chevrev

iTrader: (2)

I've got a boat load of accessories in my LS powered '56 Chevy...DVD, alarm system, a/c, power windows, door locks, antenna, speaker amp, electrically controlled air ride suspension manifold/switches, etc...

Complete new wiring harness throughout.

My battery goes dead after about 3-5 days of sitting (this is the 3rd new battery I've tried)

With my multi-meter on a 10A setting going from the negative battery terminal to the negative cable, I get a reading that fluctuates from 0.01 to 0.02 (initially the reading is at 0.18 for ~40 seconds, then drops to 0.01/0.02).

This is a pretty low (normal) amp draw, right? Shouldn't be enough to drain the battery in just a few days should it?

Any ideas what could be draining or killing the battery?

bczee

iTrader: (12)

Seem that you have a circult that is pretty active and causing the drain.. try the same as far as connecting the DVM.. then pull on fuse at a time and see if there is any drop or change in the reading of the DVM.

You might also disconnect the Alternator, Fans, Relay, etc (one at a time)... one of them could be bad.

You might also do a google search on "Finding car Battery Drain".. you will find many write up on different ways..


Good luck..

BC

chevrev

iTrader: (2)

Most tech articles I read say that if the static amp draw is less than .035 amps, then it is normal.

If my reading is between .01 and .02, I should be fine, right?

soundengineer

iTrader: (16)

I would make a guess at the alarm system...
aftermarket alarms with various options to detect possible theft(including various shock sensors) typically will drain your batter in under a week...
they are meant for cars being driven often.

Rocketrod

iTrader: (2)

You should be fine with those readings, but obviuosly something is wrong. There are a tons of videos on YouTube covering this topic, here is one that seems pretty good

chevrev

iTrader: (2)

Excellent video. But I am already below the recommended amp draw threshold, which is why this is so baffling to me. Could I just be unlucky enough to go through 3 bad batteries...they have all been everstart from Wallymart. Could there be something in the wiring that wouldn't show up in the amp draw test that could be ruining the batteries?

lizeec

iTrader: (57)

You are reading your voltmeter incorrectly, if you have a reading of 0.35 amps that is 350 milliamps and that is way more than the acceptable parasitic milliamp draw of 50 milliamps. Do you have a known good quality voltmeter? Take the advice given above and start pulling fuses to find the faulty circuit, and also check your alternator and any circuits that use relays.

chevrev

iTrader: (2)

I have been through the fuses but I should check my alternator. However, my readings are not .35. My readings are between .01 and .02 on the 10a setting. Tried two different multimeters and both give the same reading.

gofastwclass

iTrader: (2)

Like Lizeec said, do you have a known good quality multimeter? I personally have a Fluke brand (way overkill, but I purchased it for other reasons and also use it on my cars) and have noticed a significant difference between it's readings and the super cheap stuff some friends of mine have. For testing like this at a minimum, I would use something with a real brand name from Lowes, Home Depot or Radio Shack (or similar). You won't need to spend a ton on a digital multimeter, there are lots of options under $100 that will do fine. Since you tried two, probably isn't that, just an idea...

You mentioned a "boatload of aftermarket accessories," it may seem redundant but I would start there.

First that comes to mind is the air ride. Does your air ride system automatically raise or lower the car? Does the system have the ability to run the compressor with the engine off? If so is there a slow leak that may cause the pump to cycle long after you have stepped away?

Do have an aftermarket AC system and does it allow for "after blow" (what Cadillac calls it) which circulates air after the engine is off for hot days to drop the cabin temperature?

Is the alarm a proximity based system that is always searching for it's mate transmitter? Is this transmitter in range while the vehicle is parked?

Just throwing out some some ideas from experience, hope something helps. Good luck.

garys 68

iTrader: (1)

You're lucky, mine took weeks to kill the battery.
Pull half the fuses on the unswitched circuits to narrow it down (going dead with no key = unswitched circuit). One you narrow that down pull half again, or one at a time.
Btw, mine turned out to be the TCC/cruise control disengage switch that I wired to the brake light circuit. It's part of the brake switch, so it seemed like a good idea at the time.

lizeec

iTrader: (57)

If you are getting .01 & .02 on the 10a meter setting, that means you are still getting a parasitic amp draw of between 100 & 200 milliamp draw which is still high. Need to pull fuses and isolate the circuit at fault.

chevrev

iTrader: (2)

I'm confused (not entirely uncommon for me). I thought that .01a would equate to 10ma?

lizeec

iTrader: (57)

I stand corrected, you are correct a reading of 0.01 on a 10a scale equals 10 milliamps sorry about the confusion, it doesnt make sense there is no way a known good battery can go dead in a few days with only a 10-20 milliamp draw.