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So I had some issues with my car not starting just over a year ago, decided that the battery was the issue and replaced it.

It was going fine till about a month ago, car was parked up for a few weeks and the battery died, I stuck a charger on it and was fine.

However since that on a few occasions after a short trip the car won't start first time, it will take a few mins to get going and if I switch off the auto lights it helps.

Got the battery tested today in Halfords (where I bought it) it has 820 out of 920 amps, "needs a charge ". But I had been out for a decent enough spin so it should have been higher. The Halfords guy said the battery was fine, but may be an issue in the car draining or not fully charging it.

Any ideas?

A non starting issue or taking time to start is related to the clutch switches, or that's where I'd be looking first, not sure of which switch it would be though.

Battery not charging fully could be down to the alternator, again that is where I would start, there are greater minds on here who may be able to offer another solution

irishmike wrote: car was parked up for a few weeks and the battery died, I stuck a charger on it and was fine.

After a couple of days of being deep-discharged the battery will sulphate to the point where it will seriously reduce its capacity to hold charge. Sounds like you might have damaged your battery.

You could try a desulphator (I'm gonna buy one of these just to see if they actually do anything) or get a new battery. Do the RS4 have a battery voltage gauge? If so see what it's displaying with the engine running?

Just for the anecdote, I keep my RS6 on a battery conditioner permanently. I took it out for a blast last weekend and it started perfectly (not just once, but while I was priming the oil pump, etc.). After my blast, I put it away but didn't put the conditioner on because I was charging something else with it. Next day I was in the garage and noticed the alarm going off. The car battery had depleted to the point that the alarm thought it was disconnected and there wasn't even enough juice for the interior lights.

The point is, my battery is worn out. It could provide enough amps to start the car but couldn't hold charge for longer than 24 hours being off the conditioner. It just needs a new battery.

The RS4 has the ability to check the voltahe; I can see it on my tablet via obd port. But it has no way of natively displaying it, not even with any little button presses like the RS6 can.

That's a pity. It's a good and quick indication of whether the alternator is working. Still, at least the information is available in other ways. Or even with a voltmeter on the battery if it comes to that.

Yeah I'm thinking that the capacity has been diminished since it ran down. Will stick on Vagcom to check for clutch switch messages and will check for that de sulphur thing.

The battery has a 5 year warranty, do you think it's worth pursuing that?

Mike what app do you use to get the voltage?

I use torque obd to monitor Maf, engine temp, voltage, actual speed etc. Have a feeling it doesn't work with Apple devices though.

irishmike wrote:on a few occasions after a short trip the car won't start first time, it will take a few mins to get going and if I switch off the auto lights it helps.

We've been focusing on the battery, but reading the OP again, it sounds like the engine is being turned over ok. Or is it turning over slowly? What makes you think it's the battery at all?

No, the engine is not turning over at all, just the odd click. It does not seem to have the crank power.

When its like this if I turn off the auto lights and aircon it tends to start quicker

Also the fact the battery or reading 820 out of 920

MikeFish wrote:I use torque obd to monitor Maf, engine temp, voltage, actual speed etc. Have a feeling it doesn't work with Apple devices though.

Cool, I have that on my android phone so will try it

I use these on my boat, hard-wired in, and on the boat batteries as I periodically charge them over the winter when they're in my basement.

http://www.batteryminders.com/12v-atv-j ... ry-charger

I have also used it to recover a battery that was not holding a charge, was able to bring it back to life. If one cell is truly dead, like it's sulfated enough that it's collected at the bottom of the cell and shorted out the plates, not much will help.

I swear by them.

irishmike wrote:No, the engine is not turning over at all, just the odd click. It does not seem to have the crank power.

When its like this if I turn off the auto lights and aircon it tends to start quicker

Also the fact the battery or reading 820 out of 920

Have you ruled out starter motor? when this goes on the RS4 it typically does nothing when you press the start button but will then kick into life about 10 or 20 seconds later. This gets longer then worse the startr motor gets though. It won't make your battery go flat after a couple of days altough it might mean you can't start the car when cold.

Starter was replaced about 2 years ago. Oddly enough it seems to happen if there is a short period between stopping and starting again, like filling up petrol. It's nearly never an issue overnight or after it's been parked up a few hours like at work.

My Fiat coupe was like that, always leaving me stranded at the petrol station where you can't get a jump start amd annoy everyone cos you're taking up the space at a pump. Turned out it was the starter solenoid that got stuck when it got hot. Had to wait half hour sometimes for it to cool down before starting.

Yeah, have gotten a few nasty looks just sitting there pressing the button

Happened this evening at the pump, I just switched auto lights to off and it fired up.

I'll scan it tomorrow for faults.