I want to check the current that my car is using whilst at rest (brand new
battery goes flat over two days).
Will a multimeter be of use and if so what range would I need to use?

Battery is 55ah

Regards

Tony

On Sun, 01 Jul 2007 18:03:38 GMT, "Tony P"
wrote:

I want to check the current that my car is using whilst at rest (brand new
battery goes flat over two days).
Will a multimeter be of use and if so what range would I need to use?

Battery is 55ah

---
Two days is 48 hours, so if your battery's rated for 55AH and it
goes flat over that time, it's probably delivering an amp or so to
the load.

You could use a multimeter to make the measurement, but use the
highest range you have available. For cheap multimeters that's
usually 10 or 20 amps, DC.

What you'll need to do is make sure the ignition and accessories are
all off, (including the interior lights, and also unplug anything
you may have plugged into the cigarette lighter socket) then
disconnect one of the battery terminals from the battery and connect
the ammeter between the battery and the disconnected terminal.

The meter will then display whatever current the battery is
delivering.


--
JF

Thank you John I will try this.

"John Fields" wrote in message
...
On Sun, 01 Jul 2007 18:03:38 GMT, "Tony P"
wrote:

I want to check the current that my car is using whilst at rest (brand new
battery goes flat over two days).
Will a multimeter be of use and if so what range would I need to use?

Battery is 55ah

---
Two days is 48 hours, so if your battery's rated for 55AH and it
goes flat over that time, it's probably delivering an amp or so to
the load.

You could use a multimeter to make the measurement, but use the
highest range you have available. For cheap multimeters that's
usually 10 or 20 amps, DC.

What you'll need to do is make sure the ignition and accessories are
all off, (including the interior lights, and also unplug anything
you may have plugged into the cigarette lighter socket) then
disconnect one of the battery terminals from the battery and connect
the ammeter between the battery and the disconnected terminal.

The meter will then display whatever current the battery is
delivering.


--
JF

On 2007-07-01, Tony P wrote:
I want to check the current that my car is using whilst at rest (brand new
battery goes flat over two days).
Will a multimeter be of use and if so what range would I need to use?

Start on 10A and work down if it reads 0,

Battery is 55ah

2 days would imply approx 1A drain,

you could try placing pulling fuses and putting the meter across the
terminals, that'll tell you which circuit is the thirsty one.

Bye.
Jasen

I have done what you suggested and I have a reading of 0.39A
I do not know if this is excessive for a car.
The problem is intermittent and at the moment there does not seem to be
anything wrong (touch wood). I will wait for the problem to return and try
again.
"Jasen Betts" wrote in message
...
On 2007-07-01, Tony P wrote:
I want to check the current that my car is using whilst at rest (brand
new
battery goes flat over two days).
Will a multimeter be of use and if so what range would I need to use?

Start on 10A and work down if it reads 0,

Battery is 55ah

2 days would imply approx 1A drain,

you could try placing pulling fuses and putting the meter across the
terminals, that'll tell you which circuit is the thirsty one.

Bye.
Jasen

"Tony P" wrote in message
o.uk...
I have done what you suggested and I have a reading of 0.39A
I do not know if this is excessive for a car.
The problem is intermittent and at the moment there does not seem to be
anything wrong (touch wood). I will wait for the problem to return and try
again.
"Jasen Betts" wrote in message
...
On 2007-07-01, Tony P wrote:
I want to check the current that my car is using whilst at rest (brand
new
battery goes flat over two days).
Will a multimeter be of use and if so what range would I need to use?

Start on 10A and work down if it reads 0,

Battery is 55ah

0.39A x 48 h = 18.7 Ah

That's too much standby drain. If you go on a week-long trip, your battery
is going to be very dead.

Charles wrote:
"Tony P" wrote in message
o.uk...

I have done what you suggested and I have a reading of 0.39A
I do not know if this is excessive for a car.
The problem is intermittent and at the moment there does not seem to be
anything wrong (touch wood). I will wait for the problem to return and try
again.
"Jasen Betts" wrote in message
...

On 2007-07-01, Tony P wrote:

I want to check the current that my car is using whilst at rest (brand
new
battery goes flat over two days).
Will a multimeter be of use and if so what range would I need to use?

Start on 10A and work down if it reads 0,


Battery is 55ah


0.39A x 48 h = 18.7 Ah

That's too much standby drain. If you go on a week-long trip, your battery
is going to be very dead.


Make sure you dont have a under-the-hood light that is on when you take
the measurement. 390 ma is just about what that lamp would draw.
I think the lamp works with a level switch, hood up, light on, hood
down, light off-- I would start there, make sure the light is not
staying on when the hood is shut. (If you have one of those lights, not
all cars do.)

On Tue, 03 Jul 2007 14:15:48 -0500, Skenny
wrote:

Charles wrote:
"Tony P" wrote in message
o.uk...

I have done what you suggested and I have a reading of 0.39A
I do not know if this is excessive for a car.
The problem is intermittent and at the moment there does not seem to be
anything wrong (touch wood). I will wait for the problem to return and try
again.
"Jasen Betts" wrote in message
...

On 2007-07-01, Tony P wrote:

I want to check the current that my car is using whilst at rest (brand
new
battery goes flat over two days).
Will a multimeter be of use and if so what range would I need to use?

Start on 10A and work down if it reads 0,


Battery is 55ah


0.39A x 48 h = 18.7 Ah

That's too much standby drain. If you go on a week-long trip, your battery
is going to be very dead.


Make sure you dont have a under-the-hood light that is on when you take
the measurement. 390 ma is just about what that lamp would draw.
I think the lamp works with a level switch, hood up, light on, hood
down, light off-- I would start there, make sure the light is not
staying on when the hood is shut. (If you have one of those lights, not
all cars do.)

---
Also, an in-trunk lamp with a broken switch.


--
JF

On Tue, 03 Jul 2007 17:53:01 GMT, "Tony P"
wrote:

I have done what you suggested and I have a reading of 0.39A
I do not know if this is excessive for a car.

Generally, over a longer term, it is excessive. Ideal parasitic draw
should be about 50 MA (0.050 A), so you are *well* above ideal values.
However, monitoring requirements do both vary from vehicle to vehicle,
and over time as computers go to sleep and wake up. Best to check draw
about 30 to 60 minutes after stopping and closing the car. Do not open
doors, or otherwise let the car know you are there (like doing the
power remote locks, etc.)

"Tony P" wrote in message
o.uk...
Thank you John I will try this.

"John Fields" wrote in message
...
On Sun, 01 Jul 2007 18:03:38 GMT, "Tony P"
wrote:

I want to check the current that my car is using whilst at rest (brand
new
battery goes flat over two days).
Will a multimeter be of use and if so what range would I need to use?

Battery is 55ah

---
Two days is 48 hours, so if your battery's rated for 55AH and it
goes flat over that time, it's probably delivering an amp or so to
the load.

You could use a multimeter to make the measurement, but use the
highest range you have available. For cheap multimeters that's
usually 10 or 20 amps, DC.

What you'll need to do is make sure the ignition and accessories are
all off, (including the interior lights, and also unplug anything
you may have plugged into the cigarette lighter socket) then
disconnect one of the battery terminals from the battery and connect
the ammeter between the battery and the disconnected terminal.

The meter will then display whatever current the battery is
delivering.


--
JF


And after this, you may have to reprogram the radio (as many are designed to
lock out if power is removed so that they are of no use to thieves. Be sure
you have the code to reset it.


--

Don Kelly
remove the X to answer
----------------------------

PeterD wrote:
On Tue, 03 Jul 2007 17:53:01 GMT, "Tony P"
wrote:

I have done what you suggested and I have a reading of 0.39A
I do not know if this is excessive for a car.

Generally, over a longer term, it is excessive. Ideal parasitic draw
should be about 50 MA (0.050 A)

50 MegaAmps - crikey lol

, so you are *well* above ideal values.
However, monitoring requirements do both vary from vehicle to vehicle,
and over time as computers go to sleep and wake up. Best to check draw
about 30 to 60 minutes after stopping and closing the car. Do not open
doors, or otherwise let the car know you are there (like doing the
power remote locks, etc.)

My car (older toyota) with immobiliser, alarm, stereo, clock and no
other draw sits at around 200ma and I thought that was fairly excessive,
so i'd be inclined to agree.

On Fri, 27 Jul 2007 17:37:54 +0100, coyoteboy
wrote:

PeterD wrote:
On Tue, 03 Jul 2007 17:53:01 GMT, "Tony P"
wrote:

I have done what you suggested and I have a reading of 0.39A
I do not know if this is excessive for a car.

Generally, over a longer term, it is excessive. Ideal parasitic draw
should be about 50 MA (0.050 A)

50 MegaAmps - crikey lol

But at only 1 mV... g


, so you are *well* above ideal values.
However, monitoring requirements do both vary from vehicle to vehicle,
and over time as computers go to sleep and wake up. Best to check draw
about 30 to 60 minutes after stopping and closing the car. Do not open
doors, or otherwise let the car know you are there (like doing the
power remote locks, etc.)

My car (older toyota) with immobiliser, alarm, stereo, clock and no
other draw sits at around 200ma and I thought that was fairly excessive,
so i'd be inclined to agree.

I'd call 200 mA (better?) too much too. I suppose if you drive every
day, that's OK, but skip a few days and that battery will be flat.