markeldeiry

Ok, some of you might have been reading my posts from this past week but most probably have not. Here is the only relevant fact right now...

I took the ground wire off my negative terminal so I could put a multimeter in series with my circuit and test for a parasitic draw. When I did, I got 1.4A with the leads one way. For some reason I switched the leads around to see what would happen and I got -2.8A.

This made no sense to me but for some reason it made me test for voltage between the negative and the ground - I got 12.4V!

From Positive to Negative (regular battery test) I get 12.4V (yes, a bit weak but that is why I was doing the test - I am convinced something is draining my battery way too fast).

From positive to ground - ZERO!

I guess that means my positive battery cable is grounding out somewhere on the chassis, right?

Anyone have any thoughts on how to test to find where the short is? What's the best way to do it and is there a way to save time in the process?

Thanks.

Nopike

iTrader: (2)

Once you connect the negative terminal of the battery to ground you will measure zero volts between the negative terminal and all grounds. What you measure with the negative terminal of the battery removed is not relevant.

Unlikely that the positive battery cable is grounding out somewhere on the chassis because you would probably blow a fuse or start a fire.

Connect the negative terminal as normal. Remove the positive terminal of the battery . Check the current draw by putting your meter between the positive terminal and the lead that goes to that terminal.

Check out this thread it may help you find your battery drain issue. http://forums.maxima.org/4th-generat...rain-help.html It is for a 4th Gen drain problem but I would expect the 5th Gen to measure in a similar manner. The basic design of the electrical circuits remains the same. I have not had time to check but my guess is The 5th gen requires sleep mode just like the 4th.

CMax03

iTrader: (3)

Polarity is important when measuring current (Amps) so you're just confusing the VOM! as for there being voltage between the negative lead (disconnected) and the Negative post thats correct! Your VOM is completing the circuit and it's really in parallel! If you disconnect the (+) Positive lead and measure between the (-) negative lead and the (-) negative battery post you will find no potential (voltage)...It's not magic just basic electricity!

markeldeiry

I was doing this same thing but with the negative terminal. The meter was between the negative terminal and the lead that goes to that terminal. Why would that give a different draw than the positive terminal and positive lead? Or a different voltage for that matter?

It is simply a matter of preference and it is a bit safer from the stand point of the battery because if you touch a ground with the negative terminal, it makes no difference.

I will check out that parasitic draw guide though. Thanks for the help!

Amerikaner83

iTrader: (17)

Think about it like a dollar. You have a dollar to start (positive terminal) and then along the course of getting to the end (negative terminal) you have nothing. If you're measuring how fast the dollar goes away, you don't measure from the point at the end. you measure from the beginning to get the rate of flow.

^^ it's oversimplified there but it should explain why you need to take the POSITIVE cable off.
I get that it's a matter of preference, but you're doing it wrong.

You shouldn't have trouble with this...seriously. Just take the positive cable off, keep it up in the air away from the grounds or anything, super easy, and take your meter and use the meter (set to Amps) to complete the path between cable and positive battery terminal.

Nopike

iTrader: (2)

True it does not matter which terminal you use. I would tend to use the positive. That way you would not be wondering why you are measuring 12vdc between the negative terminal and ground :-)

Polarity, how you place your meter leads, does not matter when measuring current. You should have the same amount of current flow in either direction. The meter itself should only measure current flow and not effect how much of it occurs. Regardless of how you place your leads.

What good would a meter be for measuring current flow through a circuit if the meter itself caused the value to change.

Matt93SE

iTrader: (44)

Sorry dude, that's completely wrong when you're measuring current draw. If you were worried about voltage drop, then that would be one way to do it.
But when you're measuring current, every electron that leaves the battery on the - terminal MUST go through the circuit and back in the + terminal.
Thus you will measure the same amperage anywhere in either the + or - lines.
No ifs and or buts. Physics don't change.

Nopike

iTrader: (2)

OP I only glanced over some of your other thread about this issue. I'm assuming your battery is getting discharged?

If you think a sensor is causing excessive current draw remove the fuse providing power to that sensor and see what it does to current draw.