is there any known faults with batteries discharging on octavias? there's nothing wrong with the battery as this is the 3rd good battery i have tried! if i leave the car stood for a while with the cobra "alarm off" in the garage the volts go down every day. something is drawing power and i can't figure it out. it's not the stereo system as it did it when i 1st got it without it!

any ideas?

I'd check for the amount of current it takes if possible. That might give you an idea what fuse rating to check out.

I suspect though that it will end up being one of the aftermarket bits of gear that takes the current. Amps perhaps?

it is DEFFINATLY not the system, i have taken the main 250amp fuse out before and it still did it!

I'd check for the amount of current

how dod you do that with a multi-meter?

Hmm if you took out the fuse then it's very odd :|

For measuring current (please note you cant usually measure more than 10 Amps with a cheap meter !!)

+ ---> into meter common socket (meter in middle on Amp (or current) setting) --> second socket (usually marked as 10A or something) --> appliance.

Thing is be careful as you wouldnt want to set it to amp and then measure across your battery terminals as that would short them.

To check battery drain you want to disconnect the battery on the earth and connect an ammeter between the battery terminal and the clamp.

Should have no more than 0.2 amp with everything off (note you will need to lock the car up and leave for 5-10 mins for the ECU's to power down to sleep mode).

how i've done it in the past is similar to what you said, only i use a test light bulb and the brighter it glows the more discharge you have! it did glow a bit but didn't leave it 15 mins for everything to discharge!

is it possible the alarm draws currant when not activated as i leave it off during the day when it's in the garage.

The alarm will draw a bit of current but with a good battery you shouldnt have to worry for a couple of weeks minimum I'd have said.

There must be something else pulling power still.

You need to hook up an ammeter and then, wait for things to discharge and then one by one pull individual fuses out of the fuse box. When the amps drop out you have found the circuit that is drawing the power.

also, you mentioned earlier that i would need to lock the car 1st before carrying out any tests..........why?

Because you need to have the vehicle at rest t check for current drain. Cerain ECU's only power down once the vehicle is locked and left alone.

Have you have checked that the boot light is off when the boot is closed?

Cerain ECU's only power down once the vehicle is locked and left alone.

that would explain why the fuel pump kicks in when you open a door.

that could be half my problem! i don't lock the car or arm it when it's in the garage, only when off my property!

just checked the altetrnator and it's reading 14.7/8 volts and battery is reading 12.7 volts when engine is off.

the battery is an odyssey pc1700 and the alternator is a 120 amper off an audi tt225.

Have you have checked that the boot light is off when the boot is closed?

no bulb in boot as the ice builds went over where it was so took it out

no bulb in boot as the ice builds went over where it was so took it out

Do the sunvisors have illuminated mirrors?

Glovebox light is also a possibility.

Check the alternater is not causing it..... i had a similair problem on avectra sri...

several times i have left the interior light on on my octy and its never gone flat from that... and i have a 600W system in there ... the battery never seems to run down from these

He's checked the alternator if is kicking out 14.7 volts its fine.

i changesd the alternator for a nearly new 120amp jobbie. i'm going to start locking/arming the car when it's stood still now and see if that makes a diffrance.

Hopefully it will help. You're right to be concerned though as there is something odd going on there :(

Sorry I couldnt think of anything else - it's rather annoying me now so hope you will find it & post back what it was

Have you checked the glovebox light?

Have you checked the glovebox light?

think this only comes on when the head lights are on?

..maybe a faulty diode pack in the alternator ? I had a simliar problem after I had some MIG welding done on a previous car...they forgot to disconnect the alternator when welding and fried the diodes.