Battery issues, Alarm?

[Taede]

My Superb seems to destroy batteries, It's had about 4 in the last 5 years. The last one has lasted less than 6 months before not holding its voltage, they seem to last less and less long.

 

The car is mainly used for sort journeys, but not so short that the battery should deteriorate *that* quickly. The car does have a dash-cam hardwired and an aftermarket radio installed. The dash-cam feed is set to cut off when battery voltage drops below 12.4 or after 12hours after ignition is turned off, whichever comes first.

 

The voltage just after turning off is ~12.4-12.7v, and with the engine running its 13.8-14.3v. The alternator has a fixed pulley so is always turning with the engine on. Early last week it refused to start so I used a lighter-socket voltmeter for a quick check and sure enough it was low (11.1 or something). I took the wife's car to work, and had left the car unlocked and the voltmeter on. Came back from work to find that voltage hadn't dropped at all. Locked the car, came back a few hours later to find that voltage had dropped from 11something to 9v. This may be a coincidence but I'm now wondering if its the alarm that's draining the battery when armed.

 

Sometime last year I used a multi meter between the battery post and lead to check for currents. Iirc the current dropped to something like .01A (the smallest it can measure at the required setting) a few seconds after turning off the ignition. Pulling the fuse for the dash cam or radio made no difference. I did not check for what happens if I lock the car, I shall have to see if I can do that sometime

 

Once I charge the battery I'm going to lock the car without arming the alarm (I believe using the key in the door lock achieves that) and see what happens.

 

Is the alarm integrated in the convenience module under the passenger seat? How would I go about finding out why this drainage is happening if this is indeed the cause?

 

PS: the car should not be suffering from water ingress. The filter area was sealed before I got the car, and I sealed the door panels a long time ago. There is no sunroof.

[J.R.]

The pcb mounted back up batteries in the alarm have failed & leaked acid over the circuit board, disconnect it!

[Taede]

Thanks, I will.

 

Just to confirm though, it is located in the convenience module under the passenger seat?

[J.R.]

Not sure on your model but I doubt it, its usually a separate siren unit, on my Octavia it was under the RH  front wheel arch, the noise from the Yeti sounds to be from the same area.

[Taede]

After a call to the nearby skoda dealer I've found the alarm siren. Turns out it is located in the plenum chamber, wedged between the battery and the brake servo. (I have also finally ordered a new scuttle panel as I was on the phone to them anyway, meant to do that for ages)

(Pics are of an RHD model, LHD models will be mirrored here)

 

Removal necessitates removal of battery first. Once the battery is out, undo the nut circled in red, preferably without dropping it. The nut has a captive washer.

 

Once this nut is loose, wiggle the unit as a whole out. It has a lip at the bottom which catches on the battery tray for security, so you'll need to pull and twist at the same time until it comes out.

Once it is free, you can undo the plug which is located on the side facing the brake servo, with the plug facing straight down.

 

Et voila, it is removed.

 

Currently the battery is on the charger. I will reinstall it later and see how much it has deteriorated before trying to get it replaced under warranty.

[J.R.]

If you can live with your conscience then good luck, a similar current drain took my 2 month old Varta below the 10.6v point of no return, my CCA tester showed that it had lost a lot of its life and its resting cell voltage has been low ever since but its still starting the vehicle 18 months on, we all learn from our mistakes and the price we pay for them.