JustJeff

iTrader: (13)

I've been fighting electrical gremlins and am ready to take it to a shop. What I've read and seen says anything lower than 40mA is acceptable. I read someone else's thread (linked by Satch on a related thread) getting advice that lower than 20mA is acceptable. I have a draw of 5mA, but a battery that will die rather quickly. A friend and repair shop owner says that my 5mA is a concern and that acceptable is 1mA.

I've pulled all the fuses at the kick panel while my meter was in series with the negative battery terminal and have not seen the 5mA come down at all. I've previously pulled all but the engine fuse off the main fuse box and seen no change in my amp draw. IIRC I've disconnected my alternator and seen no change in my amp draw. Tomorrow after work I plan on disconnecting the alternator again just to make sure my memory serves me correctly.

Possibly related, the last time I drove the car I restarted the engine after a brief stop and watched my AEM boost gauge climb to 5psi and sit there at idle. As I was driving it rose higher and higher sporadically until it now sits somewhere around 15psi at idle. The gauge rises and goes into vacuum as I drive, but every time I start up the engine it's at around 15psi at idle. I'll have to look at my wiring again, but IIRC I have some common grounds for a total of 4 aftermarket gauges (AEM analog boost, Innovate wideband, Prosport water and oil temp gauges). All the others seem to be working fine.

DC5Daniel

iTrader: (10)

Your friend at the repair shop is most likely a mechanic, someone who is generally terrified of and confused by anything electric. I'm a certified professional mobile electronics installer and nearing completion of my degree in electrical engineering, so I have confidence in saying he is wrong. 5mA is a spectacular parasitic draw. 20mA is a suitable number for a small car with a relatively small battery. 40mA would be acceptable for something massive like a Tahoe with a big battery. To put this all into perspective, the current draw from an active relay coil is 150-200mA. So if you had a draw anywhere near that, you'd have reason to believe a relay or some device was at fault.

A few questions:
- Are you confident your reading was taken in DC? Many multi-meters, including my $400 Fluke, default to AC current reading.
- Have you metered voltage both at idle and while driving? You could have a failing alternator not effectively charging.
- Have you inspected your battery ground cables? About 1ft down the harness where it splits via a factory crimp is a source of major corrosion which could be handicapping your charging system.
- Finally, have you had the battery load tested? It's within reason that the battery's useable life could be up. Have it tested.

AGreen

iTrader: (11)

To add to that, try charging the battery, then load test it. Let it sit for a day disconnected, then load test it again. An internal short from aged batteries is common, and can lead to a battery dying quickly... even without any load connected. I've also seen relatively new batteries get internal shorts due to deep discharges, followed by recharging. Automotive batteries are generally not designed to completely discharge. They're designed to maintain a constant voltage, discharging a little bit only when necessary for starting or large current transients that the alternator cannot quickly respond to.

And he's right. Usually 20mA is the standard for parasitic draw.

JustJeff

iTrader: (13)

• Battery is a new Optima Yellow. I got it a month or two ago.
• I've replaced factory grounds and cleaned the ground points. IIRC I have 4ga on top of the engine keg to the firewall, 4ga from battery terminal to OEM location on driver shocktower and then to starter through bolt. Though it could be 4ga straight to the through bolt on the starter.
• The alternator is a S5 modded up to 130A. I've suspected the alternator and had it tested at an alternator shop. Its good to 128A
• I have not metered voltage at idle and driving. I do have the OEM volt meter which for the most part shows that the alternator is charging at 14V. Though I can drive the car to my first stop, come out and start up the car and the OEM volt meter will be barely nudging 12V at idle. It doesn't happen every time, but it's sporadically it happens.
• Also there is definitely a drain on the battery. The last day the OEM volt meter showed barely 12v at idle it slowly rose and by the time I got out of the parking lot and on the street it was nearly 14v. I decide to stop for another errand but check voltage on the battery before going it. I don't remember the exact reading but it was 12.something. I'm in the store for a half hour and check it again before leaving and it had dropped something like .2-.3 or so volts. I disconnect the negative battery terminal every time I turn the engine off. If it sits over night battery will drain significantly.

Here is a link I created previously wondering about my wiring. I probably should have put the question in that same thread but my thinking was that amp draw was my specific question and to help others searching on the forum I'd create a thread title for the specific question.
https://www.rx7club.com/2nd-generati...blems-1042517/

lastphaseofthis

iTrader: (8)

shooting for .050 amps, or 50 mAh is the level of acceptable draw. most cars go as low as .011 to .005 but even a new bmw with 40+ computers doesn't draw over .050

JustJeff

iTrader: (13)

Seems that the most critical of the electrical is sorted out. The shop that sold me the modded alternator replaced it at no charge. Yesterday I got my pulley back from powder coating and put the alternator on. No amp draw over night!

I still have something curious with my AEM boost gauge. It every so often spikes as if it's getting too much voltage. It's currently idling at 10psi. I imagine it's the ground and I'll look at it on a warmer day.