Multimeter and draining battery

scott540 · scott540's Garage

Ok, I'm new to all this. Battery has been draining really fast Drove on Saturday, battery dead on Monday night. Battery only showed 11 with voltmeter, enough to keep the clock running but not enough to start the car. It's done this quite often and consistantly lately. Charged the battery. Started right up. I'm trying to do the drain test in Wayne's book but but I'm new with a mulitmeter. I disconnected the the negative lead and put Multimeter between the post and the cable, set the meter at 200mA and I get 0. I also tried the 10A seting and got 0. What am I doing wrong?

RWebb · RWebb's Garage

set the meter to a voltage range

scott540 · scott540's Garage

I thought I was trying to measure milliamps. Bentley book says 100 is normal. Wouldn't I set it to Amps DC and 200m?

equality72521 · 05-13-2008, 07:53 PM

I think Randy believes you are trying to measure voltage. You are correct in what you are doing but did you move the meter leads to the appropriate holes on the meter?

equality72521 · 05-13-2008, 07:59 PM

In my case in the pic above the red lead would be moved to the hole just to the left of the black lead.

scott540 · scott540's Garage

I've got it in the right holes I think. 200mA Max fused. It's a craftsman meter- model 82141. I touched one probe to the negative post and the other probe to the negative terminal I took off of the negative post.. Reads 0. Man, this is frustrating. Thanks for trying though.

rick-l · 05-13-2008, 08:24 PM

Set the meter to ohms and stick the red lead in the amps terminal and then the milli amps terminal. The manual (or printed on the back) will tell you what resistance you should read (probably less than 1 ohm for sure) This is to see the fuses are good.

911pcars · 05-13-2008, 08:27 PM

It could be like my meter. The internal fuse is dead. Remove the cover from the meter and take a look. The fuse often blows when the ammeter is connected in series in a circuit that exceeds the current limit (10A).

Sherwood

rattlsnak · rattlsnak's Garage

First things first, is it a digital meter or analog meter?

rattlsnak · rattlsnak's Garage

duplicate

rattlsnak · rattlsnak's Garage

OK, i see what you have. It appears you are hooking it up correctly, but make sure you use the correct plug for the red lead. Start at the left side and if its below the rating on the right, then switch it. It would appear that the internal fuse has blown.

RWebb · RWebb's Garage

also if you have current flowing thru the meter, then there is a load connected, right?

javadog · 05-14-2008, 04:45 AM

yes.

JR

scott540 · scott540's Garage

Yeah, it looks like fuses blew. Thanks Guys. I would have thought the meter wouldn;t work at all if the fuses blew but I guess not. So after I replace the fuses, start on the left side (10A) with the red lead? I don't want to blow the fuses again

javadog · 05-14-2008, 06:30 AM

Start at 10A.

JR

IROC · IROC's Garage

FWIW, I recently went through this and with nothing on (except the clock) I saw about 4 mA of current flow.

If your multimeter has autoranging, you should be fine. The thing that blows ammeter fuses is typically connecting the ammeter in parallel. BTDT.

dshepp806 · dshepp806's Garage

QUOTE=scott540;3941442]Yeah, it looks like fuses blew. Thanks Guys. I would have thought the meter wouldn;t work at all if the fuses blew but I guess not. So after I replace the fuses, start on the left side (10A) with the red lead? I don't want to blow the fuses again[/QUOTE]

These fuses have nothing to do with the internal metering operation (display, etc.) Assuming the fuse was blown (with proper connections, that is), then it's a matter of exceeding the fuse rating,..bottom line. Now, if one were to hook it up in some misguided way, all bets are off. Anywaze,..you seem to "know" this.

"Looks like the fuses blew",..meaning you've removed and measured them?

Have you looked the alternator/reg check values? Don't want to get bitten by a bad charging system...just a thought,...and maybe not applicable in your case...? Howabout a battery load test? Just curious about hitting the drain measurement so quickly without commenting (did I miss it?) on battery integrity or ALT voltages when she IS running?.....respectfully preposed, I might add.

So,.............got the fuses changed yet?!?!?!?!?!

Best,

scott540 · scott540's Garage

Thanks Doyle, Heading to the store after work to get new fuses. Just to make sure I do this right - Positive probe of meter to the neg battery post and neg probe of meter to the neg battery cable? Don't want to blow fuses again. and they are blown I can see them .

I have a a big drain going on. Last night battery was at 12.6 after I charged it. This morning it was right at 12. Charged it up and now it's at 12.6. I checked with car running and at idle I have 14.0. Sound right?

RWebb · RWebb's Garage

you might hook a small 12 V DC light bulb in series with the load.

see how bright it glows.

if no glow, test again at night & look for orange filament...

911pcars · 05-14-2008, 03:01 PM

Quote:

Originally Posted by RWebb

you might hook a small 12 V DC light bulb in series with the load.

see how bright it glows.

if no glow, test again at night & look for orange filament...

Randy,
Not sure the objective of this connection?

Scott540
"I have a a big drain going on. Last night battery was at 12.6 after I charged it. This morning it was right at 12. Charged it up and now it's at 12.6. I checked with car running and at idle I have 14.0. Sound right?"

Charging systems sound normal. Battery sounds normal. Current drain isn't.

Sherwood