Need help to measure battery drain current.

[dj_factor]

Hello Lads,
I had previous posted here, that my 2001 S320 is going flat over a period of 8-10 hours. A gentleman had suggested to check for quiescent current and thus I ordered a multimeter , which has arrived yesterday, but I dont know which setting to choose and how to check.

If someone can be kind enough to tell me which settings should I choose - IE - DCV-200-20-2000m etc, ACV, DCA or 10A. Also As i read the manual (seems quiet complicated), The negative/black wire will go into 10ADC and the red should go to COM. Am i right.

Also, what reads should i check on to ensure that there is a drain of current.

Thanks Lads, must appreciate that I have always got a positive help from you all, GOD BLESS

 

[vijilants]

You would have to set this up to 10a dc, but it has to inline and not across the battery.

 

[markmifsud]

word of warning, dont try and start your engine once you have the meter wired in as your going to pull a few more amps than the 15 or 20 that the meter will hold until it burns up

 

[johnsco]

Set the meter to 10 amps DC.
Put the red lead in 10ADC and the black lead in COMMON

DO NOT CONNECT THE METER ACROSS POSITIVE AND NEGATIVE OF YOUR BATTERY OR YOU WILL BURN OUT THE METER ON THIS SETTING.

Make sure that all lights and other systems are turned off
Remove the positive battery terminal.
Connect the red lead to the positive pole of the battery and connect the black lead to the terminal that you have just removed from the battery pole.
Any leakage current will now flow through the meter and will be measured by the meter.

Do not try to start the car or switch on anything more than door-operated courtesy lights with the meter in cicuit this way, or you will risk damaging the meter.

Hope this helps.
Johnsco.

 

[dj_factor]

Thanks lads, I will try this straight away. I have just jumped started the car now and will take it for a good 10 mile run to let the battery charge a bit. Will then try this technique.

Just to confirm once (Sorry never operated electrical meter or voltage checking item before) I should set the switch to 10A (the part shadowed in RED is it). Also, what is the right reading I should get and Do i start pulling each fuse and check the reading..
Thanks

 

[Dieselman]

Just to confirm once (Sorry never operated electrical meter or voltage checking item before) I should set the switch to 10A (the part shadowed in RED is it). Also, what is the right reading I should get and Do i start pulling each fuse and check the reading..
Thanks

Yes, set it to the RED section to start with and leave the car to shut down any live systems like the CAN.
After a while you will probably find the reading is too low to register on the 10A setting so turn it down to 200m and observe.

200milliAmps is 0.2A so is enough to drain the battery. You will probably have a drain of less than 100mA or even lower.
Just keep turning the dial once the reading is too low to display on the higher setting.

If you do connect up incorrectly it will blow the fuse inside the meter case.

Has the car got Comand installed, if so start there.

 

[st13phil]

Yes, set it to the RED section to start with and leave the car to shut down any live systems like the CAN.
After a while you will probably find the reading is too low to register on the 10A setting so turn it down to 200m and observe.

While I agree with the principle, it's going to be pretty difficult to achieve with that particular meter as the +ve connection for the 10Amp range is different to the one for the lower DC current ranges.

What the OP is going to have to do is start off with the meter connected on the 10Amp range and wait for the car's systems to shut down, then touch the car's +ve lead back on the battery post (taking the meter out of circuit), reset the probe connection and meter range and with the meter probes still on the battery post and the car's +ve lead, remove the latter from the battery post. It may be easier with a second pair of hands...

 

[Dieselman]

Crocodile clips or twisted wire will hold the probe onto the battery post and clamp.

 

[dj_factor]

Thanks chaps, the car doesnt have a command or telephone. just normal cd changer.

 

[Ted]

If you're worried about damaging the meter, put a headlamp bulb in series (in line) with one of the connectors.
This will limit the maximum current draw to 5 amps, and, should not affect the current drain that you are looking for.
Worst that can happen then is the bulb will light up.

 

[st13phil]

Crocodile clips or twisted wire will hold the probe onto the battery post and clamp.

True, croc clips are what I'd use, but as the OP has only just purchased a meter he may not have any (nor wire come to that ).

Actually, from the first post where he says the battery is going flat in 8-10 hours, I doubt he'll need the 200mA scale anyway

 

[acm718]

Have you tried removing all the fuses bar one, then trying each circuit by itsself overnight? Might take a month with an S class (how many fuses would it have?) but it'll give an idea of where the drain lies.

 

[Sp!ke]

I'd measure the current by taking out each fuse one by one and use the multimeter across each circuit to establish where the current drain is coming from.

You'll need to do this with the doors and boot closed.

Have you checked the obvious things like the glove box light and boot light switch are working?

An 8 hour drain is fast so should be easy to track down.

 

[dj_factor]

Hi Spike, I have checked the boot light switches off when the boot is closed and so does the glove box. One more thing. The cluster is giving me an error for a rear light bulb, which is absolutely working fine, its not blown, but when i check the bulb, its not lighting up, I dont know why. When i move the bulb to the left hand side, its working. Maybe rusty current lines, can it be. Can this be the problem to this drainage thing.

 

[dj_factor]

Guys I have checked using this method, pulled out and checked all fuses and relays in the bonnet section and the reading is still 2.87 on the amp meter if I let it on the 10A (RED MARKED) setting. I have even pulled and the fuses underneath the rear passenger seat and when I pull out the extreme left - 15AMP fuse, the reading drops to 2.47. I wasnt able to pull out any of the relays underneath as I cant get my hands there. Is it possible to pull them out and what do you guys think the problem would be now, if all the fuses are ok.

Also can I get a fuse chart for an S320 2001 model. There is nothing in the boot and nothing in the handbook too.
Thanks

 

[mr. shr]

Also can I get a fuse chart for an S320 2001 model. There is nothing in the boot and nothing in the handbook too.
Thanks

You certainly can. I've just recently bought a replacment for mine. Less than three quid.
Part number for mine is: A0005451500

Will probably be the same for yours but pm me your VIN and I'll check for you.