Testing For Current Drain That Runs Down Car Battery

[paulhunter123]

this is a simple trick thats saves so much time and money

[UFGatorGuy20]

When I did this, my meter read .52 Amps for about 2 seconds, then went to 0 Amps after 2-3 more seconds. I pulled the meter leads off, and it read 0 Amps. I reconnected the battery and retested and it again read .51 Amps for about 2 seconds, then went down to 0 Amps. Do I have current drain occurring or is this some residual effect? Car was off for about 30 minutes. Voltage read 12.76V when I first shut it off, then 12.68V about 30 minutes later.

[billpage]

cool

[mynamesmitchel]

Well my car sparks when i hook up the terminals, so i know its leaking. how do find out where?

[TheHortond]

I have the same problem with my 66 mustang. I found that the fancy radio that I installed was draining the battery and after 3 days it was dead as a doornail. I didn't use a multimeter to test the drain (even though I have several) I simple removed the plus side of the battery and when I touched it back the to the post I would see a small spark letting me know it was draining power. I unplugged the harness from the back of my radio and tried it again and no spark. It drains it in winter.

[SSUNBRN]

Can someone please tell me what specific setting I should be using on my multimeter. I have two different meters with multiple settings and 3 different connections for the leads. Please take a look here for a front facing picture of my meters:

ls1tech.com/forums/15309372-po­st9.html

Thanks!

[airlocktechnics]

@SSUNBRN Black lead goes in the COM. If you are measuring current like this guy then you are doing so in SERIES, put the red probe in the A (amps) port on the multimeter(not your bum as others have mentioned). set multimeter to 200m on the A (DC) portion of your multimeter.

You can measure voltage drop, like across a car fuse, in PARALLEL put red in the V (DC) port and set dial to V(DC) usually 20 or less depending on what the circuit is capable of.

[MrMooseful]

Oh man, had I known this trick it would have saved me a ton of BS from the local garage... Thanks for posting thi.

But small question, do you actually keep your bare fingers on the metal of the probes? Didn't that... shock you?

[ifitjams]

@MrMooseful

You can lick your fingers and put them on the battery, it still won't shock you. It's just 12 Volts.

Morris

[EvokeDawn]

@ifitjams 12 volts is not anywhere near enough to shock you, it takes roughly 4k-6k volts to shock you lucky us haha

[MagicAyrtonforever]

@MrMooseful yeah, I also pull my own teeth out.. much cheaper than going to the dentist...

[CheffreyGriffin]

@MagicAyrtonforever if you think testing current drain is on the same level as dentistry, you should never come in contact with a motor vehicle.

[eurokid83]

@Oppland29 Hahaha, exactly what I was thinking. CRAP!

[Tokopol]

@azrial4421 I think you should purchase some time with a good psychiatrist.

[MAIMPORT]

Please I am need to know, if you buy battery from some 1 how can u tell if it is been used or brand new using an electric multimeter?

For example if some one sold me a battery he used it for 1 year already,

if I test it it will give me the same voltage & everything,

But

when I use it I will find out that it does not hold charge for more than couple of hours

So how can I test it since beginning if it has been consumed or not?

Very important

I would appreciate if you can help me out

Thanks a lot

[HumanityWins]

whre did you stick the negative probe?

[schoolboycc]

Parasitic loads should be measured using an inductive pickup and DVOM because taking the cable off the post could "reset" the draw or disable it (ie sticky relay) in which case it will disappear and you won't be able to find it. Also, you should be doing this on the negative side of the battery to alleviate voltage spikes on the positive side which could damage ECM's and modules. Also, test lights do not work between post and cable. Hope this helps.

[Northropfam]

@schoolboycc That's not entirely true about using an inductive pickup. You can use a DVOM and not break the circuit I do it all the time. You loosen the terminal without taking it off then you put the test lead on the battery post and attach the other lead to the terminal and just slide the terminal straight up over the lead. The circuit never breaks but now you can measure the amps with the meter.

[imallpissedoff]

AAAHH !!

He's using a Harbor Freight meter and he's about to touch live terminals !

RRUUUNNN !!

[vlupywwr]

Max recommanded drainage after like 30 min with the ampermeter plugged for the car to pass into the sleep mode, is supposed to be maximum 0.03 Amp or 30 milliAmp !

[heyscuba]

where's the part about pulling the fuses,...? this guy (for the video's purpose) knows where the drain is,... the dome light, but if you don't know whats causing the drain (this would be why you're doing this) after you hook up the meter and see the drain you start pulling fuses and checking the meter, when the drain goes away, you've found where the problem is starting, check the chart for what that fuse controls and now you know where to focus you attention too,...

[spelunkerd]

The big problem with using an ammeter is the fact that during a short you may have high enough amperage to blow the fuse on your meter. I like the voltage drop test across a small resistor in series, since even high amperage is safely quantifiable without damaging your meter. Or, you could put a continuity tester in series with either pole of the battery and then start pulling fuses.

[jmholcomb1]

@gtuani

when testing amperage, you connect ammeter in SERIES. when testing voltage, connect voltmeter in PARALLEL. so to check amperage of the parasitic load, you would disconnect the positive battery terminal (or negative) from the battery post and then connect ammeter in SERIES. one lead to terminal, one lead to battery post. simple. if you get a negative reading, either swap the leads or erase the negative from the number.

[5191228]

Nick leckie is gay

[FahimMotoGP]

Thanks buddy, easy check up no one should have trouble with. Keep it up

[gtuani]

i dont get it. the ohm positive terminal to the positive post? and then negative ohm terminal to the positive terminal cable?

[ifitjams]

@gtuani

Not measuring Ohms, measuring Amps.

[gtuani]

@ifitjams

OH YEAH I mean Amps, sorry. can you tell me exactly how the conection is? cuz i didnt get it. remove the positive battery terminal? then???....

[tikafabulous]

something is drain my van. the alarm goes off at least 3 times a week when I try to unlock it. and the radio does not work although it is still connected...could those be a prob?

[sobolanudepeperete]

i did this thing and it says 0.04-0.05 is this ok?

[nOTMRNICEANYMORe]

In that case my car battery should be changes

[JAZZSTARish]

I have an 88 jetta was a fuel injection changed to carb..it has a new starter..and the solenoid is new (mounted on fender close by the firewall) now it doesn't start when just driving for a few blocks..and I just hear a strong clicking noise from the solenoid..and I have to jump start it..now when I start the car and remove the pos. cable it doesn't stall or idol. When I remove the positive cable..the RPM needle sways all the way back and forth really fast..is there a short. Thanx.

[bkdkley]

Exactly what I was looking for.  Thanks,

[foxized]

Me too. Thanks for the video OP

[5thwheelsandgrills]

u forgot to mention what setting to put the metter on dummy

[jussipejulliano]

When my car is about to start,  at morning basically....

It gives hammering sounds. Today. I cleaned up the terminals and tried to start. But with luck it started with some hammering sounds.

Is this the same battery problem?

Once the car starts, it runs easily all day. But only at morning ='((

pls help me. thX =)

[MarkKlarrk]

Very good video it helped me out on my hands on test, because I did forget the process. So thanks

[dagreenone00]

Hi I have an 800w continous 12v to 120v power inverter which I connect to my good old 2000 chevy cavalier or my 98 gmc sonoma's battery with the included battery clamps. Each has a new battery. If I have my car parked running with all accesories off with a continuous load of say 600w on the 120v side, would i be straining my alternator or my battery? Thanks.

[jheetman]

890 milliamps would discharge a typical battery in a couple of hours

[ifitjams]

J,

Don't remember the TV commercials leaving the headlights on parked on a glacier overnight ? (DieHard).

890 miliamps won't kill a healthy battery in hours. Some cars with alarm systems and lots of computing power draw of 250 milliamps as a normal thing.

Even cheapo car batteries with an amp hour rating less than 45 will carry a draw over 2 amps for a day before dropping below cranking voltage. At a  draw under one amp, a decent battery will hold up much longer.

Morris

[jheetman]

i'm not trying to be argumentative, but i was always told that anything over 80mA was not acceptable. i know that most batteries can handle 100-120mA if they are run every day, but i've seen on multiple occasions that same 100-120 draw cause a slow or no crank after 2-3 days of not running. granted not all batteries are created equal, but thats what they taught us in tech school was 80 or so mA for a limit. has the ante been upped with newer stronger batteries?

[JAZZSTARish]

@jheetman I have an 88 jetta was a fuel injection changed to carb..it has a new starter..and the solenoid is new (mounted on fender close by the firewall) now it doesn't start when just driving for a few blocks..and I just hear a strong clicking noise from the solenoid..and I have to jump start it..now when I start the car and remove the pos. cable it doesn't stall or idol. When I remove the positive cable..the RPM needle sways all the way back and forth really fast..is there a short. Thanx

[JAZZSTARish]

@ifitjams I have an 88 jetta was a fuel injection changed to carb..it has a new starter..and the solenoid is new (mounted on fender close by the firewall) now it doesn't start when just driving for a few blocks..and I just hear a strong clicking noise from the solenoid..and I have to jump start it..now when I start the car and remove the pos. cable it doesn't stall or idol. When I remove the positive cable..the RPM needle sways all the way back and forth really fast..is there a short. Thanx

[JAZZSTARish]

@jheetman I have an 88 jetta was a fuel injection changed to carb..it has a new starter..and the solenoid is new (mounted on fender close by the firewall) now it doesn't start when just driving for a few blocks..and I just hear a strong clicking noise from the solenoid..and I have to jump start it..now when I start the car and remove the pos. cable it doesn't stall or idol. When I remove the positive cable..the RPM needle sways all the way back and forth really fast..is there a short. Thanx

[8320884]

i want to put a second battery on my suv cause i have alot of bass can u help me out. If i connect my amplifier straight to the second battery how long until it drains if i have the bass up loud?

[zagan1]

You get yourself in isolator, hook up the main batt to isolator then second (deep cycle) batt to the isolator the isolator starts open (charges main batt) then closes once main batt is charged then second batt gets charged up.

[ifitjams]

Afgan,

Max output depends on the maker, I don't think anybody specifies an idle rating, depends on RPM, at least for the average (RMS) current, which is always changing.

Morris

[AfghanKnight007]

Hi how many amps does an alternator out puts at idle. thankyou