How to use a multimeter?

[NGOT8R]

How would I do that test I just disconnect the battery while the cars running and see if the alternator can keep it running?

Yes. You can remove the negative cable and make sure it doesn’t touch anything and the engine should continue to run.

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[AnthonyA1234]

Yes. You can remove the negative cable and make sure it doesn’t touch anything and the engine should continue to run.

I assume I should only do this really quickly right

 

[NGOT8R]

I assume I should only do this really quickly right

No need to hurry. Let the car run For 30-45 seconds or so with the negative cable removed., then turn the engine off, reinstall the cable, check battery voltage with multimeter and then go for your test drive (keeping RPMs up by staying in 3rd and 4th gear). Come back and check battery voltage with multimeter.

 

[AnthonyA1234]

Will do thanks for all the help

 

[NGOT8R]

Will do thanks for all the help

Yessir! Let me know how everything worked out after testing is complete.

 

[Elp_jc]

How would I do that test I just disconnect the battery while the cars running and see if the alternator can keep it running?

NEVER DO THAT; you can fry sensitive electronic components on modern cars. We don't live in the 80s anymore, folks. You can measure the voltage with the battery connected, to check if alternator is working. Remember our cars have BMS (battery management system), which varies the voltage from 12.0 to 14.5V, I believe. I'm afraid Ford programmed it more to save fuel than to keep the battery healthy. My car also shows 12.0V most of the time, but my battery is always fully charged. I keep a charger connected because it discharges way more than normal, for some reason, and nothing is on. So decided to leave it connected all the time (Optimate6 here).

 

[WildHorse]

You guys realize these cars use Fords 'smart charging' right ?

 

[lew]

You don't want to unhook your battery while the engine is running. It upsets all the electronic sensors. If you think you have a current draw when the engine is turned off you can check this safely. With the engine ignition off and no inside lights/accessories on. Remove the negative wire from the battery and place your muti-meter between the negative post of the battery and the positive to the end of the battery wire. This puts the meter in series and will measure any current flow through ground as the car sits off. You will have to set your meter on milliamps as there should be virtually 0 current. If there is it is referred to as Parasitic Draw. Most modern electronic systems allow for certain amount of PD to supply ready systems. The current draw allowed for these systems is very small in the milliamps. A service manual will have have the allowable draw levels for variuos stages of usuage. If you read more than a couple of milli's then you possibly have something causing this. Could be some faulty equipment or wiring or perhaps something not compatible with any electronic additions you may have made.

 

[AnthonyA1234]

You guys realize these cars use Fords 'smart charging' right ?

So do my readings of 12 volts fall within this?

 

[WildHorse]

Not sure of the thresholds but it'll charge, then stop, charge, stop, etc., etc.

 

[Rapid Red]

Yes. You can remove the negative cable and make sure it doesn’t touch anything and the engine should continue to run.

Negative not with these cars, different animals they are.

 

[Dr. Norts]

I assume I should only do this really quickly right

No you should not do this at all, this is terrible advice.

You can see if there is a phantom load with the car turned off.

Disconnect your positive terminal of the battery and hook your meter up in series between the positive battery cable and the positive post on the battery.

Set your meter to AMPS with the meter leads in the common(black) and 10A(red) current ports.

DON'T attempt to start the car with it hooked up like this.

 

[Mach VII]

You don't want to unhook your battery while the engine is running. It upsets all the electronic sensors. If you think you have a current draw when the engine is turned off you can check this safely. With the engine ignition off and no inside lights/accessories on. Remove the negative wire from the battery and place your muti-meter between the negative post of the battery and the positive to the end of the battery wire. This puts the meter in series and will measure any current flow through ground as the car sits off. You will have to set your meter on milliamps as there should be virtually 0 current. If there is it is referred to as Parasitic Draw. Most modern electronic systems allow for certain amount of PD to supply ready systems. The current draw allowed for these systems is very small in the milliamps. A service manual will have have the allowable draw levels for variuos stages of usuage. If you read more than a couple of milli's then you possibly have something causing this. Could be some faulty equipment or wiring or perhaps something not compatible with any electronic additions you may have made.

No you should not do this at all, this is terrible advice.

You can see if there is a phantom load with the car turned off.

Disconnect your positive terminal of the battery and hook your meter up in series between the positive battery cable and the positive post on the battery.

Set your meter to AMPS with the meter leads in the common(black) and 10A(red) current ports.

DON'T attempt to start the car with it hooked up like this.

I agree with all of this but recommend you always start on the highest setting on the multimeter (in this case Amps vs mAmps) so that you don't fry your meter. Switch to lower settings to get most accurate reading without exceeding selected range.

 

[AnthonyA1234]

No you should not do this at all, this is terrible advice.

You can see if there is a phantom load with the car turned off.

Disconnect your positive terminal of the battery and hook your meter up in series between the positive battery cable and the positive post on the battery.

Set your meter to AMPS with the meter leads in the common(black) and 10A(red) current ports.

DON'T attempt to start the car with it hooked up like this.

Ok will do can you give some more explanation on how I do this. What should the meter read how do I know if I have a draw?

 

[AnthonyA1234]

After doing some tests with my multimeter the battery read 12.59 volts when the car is off, 10.5 when cranking to start then it shoots up to 14, then it settles and idles at around 13.5. After turning on everything such as high beams, fog lights, radio at max volume, the voltage didn’t drop below 13. Everythinf looked good to me what do you guys think. I will be doing the parasitic draw test later today.

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