jjubert

iTrader: (2)

So I have an optima yellow top that has drained over night all the way to as low as 6 volts I have recharged the battery, and done a parasitic drain test showing a 2 amp draw present somewhere so I did the whole removing fuse by fuse to see if the amps would drop any but it remained the same.


After that, I removed the 12mm alternator nut, and tested it to see if there was any charge on it, and sure enough there was a 5 volt charge still present on the alternator even though it was disconnected....could that be the culprit?


So far I have recharged a completely dead battery 3 times, so I fear the battery might be ruined at this point, and it is only a few months old. I have researched and researched this issue over the weekend, and I am stuck, so any help on the subject matter would be greatly appreciated

DennisMik

iTrader: (2)

I assume it should be zero volts, but I have never removed the thick black wire and checked for voltage on the stud, so I really don't know. In order for that to happen, the voltage would have to come into the alternator from one of the wires in the little plug, go through the voltage regulator, into the rotor, somehow produce a changing magnetic field (remember we're talking about dc current) that is picked up by the stator and then goes through the diode rectifier to show up on that post.

There are 2 wires in the little plug on the alternator. The yellow/red stripe wire has 12 volts from fuse # 70 located in the fuse block by the battery. The brown wire should not have a voltage reading when the ignition switch is turned off.

Have you tried checking for the drain with all the wires disconnected from the alternator?

I doubt that the battery has been damaged, it has only been discharged a few times. It would probably have to happen hundreds of times to cause damage to the battery.

jjubert

iTrader: (2)

Thanks for chiming in, I disconnected both battery post and the alternator, and there is still a 5 volt charge there which has me baffled because there shouldn't be any current at this point right? I did switch my multimeter back to dc volts when I checked it too, I'm pretty mindful when going back and forth between amps and volts, being that i'm not an electronics expert, my paranoia keeps me from trying to fry anything

MaximaNoob1

It's an Optima, that's your problem hahaha (I had one and it sucked). Kidding aside, if you need to get a new battery, go with the Walmart branded one. I got one with 750CCA's for just under $100. Works fantastic.

DennisMik

iTrader: (2)

If you have all the wires (the thick wire and the plastic 2 wire connector) off the alternator, there is no way you can be getting a voltage reading. You somehow are not doing what you think you are doing.

Maybe your voltmeter is out of calibration and is displaying 5 millivolts and you are misinterpreting it. Get your voltmeter and set it for dc volts. If the meter is not an auto ranging meter, select the lowest voltage range and then touch the probes together. It should show zero.

jjubert

iTrader: (2)

https://maxima.org/g/picture/6033549


Here's a pic of what I mean, the voltmeter is set to dc volts, alternator is disconnected both the harness and 12V terminal, also both battery posts are disconnected....I have the voltmeter on the disconnected alternator 12V terminal(not the stud), and the ground on one of my engine block grounds and I'm getting voltage


And then this happened:




Now as I disconnected the clicking relays, the clicking would just shift to the next relay...Where's muh beer

DennisMik

iTrader: (2)

OK... You are measuring voltage in the car's wiring, not the alternator like I was thinking. That wire is connected directly to the battery and would always read whatever the battery voltage was. The amazing thing is that the battery is disconnected, so there should be no voltage.

So that means there is something else in the car that can supply voltage, something that is not put in by Nissan. Do you have a sound system with a high wattage subwoofer that uses big capacitors? Or something else like an ac/dc inverter? If so, disconnect the 12 volt wires that power those things and see what happens.

As for the relays clicking, I don't have any theories on that. What ever is causing the feedback is allowing the relays to try to energize, but the 6 volts is not sufficient to keep the relay energized and the relay drops out, then repeats over and over.

jjubert

iTrader: (2)

I found out where the parasitic drain was coming from, turns out my passenger side fog light was out due to corrosive wiring causing a short...got them cleaned and soldered, rechecked the amp draw and voila no more Hopefully this solves my battery drain issue, but i'll keep monitoring the voltage for now to make sure.


That alternator voltage present while disconnected could have been coming from the battery in my trunk I have on my amp, in the heat of things I forgot all about it...anyways thanks for the advice, dead on once again bro

DennisMik

iTrader: (2)

Good job finding that drain!

Fuse # 6 in the dash (labeled FR FOG LAMP) supplies the voltage for the fog lights, so could have overlooked pulling that fuse somehow? Or are the fog lights not factory?

jjubert

iTrader: (2)

I have aftermarket HIDs in the fogs. i pulled every fuse on multiple occasions to insure i wasn't missing any and still nothing showed up. I was even more particular about testing the fuses connect to the fog, head, and interior lights especially that passenger fog light being that it was out. the amps only dropped after the wires were cleaned and soldered by the shop that did them for me...only cost $35, so i'll take that over buying new battery or alternator any day.