Disconnecting dead battery on A3 causes intermittent beeping, any advice?

[amoxitine]

Hi there,

I was wondering if someone might be able to help. I inadvertently left my dashcam plugged in whilst I was on holiday and I have since returned to find the battery on my A3 is totally dead. I've ordered a replacement and this evening I was looking to remove the old battery and place it on charge just to see if it might take a bit, but as soon as I disconnected any terminal, within seconds the car would start to beep for around 30 seconds, then stop and then repeat beeping (but no lights flashing).

I'm assuming that it's related to the alarm in some way that has it's own battery backup (alarm was active when I left the car last week) but I just can't fathom out how to stop it beeping, so any advice would be welcome. Also once the new battery arrives would I be OK to just swap them over (putting up with the beeping whilst doing so) and then trying to start it up or is it not as straightforward as that?

Thanks in advance for any advice!

Cheers,

Dave

[Magnet]

Hello Dave,

Not quite sure why you are replacing the battery if it has simply discharged and had not previously given any symptoms - of course, you may well have had previous issues and knew it was not very serviceable. 

Also, as long as you ensure you connect the battery charger wires to the correct polarity then it isn’t  essential to disconnect the battery before charging. After all, you certainly cannot disconnect the battery if you jump start it, and under those circumstances you are inputting comparatively high currents. 

If it were mine, I would just charge the battery in situ. If/when you actually change the battery, you would be wise to do so using a ‘code saver’ device which ensures 12v is continuously supplied to the car ( general via. a slave battery) so that radio codes etc.are not lost. 

Kind regards,

Gareth. 

[cliffcoggin]

Dave. You don't need to remove the battery to charge it, though I appreciate it may not be practical if you park in the road.

[amoxitine]

Hi Gareth & Cliff,

Many thanks for your replies. Just an update on things, the reason why I was trying to take the battery off was due to the fact that I'd tried a jump start yesterday but had no joy (albeit I only tried for a couple of minutes) plus I was too far away from my flat to be able to charge it whilst attached, hence why I thought I might be able to just whip it off and do a main charge indoors. In the past I've flattened the battery by leaving the dashcam plugged in overnight during cold periods but normally I could open the car with the key fob, the ignition lights would come on, but just get the flickering when you try to fire up the engine cold, but this time I had none of that.

Good news is that I was able to do a prolonged jump start this morning (ie leaving it charging for about 10 minutes) and although I had disconnected and reconnected the battery a few times last night, apart from the date and time, nothing else had visibly reset (e.g radio) so I'm back in business.

Interestingly what I did notice is that initially when I realised I'd drained the battery, I had zero response from the car (had to unlock drivers door manually, no dash display or interior light and completely dead when ignition key turned) which made me think the battery was knackered this time, especially when having tried a quick jump start yesterday it was still fully unresponsive. This morning however, as soon as I reconnected to the battery terminals with a 2nd jump start attempt, the alarm immediately went off (this time with flashing indicators), so disabled that via the key fob and when I re-open the drivers door to my surprise the mileage and time was now showing on the dash plus the interior light came on and I could turn on the radio, none of which was possible when I did the jump start yesterday (so behaving like it has done in the past when the battery was flat from leaving the dashcam plugged in overnight)

It's almost as though it had provisionally gone into some kind of power hibernation that it only was woken out of after I'd done the multiple disconnect / reconnect last night that had triggered the alarm, then jumped it for a second time this morning (the only way I can describe it!)

Very confusing, but at least I'm all good now and also learned that getting zero response from a flat battery doesn't necessarily mean it's completely knackered! 

Now it's time to get the new battery sent back that arrived this morning :') !

Cheers,

Dave

[cliffcoggin]

Glad to hear the car is running again. If you have flattened the battery a few times in the past its capacity will have been reduced, so it might be worth keeping the new battery.

[Adam B]

Hi Dave,

I had the same issue with my Audi A4 Avant (B8) where i didnt use if for about 3 weeks and when I came to start it noting happened. Manage to jump start it first time so the batter wasnt as dead as yours I dont beleive however since then after starting the car and after about 15/20 seconds I have an interior beeping happen then then it stops. 

After some research I found out this is has something to do with the alarm system which sounds just like yours.

When you gave the battery a full charge did this stop the beeping? I am debating charging the battery or getting a new one?

Thanks for you help in advance.

Adam

[Magnet]

Hello Adam,

You would not normally expect a battery not to start a car after standing for 3 weeks, so something is wrong. 

Problem could be the battery is no longer serviceable - original to the car? 

There is a parasitic drain taking charge out of the battery while it’s standing.

The alternator is not providing an adequate charge level. 

If this were mine, I would charge the battery overnight and get its efficiency checked  - Halfords should be able to do this. It found to be sub standard - buying a new one from Halfords?? 

My replacement purchase if needed, would be either a Varta or Bosch with a minimum of 4 years warranty. I have used Tayna, Battery Megastore, Plymouth Batteries etc as reliable and competitive on line suppliers. No connection. Try their eBay listings first since strangely they provide free carriage if you buy via. this route, but can charge you if bought direct. 

Kind regards,

Gareth. 

 

[Adam B]

Thanks for your response Gareth

It could well be the original battery to the car to be honest which is on a 2009 plate so if it is then the battery would be quite old and not functioning properly.

I am having it check to see what output it has and I am also going to charge the car overnight to see if this solves the problem of the beeping from the alarm. Failing that I will bite the bullet and buy a new battery to see if this helps.

Thanks again and will post an update when I have one.

Adam

[Magnet]

Hello Adam,

What I meant was to charge it overnight before getting it tested, to ensure you have a meaningful test result.

Kind regards,

Gareth.