STPSZ

Went to start the car today and battery completely dead, I mean 2.5V at battery posts. The only mods that were done are iSimple i-pod connector and column lock bypass. I did leave the i-pod plugged in but I thought it is hooked up to the ignition switch, with switch off there should be no charging. I do not think column bypass has anything to do with it. The car has been parked without starting for about a month. How to prevent battery from discharging besides to leave a charger on or disconnecting battery?
Any advice.

Black 03 Z06

These cars just seem to eat up batteries at rest. If your battery is older or at all suspect a month of inactivity will drain it. Throw it on the charger and see if you can get the voltage back up. However the voltage may be so low that some chargers will not start.

Get a Battery Tender of some type to maintain the battery when the car is not in use.

dadaroo

Even with a top notch battery fully charged, one month is too long to expect the normal drain to keep from leaving you with a dead battery.

NukeC5

Once you get it charged or a new battery, consider using a float charger if it's garaged parked. It will keep it from draining. You can get one for AGM batteries for $35 at autozone. Or as low as $6 at harbor freight if it's a led-acid type.

STPSZ

I charged the battery with 10A charger, it only took 1 hr, voltage was up to 12.7V. Car started fine. After that I put it on a Ctek 4.3 charger/maintainer and it should be good now. I also disconnected iPod, btw, battery is only couple years old.

motoman250f

This is all true but if your car is drawing more than 20 - 30 milliamps there is something wrong and should be fixed. get an ammeter right in line with the battery and let it sit, key off for 15 min so all the computer stuff rests. should settle to 25 mamps. if your seats switches are bad or a light is on it will draw the system down in just a few days.

Bill Curlee

I AGREE!! You have to see what the Car at rest SLEEP current draw is. if it isn't in spec, you will always have dead batteries very quickly!

Some Ipod adaptors were wired incorrectly and were a constant current draw. Make sure that the Ipod adaptor isn't connected so that its always ON.

Bill

STPSZ

I disconnected iPod already, no chance to draw current now. I was certain that there is no charging once the ignition is off. In any case, I also left battery on a ctek maintainer, it should be good to go. Thanks for everyone's help.

Bill Curlee

The I Pod Adapter its self is powered and if it is wired incorrectly will draw current its self I Pod connected or not. See if your adapter has TWO power wires. One thats suppose to be connected to hot at all times and one that is suppose to be connected to an ignition switched source. OR if the single power wire is connected to the hot at all times source vs a switched source.

BC

jackthelad

Depends. I have left mine for 4-5 weeks before now, and it started right up. Sears Platinum battery.

STPSZ

Bill,
It would be hard to look wiring up right now since dash, ac controls and radio would have to come out. I connected everything this past summer per manual that came with ISimple. I'm pretty sure that with the ignition off, iPod was not charging so go figure.

StatmanRN

Ive had problems like this as well, hard to track. I have looked at a device that disconnects the battery when voltage drops below 'X' value. Anyone have experience with those?

Concern about reliability, also resetting codes, ecm relearning...and my FM presets

motoman250f

Yeah, no matter how you dice it up you will still be dealing with resets, computer relearning, etc. you really have to just find the drain. Find someone who can run an ampmeter and get it inline and pull fuses until you find the drain, good luck

dadaroo

Here is some info for determining if you have a parasitic drain. Let me know if I need to clarify anything of if I can help in any way.

Suggest you remove the hood light bulb first so it does not provide a drain.

For measuring battery drain I would hook up an ammeter to the negative side of the battery by removing the negative cable and measure between the cable and the negative battery post.

When you connect the ammeter the car should draw several amps until it goes into "sleep" mode which can take several minutes. Normal sleep mode drain should be between 17-22 milliamps. You will need an ammeter that can transition from whatever the drain is down into the sleep mode. If you have a drain I suggest the following:

Once you determine you have a drain with an ammeter what I recommend first is to listen to each fuse box and see if you hear any relays operating. If not, then place your hand on each relay to see if any of them feel hot. That can be the start if you find something like that is happening.

If nothing shows up you can hear or feel then I recommend you separate the two fuse boxes from each other. This is easy and done by removing the Red cable from the engine fuse box that feeds the passenger fuse box. It is on the right rear side of the engine fuse box. There is a stud there where the large Red wire from the battery connects. Just remove the nut and disconnect the large Red wire feeding the passenger fuse box and reattach the Red battery cable. NOTE: I would recommend disconnecting the negative ammeter hookup when working on the positive side doing this.

What you will be doing is measuring the drain with an ammeter to see if disconnecting the passenger fuse box causes the drain to go away or not. By depowering the passenger fuse box you will depower the BCM which controls the sleep mode so do not expect the sleep mode to happen.

If removing the feed to the passenger fuse box you then see you have eliminated the drain then you know it is something related to those circuits. If it does not reduce the drain then you know it is related to the engine fuse box. It could be a rare case where you have some drain via both fuse boxes and we can deal with that if you think it is the case.

Once you basically know where it is then you can remove fuses and relays to see where the drain is coming from.

motoman250f

Great info, this process will save a lot of time!