Strange power drain

[Northern]

I went out and checked for some sort of delayed drain, and after 10, 20 minutes there was nothing.

Checked the voltage across the battery terminals after I charged the battery, it measured 12.5v. I installed it in the car and started it, at idle it measured 13.6v, and once I turned on all the accessories I could, it measured 12.8v.

From what I've read from a few searches, this seems to be normal. No idea what is causing the drain still.

[Northern]

Brought the battery to the store where I bought it, they charged it up and tested it 3 times. Tested above spec all 3 times over the course of 2 days.

Its home on the floor now, and I'm monitoring its voltage. So far it seems to be holding between 12.6-12.7v

The car is draining power, but every time I take a measurement, I get 60mA-70mA.

I have sat and tested for any delayed drain for ~20mins or so and found no change, but I have yet to test for any drain when the car is wet.

[Northern]

Battery read 12.4v this morning at 6:30am, 12.3v this evening at 9pm.

I have an old battery in the car now and I'm still only reading 60mA with the multimeter.

I still need to test for an increased drain in the rain, and I may end up swapping out the alternator with another to see if anything changes.

I also want to go for a short drive, then test for any drains that may only start after the car has been on or warmed up.

[Northern]

Now I'm confused:

12V Battery capacity vs. voltage readings:

100% 12.7
75% 12.4
50% 12.2
25% 12.0
Discharged 11.9

From: http://forums.bimmerforums.com/forum...=battery+drain

As much as the battery kept testing good, my multimeter says it is at 12.3v. According to that post, it is now only 50-75% charged after one day of sitting on the floor in the house.

Also:

13.5v with the car idling would be normal with a fully charged battery. The system voltage should rise to about 14v at 2500rpm. And it should not drop much, if at all, when you turn on the head lights and heater blower to max.

From: http://forums.bimmerforums.com/forum...=battery+drain

So if I'm only getting 12.8v on a fully charged battery at idle with accessories on, there is something wrong with my alternator?

It has a brand new voltage regulator, but its made by Kaehler, who I've never heard of.

[jlevie]

As much as the battery kept testing good, my multimeter says it is at 12.3v. According to that post, it is now only 50-75% charged after one day of sitting on the floor in the house.

If your meter reads 12.7v after fully charging the battery and the next day you read well less than that, the battery has an internal fault.

So if I'm only getting 12.8v on a fully charged battery at idle with accessories on, there is something wrong with my alternator?

It has a brand new voltage regulator, but its made by Kaehler, who I've never heard of.

That sounds like it could be a bad alternator or regulator. But bad connections at the alternator or starter or a bad engine ground strap could be part of the problem.

[Northern]

Thanks for the info Jim!

I measured the battery again (now exactly 2 days since I picked it up fully charged from the part store) and its measuring 10.3v. That sounds pretty dead to me.

It has been sitting on the hardwood floor (no concrete or metal surfaces) so I can't see it discharging from anything else.

I'll also replace the engine ground (Driver's side frame rail?) since it looks about due.

I'm going to test the Voltage Regulator that came out of the iS that is now working fine in my iX. One of the alternator bolts is seized in place very well, and I don't want to tempt fate by removing the alternator if I don't have to.

[Northern]

Battery finally tested bad today, so I ended up getting another. It was only 1.5 years old, so I have another 2.5 years of warranty on the new one.

Still have to do all the other stuff to make sure the charging system is working well.

[Northern]

Update: Been driving the car since the battery was replaced and haven't experienced any more problems. Battery seems to be the culprit, VR and alt seem fine.

[325Eblue]

I had a very similiar problem and yes my older battery could not take the strain it would die shortly after sitting without running for a day or two very close to the symptoms you have also. The end result for me was that the lithium batterys on the si board had corroded and lealed on the si board causing a drain in the circuit. Yes my tach , MPG, and coolant temp gague all worked intermittently but I did not realize what a strain this was , maybe my battery being 3 years old her the hot climate of florida is also bad or going bad but I have since replaced the si board and I have yet to have any battery troubles since. I may still need to replace the battery soon but for now I am good! by the way kinda off subject but I now have a thin orange bar light up on the dash right next to the fog light green indicator? i dont know what this means? it is not covered in the user manual? any ideas? thanks and goodluck with the new battery maybe its jjst stronger and is able to compensate for the draw, like I said a failing si board was my problem with draw causing the battery to go very low after a day or two of not driving, thanks .>>S