Multimeter usage

[8v-of-fury]

Forgive my ignorance/stupidity/lack of knowledge.

I had a dead battery this morning after the car had sat for 32 hours without being touched.. Prior to parking it was a fair drive so the battery was fully charged..

Anyhow, I clearly have a drain.. And I need to figure out where. If I set it to DC amps and put it in line between the postive terminal and the positive battery cable it will show me how much key off drain I have correct? And then I start pulling fuses one at a time until my drain is diminished then investigate that circuit yes?

Sorry brain is mush today..

Any other settings I can use to aid me in this??

[R.O.R-2.0]

turn off the rear window defroster..

my rabbit had a mysterious draw..

turned off the rear defroster, now its all good..

[8v-of-fury]

Its not on, but could be a source for the draw.. Any of the sources could be leaking a small bit of power here and there unfortunately..

[8v-of-fury]

So I got it figured out.. effin aftermarket tach was drawing 0.04a which apparently is enough to kill a battery so it wont start a diesel..

Battery still tests at 12.34v fully charged.

[ORCoaster]

Was the tach running off a keyed ignition circuit?  Or just wired to the positive side of the battery, no switch? 

Good diagnostic think, even with brain of mush.

[8v-of-fury]

It was wired in to the original stereo power wire. a.k.a 12v constant.. Been fine for the last 5 years! but this is the first year its been a diesel and the tach has been disconnected from the coil since i swapped to diesel.

Needless to say I have 0.00a draw now.. which might be alarming.. Does the analog clock in the dash and the memory for my aftermarket stereo not have a draw?? :O

[maxfax]

They do have a draw, but it's very minimal, fraction of an amp most of the time..  Even my fancy overpriced amp meter can't usually pick that up..

BTW, a car battery should charge up to 12.6v  (6 cells 2.1 volts per cell)  I wouldn't go worrying about it at 12.3 though.. 

[nathan_b]

vw alts seem to like to fail AT 12.5v .. just enough to keep the batt light off and keep the car/lights going, but not enough to charge the batttery, check the voltage at battery when running, loaded with fans/lights on. My bet is it ain't 14v, and your brushes are worn.

[8v-of-fury]

Yeah this battery is old. Its at least 5 years old, (length of time I saw it in the previous vehicle before I acquired it) and a reman at that. It used to be one of two to fire up a 7.3 International, and now it fires my 1.6 Kraut.

Its like 1050cca (32f) which is like 350 more amps than needed for my application I think. Lol

Engine turned like a low compression jeep this morning.. Lmao nananananananananan (not that many na's it fired first nana, but it was sre turning fast! Lol) 

[8v-of-fury]

Nathan I'll try that on my lunch today. I'll give it 100% load . Two 90w lows, two 100w highs, two 55w fogs, fan and rear defog. Should pretty much max out the 65amps lol. 39a in just lighting alone!

[8v-of-fury]

14.10v running with nothing on after 10 minutes driving around. Battery obviously fully charged.

Turn it all on. Lows, highs, fogs, cabin fan on full, and the rad fan on (I have it manually switched), still pulled an impressive 13.26V.

I have a healthy alternator

[R.O.R-2.0]

14.10v running with nothing on after 10 minutes driving around. Battery obviously fully charged.

Turn it all on. Lows, highs, fogs, cabin fan on full, and the rad fan on (I have it manually switched), still pulled an impressive 13.26V.

I have a healthy alternator

ill second that 

[8v-of-fury]

It was a reman Bosch that came with a wrecked golf I bought in 08. I didn't even know if it worked when I swapped it in lol.

Even made up a bracket to raise it up near the pump so it could have more wrap on the water pump pulley.

[mtrans]

14.10v running with nothing on after 10 minutes driving around. Battery obviously fully charged.
Turn it all on. Lows, highs, fogs, cabin fan on full, and the rad fan on (I have it manually switched), still pulled an impressive 13.26V.
I have a healthy alternator

Alternator is OK you need battery,simple chek WHILE engine run put SOME LOAD aka lights and pull off + from bat.If cantinue to work than alt is OK,this tested on older alt.

[8v-of-fury]

I could hear the rpm's drop each time I turned on one of the electrical components. I will give it a try though anyway didn't think of this test at all..