Battery Draining?
 

Sorry to start another one of these threads, but this one seems weird to me.

My car keeps draining the battery when the car isn't in use. It used to take awhile, like a few weeks, but recently it's gotten worse, like I can't start the car after a few hours.

1. Recently replaced the battery. Full size battery kept coming up unable to start the car... figured the battery was old enough to replace. Picked an odyssey pc680 because racecar. Maybe a fatal mistake, idk.

2. Still had issues starting the car after it had sat only a few hours. Read up on the forum... figured it was safe to assume the voltage regulator was bad. Even if it wasn't, I was gonna replace the idler pulleys anyway since I knew they're pretty loose. Replaced the regulator while i was in there.

3. Problem persists. I figured maybe the odyssey battery might be the problem, so I left the car on the charger, checked how many times the battery can start the car back to back. The answer is about 6 times.

4. I took my amperage meter to the car when it was off. I disconnected the ground and checked for current draw while the car was off. 25mA. I had to disconnect the battery to do this... so I'm wondering if maybe if the draw is being directed by the DME (like maybe some security system fault), then maybe this test isn't capturing the problem because the DME had to be reset.

5. Today I jumped the car because the battery was dead. Just used one of those small lithium ion jumpers. Drove home about 30 minutes. When I got home I checked to see if I could start the car again right after I turned it off. Started just fine. Makes me think the charging system is fine.

5. Came back 5 hours later and the battery is dead, can't start the car.

6. Idk if this has anything to do with it, but when i locked the doors, the car used to honk maybe 10 seconds later. Now it does nothing. I've checked for drain with and without locking the doors. It seems to drain in either case.


Any ideas? Some tests I can do to see if maybe there's some sort of intermittent drain? Tomorrow I think I'll test again, but with aftermarket radio disconnected. I also thought maybe it's the ignition switch, but I hoped line item number 4 would have caught that.

Go to youtube look up "parasitic draw test" learn how to do the test.

You can save some time for yourself if first you exclude the possibilty of your battery being faulty. Just disconnect the battery right after you stopped the car and try again the day after. If it starts just fine you can go ahead and seek for parasitic draw. If not, your battery loses power and needs replacing. If it's the former scenario and you can't find out yet what's going on but want to keep using the car, buy a battery quick disconnect switch, it's like 8 bucks on Amazon.

Thanks guys. I'll try these out tonight.

So here's an update. Maybe I'm done... I might keep working on this, but things are better now. Thanks guys so much for pointing me in the right direction.

I didn't have as much time to look at things as I'd hoped, so I kinda did things out of order.

First night I connected the car to a durametric, and found that the alarm system was reporting error 34--the passenger compartment sensor was grounding and malfunctioning. So I immediately removed it. That's the thing I did out of order lol. It's likely that this thing was causing all the drain. I should note that the last couple years, my alarm would go off spontaneously on super hot days. I think this was the sign that the compartment sensor was dying a slow death... but i never looked into it.

Next day I did a proper parasitic draw test by actuating the hood latch with a screwdriver, then putting my multimeter in line with battery ground and keeping it connected while removing the battery ground cable from the battery. Car was locked (no honk...). Draw was 120mA.

So to my knowledge... 120mA is too high. Idk, is it? I think should be closer to 80? Maybe I'm splitting hairs here. At this point, I ran out of time, but I figured I would disconnect the fuse for the alarm system to see what would happen (fuse C3). Parasitic drain dropped to 90mA. Plugged it back in and let the car sit overnight.

Oh I also unplugged my aftermarket radio and saw that it made no change to parasitic draw. So that's good.

Then this morning I started the car after it had sat all night. It def started, had the juice. But was a little slow to start. I'm worried maybe it's just that the pc680 doesn't have enough cranking amps to really start the engine super quick... that or the parasitic draw is still a little too high. Will prob go thru the fuses today to see if anything can get me back down to <80mA.

From my understanding the car will stop drawing almost everything once the alarm has been activated for a certain amount of time. I think it is a few days, i can't remember exactly. If it isn't armed then the drain will go on until thy battery dies.

I know that the car turns off some systems because I armed the car outside last winter with a battery tender in the cigarette lighter. The light would flash red after a few days stating it is not charging. I opened up the car and took the plug out. Put it back in and all was well. A few days later the same thing. I tried it again but didn't arm the alarm. The rest of the winter it was fine. Makes me think that arming the alarm at least disables the lighter circuit.