Help with Electrical Measurements

[cpg]

I need a favor if anyone can measure the battery drain on there 80.

With the doors shut dome light switches turned off and key out of the ignition.

Disconnect negative battery cable and any wires.

Connect Multi Meter set to DC amps(I am using the 200m setting) in between negative terminal and ground cable.

Measures 23.10 milli amps

Disconnect Main Positive cable leave fusible link connected.

Measures 20.3 mlli amps

Pull ECU B Fuse (fuse box under steering wheel)

Measures 17.3 milli amps

Pull Dome light fuse

Measures 5.1 milli amps

Thank you





On some 80's the door switches are not totally turning off the dome lights.
Lights dont light up but the is a larger draw. Usually it is the rubber wearing thin. You can test by pushing the button in by hand and see if you get a different draw reading.

 

[cpg]

Any one?

 

[Rookie2]

Well I tried to give it a go, but may have blown the fuse in my multimeter. It started to read but then went to zero. I'll take a look at the fuse tomorrow, but not too sure why it would have done that. I'm still an amatuer on this circuit read stuff. Sorry.

 

[cpg]

Thanks for trying!!
You probally did blow a fuse. Did you have the door open or anything on?

 

[Rookie2]

Thanks for trying!!
You probally did blow a fuse. Did you have the door open or anything on?

Yeh, the fuse was blown. The door was closed, key out of the ignition and nothing on that I'm aware of. When I put the ground cable back on the battery terminal, I could here the 6 disc CD changer shufflling through the stack so I guess it pulls some current. The fuse that blew was 315 mA. I put another one in. Any other ideas?


Rookie2

 

[Rookie2]

Okay cpg:

I replaced the fuse and went at it again. Thought... the only thing that is not factory is my amp so I pulled the fuse to it and checked the readings again. The multimeter fuse didn't blow this time .

With negative terminal unhooked, I got two different readings on subsequent tries. The first time (on the 200m setting) I got 0.1. The second time I got 3.6 and I could hear the 6 disc changer cycling through the stack. Tries after that continued to give 0.1.

Next I disconnected the positive cable and got 3.6 (with disc changer cycling) both times.

With ECU-B fuse pulled 0.1

With dome light fuse pulled 0.1

Quite a bit different numbers than you're pulling. What do you think?


Rookie2

 

[cpg]

HI Rookie,
The .1 means you areo out of range or your fuse blew again. Seems like your stereo is sucking some juice. Can you disconnect or pull the fuse to it?
If you are out of range with the fuse not blown I would assume your battery would be draining fairly fast. Has this been a problem after the car has sat for a while?

 

[Rookie2]

Hmm..., haven't had any problem with the battery draining, but the most it's set is 4 or 5 days without driving. So it's not possible that the reading could be that low? I removed the fuse to the radio (which stops the CD player from suffling through) but now the reading is 00.0. When I put it back in, I get the player shuffling again and 3.6 on the multimeter.

As a further note, when I am getting the 00.1 reading, it first starts at 00.2 or 00.3 but settles at 00.1.

Oh... and checked multimeter fuse, and fuse is still good.

 

[cpg]

Is your positive and negative disconnected? Or just the positive?
Does your 200m setting have 00.0 and your 2 setting .000 ?
What kind of meter?
Thank you

 

[Rookie2]

Is your positive and negative disconnected? Or just the positive?
Does your 200m setting have 00.0 and your 2 setting .000 ?
What kind of meter?
Thank you

Just the negative (black) cable was disconnected.

It has a 200 m setting that 00.0 shows up in the display to start, and then a 20 m setting that shows 0.00, then two other settings.. a 200u and 2000u.

It's an Actron digital multimeter(CP7672).


Rookie2

 

[cpg]

Is your battery still diconnected?
If so you can try and test with all the fuses in and open the drivers door and see what your reading is. Do this with the dome light switches turned off.
Did you try your 20m setting? At the 20m setting mine will go to 1 (out of range). Your numbers 00.1 at the 200m setting does not seem right.
I am seeing out of 10 96 and up vehicles 14.1 to 53.1.
Your clock would pull more than 00.1. I looked up your meter but cant decifier from the photos. Maybe are scales are mixed up. I am not sure what the 200m setting is I believe it will read up to 200 milli amps. But then you would think that the reading would be 000.0 not 00.0 l

 

[cpg]

I just found this. I have a BK type and you have a CEM type.
Where is your red lead it should be in the VWma.

There are two differen types of multimeter in use in our labs but their operation is (basically) the same and the main practical difference is in plugging in the leads. One meter type is by CEM and the other by BK Precision. Lean Connection as follows: CEM Type:
Or
Black Lead always in COM(mon) socket.
Red Lead (almost) always in VWmA (volt ohms milliamps) socket.
Red Lead in 10A socket only if the current is expected to be very large (like Amps).
BK Type:
Or
Or
Black Lead always in the COM(mon) socket.
Red Lead in the VW (volt ohms) socket to measure volts and resistance.
Red Lead in the mA (milliamp) socket to measure small currents.
Red Lead in the 10A socket only if current is expected to be very large (like Amps).


To measure a current you must break the circuit and connect the meter leads across the break so that the current flows through the meter. To set the meter to measure DC current rotate the single control knob to the DCA segment (or the A segment on the BK type) and select a number in that segment which corresponds roughly to the current you anticipate. A setting of DCA 200m means that the meter is set to measure a maximum of 200 milliamps. If the reading on the meter when is use is 77 then this means that the current is 77 miliamps. A meter setting of DCA 200µ means that the meter is set to measure a maximum of 200 microamps. If the reading on the meter when in use is 77 then this means that the current is 77 microamps.

To measure a voltage across a circuit component you must connect the two leads across that component. Set the control knob to the DCV section (V--on the BK type) to measure DC volts. Choose a setting in this section to correspond to approximately the voltage you expect. A setting of 20 on the DCV means the meter is set to read a maximum of 20 volts. A setting of 200m on DCV means the meter is set to read a maximum of 200 milivolts.

When measuring voltage the red lead is supposed to be connected to the positive side of a component (e.g. the positive side of a battery) and the black to the negative side. If you have connected it the wrong way round then the meter reading will have a negative sign in front of the digits. This does not harm the meter and just means you have the connections the wrong way round. If you wish you can change them. Alternatively just remember that with the negative sign this means the red connection is in fact connected to the negative side of the object and the black connection is connected to the positive side.

When measuring current the red lead is supposed to be connected to the point where current enters the meter and the black lead to the point where it exits the meter. If the reading on the meter has no sign in front of it then this means you have connected it the right way and you can determine the direction of current flow. If there is a negative sign in front of the digits it means the meter is connected up the wrong way round. You can either reverse the connections of the leads or else just remember that the red side is in fact connected to the point where the current exits (and the black to the point where it enters).

These meters can also be used to measure resistance of a resistor. Connect the leads to the object whose resistance you wish to measure and rotate the control knob to an appropriate part of the circular scale. The meter automatically provides a voltage across its two leads and measures the current which flows and calculates the resistance of the resistor.

There are other scales on this meter which will not be used in this lab.

Sometimes you will find that the reading of the meter changes in the last digit while you are measuring something which you had expected to be constant. This is because in real circuits there are slight fluctuations in current flow and voltage due to thermal effects at connections. It is not a fault in the meter. If the meter is changing then the best you can do is to take the average value of the reading and use the variation in the reading as a measure of accuracy. For example if the meter is set to measure DCA 200 m and the reading is changing between 75.5 and 75.6 then the best you can say is that the current is 75.55 mA with an accuracy of +/- 0.05 mA.

If the desplay shows the word "BAT" then this means the bettery is going flat; bring this to the attention of the TA who will have it fixed. If, when attempting to measure surrent, you get no reading at all then it is possible that the internal fuse has "blown"; bring this to the attention of the TA who will have it fixed.

 

[Rookie2]

Okay, with the neg cable disconnected, and door open, dome light turn to off, I'm getting 10.8 door closed 3.8. both versions the cd player starters shuffling through the disc once I put touch the leads like before.

 

[cpg]

Okay that sounds good. So the truch is stock with a after market stereo?
You have a much lower draw than I do. 23. 1 door closed. I tested a 94 80 and it was 27.0 yours seems super low. Maybe someone else will post up.

Thank you

 

[RavenTai]

unfortunately my meter (11 year old FLuke 73 series 2) does not have a miliamp scale so it is not as sensitive in this range, bouncing between 0.01 and 0.00 is not a good resolution for this level of current, but from what I can tell mine lines up closely to what you get.

be ware of just turning the dome light off, the doors will still light with the door open and dome off, also the warning light on the cluster

Dome 0.01A
Haz/Horn 0.01 to 0.02
ECUB 0.01 to 0.00
Radio 0.01 to 0.00 (0.35 when first hooked up as OEM cd changer goes through its motions)

All together 0.02 to 0.03 amps witch is really close really close to your 0.0231 amps reading considering the scale difference.


The clock gets its power from the dome fuse so that explains that draw

The alarm gets it power from the haz/horn fuse, that explains that draw

The ECU B powers a lot of boxes, SRS, ABS, light retainer relay, data link connector, cruise control, combination meter, automatic AC amp (LX only) not sure witch of those is the one drawing the current but it seams a reasonable amount.

the radio has a draw though I am not sure why, this radio (LX OEM) does not have any volatile memory that would need maintenance that I am aware of, although it does have that theft lock thing that knows when it is disconnected form power maybe it draws power to preform this function?

 

[cpg]

Hey Raven do you have a lifeline battey installed?
If so what voltage is it after sitting at night after a drive long enough to charge it?

 

[RavenTai]

Hey Raven do you have a lifeline battey installed?
If so what voltage is it after sitting at night after a drive long enough to charge it?

yes two,

I have been watching charging voltage more than batt voltage, but anywhere from low 12's to high 12's depending on how my alternator was acting on the previous drive.


BTW, when I went into town after pulling the fuses my AC forgot what the previos button positons were and the Antenna forgot where it should be, so there are two volitile memory sources of current draw that explain the Radio and ECU B fuses

 

[cpg]

Watching my voltage while charging I get 14.8 to 13.2 .
After starting 14.5 then settles to 13.5.
My Lifeline Group 27 should be at 12.8 after a long drive but I only get 12.6
I think it is not working proberly.

 

[RavenTai]

shoulednt charging voltage stay in the lower 14's?

that could account for the .2v lower than expected, ever any starting problems?

 

[cpg]

It does until it is charged then drops down below 14v. My battery will be at 12.8
then over night will drop to 12.6. I thought it was parasitic current draw but with the battery disconected it is still losing some voltage. They are going send another battery and check this one out. I tried the equalizing charge also.
Thats why i was wondering what your voltage was reading after a full charge and the float charge was removed. Should be 12.8 and I get 12.6 then goes down hill from there. I have a digital volt meter that is switched and can monitor while driving seems like the alternator is working fine.

3 Stage Chargers
Bulk 14.2 – 14.4 volts
Acceptance 14.2 –14.4 volts
Float 13.2 – 13.3 volts


2 Stage Charger
Bulk 14.2 – 14.4 volts
Float 13.2 – 13.3 volts


Single Stage Charger
Bulk 14.2 – 14.4 volts
Once the battery is fully charged, remove it from charger.
________________________________________
Battery Equalizing and Deep Discharge Conditioning

Charge:
Charge with voltage-regulated (Constant voltage) charger.

Charge1 @ 15.5 volts for 8 hours.

100% SOC 12.80 volts or greater
75% SOC 12.55 volts
50% SOC 12.20 volts
25% SOC 11.75 volts
0% SOC 10.50 volts