So as of a few days ago I have a fairly serious battery drain issue. I don’t think I’ve added anything recently (a radar detector, but I confirmed it stays off when engine is off), so I can’t explain the drain. The car does have other electronics added, but those have been there a long time. I lose about 1V overnight. which is significant.

How can I do the multimeter test? (connect in series, shut down everything and start pulling fuses)? There aren’t even door courtesy switches to tape up so that the car would go to sleep.

Alternatively, is there like a low power diagnostic mode I can activate using Esys?

Thanks!

 

I'll try to be of some help.

First you need a way to measure current draw probably at the battery. You want to establish a base line value. Normally the draw after a few minutes as systems shut down/enter their lowest power mode the draw should be under 100 milliamps down around (my limited experience) 60 milliamps or a bit less.

I'm going to fall back on last thing touched first thing suspected. So while you think the radar detector is off either turn it off or better yet disconnect it.

Then pull a fuse that controls one of the circuits that one of the added electronics is connected to. If you then measure a big drop in draw that's the suspected circuit.

You want to be sure you wait long enough for the more power hungry systems to shut down. The engine controller is probably the biggest electronic consumer of electricity while the vehicle is in operation. It can take a few minutes to reach its lowest power state.

If you find pulling a fuse seems to cause a big drop in power consumption you might want to do this several times to ensure the drop in power consumption is consistent that you don't just happen to pull the fuse concurrent with another electrical load going away.

 

Thanks - yep that's what I'm looking to do, but in order to actually do that, I need to be sure the car is fully shut down / in a full idle state, and drawing no power to begin with - but with these cars, the moment you open the door, the car comes fully alive with fuel pump, this, that and the other. So I'm looking for the correct way to start this process to make sure the car is actually shut down so that I'm at a baseline power draw.

Since I'm looking for a <80mA baseline (the level above which the DME throws an error code), I really must not have any lights, fuel pump, DME activity, etc in order for this to be useful, and that's what I'm trying to figure out how to do. So to be more specific:

1. Can I just leave the car with the doors / hood / trunk open for an hour and expect that it will be "asleep"?
2. But then, if I disconnect the battery, connect the multimeter in series and reconnect the battery, won't it go through a re-activation process? If it takes >10A at that point, it will blow the multimeter's fuse.

So... how to do it properly is the question. I came across a few threads but it looks like most people just take it to the dealer, lol.

 

I would try the leave the windows down so you don't have to open a door. And I would arrange to have the multi-meter connected/setup to measure current draw *before* you do anything else.

If the hood or trunk being open keeps the car alive and the power consumption high you might address this by unplugging any lights in the engine compartment or trunk area. I watched techs do this with a couple of my cars but I don't know what is involved with your MINI.

Or you could just leave the hood/trunk open and see if the current draw falls down to some reasonably low level. Or by judicious fuse pulling just turn off the door/hood/trunk circuits. The assumption is these are not the circuits you are going to find bad.

Another way is open the hood/trunk and get the multi-meter setup. If you need a door open to access the fuse box leave the door open.

Wait. I would think current usage would decline maybe not to the level it would otherwise but low enough. When you pull a fuse of a suspected circuit the assumption is there should be none to very little current being consumed by that circuit. If you see a drop of more than a few milliamps that's (probably) the circuit you need to investigate further.

 

The challenge is this: doors closed, can't reach the fusebox that's under the glovebox. So has to be doors open. And then, the following problems happen:

1. When I wire the multimeter in series and reconnect everything back - car will likely do "startup" stuff. Will this draw >10A? If yes, I need a new multimeter because mine is fused for 10A.
2. If I pass test #1: if the car isn't fully shut down, let's say I show a constant 3A draw with doors and hood open (there is no light anywhere). Fine. But if I can't force the car to a "sleep" mode with everything open, how do I know if this is legit power draw that would go away when I close and lock the doors and park the car, vs. a parasitic one that won't? I may be chasing wild goose there. For a specific example, I don't know, let's say there's the fuel pump. I will pull the fuse for the fuel pump and see current drop, and I'll be like, woohoo! I found the draw, ... and then discover it's the fuel pump. Oops. But that's an obvious example; what if it's something far more insidious, like the DME? That's also likely alive for a long time even after the door locks are engaged.

 

Now you know what generally cars manifesting a suspected parasitic draw end up at a shop.

Having a multi-meter that can handle the max current draw is pretty much required. Too many hoops to jump through otherwise.

Next you can button the car up as much as possible to give the electronics time to enter low power state.

Observe the multi-meter. After some time (I've seen ECUs take around 10 minutes to really start to lower power consumption.) When you have waited "long enough" then remove a fuse of a suspected circuit. I'd not bother with the fuel pump or ECU circuits. I'd go straight to any circuit with something extra added to it.

Let the car again obtain a low power state. You know from the 1st time how long this took and what the power consumption was. So if after the same amount of time if the power level isn't down by just a negligible amount but something or significant that suggests the fuse you pulled is the circuit that is drawing power when it shouldn't.

But do this for all suspected circuits. What I'm expecting for, ok hoping for, praying for, is you will find one circuit that when its fuse is pulled has the power consumption down a significant amount.

Sure ideally you'd like to have a magic wand -- aka diagnostic computer which you could use to put the car into low power mode, shipping/storage mode. (This mode might be accessible via some special button presses that bring up a manufacture's menu.)

But absent that you'll have to experiment and see if you can find a way to let the car obtain a low power consumption mode by well, waiting. If the ignition is not turned on while the power consumption will sort of kind of skyrocket it should be short lived.

 

Ok, I think this discussion has veered too far into the theoretical. I used my "call a friend" card and called up a friend who's a BMW master tech, and here is what he said.

1. Do not disconnect the negative pole, break the circuit, and wire the multimeter in. By breaking the circuit, you might actually cause the parasitic draw to disappear in case it is a device that goes to sleep after power loss, so you will be wasting time hunting for it.
2. If you do wire a multimeter in, do it as follows:
a) open the doors. Then, latch them with a screwdriver (there are no courtesy switches on a BMW, so just flip the locks closed manually).
b) wait approx. 16 minutes (yeah, sixteen) for the car to go to sleep. You can see the red start/stop button go "off". That's how you know it has entered the sleep mode you need. There are multiple sleep modes in a Mini, but start/stop button going dark is the sleep mode you want.
c) now, under the hood, open the battery compartment and use a booster cable to connect the negative pole to a good ground point on the body. Do not use the main ground point because you're building a backup ground line here.
d) confirm your multimeter is set to 10A (double digit amps). If you have a 20A that's even better, just in case. Fused so you don't set your car on fire.
e) Now, make sure your backup ground is stable, and unbolt the main ground point (13mm nut) and clamp the multimeter to that cable + the bolt on the body. You now have two parallel negative lines running.
f) Now, unclamp your battery clamp from the backup point you have created. You will now have all electricity running through your multimeter.
g) You can now begin testing. By the way: do NOT lock the car. If you lock it, the alarm turns "on", and then when the key approaches the car, it starts unlocking itself. Once you flip the locks in a) above, put the key far away and don't touch it. Start pulling fuses and looking for a current drop, etc. You are looking for idle current to be <80mA (that's where the DME throws an error).

He also suggested that if I can get my hands on a Fluke amp-clamp, it will save me the whole trouble of wiring a multimeter in series, because those induction meters are good enough to detect current to the levels you want, so you can skip the entire battery rewiring piece. So I ordered one and will try that first.

 

You just underlined why these types of issues end up in the hands of a professional. They have the proper training/knowledge to effectively trouble shoot these issues correctly and efficiently.

I was trying to get you moving but you did one better and contacted a tech who was able to give you better guidance. This is good.

Best of luck getting this suspected parasitic draw sorted to your satisfaction.

 

i pulled the light outta my trunk. you cant tell its on and while closed, my trunk surprizingly thinks it is open. working on the real issue.

 

One thing you might try, which I learned from owning a Porsche, is to make sure your car is locked, even in the garage. It seems German cars’ electronics continue at a low rate to monitor the car. Locking it shuts that off.

 

My experience as well. And other brands of cars can be equally bad or even worse. Might add with my Porsche cars the security system would after IIRC 5 days disable parts of the security system -- I think the inside motion detector -- to reduce battery drain.

Locking the car tells the car's electronics they will not be needed again for a while so the electronics will enter lower power modes sooner.

And cars with remote entry it is important to store any keys far enough from the car the keys can't keep the car's electronics awake. In my case my cars are parked some distance from where I live so that is not a problem. But if one parks in the attached garage and walks through the door into the into the house (a mud room maybe) and puts his keys on the shelf with the car just a few feet away...

 

Aftermarket alarm system?

 

Nope. So it’s the weirdest thing. We narrowed it down to the retrofitted LCI digital cluster. Basically the dealer put the car on a tester and when they’d pull the power to the cluster, the drain would stop, and when they’d put it back it’d restart. Which was already weird. But the stranger thing is … they told me the only way to fix it is to put the OEM z cluster back and sent the car back as is to me.

And the drain was gone and hasn’t come back.

Funny thing is, of COURSE i’ve pulled the negative to try and solve this so i’m not completely convinced the dealer was right, but then again, they charged me “only” $70 for a diagnostic, so it’s unlikely they actually DID anything outside of that. So it’s a mystery, as mysteriously gone as appeared.

 

WTF....I wonder if other people who have done the retrofit have this issue or maybe it's a coding problem? Who coded your retrofit?

 

Posted in the retrofit thread but nobody responded. It was done by a local shop - unfortunately, I got the car with it, otherwise I’d have done it myself. now I’m waiting to see if it ever comes back or not. Have the OEM a cluster that came with the car, so isn’t an issue to revert, but I find that a very sus explanation, I dunno.

 

Many people have done that retrofit and I've never heard of this issue before. Did you use an OEM BMW optic cable to connect it to the headunit?

 

You’re saying the cluster uses an optical cable to connect to the head unit? Interesting. I thought there was just a single harness.

 

Yes there is a fiber optic cable that runs from the digital cluster to the back of the head unit. If you're missing it, that could be causing the issue although I don't understand how it works at all without it. It's something like this:

 

Ah interesting. I don’t think I’m necessarily missing it - I was saying single connector based on pictures I was looking at, I didn’t actually disassemble mine … though hmm, I should, if only for educational purposes. It’s really odd in so many ways tho, for sure.

 

My only logical guess is something was miscoded. I could be wrong though. Perhaps an issue with the cluster itself.