
I fitted it and went for a drive and looking again it has just a hint of green in it.
How long should you let it charge for? Would of thought overnight is adequate unless the battery is feked?

[bluequattro]

I've left them for 6 months (disconnected from car) and they've started straight away(one was a tdi too)
Current tdi charges 14.4v
Have you any flashing immo light or anything? May not be big draw but if battery not great to start with...

[UrS4boy]

Battery was bought brand new about 2 months ago, I charged it up overnight

I say take it back and demand a fully charged replacement. Sounds "fecked" to me.

[Ian_C]

The original battery in my June 2003 S4 4.2 lasted to March 2014 (around 84,000 miles)

[GazzaG60]

i have found out recently that it seems theses care like a good charged battery on tham for a while before all things work good. my view that power flows from word go doesn't seem to be true. after 2 days with battery connected. all bits work well whereas after just reconnecting it no windows, dash lights etc.

id say charge it a coupel of days and connedct it 2 days before you use it. maybe get a constant trickle device.

[diesel des]

My dad has a passat 130 Tdi 2003. Original battery was getting tired but still starting the car so we changed it a few weeks ago....

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[LHD_Kid]

My dad has a passat 130 Tdi 2003. Original battery was getting tired but still starting the car so we changed it a few weeks ago....

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My mums X reg (2000) Fiesta is on original battery ... no signs of giving up...

I bought a Bosch silver which lasted 25 months tops... put my old battery back in (some dodgy cheap make) and it's ok battery is 10 yrs old - holds enough charge to start the S2 for at least a month...

[varia]

Ive purchased many different batteries in the last ten years. some was good, while other were not so great (southern Californian, so no cold, freezing temperature)
One of the urs6 i parted out came with a Varta battery, i swapped over to my C4 A6. The battery is over 9 years old now, and still good.

Next time i will need a new battery, i will only buy Varta even if I have to go and get it from the dealer.

[GazzaG60]

varta of old is not varta of new.

company was broke up a few years back into different divisions.

company i used to work for was owner who split it into different areas such as hearing aids, consumer and auto. iirc only hearing aid and consumer under original owner.

[Rubberdubber]

Your battery sounds fecked just as someone said above. I wouldn't expect problems so soon into ownership as that and you certainly want it changed under warranty, longer you keep it the less likely that will happen in my experience. In saying that I bought a few Halfords calcium batteries a few years ago, mainly because I had managed to get a trade card so could get a discount and the calcium ones give a 5 year warranty as opposed to the normal 4 years. One lasted about 2 years in a car that was by that time off the road, so I blamed it on lack of use and maybe my fault a bit but I tried charging it and so on and came to the conclusion it wasn't right. So I took it back, told the guy at the counter the story and what I had tried and he looked a bit puzzled and asked if I could wait while he went through the back. I thought he would maybe want to check what I had done/said, maybe suggest I had done something to it, send it for tests himself? but when he came back it was with a brand new battery, no questions asked and my warranty extended for another 5 years, result. I don't have many 'Halfords recommendations' but this would be one.

[Tonybolony]

I would suggest putting the battery back on charge, not just overnight- but for 3 or 4 days. I'm assuming that you're using an intelligent charger (or at least one that has overvoltage protection?).
We sell leisure batteries in work, and the staff on the counter regularly get asked if our batteries are fully charged on the shelf. My standard answer is 'If it takes 3-4 days to fully charge a 110ah leisure battery, would you honestly expect them to come from the factory fully charged?'
Your average motor factor may get away with telling you that their batteries Are fully charged, and if there is enough in them to start the car, are you going to argue as the engine is now running, and the alternator is now feeding it? (The difference for my customers is that they are about to put their new battery straight onto a caravan/motorhome, and potentially in to a discharge situation, if no mains electricity available)

The way I've always looked at the subject of charging this type of battery is in comparison to an air compressor filling an air receiver tank, ie an average charger could get an average battery to maybe 50% overnight, but surely the remaining 50% of the charge is the most important, but that takes time- another few days. My comparison would be maybe an air compressor cylinder of, say, 1000cc would pump 1000cc per stroke into the tank when the tank is at atmospheric pressure but as the pressure in the tank rises, the piston is going to pump less and less per stroke, maybe to as little as 100cc/stroke as the graph line flattens out- but you wouldn't switch the compressor off before the pressure switch does???