new battery dead

[Brianmoooore]

Definitely red lead to the negative battery terminal, and black lead to the clamp that you took off of the battery!

[Speedtouch]

Well, that conflicts with this mechanic's demo, which clearly shows the black lead being put to the battery '-' terminal:



And this shows what happens if you initially put the leads with the red one going to battery '-':


As you can see, our friend Bono quickly realised the error of his ways and swapped them around to get a proper reading!

But, not to worry, if you're using a digital multimeter it won't harm the meter if you get a negative reading - just swap the leads around if you're worried about it. But if using a moving coil meter, be sure to get the leads the correct way round, otherwise you can damage the meter coil or cause it to stick in the negative extremity.

[Billwill]

When using a multimeter in "Amps" mode you not only switch the dial on the meter to AMPs...you will need to move the one meter lead to the point marked something like "10 Amp max"

Hopefully your meter will come with an instruction manual.

Main points are:

Do not put a meter that is in Current mode ie. Amps across the battery.
Likewise do not use the Resistance mode for anything other than measuring a components' resistance while all power is turned off.
As stated...do not start the engine with an Amp-meter in series with the battery...you will blow the fuse.
If using a digital meter, which would be the best choice, it will not cause any harm if the leads are the wrong way around.
You will only be using the Voltage setting to measure the charging voltage across the battery and you will use the Amp setting to measure current in series with the battery...with everything turned Off on the car you should see about 30 milli amps ie. 0.03 Amps or less .
If you see a lot more ie. about 300 milli amps...you need to pull fuses out one-by-one to see which circuit is causing the main drain of current.

[twoscoops]

Really appreciate all the time guys and clear explanations. I am very keen to get this all sorted as i am currently taking the battery out rather than leaving it in and letting it drain. I will update the thread when I get a chance to have a look at it and see what the readings are.

[BenHar]

You don't need to take the battery out. Just disconnect the negative terminal. That will stop it from draining.

Ben

[Z3I]

I've used these in the past, and may well buy another for my 325i, as more often than not the batterys too low when I want to start it over winter. Makes things easy when you want to disconnect the battery on a regular basis.

http://www.ebay.co.uk/itm/RICHBROOK-DIS ... 5648e846b1

[kam-325i]

one last note on the setting meter, make sure its set to DC & not AC.

[twoscoops]

guys I dont appear to have a position on my multimeter that says mA anything on it???

This is the machine I have;

http://www.petervis.com/electronics%20g ... M-830B.gif

What position should I have it set at? Do I need to move the black and red lead positions into the multimeter?

Cheers

[Grrrmachine]

You see the section marked A? And the number with 20m? That'll measure up to 20mA

You should set the machine to 200m in the A group, to measure up to 200mA, since the drain will be in the 30-100mA range.

You'll also want to plug the red lead into the middle of the three plugs, and the black lead into the bottom one, marked COM.

[twoscoops]

Legend! Thanks