I've been running a mini battery for around a year. I replaced it with the PC680 thinking the battery was dead. Previous battery was not an automotive high CCA battery. Just a VRLA battery with automotive posts adapted to it. I sold batteries for a living for around 11 years.

I parked the car Saturday night around 11. At 6:00 AM I didn't have enough to turn the car over. That's not the problem.

 

Well what was the voltage on the battery when you parked it? What does the discharge curve of the 680 look like? Based on the discharge curve how much capacity was left on the battery when you parked it. As I already said the .18amp draw you measured is completely normal for our cars so that's not your problem.

 

I parked the car last night with 12.9v. 12.8 this morning. 12.8 right now as I just checked it. Last night I unplugged the battery. This morning I went for a drive. Came back and unplugged the battery. Came back an hour later. Checked voltage and hooked it up.

Whatever is draining my battery loses it's connection when I disconnect the battery, seemingly.

The only thing that totally zero's out my draw is pulling out the yellow fuse block with the radio/interior fuses. I thought that was my culprit. Pulled it one morning before I walked into the hub instead of disconnecting my battery. Still drained. 13 hours later I didn't have enough to turn the car over.

 

The draw isn't suppose to be zero though, the ecu needs power for its memory, the airbag ecu needs power, the clocks and etacs need power. .18amps is only 2.5 watts rounded up.Maybe the problem has more to do with the cranking amps you are drawing, check the contacts on the starter and maybe check out the trouble starting thread. I'll try and dig up a link.

 

No, because when I get out to the car and check the voltage it'll be close to 10 before trying to start it.

 

https://www.evolutionm.net/forums/ev...ied-fixed.html

 

Well like I said .18 is normal so either your battery isn't charging completely, it's sitting too long for its capacity, or it's capacity is not what it should be.

 

Voltage is 12.8v right now. I'll check it when we get back from the firework display. I guarantee that it'll be 12.8. Tomorrow when I get to my car after work it'll be under 11v.

Identical issues with two different batteries. Different brands. It's not a problem with the battery. Something is draining it after I drive for a period of time. My morning commute is 20-30 minutes of mixed driving. I'll check the voltage when I park the car in the morning and note the time. Then I'll check the voltage and note the time when I get back to the car before I start it. Voltage across the battery when the car is running is over 14, so the alternator is charging fine. I also drove 3 hours to Austin and 3 hours back this weekend with no issues. Just died overnight after I parked it. I've been keeping my spare mini in the car to jump it when it dies.

First time this happened I wasn't able to unlock the doors with my keyless because the voltage had dropped so much during the day. Happened a few days and then it was fine for a few days. Then started up again.

 

Sounds like a plan, if you can find a discharge curve for the battery that will also be very helpful. Make sure to check the battery voltage while it is hooked up. The battery needs to be under load to get an accurate reading.

 

It's hooked up right now. I'll keep you posted.

 

Just watched this short video on testing. The last method he discusses uses the multimeter to measure voltage drop in mA across fuses without disconnecting the battery for the very reason I'm thinking I'm having trouble. So as I had the battery disconnected earlier, every fuse under the hood was 0.000. I'll try to get to work early tomorrow, let the car sit for about 10 mins, then do the test. Making sure to use my keyless, headlights, AC, radio, power locks, etc., on the way to work.

 

Just checked the voltage. 12.8. It's been connected for at least 4 hours and hasn't dropped a bit.