Battery drain ?????

Just wondering if anyone could tell me if I could/how to check battery drain on a multimeter OR would I need something else.

The car in question is a 2000 VW Lupo GTI with 114k, changed many battery in the last couple of years & now have another good battery on it, I've checked charging & all is good with loaded & unloaded.
The engine seems slow to turn over & the central locking shunts when starting.
Was also thinking of possible the starter motor is pulling big amps...... still need to check this when I get 5mins.
A fully charged battery will last a week then these problems begin.
There is a sub/amp fitted with a switch to turn the amp (blue wire) off.

Any help/ideas would be great.

Cheers

Without knowing the particular vehicle, so just general hints for this kind of thing...

You'll need an ammeter with a current range of at least ten amps - most cheap digital multimeters will do the job. Alternatively, the low-tech solution is a 12v bulb and a bit of wire...

Remove master fuse, if there is one, or the battery positive lead if there isn't, and measure the current across its holder (or stick the bulb there and see if it lights up). Ideally, the only standing current with the ignition off and the doors closed will be a few tens of milliamps feeding the alarm, the remote locking, and possibly a keep-alive on the radio.

If you're seeing more than that, you then need to start removing fuses from the fusebox. When you find one that suddenly decreases the current, you've found your problem. If removing all of them doesn't remove the current, probably best - unless you have at least a detailed wiring diagram - to get an auto electrician in.

As above, around 30mA max is good.

just had my caddy sportline in for a battery drain problem, turned out to be one of the door lock switches had corroded (they turn the interior light on - built in the actual lock) so the van thought the door was open.

another thought you have not changed the head unit recently?

just a couple of ideas

Cheers guys for your input.

Headunit is standard vw tape player with multichanger fitted below.

Will hope to get a chance to look at it this weekend :-)

Unplug that sub/amp from the battery. May not be switching correctly and draining your battery.

Sorry ti Hijack your thread,but my coop has similar issues.
I left it for two days and nothing,totally dead! This also happened two weeks ago and I thought the new battery I put in was faulty so I took it back and got it replaced with a highr voltage/starter battery.
The open door warning light appears on at times so I slam it shut while driving. Also had a new DAB radio fitted recently so Im thinking about what you guys have said above?
I havnt noticed the interior light on though.
Thoughts?

It could be the head unit, see this thread