Can anyone tel me what sort of current draw I can expect from my 2001 model octavia? I've recently measured approx. 0.5A but with my little experience in this area was expecting a fraction of this.

Am I right in thinking that only the clock and alarm/imobiliser will be drawing current when it's standing? I don't see anything obvious like lights still on.

The reason I ask is that I have an issue where the battery is losing it's charge in less than a week of standing and the battery is barely 18months old. I want to make sure there is nothing else that could be causing this before I suspect a faulty battery and start chasing the supplier for a replacement (it's within its 4yr warranty).

Hi there,

Just to keep the maths simple (for my benefit) if your battery was rated at 50 ampere hour it should deliver 50 Amps for 1 hour or 5 Amps for 10 hours or 0.5 Amps for 100 hours, so it is conceivable that a drain of 0.5A will discharge your battery within 4 days, though its likely your battery is rated around 70 ampere hours and will last a little bit longer but not much.

Possibly the fastest way to find the culprit is to measure the drain on your battery in the same way you have already done, and whilst doing this pull the fuses one by one until you notice the drain drop significantly. Find out which circuit the fuse controls and you will be somewhere close to the problem.

It could well be a duff battery, but when you get a dead cell it tends to show up as one day it starts fine the next the battery is flat and even when recharged it will continue to be totally unreliable.

Hope that gives you some help with identifying the fault.

Edited 24 November, 201015 yr by smileonimpact

hmmm interesting...Mine is doing exactly the same. I have asked the question about battery replacement as I have read that some people have blown the ABS ECU when plugging in the new battery due to power spikes!! Scary...

A common culprit is the central locking.

Do all the doors/windows/adjustable heated mirrors/flashing led/driver door central locking switches work OK?

Try fuses F38 and F37.

It could also be Central Convenience Unit (CCU) related.

Try fuses F10, F14 and F5.

Hi there,

Just to keep the maths simple (for my benefit) if your battery was rated at 50 ampere hour it should deliver 50 Amps for 1 hour or 5 Amps for 10 hours or 0.5 Amps for 100 hours, so it is conceivable that a drain of 0.5A will discharge your battery within 4 days, though its likely your battery is rated around 70 ampere hours and will last a little bit longer but not much.

Possibly the fastest way to find the culprit is to measure the drain on your battery in the same way you have already done, and whilst doing this pull the fuses one by one until you notice the drain drop significantly. Find out which circuit the fuse controls and you will be somewhere close to the problem.

It could well be a duff battery, but when you get a dead cell it tends to show up as one day it starts fine the next the battery is flat and even when recharged it will continue to be totally unreliable.

Hope that gives you some help with identifying the fault.

Top answer

I'd have said 0.5A is a bit high.If it had been a Rover,I'd suspect the diode pack in the alternator to be on the way out.This allows backfeed from battery to alternator,when it gets nearer 1A you can hear/feel the alternator humming.

If you couldn't leave your car for two weeks,everybody comming back from holiday would have a dead battery.

As to spikes when changing the battery,I would think most cases are where a third party has changed it,and touched a spanner on the body,then said "they all do it mate"

Always disconect earth first and connect it last,you can't touch a spanner to earth from the live if there isn't one.

Alot of Rover TDi ECU's that get fried in fact just blow the internal earth wire to the case,A bit of carefull soldering,and good as new.

It seems to be a commonish problem on the c2000 year octavias. My brother's taxi got this fault, after much money spent on 'experts' and parts, gave up and fitted a battery disconnect switch! Far from ideal.

I left mine in a Heathrow car park for over 3 weeks last Christmas. It started no problems. I would say that a battery life of less than a week was definitely not usual.

I left mine in a Heathrow car park for over 3 weeks last Christmas. It started no problems. I would say that a battery life of less than a week was definitely not usual.

It's not. The current drain on a standard car should be about 20mA. That's about 0.5Ah/day.

It's not. The current drain on a standard car should be about 20mA. That's about 0.5Ah/day.

2nd that. Although I I wouldn't be alarmed by anything up to 50mA

The only course of action is as siad above - monitor the drain whilst removing fuses in turn until you find one that dramatically drops the current draw.

Allow the system to stand a while after fitting any current measuring equipment, as various systems on the car will remain active for a period after the ignition is switched off (or battery disconnected/reconnected). So to get a true measurement of standing current, wait 10minutes or so to let it settle.

A common culprit is the central locking.

Do all the doors/windows/adjustable heated mirrors/flashing led/driver door central locking switches work OK?

Try fuses F38 and F37.

It could also be Central Convenience Unit (CCU) related.

Try fuses F10, F14 and F5.

The rear passenger side window hasn't worked for the 18mths or so that I've had the car. As we've had a baby in that seat with a sun visor up so it hasn't been an issue. However since you mention it I'm now starting to wonder if it's related.

Cheers all for the feedback and suggestions - weather permitting I'll be trying to get to the bottom of it this weekend. I'll give an update in due course.

Can anyone tel me what sort of current draw I can expect from my 2001 model octavia? I've recently measured approx. 0.5A but with my little experience in this area was expecting a fraction of this.

Am I right in thinking that only the clock and alarm/imobiliser will be drawing current when it's standing? I don't see anything obvious like lights still on.

The reason I ask is that I have an issue where the battery is losing it's charge in less than a week of standing and the battery is barely 18months old. I want to make sure there is nothing else that could be causing this before I suspect a faulty battery and start chasing the supplier for a replacement (it's within its 4yr warranty).

after connecting an ammeter ,you need to wait a short while,because the current draw is higher,whilst the interior light ,and car alarm,etc needs to turn off, to measure the true continuous current drawn .In my case it was about 500 mA (0.5A) at first, which dropped to 150mA (0.15A). This was in fact the car alarm current, and quite normal. Overall its a case of how far the car is being driven ,in day or night ,whether the heater fan,rear screen heater has been used etc before you switch off.