Conor wrote:
On 10/03/2010 11:06, Dave Plowman (News) wrote:

You have to use guile when carrying this out with some cars as the
inrush current when connecting the battery can blow the DVM fuse.

Only if its a bag of **** you bought from the Pound Shop.

there is often a very healthy crackle when connecting the battery, some
vehicles fire the central locking, so the initial current can be far higher
than is safe even for expensive multi-meters, and in any case why risk it?
just connect the meter to the battery terminal, hold the battery lead
against the terminal and connect the other meter lead to the battery lead,
separate the battery lead from the battery keeping one meter lead on the
battery terminal and the other on the battery lead, simples. read battery
drain with little risk to anything.

It happens that Conor formulated :
On 10/03/2010 11:06, Dave Plowman (News) wrote:

You have to use guile when carrying this out with some cars as the inrush
current when connecting the battery can blow the DVM fuse.

Only if its a bag of **** you bought from the Pound Shop.

Rubbish!

Some cars can take quite a bit of initial in rush current when the
battery is first connected, more than enough to wreck a meter set on a
2amp range.

If there is any substantial discharge, as in a fault, then the meter is
still at risk. Rather than using a meter for the first test, safer
would be to insert a low wattage lamp in series with the battery lead
to see if it passes enough to light it up - say a 16w indicator lamp,
or a 5w tail lamp.

The best way is to short the meter terminals out until it has settled
and make sure no doors are opened or lights are turned on with the
meter in line. 35mA - ish is about right, though some cars may
initially show more and the current required decreases over the first
30 minutes as things gradually shut down.

It might also be worth checking the voltage across the battery with
engine running, with various loads on and not running, to make sure it
is getting a good charge.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Wed, 10 Mar 2010 17:28:33 -0000, Mrcheerful
wrote:

GB wrote:
Actually, you can trace the current drain quite easily and quite
specifically - without disconnecting the battery.

1. switch everything off
2. open fuse block lid
3. take out one fuse and connect ammeter leads across the socket -
make a note of the current if significant
4. replace fuse
5. rinse and repeat

that would not trace one of the most common drains: the alternator



I'm fairly certain that's not very common, it's just very troublesome.

--
Duncan Wood

On Wed, 10 Mar 2010 16:22:44 -0000, Conor wrote:

On 10/03/2010 11:06, Dave Plowman (News) wrote:

You have to use guile when carrying this out with some cars as the
inrush
current when connecting the battery can blow the DVM fuse.

Only if its a bag of **** you bought from the Pound Shop.




The pound shop don't sell spare fuses for Fluke 867s so either your
accounts been hijacked by the Tiscali idiot or you've lost it.


--
Duncan Wood

Duncan Wood wrote:

that would not trace one of the most common drains: the alternator

I'm fairly certain that's not very common, it's just very troublesome.

It would certainly trace the light in the boot and all that sort of problem.

In fact, I first did this over 40 years ago, when I had just learnt about
electricity at school. By the time I located the problem (light in the boot
ofc), my dad had already been sold a new battery and dynamo by the garage.
If I hadn't found it, I think they'd have sold him a new car.




--
Electric cars are very healthy - when the battery runs out you have to
walk home.

In article ,
Conor wrote:
You have to use guile when carrying this out with some cars as the
inrush current when connecting the battery can blow the DVM fuse.

Only if its a bag of **** you bought from the Pound Shop.

Shows how much you know about such things.

Oh - I suggest you look up how much a fuse costs for a Fluke DVM...

--
*Remember, no-one is listening until you fart.*

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Harry Bloomfield wrote:
Some cars can take quite a bit of initial in rush current when the
battery is first connected, more than enough to wreck a meter set on a
2amp range.

I've had the fuse go on the 10 amp range...

--
*Middle age is when it takes longer to rest than to get tired.

Dave Plowman London SW
To e-mail, change noise into sound.

On Mar 10, 9:31*am, paulfoel wrote:

If it is, how do I find out what?

Isolate the different circuits in turn in the following order until
the excess current stops.

Pull out each fuse in turn.

Pull out each relay in turn.

Remove the plug in the back of the alternator. (Usually involves
accessing from underside of car)

GB used his keyboard to write :
It would certainly trace the light in the boot and all that sort of problem.

In fact, I first did this over 40 years ago, when I had just learnt about
electricity at school. By the time I located the problem (light in the boot
ofc), my dad had already been sold a new battery and dynamo by the garage. If
I hadn't found it, I think they'd have sold him a new car.

The easy test is to open the boot, feel the light and if it is warm -
it is staying on. Though some cars are fitted with a battery saver
relay, these turn of the supplies to such things around 30 minutes
after the car has been left undisturbed for that length of time. In
other words leave it parked in the garage with a door open, the
interior light should go out after 30 minutes and not come back on
unless you close then reopen the door.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

paulfoel wrote:
Battery is always pretty much flat every morning - car starts just
about. However, once its started in the morning its pretty much ok for
the rest of the day.

Sorry for being thick, but can I use a multimeter to see if anything
is draining the battery?

If it is, how do I find out what?

It's far more likely to be a shagged battery than a leak. The volts
across them drop due to the overnight cold especially at this time of year.