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I fixed a parasitic drain on my car in 408 days

davidmuller.github.io

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Re: I fixed a parasitic drain on my car in 408 days

#271

Post by ninjanicely »

skittlebrau wrote: post #257
ninjanicely wrote: post #194

Earlier quoted context omitted.

I have a 2019 Outback as well. I just went through some battery dying issues. Took it to the dealership, they said that the Onstar module (after 2-3 years) will start to malfunction and create a parasitic drain. The only fixes they have (as of a couple weeks ago) was to a) buy a new module (which are on back order because a number of peeps are having this problem) -- which will eventually break because they haven't r…

I have the same issue, seemingly, with my 2017 Outback. My battery kept dying for which I got a lot of run around from the dealer (gaslighting about keyless entry drains it if the key is too close to the car, etc.) Eventually I found a Reddit post about the DCM (Starlink) module, removed this fuse, and it hasn't died since. It sounds like it wakes up in the middle of the night to do something and thereby drains the b…

Starlink! (not Onstar) ... I'm not subscribed myself so I can never remember the name.

> Having that fuse out kills some speakers and the mic too, so it's a kind of annoying solution.

That's exactly why I didn't choose that option.

One thing I'll mention about the center console solution (which I'm having trouble confirming), when I was driving home I thought the sound from the speakers was much quieter. I tried zoning the music to the quiet speakers and there was little to no sound coming out. I took it back and they took the console apart and reset everything and then it "just started to work". The tech seemed as baffled as me, he was frustrated he couldn't tell me why it started working. All that's to say YMMV.

Re: I fixed a parasitic drain on my car in 408 days

#272

Post by tokamak-teapot »

localhost wrote: post #34

While not a fix for this problem, a nice form of insurance is a Lithium Ion jump start battery[1]. I'm amazed that a hand-held battery can discharge fast enough to jump start my car, but ... it works great. [1] https://www.amazon.com/dp/B0B55RFM1Z

Might the battery charge a capacitor?

Re: I fixed a parasitic drain on my car in 408 days

#273

Post by zwieback »

Scoundreller wrote: post #235
zwieback wrote: post #81

Not just for highly computerized cars, I have a 97 Ranger where literally everything is manual and I don't even have a dome light anymore. There's a parasitic drain I can't quite figure out so I just make sure to start it every once in a while. Since I'm a year round bike commuter the truck can sit around for a long time, especially in winter when there's no house and garden projects. I've considered adding a manual…

Solar panel? Depends how big the draw is.

Good idea, solar panel for trickle charge. Could power a few other things like a wildlife cam and weather station.

Re: I fixed a parasitic drain on my car in 408 days

#275

Post by garyfirestorm »

lylejantzi3rd wrote: post #28
overthrow wrote: post #3

Well this is timely. I have a parasitic draw on my NC Miata. The first mechanic just replaced the battery. The second told me it's normal for the battery to die if you don't drive it for 3 days (because "cars have computers now"). It seems like mechanics really don't like digging into the electrical part of the car... but these days that encompasses more and more of what can go wrong. Without time to dig into it myse…

> It seems like mechanics really don't like digging into the electrical part of the car... Tell me about it. I'm in a similar boat. My audi a4 has had a parasitic draw for the past 10 years. My mechanic didn't want to take the time to address it because that sort of thing takes a serious amount of time and he's always backed up. I got out my fluke and narrowed the cause to what I believe is the comfort control unit.…

> I can’t replace it myself because it’s a coded part.

Can you please explain this? Why does it need ‘coding’? It’s not a VIN specific part I’d think - i.e. engine controller. Also have you explored Ross Tech VCDS tool? You might be able to identify the coding on your part and use it on a new part. Replacing an ecu should be straightforward imo.

Re: I fixed a parasitic drain on my car in 408 days

#276

Post by xattt »

chemmail wrote: post #274

This guy should look into replacing the fuse/relay for that module. Sometimes the relays can get stuck. Thats what happened to my leaf as it would get a TCM error and drain the battery every 3-4 days. Finally figured it out after a year too lol.

Yes, but then where is the story of struggle and sacrifice of having to use a metal key each time to unlock the car?

Re: I fixed a parasitic drain on my car in 408 days

#278

Post by BoorishBears »

throwawayf37jg wrote: post #252
legitster wrote: post #224

Earlier quoted context omitted.

I mean, I guess if you are limiting yourself to that exact style of car then yeah I guess. (Although the Mazdaspeed6 was 90% of a BMW with 10% of the maintenance bill).

I agree it may be 90% as fun to drive (which is subjective), but you're comparing FWD to RWD. I'd much rather have a 80's-90's Nissan or Subaru, especially built, than a modern BMW, though. Much more soul in vintage cars imo. Some vintage BMWs were pretty reliable, a lot of modern Nissans have awful reliability.

It's AWD, but the MS6 has about 100% the repair bills of any old BMW, this person just has no idea what they're talking about. Maybe they owned one when they were new and doesn't realize what long term reliability is like

Re: I fixed a parasitic drain on my car in 408 days

#279

Post by BenjiWiebe »

acapybara wrote: post #251
cwillu wrote: post #63

Earlier quoted context omitted.

If you can identify the fuse for the unit, it might be less annoying to pull it when parking rather than hooking up a charger.

WiFi arduino + disconnect relay on the battery. Completely disconnect battery when not in use.

Make sure your relay is rated for enough current.

Re: I fixed a parasitic drain on my car in 408 days

#280

Post by aksss »

cwillu wrote: post #242
MaKey wrote: post #207

Earlier quoted context omitted.

AFAIK the fuses have contact points you can use to measure the current.

You can check continuity across the contact points, but measuring a 75mA current via the voltage drop across a 0.0034ohm resistance (give or take) means reading 0.2mV, which is… borderline for a consumer multimeter.

I wonder if one couldn't identify the time it takes for the battery to get to some low point (50%?) and then determine the order of magnitude draw they would be looking for. 75mA would take a long time (I think) to drain the battery to where starter can't turn over (like a week?).
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