I’m pretty sure my 2009 Octavia has the common alarm siren/back up battery issue.

I’ve done some searching and understand the siren/back up battery resides in the drivers front wheel arch.

Would I be correct in assuming that if I simply disconnect the wiring connector from the unit that it would no longer try and charge the backup battery? I’m 99.9% certain that a faulty back up battery is causing significant drain and as a temporary measure until I can fix/replace the unit I’m thinking just simply disconnect it for now?

Likely to cause any issues with simply disconnecting it?

Thanks

Nick

Our Indy did just that on one of our Octy 2s. Car is still running fine with no problems.

BTW look on aliexpress.com for a new alarm; between 40-50 squid at last look.

Cheers Mike

Removed the siren/battery back up unit today.

Had a 30min drive and car locked up fine no issues so far.

I’ve just opened up the unit for a nosey and it’s returning 3.5v so I’m assuming it’s goosed should be 6v? No signs of battery leakage or bad circuits but one of the capacitors has come away from the board and was rattling around inside.

I’m assuming the backup battery tries to pull a charge from the main battery to stay at 6v is this correct?

In principle that is correct. Alkaline batteries of the type being used tend to die after 5 years or so.

4 minutes ago, pikpilot said:

In principle that is correct. Alkaline batteries of the type being used tend to die after 5 years or so.

Cheers Pikpilot,

I’ve got stacks of history with the car and it has FSH with relatively low mileage for its age circa 82k but no mention of it ever having a replacement unit.

if it’s still the original unit at circa 17 years old that’s definitely some innings 😁

Part number is 1K8 951 005

That must be a record. Skoda recommend replacing at a much shorter period and they usually fail between 6 and 10 years old although mine lasted a bit beyond that.

All my skoda when I bought them with full service history have no mention of battery replacement. My 08 plate siren still works. My 2012 plate siren doesn't. Did have an old volvo 940 that used to drain battery in the same way. (used the same supply as clock for charging which kept blowing fuse) I removed siren/battery to discover it was pretty near to being on fire. Batteries were melted including plastic surround. Never bothered fitting another one.

Alasdair

5 hours ago, Alasdair1 said:

All my skoda when I bought them with full service history have no mention of battery replacement.

It is on the service list used by Skoda dealers

Mine were all serviced at independant garages once the warranty ended so probably didn't bother with checking alarm etc.

Alasdair