Battery Drain Update

Well, my battery drain dilemma has taken a new twist. I had originally posted that I thought the bluetooth was the culprit, powering up randomly and searching for a paired phone. So we started turning the bluetooth off on our phones. All was fine for a month, thought I had found the problem. Then last night the car went back into "high drain" mode. Knew there was trouble when the battery was at only 12.15 volts when I unplugged the EVSE and checked it. Sure'nuff, the battery tender couldn't keep up with the 1 amp drain. Even after taking the car for a 30 mile drive, drain was the same when I shut it down. The dealer wants the car for testing, but it's a big hassle to get it there, and will cost me 200 miles of my lease, which is already a thou over! So I just disconnected the battery for 10 sec or so (discovered that a short interval will keep the radio from losing all its presets and clock setting). Resting drain immediately dropped to the normal .13 amps. OK for another month! Sure would like to know why this is happening. I know mine's not the only one either.

How are you able to measure the 12v battery current?

I don't have a clamp on ammeter so I use my digital vom, hold 1 lead on the negative battery post, and one lead on the negative clamp, then lift the clamp off the post. The meter is then reading the current draw from the battery. Important not to break the connection when removing the battery clamp, as that will reset the car's electronics.

Hello,
Next time it's drawing excessively try to preserve the conditions of the test. Hook up your current meter and begin pulling fuses to things you suspect. A quick look at the schematics in the service manual will tell you what has power when the system is off. Check them one by one. Best way would be to have a current clamp so you don't have to disconnect anything to verify the draw. Classic trouble shooting 101. The amount of current being drawn will tell you what devices might be causing it. Could be a short faulted driver latching and holding a relay closed (like for wiper) even though power is cut to the contacts the coil could be energized. Things like that. Knowing the actual current draw tells a lot.

Good advice. I wish I had a service manual and a clamp meter. I did, previously, do exactly what you suggest. Pulled virtually every fuse in the car and checked the amp draw. I did see some draw from the brake capacitor (probably normal), some draw from the audio which went away when I pulled both audio fuses. I checked that this time however, and the draw was minimal. It seems to occur after a charging session, computer possibly holding a relay closed?

There are fuses in the cockpit fusebox labeled "meter 1, meter 2, and power switch (I think) that also seemed to be drawing current. Since they serve multiple circuits, I'm kinda lost without a wiring diagram.

The current draw in "drain" mode is .98 amps. Normal is .13 (130 ma or so).

I did something like this a few years back. It's a lot easier if you use clip leads:

I would be surprised to learn that Bluetooth functions when the car is turned off. Same for the audio system. Even the brake capacitors...I suppose the supercaps could have some leakage, but it would be unacceptable if it were much.

In my test, I was looking at the current drain versus what the solar panel could supply. The car initially draws a fair amount of current (when you turn it off, when you open the door, when you reconnect the battery, etc.) because the computers are talking and Carwings is doing its thing, but after a while, they all go to sleep and the current drops to a low value. So low, in fact, that the solar panel is actually able to put current into the battery (over 35 mA in direct sunlight :lol: )

That's pretty much what I did when I did my first round of fuse pulling. My 2013 draws 125ma in normal rest mode. And I don't have nav or carwings. As of now, I don't know where the large drain is coming from. My bluetooth theory was wrong. I'm glad I added the battery tender plug inside the charge door!

Hi, I know it is an old post but it completely describes my problem. I also have a 1A drain. Did you find the source?